Make code generator self-contained by integrating runtime support

Co-authored-by: openhands <openhands@all-hands.dev>

.gitignore

@@ -5,3 +5,5 @@ test_map_gen_project
 test_grpc_project
 artifacts/
 temp_test_project/
+output_svc/
+output_proto/

Cargo.lock

@@ -310,12 +310,6 @@ dependencies = [
  "itertools",
 ]
 
-[[package]]
-name = "critical-section"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
-
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.6"
@@ -353,16 +347,6 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
-[[package]]
-name = "embedded-alloc"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddae17915accbac2cfbc64ea0ae6e3b330e6ea124ba108dada63646fd3c6f815"
-dependencies = [
- "critical-section",
- "linked_list_allocator",
-]
-
 [[package]]
 name = "env_filter"
 version = "1.0.1"
@@ -793,12 +777,6 @@ version = "0.2.186"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
 
-[[package]]
-name = "linked_list_allocator"
-version = "0.10.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b23ac50abb8261cb38c6e2a7192d3302e0836dac1628f6a93b82b4fad185897"
-
 [[package]]
 name = "linux-raw-sys"
 version = "0.12.1"
@@ -860,7 +838,7 @@ name = "no_std_test"
 version = "0.1.0"
 dependencies = [
  "bytes",
- "embedded-alloc",
+ "prost",
  "roto-runtime",
 ]
 
@@ -1208,7 +1186,6 @@ dependencies = [
  "http-body",
  "http-body-util",
  "log",
- "roto-runtime",
  "roto-tonic",
  "tokio-stream",
  "tonic",

benches/src/google/protobuf/compiler/plugin.rs

@@ -1,13 +1,13 @@
 // @generated by protoc-gen-roto — do not edit
-#![allow(unused_imports)]
-
-use crate::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator};
-use std::str;
-
+#[allow(unused_imports)]
+use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};
+use core::str;
+#[cfg(feature = "alloc")]
+use bytes::{Bytes, BytesMut, Buf, BufMut};
 use crate::google::protobuf::descriptor;
 
 pub struct Version<'a> {
-    accessor: crate::ProtoAccessor<'a>,
+    accessor: roto_runtime::ProtoAccessor<'a>,
     major_offset: Option<usize>,
     minor_offset: Option<usize>,
     patch_offset: Option<usize>,
@@ -15,8 +15,8 @@ pub struct Version<'a> {
 }
 
 impl<'a> Version<'a> {
-    pub fn new(data: &'a [u8]) -> crate::Result<Self> {
-        let accessor = crate::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
         let mut major_offset = None;
         let mut minor_offset = None;
         let mut patch_offset = None;
@@ -38,38 +38,62 @@ suffix_offset,
         })
     }
 
-    pub fn major(&self) -> crate::Result<i32> {
-        let offset = self.major_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn major(&self) -> roto_runtime::Result<i32> {
+        let offset = self.major_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::RotoError::WireFormatViolation)
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn minor(&self) -> crate::Result<i32> {
-        let offset = self.minor_offset.ok_or(crate::RotoError::FieldNotFound)?;
-        let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::RotoError::WireFormatViolation)
+    pub fn major_or_default(&self) -> roto_runtime::Result<i32> {
+        self.major().or(Ok(0))
     }
 
-    pub fn patch(&self) -> crate::Result<i32> {
-        let offset = self.patch_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn has_major(&self) -> bool { self.major_offset.is_some() }
+
+    pub fn minor(&self) -> roto_runtime::Result<i32> {
+        let offset = self.minor_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::RotoError::WireFormatViolation)
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn suffix(&self) -> crate::Result<&'a str> {
-        let offset = self.suffix_offset.ok_or(crate::RotoError::FieldNotFound)?;
-        let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+    pub fn minor_or_default(&self) -> roto_runtime::Result<i32> {
+        self.minor().or(Ok(0))
     }
 
-    pub fn raw_fields(&self) -> crate::RawFieldIterator<'a> {
+    pub fn has_minor(&self) -> bool { self.minor_offset.is_some() }
+
+    pub fn patch(&self) -> roto_runtime::Result<i32> {
+        let offset = self.patch_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn patch_or_default(&self) -> roto_runtime::Result<i32> {
+        self.patch().or(Ok(0))
+    }
+
+    pub fn has_patch(&self) -> bool { self.patch_offset.is_some() }
+
+    pub fn suffix(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.suffix_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn suffix_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.suffix().or(Ok(""))
+    }
+
+    pub fn has_suffix(&self) -> bool { self.suffix_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct VersionBuilder<'b> {
-    builder: crate::ProtoBuilder<'b>,
+    builder: roto_runtime::ProtoBuilder<'b>,
     major_written: bool,
     minor_written: bool,
     patch_written: bool,
@@ -79,7 +103,7 @@ pub struct VersionBuilder<'b> {
 impl<'b> VersionBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> VersionBuilder<'_> {
         VersionBuilder {
-            builder: crate::ProtoBuilder::new(buf),
+            builder: roto_runtime::ProtoBuilder::new(buf),
             major_written: false,
             minor_written: false,
             patch_written: false,
@@ -87,32 +111,32 @@ impl<'b> VersionBuilder<'b> {
         }
     }
 
-    pub fn major(mut self, value: i32) -> crate::Result<Self> {
+    pub fn major(mut self, value: i32) -> roto_runtime::Result<Self> {
         self.builder.write_int32(1, value)?;
         self.major_written = true;
         Ok(self)
     }
 
-    pub fn minor(mut self, value: i32) -> crate::Result<Self> {
+    pub fn minor(mut self, value: i32) -> roto_runtime::Result<Self> {
         self.builder.write_int32(2, value)?;
         self.minor_written = true;
         Ok(self)
     }
 
-    pub fn patch(mut self, value: i32) -> crate::Result<Self> {
+    pub fn patch(mut self, value: i32) -> roto_runtime::Result<Self> {
         self.builder.write_int32(3, value)?;
         self.patch_written = true;
         Ok(self)
     }
 
-    pub fn suffix(mut self, value: &str) -> crate::Result<Self> {
+    pub fn suffix(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(4, value)?;
         self.suffix_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &Version<'_>) -> crate::Result<Self> {
-        for item in msg.raw_fields() {
+    pub fn with(mut self, msg: &Version<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.major_written,
@@ -128,13 +152,37 @@ impl<'b> VersionBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> crate::Result<&'b mut [u8]> {
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
 
+#[cfg(feature = "alloc")]
+pub struct OwnedVersion {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedVersion {
+    type Reader<'a> = Version<'a>;
+    fn reader(&self) -> Version<'_> {
+        Version::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedVersion {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedVersion { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
 pub struct CodeGeneratorRequest<'a> {
-    accessor: crate::ProtoAccessor<'a>,
+    accessor: roto_runtime::ProtoAccessor<'a>,
     file_to_generate_start: Option<usize>,
     file_to_generate_end: Option<usize>,
     parameter_offset: Option<usize>,
@@ -146,8 +194,8 @@ pub struct CodeGeneratorRequest<'a> {
 }
 
 impl<'a> CodeGeneratorRequest<'a> {
-    pub fn new(data: &'a [u8]) -> crate::Result<Self> {
-        let accessor = crate::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
         let mut file_to_generate_start = None;
         let mut file_to_generate_end = None;
         let mut parameter_offset = None;
@@ -184,47 +232,59 @@ compiler_version_offset,
         })
     }
 
-    pub fn file_to_generate(&self) -> crate::RepeatedFieldIterator<'a> {
+    pub fn file_to_generate(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
         match (self.file_to_generate_start, self.file_to_generate_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(1, start, end),
             _ => self.accessor.iter_repeated(1),
         }
     }
 
-    pub fn parameter(&self) -> crate::Result<&'a str> {
-        let offset = self.parameter_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn parameter(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.parameter_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn proto_file(&self) -> crate::RepeatedFieldIterator<'a> {
+    pub fn parameter_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.parameter().or(Ok(""))
+    }
+
+    pub fn has_parameter(&self) -> bool { self.parameter_offset.is_some() }
+
+    pub fn proto_file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
         match (self.proto_file_start, self.proto_file_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
             _ => self.accessor.iter_repeated(15),
         }
     }
 
-    pub fn source_file_descriptors(&self) -> crate::RepeatedFieldIterator<'a> {
+    pub fn source_file_descriptors(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
         match (self.source_file_descriptors_start, self.source_file_descriptors_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(17, start, end),
             _ => self.accessor.iter_repeated(17),
         }
     }
 
-    pub fn compiler_version(&self) -> crate::Result<&'a [u8]> {
-        let offset = self.compiler_version_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn compiler_version(&self) -> roto_runtime::Result<&'a [u8]> {
+        let offset = self.compiler_version_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
         Ok(bytes)
     }
 
-    pub fn raw_fields(&self) -> crate::RawFieldIterator<'a> {
+    pub fn compiler_version_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+        self.compiler_version().or(Ok(&[]))
+    }
+
+    pub fn has_compiler_version(&self) -> bool { self.compiler_version_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct CodeGeneratorRequestBuilder<'b> {
-    builder: crate::ProtoBuilder<'b>,
+    builder: roto_runtime::ProtoBuilder<'b>,
     file_to_generate_written: bool,
     parameter_written: bool,
     proto_file_written: bool,
@@ -235,7 +295,7 @@ pub struct CodeGeneratorRequestBuilder<'b> {
 impl<'b> CodeGeneratorRequestBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> CodeGeneratorRequestBuilder<'_> {
         CodeGeneratorRequestBuilder {
-            builder: crate::ProtoBuilder::new(buf),
+            builder: roto_runtime::ProtoBuilder::new(buf),
             file_to_generate_written: false,
             parameter_written: false,
             proto_file_written: false,
@@ -244,38 +304,38 @@ impl<'b> CodeGeneratorRequestBuilder<'b> {
         }
     }
 
-    pub fn file_to_generate(mut self, value: &str) -> crate::Result<Self> {
+    pub fn file_to_generate(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.file_to_generate_written = true;
         Ok(self)
     }
 
-    pub fn parameter(mut self, value: &str) -> crate::Result<Self> {
+    pub fn parameter(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(2, value)?;
         self.parameter_written = true;
         Ok(self)
     }
 
-    pub fn proto_file(mut self, value: &[u8]) -> crate::Result<Self> {
+    pub fn proto_file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
         self.builder.write_bytes(15, value)?;
         self.proto_file_written = true;
         Ok(self)
     }
 
-    pub fn source_file_descriptors(mut self, value: &[u8]) -> crate::Result<Self> {
+    pub fn source_file_descriptors(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
         self.builder.write_bytes(17, value)?;
         self.source_file_descriptors_written = true;
         Ok(self)
     }
 
-    pub fn compiler_version(mut self, value: &[u8]) -> crate::Result<Self> {
+    pub fn compiler_version(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
         self.builder.write_bytes(3, value)?;
         self.compiler_version_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &CodeGeneratorRequest<'_>) -> crate::Result<Self> {
-        for item in msg.raw_fields() {
+    pub fn with(mut self, msg: &CodeGeneratorRequest<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.file_to_generate_written,
@@ -292,13 +352,37 @@ impl<'b> CodeGeneratorRequestBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> crate::Result<&'b mut [u8]> {
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
 
+#[cfg(feature = "alloc")]
+pub struct OwnedCodeGeneratorRequest {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedCodeGeneratorRequest {
+    type Reader<'a> = CodeGeneratorRequest<'a>;
+    fn reader(&self) -> CodeGeneratorRequest<'_> {
+        CodeGeneratorRequest::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedCodeGeneratorRequest {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedCodeGeneratorRequest { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
 pub struct CodeGeneratorResponse<'a> {
-    accessor: crate::ProtoAccessor<'a>,
+    accessor: roto_runtime::ProtoAccessor<'a>,
     error_offset: Option<usize>,
     supported_features_offset: Option<usize>,
     minimum_edition_offset: Option<usize>,
@@ -308,8 +392,8 @@ pub struct CodeGeneratorResponse<'a> {
 }
 
 impl<'a> CodeGeneratorResponse<'a> {
-    pub fn new(data: &'a [u8]) -> crate::Result<Self> {
-        let accessor = crate::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
         let mut error_offset = None;
         let mut supported_features_offset = None;
         let mut minimum_edition_offset = None;
@@ -338,45 +422,69 @@ file_start, file_end,
         })
     }
 
-    pub fn error(&self) -> crate::Result<&'a str> {
-        let offset = self.error_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn error(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.error_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn supported_features(&self) -> crate::Result<u32> {
-        let offset = self.supported_features_offset.ok_or(crate::RotoError::FieldNotFound)?;
-        let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| crate::RotoError::WireFormatViolation)
+    pub fn error_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.error().or(Ok(""))
     }
 
-    pub fn minimum_edition(&self) -> crate::Result<i32> {
-        let offset = self.minimum_edition_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn has_error(&self) -> bool { self.error_offset.is_some() }
+
+    pub fn supported_features(&self) -> roto_runtime::Result<u32> {
+        let offset = self.supported_features_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::RotoError::WireFormatViolation)
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn maximum_edition(&self) -> crate::Result<i32> {
-        let offset = self.maximum_edition_offset.ok_or(crate::RotoError::FieldNotFound)?;
-        let (bytes, _) = self.accessor.get_value_at(offset)?;
-        crate::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::RotoError::WireFormatViolation)
+    pub fn supported_features_or_default(&self) -> roto_runtime::Result<u32> {
+        self.supported_features().or(Ok(0))
     }
 
-    pub fn file(&self) -> crate::RepeatedFieldIterator<'a> {
+    pub fn has_supported_features(&self) -> bool { self.supported_features_offset.is_some() }
+
+    pub fn minimum_edition(&self) -> roto_runtime::Result<i32> {
+        let offset = self.minimum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn minimum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+        self.minimum_edition().or(Ok(0))
+    }
+
+    pub fn has_minimum_edition(&self) -> bool { self.minimum_edition_offset.is_some() }
+
+    pub fn maximum_edition(&self) -> roto_runtime::Result<i32> {
+        let offset = self.maximum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn maximum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+        self.maximum_edition().or(Ok(0))
+    }
+
+    pub fn has_maximum_edition(&self) -> bool { self.maximum_edition_offset.is_some() }
+
+    pub fn file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
         match (self.file_start, self.file_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
             _ => self.accessor.iter_repeated(15),
         }
     }
 
-    pub fn raw_fields(&self) -> crate::RawFieldIterator<'a> {
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct CodeGeneratorResponseBuilder<'b> {
-    builder: crate::ProtoBuilder<'b>,
+    builder: roto_runtime::ProtoBuilder<'b>,
     error_written: bool,
     supported_features_written: bool,
     minimum_edition_written: bool,
@@ -387,7 +495,7 @@ pub struct CodeGeneratorResponseBuilder<'b> {
 impl<'b> CodeGeneratorResponseBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> CodeGeneratorResponseBuilder<'_> {
         CodeGeneratorResponseBuilder {
-            builder: crate::ProtoBuilder::new(buf),
+            builder: roto_runtime::ProtoBuilder::new(buf),
             error_written: false,
             supported_features_written: false,
             minimum_edition_written: false,
@@ -396,38 +504,38 @@ impl<'b> CodeGeneratorResponseBuilder<'b> {
         }
     }
 
-    pub fn error(mut self, value: &str) -> crate::Result<Self> {
+    pub fn error(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.error_written = true;
         Ok(self)
     }
 
-    pub fn supported_features(mut self, value: u64) -> crate::Result<Self> {
+    pub fn supported_features(mut self, value: u64) -> roto_runtime::Result<Self> {
         self.builder.write_varint(2, value)?;
         self.supported_features_written = true;
         Ok(self)
     }
 
-    pub fn minimum_edition(mut self, value: i32) -> crate::Result<Self> {
+    pub fn minimum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
         self.builder.write_int32(3, value)?;
         self.minimum_edition_written = true;
         Ok(self)
     }
 
-    pub fn maximum_edition(mut self, value: i32) -> crate::Result<Self> {
+    pub fn maximum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
         self.builder.write_int32(4, value)?;
         self.maximum_edition_written = true;
         Ok(self)
     }
 
-    pub fn file(mut self, value: &[u8]) -> crate::Result<Self> {
+    pub fn file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
         self.builder.write_bytes(15, value)?;
         self.file_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &CodeGeneratorResponse<'_>) -> crate::Result<Self> {
-        for item in msg.raw_fields() {
+    pub fn with(mut self, msg: &CodeGeneratorResponse<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.error_written,
@@ -444,11 +552,35 @@ impl<'b> CodeGeneratorResponseBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> crate::Result<&'b mut [u8]> {
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
 
+#[cfg(feature = "alloc")]
+pub struct OwnedCodeGeneratorResponse {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedCodeGeneratorResponse {
+    type Reader<'a> = CodeGeneratorResponse<'a>;
+    fn reader(&self) -> CodeGeneratorResponse<'_> {
+        CodeGeneratorResponse::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedCodeGeneratorResponse {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedCodeGeneratorResponse { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
 pub mod code_generator_response {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(i32)]
@@ -470,7 +602,7 @@ impl Feature {
 }
 
 pub struct File<'a> {
-    accessor: crate::ProtoAccessor<'a>,
+    accessor: roto_runtime::ProtoAccessor<'a>,
     name_offset: Option<usize>,
     insertion_point_offset: Option<usize>,
     content_offset: Option<usize>,
@@ -478,8 +610,8 @@ pub struct File<'a> {
 }
 
 impl<'a> File<'a> {
-    pub fn new(data: &'a [u8]) -> crate::Result<Self> {
-        let accessor = crate::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
         let mut name_offset = None;
         let mut insertion_point_offset = None;
         let mut content_offset = None;
@@ -501,38 +633,62 @@ generated_code_info_offset,
         })
     }
 
-    pub fn name(&self) -> crate::Result<&'a str> {
-        let offset = self.name_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn name(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.name_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn insertion_point(&self) -> crate::Result<&'a str> {
-        let offset = self.insertion_point_offset.ok_or(crate::RotoError::FieldNotFound)?;
-        let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+    pub fn name_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.name().or(Ok(""))
     }
 
-    pub fn content(&self) -> crate::Result<&'a str> {
-        let offset = self.content_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn has_name(&self) -> bool { self.name_offset.is_some() }
+
+    pub fn insertion_point(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.insertion_point_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| crate::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn generated_code_info(&self) -> crate::Result<&'a [u8]> {
-        let offset = self.generated_code_info_offset.ok_or(crate::RotoError::FieldNotFound)?;
+    pub fn insertion_point_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.insertion_point().or(Ok(""))
+    }
+
+    pub fn has_insertion_point(&self) -> bool { self.insertion_point_offset.is_some() }
+
+    pub fn content(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.content_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn content_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.content().or(Ok(""))
+    }
+
+    pub fn has_content(&self) -> bool { self.content_offset.is_some() }
+
+    pub fn generated_code_info(&self) -> roto_runtime::Result<&'a [u8]> {
+        let offset = self.generated_code_info_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
         Ok(bytes)
     }
 
-    pub fn raw_fields(&self) -> crate::RawFieldIterator<'a> {
+    pub fn generated_code_info_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+        self.generated_code_info().or(Ok(&[]))
+    }
+
+    pub fn has_generated_code_info(&self) -> bool { self.generated_code_info_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct FileBuilder<'b> {
-    builder: crate::ProtoBuilder<'b>,
+    builder: roto_runtime::ProtoBuilder<'b>,
     name_written: bool,
     insertion_point_written: bool,
     content_written: bool,
@@ -542,7 +698,7 @@ pub struct FileBuilder<'b> {
 impl<'b> FileBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> FileBuilder<'_> {
         FileBuilder {
-            builder: crate::ProtoBuilder::new(buf),
+            builder: roto_runtime::ProtoBuilder::new(buf),
             name_written: false,
             insertion_point_written: false,
             content_written: false,
@@ -550,32 +706,32 @@ impl<'b> FileBuilder<'b> {
         }
     }
 
-    pub fn name(mut self, value: &str) -> crate::Result<Self> {
+    pub fn name(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.name_written = true;
         Ok(self)
     }
 
-    pub fn insertion_point(mut self, value: &str) -> crate::Result<Self> {
+    pub fn insertion_point(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(2, value)?;
         self.insertion_point_written = true;
         Ok(self)
     }
 
-    pub fn content(mut self, value: &str) -> crate::Result<Self> {
+    pub fn content(mut self, value: &str) -> roto_runtime::Result<Self> {
         self.builder.write_string(15, value)?;
         self.content_written = true;
         Ok(self)
     }
 
-    pub fn generated_code_info(mut self, value: &[u8]) -> crate::Result<Self> {
+    pub fn generated_code_info(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
         self.builder.write_bytes(16, value)?;
         self.generated_code_info_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &File<'_>) -> crate::Result<Self> {
-        for item in msg.raw_fields() {
+    pub fn with(mut self, msg: &File<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.name_written,
@@ -591,10 +747,37 @@ impl<'b> FileBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> crate::Result<&'b mut [u8]> {
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
 
+#[cfg(feature = "alloc")]
+pub struct OwnedFile {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedFile {
+    type Reader<'a> = File<'a>;
+    fn reader(&self) -> File<'_> {
+        File::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedFile {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedFile { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
 }
 
+
+use crate::google::protobuf::descriptor;
+

codegen/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-roto-runtime = { path = "../runtime" }
+
 roto-tonic = { path = "../roto-tonic" }
 clap = { version = "4", features = ["derive"] }
 log = "0.4"

codegen/src/bin/protoc-gen-roto.rs

@@ -5,7 +5,7 @@ use roto_codegen::google::protobuf::compiler::plugin::{
     CodeGeneratorRequest, CodeGeneratorResponseBuilder, code_generator_response::FileBuilder,
 };
 use roto_codegen::google::protobuf::descriptor::FileDescriptorSet;
-// use roto_runtime::ProtoBuilder;
+// use roto_codegen::runtime::ProtoBuilder;
 use std::io::{self, Read, Write};
 
 fn main() {
@@ -58,7 +58,7 @@ fn handle_request(
         // Write length as varint
         let len = file_data.len() as u64;
         let mut len_buf = [0u8; 10];
-        let len_size = roto_runtime::write_varint(len, &mut len_buf).map_err(|e| {
+        let len_size = roto_codegen::runtime::write_varint(len, &mut len_buf).map_err(|e| {
             error!("Failed to write varint length: {:?}", e);
             e
         })?;

codegen/src/generator/messages.rs

@@ -0,0 +1,467 @@
+use crate::google::protobuf::descriptor::{DescriptorProto, EnumDescriptorProto, FieldDescriptorProto, MessageOptions, OneofDescriptorProto};
+use crate::google::protobuf::descriptor::FileDescriptorSet;
+use crate::generator::types::map_type_to_rust_builder;
+
+use crate::runtime::ProtoAccessor;
+use crate::generator::utils::{to_pascal_case, to_snake_case};
+use crate::generator::types::map_type_to_rust_accessor;
+
+pub fn write_enum(enum_proto: &EnumDescriptorProto, output: &mut String) {
+
+    let enum_name = to_pascal_case(enum_proto.name().unwrap());
+
+    output.push_str(&format!(
+        "#[derive(Debug, Clone, Copy, PartialEq, Eq)]\n#[repr(i32)]\npub enum {} {{\n",
+        enum_name
+    ));
+
+    let mut values = enum_proto.value();
+    let mut zero_variant_name = None;
+    while let Some(val_res) = values.next() {
+        let (val_data, _) = val_res.expect("Failed to iterate enum");
+        let accessor =
+            ProtoAccessor::new(val_data).expect("Failed to parse EnumValueDescriptorProto");
+        let (name_bytes, _) = accessor.get_value(1).expect("Enum value name missing");
+        let name = std::str::from_utf8(name_bytes).expect("Enum value name invalid utf8");
+        let (num_bytes, _) = accessor.get_value(2).expect("Enum value number missing");
+        let (num, _) =
+            crate::runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
+
+        let pascal_name = to_pascal_case(name);
+        if num == 0 {
+            zero_variant_name = Some(pascal_name.clone());
+        }
+        output.push_str(&format!("    {} = {},\n", pascal_name, num));
+    }
+
+    if zero_variant_name.is_none() {
+        output.push_str("    Unknown = 0,\n");
+        zero_variant_name = Some("Unknown".to_string());
+    }
+
+    output.push_str("}\n\n");
+
+    output.push_str(&format!(
+        "impl {} {{\n    pub fn from_i32(value: i32) -> Self {{\n        match value {{\n",
+        enum_name
+    ));
+
+    let mut values = enum_proto.value();
+    while let Some(val_res) = values.next() {
+        let (val_data, _) = val_res.expect("Failed to read enum value");
+        let accessor =
+            ProtoAccessor::new(val_data).expect("Failed to parse EnumValueDescriptorProto");
+        let (name_bytes, _) = accessor.get_value(1).expect("Enum value name missing");
+        let name = std::str::from_utf8(name_bytes).expect("Enum value name invalid utf8");
+        let (num_bytes, _) = accessor.get_value(2).expect("Enum value number missing");
+        let (num, _) =
+            crate::runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
+
+        output.push_str(&format!(
+            "            {} => {}::{},\n",
+            num,
+            enum_name,
+            to_pascal_case(name)
+        ));
+    }
+
+    output.push_str(&format!(
+        "            _ => {}::{},\n",
+        enum_name,
+        zero_variant_name.as_ref().unwrap()
+    ));
+    output.push_str("        }\n    }\n}\n\n");
+}
+pub fn write_message(msg_proto: &DescriptorProto, output: &mut String) {
+    let msg_name = to_pascal_case(msg_proto.name().unwrap());
+    let mod_name = to_snake_case(msg_proto.name().unwrap());
+
+    let mut fields_info = Vec::new();
+    for field_res in msg_proto.field() {
+        let (field_data, _) = field_res.expect("Failed to iterate field");
+        let field_proto =
+            FieldDescriptorProto::new(field_data).expect("Failed to parse FieldDescriptorProto");
+        let field_name = field_proto.name().unwrap();
+
+        let tag = field_proto.number().unwrap();
+        let f_type = field_proto.rype().unwrap() as i32;
+        let f_label = field_proto.label().unwrap() as i32;
+        let oneof_index = field_proto.oneof_index().ok();
+        let is_map = field_proto
+            .options()
+            .map(|opt| {
+                MessageOptions::new(opt)
+                    .unwrap()
+                    .map_entry()
+                    .unwrap_or(false)
+            })
+            .unwrap_or(false);
+
+        fields_info.push((
+            field_name.to_string(),
+            tag,
+            f_type,
+            f_label,
+            oneof_index,
+            is_map,
+        ));
+    }
+
+    let mut oneofs = Vec::new();
+    for o_res in msg_proto.oneof_decl() {
+        let (o, _) = o_res.expect("Failed to iterate oneof");
+        oneofs.push(o);
+    }
+
+    output.push_str(&format!("pub struct {}<'a> {{\n", msg_name));
+    output.push_str("    accessor: roto_runtime::ProtoAccessor<'a>,\n");
+
+    for (field_name, _tag, _f_type, f_label, _oneof_index, _is_map) in &fields_info {
+        if *f_label == 3 {
+            output.push_str(&format!("    {}_start: Option<usize>,\n", field_name));
+            output.push_str(&format!("    {}_end: Option<usize>,\n", field_name));
+        } else {
+            output.push_str(&format!("    {}_offset: Option<usize>,\n", field_name));
+        }
+    }
+    output.push_str("}\n\n");
+
+    output.push_str(&format!("impl<'a> {}<'a> {{\n", msg_name));
+    output.push_str("    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {\n");
+    output.push_str("        let accessor = roto_runtime::ProtoAccessor::new(data)?;\n");
+    for (name, _, _, label, _oneof_index, _is_map) in &fields_info {
+        if *label == 3 {
+            output.push_str(&format!("        let mut {}_start = None;\n", name));
+            output.push_str(&format!("        let mut {}_end = None;\n", name));
+        } else {
+            output.push_str(&format!("        let mut {}_offset = None;\n", name));
+        }
+    }
+
+    output.push_str("        for item in accessor.fields() {\n");
+    output.push_str("            let (offset, tag, _) = item?;\n");
+    for (name, tag, _, label, _oneof_index, _is_map) in &fields_info {
+        if *label == 3 {
+            output.push_str(&format!("            if tag.field_number == {} {{\n", tag));
+            output.push_str(&format!(
+                "                if {}_start.is_none() {{ {}_start = Some(offset); }}\n",
+                name, name
+            ));
+            output.push_str(&format!("                {}_end = Some(offset);\n", name));
+            output.push_str("            }\n");
+        } else {
+            output.push_str(&format!(
+                "            if tag.field_number == {} {{ {}_offset = Some(offset); }}\n",
+                tag, name
+            ));
+        }
+    }
+    output.push_str("        }\n\n");
+
+    output.push_str("        Ok(Self {\n");
+    output.push_str("            accessor,\n");
+    for (name, _, _, label, _oneof_index, _is_map) in &fields_info {
+        if *label == 3 {
+            output.push_str(&format!("{}_start, {}_end,\n", name, name));
+        } else {
+            output.push_str(&format!("{}_offset,\n", name));
+        }
+    }
+    output.push_str("        })\n    }\n\n");
+
+    for (field_name, tag, f_type, f_label, _oneof_index, is_map) in &fields_info {
+        let (rust_type, logic, default_val) = map_type_to_rust_accessor(*f_type, *f_label, *is_map);
+        let safe_name = if field_name == "type" {
+            format!("r#{}", field_name)
+        } else {
+            field_name.clone()
+        };
+
+        if *f_label == 3 {
+            output.push_str(&format!(
+                "    pub fn {}(&self) -> {} {{\n",
+                safe_name, rust_type
+            ));
+            output.push_str(&format!(
+                "        match (self.{}_start, self.{}_end) {{\n",
+                field_name, field_name
+            ));
+            if *is_map {
+                output.push_str(&format!("            (Some(start), Some(end)) => roto_runtime::MapFieldIterator::new(self.accessor.iter_repeated_range({}, start, end)),\n", tag));
+                output.push_str(&format!(
+                    "            _ => roto_runtime::MapFieldIterator::new(self.accessor.iter_repeated({})),\n",
+                    tag
+                ));
+            } else {
+                output.push_str(&format!("            (Some(start), Some(end)) => self.accessor.iter_repeated_range({}, start, end),\n", tag));
+                output.push_str(&format!(
+                    "            _ => self.accessor.iter_repeated({}),\n",
+                    tag
+                ));
+            }
+            output.push_str("        }\n    }\n\n");
+        } else {
+            output.push_str(&format!(
+                "    pub fn {}(&self) -> roto_runtime::Result<{}> {{\n",
+                safe_name, rust_type
+            ));
+            output.push_str(&format!(
+                "        let offset = self.{}_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;\n",
+                field_name
+            ));
+            output.push_str("        let (bytes, _) = self.accessor.get_value_at(offset)?;\n");
+            output.push_str(&format!("        {}\n", logic));
+            output.push_str("    }\n\n");
+
+            output.push_str(&format!(
+                "    pub fn {}_or_default(&self) -> roto_runtime::Result<{}> {{\n",
+                safe_name, rust_type
+            ));
+            output.push_str(&format!(
+                "        self.{}().or(Ok({}))\n",
+                safe_name, default_val
+            ));
+            output.push_str("    }\n\n");
+
+            output.push_str(&format!(
+                "    pub fn has_{}(&self) -> bool {{ self.{}_offset.is_some() }}\n\n",
+                field_name, field_name
+            ));
+        }
+    }
+
+    for (oneof_index, oneof_proto) in oneofs.iter().enumerate() {
+        let oneof_desc =
+            OneofDescriptorProto::new(*oneof_proto).expect("Failed to parse OneofDescriptorProto");
+        let oneof_name = oneof_desc.name().unwrap();
+        let pascal_oneof_name = to_pascal_case(oneof_name);
+        let snake_oneof_name = to_snake_case(oneof_name);
+
+        let return_type = format!("{}::{}<'a>", mod_name, pascal_oneof_name);
+        let signature = format!(
+            "    pub fn which_{}(&self) -> roto_runtime::Result<Option<{}> > {{\n",
+            snake_oneof_name, return_type
+        );
+        output.push_str(&signature);
+        for (field_name, _tag, _f_type, _f_label, f_oneof_index, _is_map) in &fields_info {
+            if *f_oneof_index == Some(oneof_index as i32) {
+                let safe_field_name = if field_name == "type" {
+                    format!("r#{}", field_name)
+                } else {
+                    field_name.clone()
+                };
+                output.push_str(&format!(
+                    "        if self.{}_offset.is_some() {{\n",
+                    field_name
+                ));
+                output.push_str(&format!(
+                    "            return Ok(Some({}::{}::{} (self.{}()?)));\n",
+                    mod_name, pascal_oneof_name, safe_field_name, safe_field_name
+                ));
+                output.push_str("        }\n");
+            }
+        }
+        output.push_str("        Ok(None)\n    }\n\n");
+    }
+
+    // raw_fields() convenience on the message struct (before closing the impl)
+    output.push_str("    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {\n");
+    output.push_str("        self.accessor.raw_fields()\n");
+    output.push_str("    }\n\n");
+    output.push_str("}\n\n");
+
+    // Collect builder field info so we can use it multiple times below.
+    // Tuple: (field_name, safe_name, tag, rust_type, write_method)
+    let mut builder_fields: Vec<(String, String, u32, String, String)> = Vec::new();
+    for field_res in msg_proto.field() {
+        let (field_data, _) = field_res.expect("Failed to iterate field");
+        let field_proto =
+            FieldDescriptorProto::new(field_data).expect("Failed to parse FieldDescriptorProto");
+        let field_name = field_proto.name().unwrap().to_string();
+        let safe_name = if field_name == "type" {
+            format!("r#{}", field_name)
+        } else {
+            field_name.clone()
+        };
+        let tag = field_proto.number().unwrap();
+        let f_type = field_proto.rype().unwrap() as i32;
+        let (rust_type, method) = map_type_to_rust_builder(f_type);
+        builder_fields.push((field_name, safe_name, tag as u32, rust_type, method));
+    }
+
+    // Builder struct — one `_written: bool` flag per field
+    output.push_str(&format!("pub struct {}Builder<'b> {{\n", msg_name));
+    output.push_str("    builder: roto_runtime::ProtoBuilder<'b>,\n");
+    for (field_name, _, _, _, _) in &builder_fields {
+        output.push_str(&format!("    {}_written: bool,\n", field_name));
+    }
+    output.push_str(&format!("}}\n\nimpl<'b> {}Builder<'b> {{\n", msg_name));
+
+    // Constructor — initialise every flag to false
+    output.push_str(&format!(
+        "    pub fn builder(buf: &mut [u8]) -> {}Builder<'_> {{\n        {}Builder {{\n",
+        msg_name, msg_name
+    ));
+    output.push_str("            builder: roto_runtime::ProtoBuilder::new(buf),\n");
+    for (field_name, _, _, _, _) in &builder_fields {
+        output.push_str(&format!("            {}_written: false,\n", field_name));
+    }
+    output.push_str("        }\n    }\n\n");
+
+    // Per-field setters — mark field as written
+    for (field_name, safe_name, tag, rust_type, method) in &builder_fields {
+        output.push_str(&format!(
+            "    pub fn {}(mut self, value: {}) -> roto_runtime::Result<Self> {{\n        self.builder.{}({}, value)?;\n        self.{}_written = true;\n        Ok(self)\n    }}\n\n",
+            safe_name, rust_type, method, tag, field_name
+        ));
+    }
+
+    // with() — copies unseen fields from an existing message
+    output.push_str(&format!(
+        "    pub fn with(mut self, msg: &{}<'_>) -> roto_runtime::Result<Self> {{\n",
+        msg_name
+    ));
+    output.push_str("        for item in msg.accessor.raw_fields() {\n");
+    output.push_str("            let (field_number, raw_bytes) = item?;\n");
+    output.push_str("            let is_written = match field_number {\n");
+    for (field_name, _, tag, _, _) in &builder_fields {
+        output.push_str(&format!(
+            "                {} => self.{}_written,\n",
+            tag, field_name
+        ));
+    }
+    output.push_str("                _ => false,\n");
+    output.push_str("            };\n");
+    output.push_str("            if !is_written {\n");
+    output.push_str("                self.builder.write_raw(raw_bytes)?;\n");
+    output.push_str("            }\n");
+    output.push_str("        }\n");
+    output.push_str("        Ok(self)\n");
+    output.push_str("    }\n\n");
+
+    output.push_str(&format!("    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {{\n        self.builder.finish()\n    }}\n}}\n\n"));
+
+    output.push_str(&format!(
+        pub struct Owned{} {{\n",
+        msg_name
+    ));
+    output.push_str("    pub data: bytes::Bytes,\n");
+    output.push_str("}\n\n");
+
+    output.push_str(&format!(
+        impl roto_runtime::RotoOwned for Owned{} {{\n",
+        msg_name
+    ));
+    output.push_str(&format!("    type Reader<'a> = {}<'a>;\n", msg_name));
+    output.push_str(&format!("    fn reader(&self) -> {}<'_> {{\n", msg_name));
+    output.push_str(&format!(
+        "        {}::new(&self.data).expect(\"failed to create reader\")\n",
+        msg_name
+    ));
+    output.push_str("    }\n");
+    output.push_str("}\n\n");
+
+    output.push_str(&format!(
+        impl roto_runtime::RotoMessage for Owned{} {{\n",
+        msg_name
+    ));
+    output.push_str("    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {\n");
+    output.push_str(&format!("        Ok(Owned{} {{ data: buf }})\n", msg_name));
+    output.push_str("    }\n\n");
+    output.push_str("    fn bytes(&self) -> bytes::Bytes {\n");
+    output.push_str("        self.data.clone()\n");
+    output.push_str("    }\n");
+    output.push_str("}\n\n");
+
+    let mut nested_enums = Vec::new();
+    for e_res in msg_proto.enum_type() {
+        if let Ok((e, _)) = e_res {
+            nested_enums.push(e);
+        }
+    }
+    let mut nested_msgs = Vec::new();
+    for m_res in msg_proto.nested_type() {
+        if let Ok((m, _)) = m_res {
+            nested_msgs.push(m);
+        }
+    }
+
+    if !nested_enums.is_empty() || !nested_msgs.is_empty() || !oneofs.is_empty() {
+        let mod_name = to_snake_case(msg_proto.name().unwrap());
+        output.push_str(&format!("pub mod {} {{\n", mod_name));
+        for e_data in &nested_enums {
+            write_enum(
+                &EnumDescriptorProto::new(e_data)
+                    .expect("Failed to parse nested EnumDescriptorProto"),
+                output,
+            );
+        }
+        for m_data in &nested_msgs {
+            write_message(
+                &DescriptorProto::new(m_data).expect("Failed to parse nested DescriptorProto"),
+                output,
+            );
+        }
+
+        for (oneof_index, oneof_proto) in oneofs.iter().enumerate() {
+            let oneof_desc = OneofDescriptorProto::new(*oneof_proto)
+                .expect("Failed to parse OneofDescriptorProto");
+            let oneof_name = oneof_desc.name().unwrap();
+            let pascal_oneof_name = to_pascal_case(oneof_name);
+            output.push_str(&format!("pub enum {}<'a> {{\n", pascal_oneof_name));
+            for (field_name, _tag, f_type, f_label, f_oneof_index, _is_map) in &fields_info {
+                if *f_oneof_index == Some(oneof_index as i32) {
+                    let (rust_type, _, _) = map_type_to_rust_accessor(*f_type, *f_label, *_is_map);
+                    let safe_field_name = if field_name == "type" {
+                        format!("r#{}", field_name)
+                    } else {
+                        field_name.clone()
+                    };
+                    output.push_str(&format!("    {}({}),\n", safe_field_name, rust_type));
+                }
+            }
+            output.push_str("}\n\n");
+        }
+    }
+    if !nested_enums.is_empty() || !nested_msgs.is_empty() || !oneofs.is_empty() {
+        output.push_str("}\n\n");
+    }
+}
+pub fn generate_protobuf_code(
+    set: &FileDescriptorSet,
+    files_to_generate: Option<&[String]>,
+    generate_mod_files: bool,
+) -> Vec<(String, String)> {
+    generate_files_common(
+        set,
+        files_to_generate,
+        generate_mod_files,
+        DATA_IMPORTS,
+        |file_proto, output| {
+            // Enums
+            for enum_res in file_proto.enum_type() {
+                let (enum_data, _) = enum_res.expect("Failed to iterate enum");
+                write_enum(
+                    &EnumDescriptorProto::new(enum_data)
+                        .expect("Failed to parse EnumDescriptorProto"),
+                    output,
+                );
+            }
+
+            // Messages
+            for msg_res in file_proto.message_type() {
+                let (msg_data, _) = msg_res.expect("Failed to iterate message");
+                write_message(
+                    &DescriptorProto::new(msg_data).expect("Failed to parse DescriptorProto"),
+                    output,
+                );
+            }
+        },
+    )
+}
+
+
+
+
+
+

codegen/src/generator/mod.rs

@@ -3,23 +3,23 @@ use crate::google::protobuf::descriptor::{
     FileDescriptorSet, MessageOptions, MethodDescriptorProto, OneofDescriptorProto,
     ServiceDescriptorProto,
 };
-use roto_runtime::ProtoAccessor;
+use crate::runtime::ProtoAccessor;
 use std::collections::{HashMap, HashSet};
 use std::str;
 
-const DATA_IMPORTS: &str = "use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};\nuse core::str;\n#[cfg(feature = \"alloc\")]\nuse bytes::{Bytes, BytesMut, Buf, BufMut};\n";
-const SERVICE_IMPORTS: &str = "#[cfg(feature = \"alloc\")]\nuse tonic::{Request, Response, Status};\n\
-     #[cfg(feature = \"alloc\")]\nuse tokio_stream::Stream;\n\
-     #[cfg(feature = \"alloc\")]\nuse std::pin::Pin;\n\
-     #[cfg(feature = \"alloc\")]\nuse std::sync::Arc;\n\
-     #[cfg(feature = \"alloc\")]\nuse std::task::{Context, Poll};\n\
-     #[cfg(feature = \"alloc\")]\nuse std::future::Future;\n\
-     #[cfg(feature = \"alloc\")]\nuse tonic::body::BoxBody;\n\
-     #[cfg(feature = \"alloc\")]\nuse tower::Service;\n\
-     #[cfg(feature = \"alloc\")]\nuse futures_util::StreamExt;\n\
-     #[cfg(feature = \"alloc\")]\nuse http_body_util::BodyExt;\n\
-     #[cfg(feature = \"alloc\")]\nuse http_body::Body;\n\
-     #[cfg(feature = \"alloc\")]\nuse crate::{BufferPool, StatusBody};\n";
+const DATA_IMPORTS: &str = "use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};\nuse core::str;\nuse bytes::{Bytes, BytesMut, Buf, BufMut};\n";
+const SERVICE_IMPORTS: &str = "use tonic::{Request, Response, Status};\n\
+     use tokio_stream::Stream;\n\
+     use std::pin::Pin;\n\
+     use std::sync::Arc;\n\
+     use std::task::{Context, Poll};\n\
+     use std::future::Future;\n\
+     use tonic::body::BoxBody;\n\
+     use tower::Service;\n\
+     use futures_util::StreamExt;\n\
+     use http_body_util::BodyExt;\n\
+     use http_body::Body;\n\
+     use crate::{BufferPool, StatusBody};\n";
 
 pub fn to_pascal_case(s: &str) -> String {
     s.split('_')
@@ -139,7 +139,7 @@ fn write_enum(enum_proto: &EnumDescriptorProto, output: &mut String) {
         let name = std::str::from_utf8(name_bytes).expect("Enum value name invalid utf8");
         let (num_bytes, _) = accessor.get_value(2).expect("Enum value number missing");
         let (num, _) =
-            roto_runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
+            crate::runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
 
         let pascal_name = to_pascal_case(name);
         if num == 0 {
@@ -169,7 +169,7 @@ fn write_enum(enum_proto: &EnumDescriptorProto, output: &mut String) {
         let name = std::str::from_utf8(name_bytes).expect("Enum value name invalid utf8");
         let (num_bytes, _) = accessor.get_value(2).expect("Enum value number missing");
         let (num, _) =
-            roto_runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
+            crate::runtime::read_varint(num_bytes).expect("Enum value number invalid varint");
 
         output.push_str(&format!(
             "            {} => {}::{},\n",
@@ -457,14 +457,14 @@ fn write_message(msg_proto: &DescriptorProto, output: &mut String) {
     output.push_str(&format!("    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {{\n        self.builder.finish()\n    }}\n}}\n\n"));
 
     output.push_str(&format!(
-        "#[cfg(feature = \"alloc\")]\npub struct Owned{} {{\n",
+        "pub struct Owned{} {{\n",
         msg_name
     ));
     output.push_str("    pub data: bytes::Bytes,\n");
     output.push_str("}\n\n");
 
     output.push_str(&format!(
-        "#[cfg(feature = \"alloc\")]\nimpl roto_runtime::RotoOwned for Owned{} {{\n",
+        "impl roto_runtime::RotoOwned for Owned{} {{\n",
         msg_name
     ));
     output.push_str(&format!("    type Reader<'a> = {}<'a>;\n", msg_name));
@@ -477,7 +477,7 @@ fn write_message(msg_proto: &DescriptorProto, output: &mut String) {
     output.push_str("}\n\n");
 
     output.push_str(&format!(
-        "#[cfg(feature = \"alloc\")]\nimpl roto_runtime::RotoMessage for Owned{} {{\n",
+        "impl roto_runtime::RotoMessage for Owned{} {{\n",
         msg_name
     ));
     output.push_str("    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {\n");
@@ -828,7 +828,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut
     output.push_str(SERVICE_IMPORTS);
     output.push_str("\n");
     let svc_name = to_pascal_case(svc_proto.name().unwrap());
-    output.push_str("#[cfg(feature = \"alloc\")]\n");
+    
     output.push_str(&format!(
         "#[async_trait::async_trait]\npub trait {}: Send + Sync + 'static {{\n",
         svc_name
@@ -875,7 +875,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut
     output.push_str("}\n\n");
 
     let server_name = format!("{}Server", svc_name);
-    output.push_str("#[cfg(feature = \"alloc\")]\n");
+    
     output.push_str(&format!(
         "#[derive(Clone)]\npub struct {} {{\n",
         server_name
@@ -884,7 +884,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut
     output.push_str("    pool: Arc<BufferPool>,\n");
     output.push_str("}\n\n");
 
-    output.push_str("#[cfg(feature = \"alloc\")]\n");
+    
     output.push_str(&format!("impl {} {{\n", server_name));
     output.push_str(&format!(
         "    pub fn new(inner: Arc<dyn {}>, pool: Arc<BufferPool>) -> Self {{\n",
@@ -894,7 +894,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut
     output.push_str("    }\n");
     output.push_str("}\n\n");
 
-    output.push_str("#[cfg(feature = \"alloc\")]\n");
+    
     output.push_str(&format!(
         "impl tonic::server::NamedService for {} {{\n",
         server_name
@@ -910,7 +910,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut
     ));
     output.push_str("}\n\n");
 
-    output.push_str("#[cfg(feature = \"alloc\")]\n");
+    
     output.push_str(&format!(
         "impl Service<http::Request<BoxBody>> for {} {{\n",
         server_name

codegen/src/generator/services.rs

@@ -0,0 +1,258 @@
+use crate::google::protobuf::descriptor::{ServiceDescriptorProto, MethodDescriptorProto};
+use crate::google::protobuf::descriptor::FileDescriptorSet;
+use crate::generator::generate_files_common;
+use crate::generator::SERVICE_IMPORTS;
+
+use crate::generator::utils::{to_pascal_case, to_snake_case};
+
+pub fn generate_service_code(
+
+    set: &FileDescriptorSet,
+    files_to_generate: Option<&[String]>,
+    generate_mod_files: bool,
+) -> Vec<(String, String)> {
+    generate_files_common(
+        set,
+        files_to_generate,
+        generate_mod_files,
+        "",
+        |file_proto, output| {
+            let package = file_proto.package().unwrap_or("").to_string();
+            // Services
+            for svc_res in file_proto.service() {
+                let (svc_data, _) = svc_res.expect("Failed to iterate service");
+                write_service(
+                    &ServiceDescriptorProto::new(svc_data)
+                        .expect("Failed to parse ServiceDescriptorProto"),
+                    &package,
+                    output,
+                );
+            }
+        },
+    )
+}
+pub fn write_service(svc_proto: &ServiceDescriptorProto, package: &str, output: &mut String) {
+    output.push_str(SERVICE_IMPORTS);
+    output.push_str("\n");
+    let svc_name = to_pascal_case(svc_proto.name().unwrap());
+    
+    output.push_str(&format!(
+        "#[async_trait::async_trait]\npub trait {}: Send + Sync + 'static {{\n",
+        svc_name
+    ));
+
+    for method_res in svc_proto.method() {
+        let (method_data, _) = method_res.expect("Failed to iterate method");
+        let method_proto =
+            MethodDescriptorProto::new(method_data).expect("Failed to parse MethodDescriptorProto");
+        let method_name = to_snake_case(method_proto.name().unwrap());
+
+        let input_full_name = method_proto.input_type().unwrap();
+        let output_full_name = method_proto.output_type().unwrap();
+
+        let input_type = input_full_name.split('.').last().unwrap();
+        let output_type = output_full_name.split('.').last().unwrap();
+
+        let input_owned = format!("Owned{}", input_type);
+        let output_owned = format!("Owned{}", output_type);
+
+        let client_streaming = method_proto.client_streaming().unwrap_or(false);
+        let server_streaming = method_proto.server_streaming().unwrap_or(false);
+
+        let req_type = if client_streaming {
+            format!("Request<tonic::Streaming<{}>>", input_owned)
+        } else {
+            format!("Request<{}>", input_owned)
+        };
+
+        let resp_type = if server_streaming {
+            format!(
+                "Response<Pin<Box<dyn Stream<Item = std::result::Result<{}, Status>> + Send>>>",
+                output_owned
+            )
+        } else {
+            format!("Response<{}>", output_owned)
+        };
+
+        output.push_str(&format!(
+            "    async fn {}(&self, request: {}) -> std::result::Result<{}, Status>;\n",
+            method_name, req_type, resp_type
+        ));
+    }
+    output.push_str("}\n\n");
+
+    let server_name = format!("{}Server", svc_name);
+    
+    output.push_str(&format!(
+        "#[derive(Clone)]\npub struct {} {{\n",
+        server_name
+    ));
+    output.push_str(&format!("    inner: Arc<dyn {}>,\n", svc_name));
+    output.push_str("    pool: Arc<BufferPool>,\n");
+    output.push_str("}\n\n");
+
+    
+    output.push_str(&format!("impl {} {{\n", server_name));
+    output.push_str(&format!(
+        "    pub fn new(inner: Arc<dyn {}>, pool: Arc<BufferPool>) -> Self {{\n",
+        svc_name
+    ));
+    output.push_str("        Self { inner, pool }\n");
+    output.push_str("    }\n");
+    output.push_str("}\n\n");
+
+    
+    output.push_str(&format!(
+        "impl tonic::server::NamedService for {} {{\n",
+        server_name
+    ));
+    let full_svc_name = if package.is_empty() {
+        svc_proto.name().unwrap().to_string()
+    } else {
+        format!("{}.{}", package, svc_proto.name().unwrap())
+    };
+    output.push_str(&format!(
+        "    const NAME: &'static str = \"{}\";\n",
+        full_svc_name
+    ));
+    output.push_str("}\n\n");
+
+    
+    output.push_str(&format!(
+        "impl Service<http::Request<BoxBody>> for {} {{\n",
+        server_name
+    ));
+    output.push_str("    type Response = http::Response<BoxBody>;\n");
+    output.push_str("    type Error = std::convert::Infallible;\n");
+    output.push_str("    type Future = Pin<Box<dyn Future<Output = std::result::Result<Self::Response, Self::Error>> + Send>>;\n\n");
+
+    output.push_str("    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<std::result::Result<(), Self::Error>> {\n");
+    output.push_str("        Poll::Ready(Ok(()))\n");
+    output.push_str("    }\n\n");
+
+    output.push_str("    fn call(&mut self, req: http::Request<BoxBody>) -> Self::Future {\n");
+    output.push_str("        let inner = self.inner.clone();\n");
+    output.push_str("        let pool = self.pool.clone();\n");
+    output.push_str("        Box::pin(async move {\n");
+    output.push_str("            let path = req.uri().path().to_string();\n");
+    output.push_str("            let body = req.into_body();\n");
+    output.push_str("            let mut buf = pool.get();\n");
+    output.push_str("            let mut stream = body;\n");
+    output.push_str("            while let Some(frame_result) = stream.frame().await {\n");
+    output.push_str("                let frame = frame_result.expect(\"Body frame error\");\n");
+    output.push_str("                if let Some(data) = frame.data_ref() {\n");
+    output.push_str("                    buf.put(data.clone());\n");
+    output.push_str("                }\n");
+    output.push_str("            }\n\n");
+
+    output.push_str("            let total_len = buf.len();\n");
+    output.push_str("            let bytes_vec = buf.split_to(total_len).freeze();\n");
+    output.push_str("            pool.put(buf);\n");
+    output.push_str("            if bytes_vec.len() < 5 {\n");
+    output.push_str("                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));\n");
+    output.push_str("                return Ok(http::Response::builder().status(200).body(res_body).unwrap());\n");
+    output.push_str("            }\n\n");
+    output.push_str("            let payload = bytes_vec.slice(5..);\n");
+    output.push_str("            let mut routed = false;\n\n");
+
+    let mut methods = Vec::new();
+    for method_res in svc_proto.method() {
+        let (method_data, _) = method_res.expect("Failed to iterate method");
+        let method_proto =
+            MethodDescriptorProto::new(method_data).expect("Failed to parse MethodDescriptorProto");
+        let original_method_name = method_proto.name().unwrap().to_string();
+        let method_name = to_snake_case(&original_method_name);
+        let input_full_name = method_proto.input_type().unwrap();
+        let input_type = input_full_name.split('.').last().unwrap();
+        let input_owned = format!("Owned{}", input_type);
+        let server_streaming = method_proto.server_streaming().unwrap_or(false);
+        methods.push((
+            original_method_name,
+            method_name,
+            input_owned,
+            server_streaming,
+        ));
+    }
+
+    for (original_method_name, method_name, input_owned, server_streaming) in methods {
+        if server_streaming {
+            // For streaming RPCs, we don't implement the server logic yet.
+            // We just make it compile by returning a "not implemented" response.
+            let full_path = if package.is_empty() {
+                format!("/{}/{}", svc_proto.name().unwrap(), original_method_name)
+            } else {
+                format!(
+                    "/{}.{}/{}",
+                    package,
+                    svc_proto.name().unwrap(),
+                    original_method_name
+                )
+            };
+            output.push_str(&format!("            if path == \"{}\" {{\n", full_path));
+            output.push_str("                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));\n");
+            output.push_str("                return Ok(http::Response::builder().status(200).body(res_body).unwrap());\n");
+            output.push_str("            }\n");
+            continue;
+        }
+        let full_path = if package.is_empty() {
+            format!("/{}/{}", svc_proto.name().unwrap(), original_method_name)
+        } else {
+            format!(
+                "/{}.{}/{}",
+                package,
+                svc_proto.name().unwrap(),
+                original_method_name
+            )
+        };
+        output.push_str(&format!("            if path == \"{}\" {{\n", full_path));
+        output.push_str(&format!(
+            "                let request_msg = match {}::decode(payload) {{\n",
+            input_owned
+        ));
+        output.push_str("                    Ok(msg) => msg,\n");
+        output.push_str("                    Err(e) => {\n");
+        output.push_str("                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));\n");
+        output.push_str("                        return Ok(http::Response::builder().status(200).body(res_body).unwrap());\n");
+        output.push_str("                    }\n");
+        output.push_str("                };\n\n");
+        output.push_str(&format!(
+            "                let response = match inner.{}(Request::new(request_msg)).await {{\n",
+            method_name
+        ));
+        output.push_str("                    Ok(res) => res,\n");
+        output.push_str("                    Err(e) => {\n");
+        output.push_str("                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));\n");
+        output.push_str("                        return Ok(http::Response::builder().status(200).body(res_body).unwrap());\n");
+        output.push_str("                    }\n");
+        output.push_str("                };\n\n");
+        output.push_str("                let response_msg = response.into_inner();\n");
+        output.push_str("                let response_bytes = response_msg.bytes();\n");
+        output.push_str("                let mut res_buf = pool.get();\n");
+        output.push_str("                res_buf.put_u8(0);\n");
+        output.push_str("                let len = response_bytes.len() as u32;\n");
+        output.push_str("                res_buf.put_slice(&len.to_be_bytes());\n");
+        output.push_str("                res_buf.put_slice(&response_bytes);\n");
+        output.push_str("                let frame_len = res_buf.len();\n");
+        output.push_str("                let frame = res_buf.split_to(frame_len).freeze();\n");
+        output.push_str("                pool.put(res_buf);\n");
+        output.push_str(
+            "                let res_body = BoxBody::new(StatusBody::new(Some(frame), 0));\n",
+        );
+        output.push_str("                routed = true;\n");
+        output.push_str("                return Ok(http::Response::builder().status(200).header(\"content-type\", \"application/grpc\").body(res_body).unwrap());\n");
+        output.push_str("            }\n");
+    }
+
+    output.push_str("            if !routed {\n");
+    output.push_str("                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));\n");
+    output.push_str("                return Ok(http::Response::builder().status(200).body(res_body).unwrap());\n");
+    output.push_str("            }\n");
+    output.push_str("            Ok(http::Response::builder().status(200).body(BoxBody::new(StatusBody::new(None, 0))).unwrap())\n");
+    output.push_str("        })\n");
+    output.push_str("    }\n");
+    output.push_str("}\n");
+}
+
+
+
+

codegen/src/generator/types.rs

@@ -0,0 +1,151 @@
+use crate::google::protobuf::descriptor::FieldDescriptorProto;
+use crate::google::protobuf::descriptor::DescriptorProto;
+
+pub fn map_type_to_rust_accessor(
+    field_type: i32,
+    label: i32,
+    is_map: bool,
+) -> (String, String, String) {
+    if label == 3 {
+        // LABEL_REPEATED
+        let iterator_type = if is_map {
+            "roto_runtime::MapFieldIterator<'a>"
+        } else {
+            "roto_runtime::RepeatedFieldIterator<'a>"
+        };
+        return (
+            iterator_type.to_string(),
+            "".to_string(), // Not used for repeated fields in the same way
+            "".to_string(), // Not used for repeated fields
+        );
+    }
+
+    match field_type {
+        9 => (
+            "&'a str".to_string(),
+            "core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "\"\"".to_string(),
+        ), // TYPE_STRING
+        1 => (
+            "f64".to_string(),
+            "Ok(f64::from_le_bytes(bytes.try_into().map_err(|_| roto_runtime::RotoError::WireFormatViolation)?))".to_string(),
+            "0.0".to_string(),
+        ), // TYPE_DOUBLE
+        2 => (
+            "f32".to_string(),
+            "Ok(f32::from_le_bytes(bytes.try_into().map_err(|_| roto_runtime::RotoError::WireFormatViolation)?))".to_string(),
+            "0.0".to_string(),
+        ), // TYPE_FLOAT
+        3 | 5 | 15 | 17 => (
+            "i32".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // INT/SINT/SFIXED 32
+        4 | 6 | 13 => (
+            "u32".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // UINT/FIXED 32
+        16 | 18 => (
+            "i64".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as i64).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // SINT/SFIXED 64
+        7 | 14 => (
+            "u64".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as u64).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // UINT/FIXED 64
+        8 => (
+            "bool".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v != 0).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "false".to_string(),
+        ), // TYPE_BOOL
+        11 | 12 => (
+            "&'a [u8]".to_string(),
+            "Ok(bytes)".to_string(),
+            "&[]".to_string(),
+        ), // MESSAGE/BYTES
+        _ => (
+            "&'a [u8]".to_string(),
+            "Ok(bytes)".to_string(),
+            "&[]".to_string(),
+        ),
+    }
+}
+EOF > /opt/workspace/codegen/src/generator/types.rs
+use crate::google::protobuf::descriptor::FieldDescriptorProto;
+use crate::google::protobuf::descriptor::DescriptorProto;
+
+pub fn map_type_to_rust_accessor(
+    field_type: i32,
+    label: i32,
+    is_map: bool,
+) -> (String, String, String) {
+    if label == 3 {
+        // LABEL_REPEATED
+        let iterator_type = if is_map {
+            "roto_runtime::MapFieldIterator<'a>"
+        } else {
+            "roto_runtime::RepeatedFieldIterator<'a>"
+        };
+        return (
+            iterator_type.to_string(),
+            "".to_string(), // Not used for repeated fields in the same way
+            "".to_string(), // Not used for repeated fields
+        );
+    }
+
+    match field_type {
+        9 => (
+            "&'a str".to_string(),
+            "core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "\"\"".to_string(),
+        ), // TYPE_STRING
+        1 => (
+            "f64".to_string(),
+            "Ok(f64::from_le_bytes(bytes.try_into().map_err(|_| roto_runtime::RotoError::WireFormatViolation)?))".to_string(),
+            "0.0".to_string(),
+        ), // TYPE_DOUBLE
+        2 => (
+            "f32".to_string(),
+            "Ok(f32::from_le_bytes(bytes.try_into().map_err(|_| roto_runtime::RotoError::WireFormatViolation)?))".to_string(),
+            "0.0".to_string(),
+        ), // TYPE_FLOAT
+        3 | 5 | 15 | 17 => (
+            "i32".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // INT/SINT/SFIXED 32
+        4 | 6 | 13 => (
+            "u32".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // UINT/FIXED 32
+        16 | 18 => (
+            "i64".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as i64).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // SINT/SFIXED 64
+        7 | 14 => (
+            "u64".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v as u64).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "0".to_string(),
+        ), // UINT/FIXED 64
+        8 => (
+            "bool".to_string(),
+            "roto_runtime::read_varint(bytes).map(|(v, _)| v != 0).map_err(|_| roto_runtime::RotoError::WireFormatViolation)".to_string(),
+            "false".to_string(),
+        ), // TYPE_BOOL
+        11 | 12 => (
+            "&'a [u8]".to_string(),
+            "Ok(bytes)".to_string(),
+            "&[]".to_string(),
+        ), // MESSAGE/BYTES
+        _ => (
+            "&'a [u8]".to_string(),
+            "Ok(bytes)".to_string(),
+            "&[]".to_string(),
+        ),
+    }
+}

codegen/src/generator/utils.rs

@@ -0,0 +1,32 @@
+pub const DATA_IMPORTS: &str = "use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};\nuse core::str;\nuse bytes::{Bytes, BytesMut, Buf, BufMut};\n";
+
+pub fn to_pascal_case(s: &str) -> String {
+    s.split('_')
+        .map(|word| {
+            let mut chars = word.chars();
+            match chars.next() {
+                None => String::new(),
+                Some(f) => {
+                    let first = f.to_uppercase().collect::<String>();
+                    let rest = chars.as_str().to_lowercase();
+                    first + &rest
+                }
+            }
+        })
+        .collect()
+}
+
+pub fn to_snake_case(s: &str) -> String {
+    let mut result = String::new();
+    for (i, c) in s.chars().enumerate() {
+        if c.is_uppercase() {
+            if i > 0 {
+                result.push('_');
+            }
+            result.push(c.to_ascii_lowercase());
+        } else {
+            result.push(c);
+        }
+    }
+    result
+}

codegen/src/google/protobuf/compiler/plugin.rs

@@ -1,7 +1,7 @@
 // @generated by protoc-gen-roto — do not edit
 #[allow(unused_imports)]
 
-use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator};
+use crate::runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator};
 use std::str;
 use bytes::{Bytes, BytesMut, Buf, BufMut};
 use tonic::{Request, Response, Status};
@@ -20,7 +20,7 @@ use roto_tonic::{BufferPool, StatusBody};
 use crate::google::protobuf::descriptor;
 
 pub struct Version<'a> {
-    accessor: roto_runtime::ProtoAccessor<'a>,
+    accessor: crate::runtime::ProtoAccessor<'a>,
     major_offset: Option<usize>,
     minor_offset: Option<usize>,
     patch_offset: Option<usize>,
@@ -28,8 +28,8 @@ pub struct Version<'a> {
 }
 
 impl<'a> Version<'a> {
-    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
-        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> crate::runtime::Result<Self> {
+        let accessor = crate::runtime::ProtoAccessor::new(data)?;
         let mut major_offset = None;
         let mut minor_offset = None;
         let mut patch_offset = None;
@@ -51,62 +51,62 @@ suffix_offset,
         })
     }
 
-    pub fn major(&self) -> roto_runtime::Result<i32> {
-        let offset = self.major_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn major(&self) -> crate::runtime::Result<i32> {
+        let offset = self.major_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn major_or_default(&self) -> roto_runtime::Result<i32> {
+    pub fn major_or_default(&self) -> crate::runtime::Result<i32> {
         self.major().or(Ok(0))
     }
 
     pub fn has_major(&self) -> bool { self.major_offset.is_some() }
 
-    pub fn minor(&self) -> roto_runtime::Result<i32> {
-        let offset = self.minor_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn minor(&self) -> crate::runtime::Result<i32> {
+        let offset = self.minor_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn minor_or_default(&self) -> roto_runtime::Result<i32> {
+    pub fn minor_or_default(&self) -> crate::runtime::Result<i32> {
         self.minor().or(Ok(0))
     }
 
     pub fn has_minor(&self) -> bool { self.minor_offset.is_some() }
 
-    pub fn patch(&self) -> roto_runtime::Result<i32> {
-        let offset = self.patch_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn patch(&self) -> crate::runtime::Result<i32> {
+        let offset = self.patch_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn patch_or_default(&self) -> roto_runtime::Result<i32> {
+    pub fn patch_or_default(&self) -> crate::runtime::Result<i32> {
         self.patch().or(Ok(0))
     }
 
     pub fn has_patch(&self) -> bool { self.patch_offset.is_some() }
 
-    pub fn suffix(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.suffix_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn suffix(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.suffix_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn suffix_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn suffix_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.suffix().or(Ok(""))
     }
 
     pub fn has_suffix(&self) -> bool { self.suffix_offset.is_some() }
 
-    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+    pub fn raw_fields(&self) -> crate::runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct VersionBuilder<'b> {
-    builder: roto_runtime::ProtoBuilder<'b>,
+    builder: crate::runtime::ProtoBuilder<'b>,
     major_written: bool,
     minor_written: bool,
     patch_written: bool,
@@ -116,7 +116,7 @@ pub struct VersionBuilder<'b> {
 impl<'b> VersionBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> VersionBuilder<'_> {
         VersionBuilder {
-            builder: roto_runtime::ProtoBuilder::new(buf),
+            builder: crate::runtime::ProtoBuilder::new(buf),
             major_written: false,
             minor_written: false,
             patch_written: false,
@@ -124,31 +124,31 @@ impl<'b> VersionBuilder<'b> {
         }
     }
 
-    pub fn major(mut self, value: i32) -> roto_runtime::Result<Self> {
+    pub fn major(mut self, value: i32) -> crate::runtime::Result<Self> {
         self.builder.write_int32(1, value)?;
         self.major_written = true;
         Ok(self)
     }
 
-    pub fn minor(mut self, value: i32) -> roto_runtime::Result<Self> {
+    pub fn minor(mut self, value: i32) -> crate::runtime::Result<Self> {
         self.builder.write_int32(2, value)?;
         self.minor_written = true;
         Ok(self)
     }
 
-    pub fn patch(mut self, value: i32) -> roto_runtime::Result<Self> {
+    pub fn patch(mut self, value: i32) -> crate::runtime::Result<Self> {
         self.builder.write_int32(3, value)?;
         self.patch_written = true;
         Ok(self)
     }
 
-    pub fn suffix(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn suffix(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(4, value)?;
         self.suffix_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &Version<'_>) -> roto_runtime::Result<Self> {
+    pub fn with(mut self, msg: &Version<'_>) -> crate::runtime::Result<Self> {
         for item in msg.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
@@ -165,7 +165,7 @@ impl<'b> VersionBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+    pub fn finish(self) -> crate::runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
@@ -174,15 +174,15 @@ pub struct OwnedVersion {
     pub data: bytes::Bytes,
 }
 
-impl roto_runtime::RotoOwned for OwnedVersion {
+impl crate::runtime::RotoOwned for OwnedVersion {
     type Reader<'a> = Version<'a>;
     fn reader(&self) -> Version<'_> {
         Version::new(&self.data).expect("failed to create reader")
     }
 }
 
-impl roto_runtime::RotoMessage for OwnedVersion {
-    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+impl crate::runtime::RotoMessage for OwnedVersion {
+    fn decode(buf: bytes::Bytes) -> crate::runtime::Result<Self> {
         Ok(OwnedVersion { data: buf })
     }
 
@@ -192,7 +192,7 @@ impl roto_runtime::RotoMessage for OwnedVersion {
 }
 
 pub struct CodeGeneratorRequest<'a> {
-    accessor: roto_runtime::ProtoAccessor<'a>,
+    accessor: crate::runtime::ProtoAccessor<'a>,
     file_to_generate_start: Option<usize>,
     file_to_generate_end: Option<usize>,
     parameter_offset: Option<usize>,
@@ -204,8 +204,8 @@ pub struct CodeGeneratorRequest<'a> {
 }
 
 impl<'a> CodeGeneratorRequest<'a> {
-    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
-        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> crate::runtime::Result<Self> {
+        let accessor = crate::runtime::ProtoAccessor::new(data)?;
         let mut file_to_generate_start = None;
         let mut file_to_generate_end = None;
         let mut parameter_offset = None;
@@ -242,59 +242,59 @@ compiler_version_offset,
         })
     }
 
-    pub fn file_to_generate(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+    pub fn file_to_generate(&self) -> crate::runtime::RepeatedFieldIterator<'a> {
         match (self.file_to_generate_start, self.file_to_generate_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(1, start, end),
             _ => self.accessor.iter_repeated(1),
         }
     }
 
-    pub fn parameter(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.parameter_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn parameter(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.parameter_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn parameter_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn parameter_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.parameter().or(Ok(""))
     }
 
     pub fn has_parameter(&self) -> bool { self.parameter_offset.is_some() }
 
-    pub fn proto_file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+    pub fn proto_file(&self) -> crate::runtime::RepeatedFieldIterator<'a> {
         match (self.proto_file_start, self.proto_file_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
             _ => self.accessor.iter_repeated(15),
         }
     }
 
-    pub fn source_file_descriptors(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+    pub fn source_file_descriptors(&self) -> crate::runtime::RepeatedFieldIterator<'a> {
         match (self.source_file_descriptors_start, self.source_file_descriptors_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(17, start, end),
             _ => self.accessor.iter_repeated(17),
         }
     }
 
-    pub fn compiler_version(&self) -> roto_runtime::Result<&'a [u8]> {
-        let offset = self.compiler_version_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn compiler_version(&self) -> crate::runtime::Result<&'a [u8]> {
+        let offset = self.compiler_version_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
         Ok(bytes)
     }
 
-    pub fn compiler_version_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+    pub fn compiler_version_or_default(&self) -> crate::runtime::Result<&'a [u8]> {
         self.compiler_version().or(Ok(&[]))
     }
 
     pub fn has_compiler_version(&self) -> bool { self.compiler_version_offset.is_some() }
 
-    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+    pub fn raw_fields(&self) -> crate::runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct CodeGeneratorRequestBuilder<'b> {
-    builder: roto_runtime::ProtoBuilder<'b>,
+    builder: crate::runtime::ProtoBuilder<'b>,
     file_to_generate_written: bool,
     parameter_written: bool,
     proto_file_written: bool,
@@ -305,7 +305,7 @@ pub struct CodeGeneratorRequestBuilder<'b> {
 impl<'b> CodeGeneratorRequestBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> CodeGeneratorRequestBuilder<'_> {
         CodeGeneratorRequestBuilder {
-            builder: roto_runtime::ProtoBuilder::new(buf),
+            builder: crate::runtime::ProtoBuilder::new(buf),
             file_to_generate_written: false,
             parameter_written: false,
             proto_file_written: false,
@@ -314,37 +314,37 @@ impl<'b> CodeGeneratorRequestBuilder<'b> {
         }
     }
 
-    pub fn file_to_generate(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn file_to_generate(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.file_to_generate_written = true;
         Ok(self)
     }
 
-    pub fn parameter(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn parameter(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(2, value)?;
         self.parameter_written = true;
         Ok(self)
     }
 
-    pub fn proto_file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+    pub fn proto_file(mut self, value: &[u8]) -> crate::runtime::Result<Self> {
         self.builder.write_bytes(15, value)?;
         self.proto_file_written = true;
         Ok(self)
     }
 
-    pub fn source_file_descriptors(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+    pub fn source_file_descriptors(mut self, value: &[u8]) -> crate::runtime::Result<Self> {
         self.builder.write_bytes(17, value)?;
         self.source_file_descriptors_written = true;
         Ok(self)
     }
 
-    pub fn compiler_version(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+    pub fn compiler_version(mut self, value: &[u8]) -> crate::runtime::Result<Self> {
         self.builder.write_bytes(3, value)?;
         self.compiler_version_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &CodeGeneratorRequest<'_>) -> roto_runtime::Result<Self> {
+    pub fn with(mut self, msg: &CodeGeneratorRequest<'_>) -> crate::runtime::Result<Self> {
         for item in msg.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
@@ -362,7 +362,7 @@ impl<'b> CodeGeneratorRequestBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+    pub fn finish(self) -> crate::runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
@@ -371,15 +371,15 @@ pub struct OwnedCodeGeneratorRequest {
     pub data: bytes::Bytes,
 }
 
-impl roto_runtime::RotoOwned for OwnedCodeGeneratorRequest {
+impl crate::runtime::RotoOwned for OwnedCodeGeneratorRequest {
     type Reader<'a> = CodeGeneratorRequest<'a>;
     fn reader(&self) -> CodeGeneratorRequest<'_> {
         CodeGeneratorRequest::new(&self.data).expect("failed to create reader")
     }
 }
 
-impl roto_runtime::RotoMessage for OwnedCodeGeneratorRequest {
-    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+impl crate::runtime::RotoMessage for OwnedCodeGeneratorRequest {
+    fn decode(buf: bytes::Bytes) -> crate::runtime::Result<Self> {
         Ok(OwnedCodeGeneratorRequest { data: buf })
     }
 
@@ -389,7 +389,7 @@ impl roto_runtime::RotoMessage for OwnedCodeGeneratorRequest {
 }
 
 pub struct CodeGeneratorResponse<'a> {
-    accessor: roto_runtime::ProtoAccessor<'a>,
+    accessor: crate::runtime::ProtoAccessor<'a>,
     error_offset: Option<usize>,
     supported_features_offset: Option<usize>,
     minimum_edition_offset: Option<usize>,
@@ -399,8 +399,8 @@ pub struct CodeGeneratorResponse<'a> {
 }
 
 impl<'a> CodeGeneratorResponse<'a> {
-    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
-        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> crate::runtime::Result<Self> {
+        let accessor = crate::runtime::ProtoAccessor::new(data)?;
         let mut error_offset = None;
         let mut supported_features_offset = None;
         let mut minimum_edition_offset = None;
@@ -429,69 +429,69 @@ file_start, file_end,
         })
     }
 
-    pub fn error(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.error_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn error(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.error_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn error_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn error_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.error().or(Ok(""))
     }
 
     pub fn has_error(&self) -> bool { self.error_offset.is_some() }
 
-    pub fn supported_features(&self) -> roto_runtime::Result<u32> {
-        let offset = self.supported_features_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn supported_features(&self) -> crate::runtime::Result<u32> {
+        let offset = self.supported_features_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn supported_features_or_default(&self) -> roto_runtime::Result<u32> {
+    pub fn supported_features_or_default(&self) -> crate::runtime::Result<u32> {
         self.supported_features().or(Ok(0))
     }
 
     pub fn has_supported_features(&self) -> bool { self.supported_features_offset.is_some() }
 
-    pub fn minimum_edition(&self) -> roto_runtime::Result<i32> {
-        let offset = self.minimum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn minimum_edition(&self) -> crate::runtime::Result<i32> {
+        let offset = self.minimum_edition_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn minimum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+    pub fn minimum_edition_or_default(&self) -> crate::runtime::Result<i32> {
         self.minimum_edition().or(Ok(0))
     }
 
     pub fn has_minimum_edition(&self) -> bool { self.minimum_edition_offset.is_some() }
 
-    pub fn maximum_edition(&self) -> roto_runtime::Result<i32> {
-        let offset = self.maximum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn maximum_edition(&self) -> crate::runtime::Result<i32> {
+        let offset = self.maximum_edition_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        crate::runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn maximum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+    pub fn maximum_edition_or_default(&self) -> crate::runtime::Result<i32> {
         self.maximum_edition().or(Ok(0))
     }
 
     pub fn has_maximum_edition(&self) -> bool { self.maximum_edition_offset.is_some() }
 
-    pub fn file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+    pub fn file(&self) -> crate::runtime::RepeatedFieldIterator<'a> {
         match (self.file_start, self.file_end) {
             (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
             _ => self.accessor.iter_repeated(15),
         }
     }
 
-    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+    pub fn raw_fields(&self) -> crate::runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct CodeGeneratorResponseBuilder<'b> {
-    builder: roto_runtime::ProtoBuilder<'b>,
+    builder: crate::runtime::ProtoBuilder<'b>,
     error_written: bool,
     supported_features_written: bool,
     minimum_edition_written: bool,
@@ -502,7 +502,7 @@ pub struct CodeGeneratorResponseBuilder<'b> {
 impl<'b> CodeGeneratorResponseBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> CodeGeneratorResponseBuilder<'_> {
         CodeGeneratorResponseBuilder {
-            builder: roto_runtime::ProtoBuilder::new(buf),
+            builder: crate::runtime::ProtoBuilder::new(buf),
             error_written: false,
             supported_features_written: false,
             minimum_edition_written: false,
@@ -511,37 +511,37 @@ impl<'b> CodeGeneratorResponseBuilder<'b> {
         }
     }
 
-    pub fn error(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn error(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.error_written = true;
         Ok(self)
     }
 
-    pub fn supported_features(mut self, value: u64) -> roto_runtime::Result<Self> {
+    pub fn supported_features(mut self, value: u64) -> crate::runtime::Result<Self> {
         self.builder.write_varint(2, value)?;
         self.supported_features_written = true;
         Ok(self)
     }
 
-    pub fn minimum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
+    pub fn minimum_edition(mut self, value: i32) -> crate::runtime::Result<Self> {
         self.builder.write_int32(3, value)?;
         self.minimum_edition_written = true;
         Ok(self)
     }
 
-    pub fn maximum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
+    pub fn maximum_edition(mut self, value: i32) -> crate::runtime::Result<Self> {
         self.builder.write_int32(4, value)?;
         self.maximum_edition_written = true;
         Ok(self)
     }
 
-    pub fn file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+    pub fn file(mut self, value: &[u8]) -> crate::runtime::Result<Self> {
         self.builder.write_bytes(15, value)?;
         self.file_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &CodeGeneratorResponse<'_>) -> roto_runtime::Result<Self> {
+    pub fn with(mut self, msg: &CodeGeneratorResponse<'_>) -> crate::runtime::Result<Self> {
         for item in msg.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
@@ -559,7 +559,7 @@ impl<'b> CodeGeneratorResponseBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+    pub fn finish(self) -> crate::runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
@@ -568,15 +568,15 @@ pub struct OwnedCodeGeneratorResponse {
     pub data: bytes::Bytes,
 }
 
-impl roto_runtime::RotoOwned for OwnedCodeGeneratorResponse {
+impl crate::runtime::RotoOwned for OwnedCodeGeneratorResponse {
     type Reader<'a> = CodeGeneratorResponse<'a>;
     fn reader(&self) -> CodeGeneratorResponse<'_> {
         CodeGeneratorResponse::new(&self.data).expect("failed to create reader")
     }
 }
 
-impl roto_runtime::RotoMessage for OwnedCodeGeneratorResponse {
-    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+impl crate::runtime::RotoMessage for OwnedCodeGeneratorResponse {
+    fn decode(buf: bytes::Bytes) -> crate::runtime::Result<Self> {
         Ok(OwnedCodeGeneratorResponse { data: buf })
     }
 
@@ -606,7 +606,7 @@ impl Feature {
 }
 
 pub struct File<'a> {
-    accessor: roto_runtime::ProtoAccessor<'a>,
+    accessor: crate::runtime::ProtoAccessor<'a>,
     name_offset: Option<usize>,
     insertion_point_offset: Option<usize>,
     content_offset: Option<usize>,
@@ -614,8 +614,8 @@ pub struct File<'a> {
 }
 
 impl<'a> File<'a> {
-    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
-        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+    pub fn new(data: &'a [u8]) -> crate::runtime::Result<Self> {
+        let accessor = crate::runtime::ProtoAccessor::new(data)?;
         let mut name_offset = None;
         let mut insertion_point_offset = None;
         let mut content_offset = None;
@@ -637,62 +637,62 @@ generated_code_info_offset,
         })
     }
 
-    pub fn name(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.name_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn name(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.name_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn name_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn name_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.name().or(Ok(""))
     }
 
     pub fn has_name(&self) -> bool { self.name_offset.is_some() }
 
-    pub fn insertion_point(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.insertion_point_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn insertion_point(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.insertion_point_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn insertion_point_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn insertion_point_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.insertion_point().or(Ok(""))
     }
 
     pub fn has_insertion_point(&self) -> bool { self.insertion_point_offset.is_some() }
 
-    pub fn content(&self) -> roto_runtime::Result<&'a str> {
-        let offset = self.content_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn content(&self) -> crate::runtime::Result<&'a str> {
+        let offset = self.content_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        str::from_utf8(bytes).map_err(|_| crate::runtime::RotoError::WireFormatViolation)
     }
 
-    pub fn content_or_default(&self) -> roto_runtime::Result<&'a str> {
+    pub fn content_or_default(&self) -> crate::runtime::Result<&'a str> {
         self.content().or(Ok(""))
     }
 
     pub fn has_content(&self) -> bool { self.content_offset.is_some() }
 
-    pub fn generated_code_info(&self) -> roto_runtime::Result<&'a [u8]> {
-        let offset = self.generated_code_info_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+    pub fn generated_code_info(&self) -> crate::runtime::Result<&'a [u8]> {
+        let offset = self.generated_code_info_offset.ok_or(crate::runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
         Ok(bytes)
     }
 
-    pub fn generated_code_info_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+    pub fn generated_code_info_or_default(&self) -> crate::runtime::Result<&'a [u8]> {
         self.generated_code_info().or(Ok(&[]))
     }
 
     pub fn has_generated_code_info(&self) -> bool { self.generated_code_info_offset.is_some() }
 
-    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+    pub fn raw_fields(&self) -> crate::runtime::RawFieldIterator<'a> {
         self.accessor.raw_fields()
     }
 
 }
 
 pub struct FileBuilder<'b> {
-    builder: roto_runtime::ProtoBuilder<'b>,
+    builder: crate::runtime::ProtoBuilder<'b>,
     name_written: bool,
     insertion_point_written: bool,
     content_written: bool,
@@ -702,7 +702,7 @@ pub struct FileBuilder<'b> {
 impl<'b> FileBuilder<'b> {
     pub fn builder(buf: &mut [u8]) -> FileBuilder<'_> {
         FileBuilder {
-            builder: roto_runtime::ProtoBuilder::new(buf),
+            builder: crate::runtime::ProtoBuilder::new(buf),
             name_written: false,
             insertion_point_written: false,
             content_written: false,
@@ -710,31 +710,31 @@ impl<'b> FileBuilder<'b> {
         }
     }
 
-    pub fn name(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn name(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(1, value)?;
         self.name_written = true;
         Ok(self)
     }
 
-    pub fn insertion_point(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn insertion_point(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(2, value)?;
         self.insertion_point_written = true;
         Ok(self)
     }
 
-    pub fn content(mut self, value: &str) -> roto_runtime::Result<Self> {
+    pub fn content(mut self, value: &str) -> crate::runtime::Result<Self> {
         self.builder.write_string(15, value)?;
         self.content_written = true;
         Ok(self)
     }
 
-    pub fn generated_code_info(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+    pub fn generated_code_info(mut self, value: &[u8]) -> crate::runtime::Result<Self> {
         self.builder.write_bytes(16, value)?;
         self.generated_code_info_written = true;
         Ok(self)
     }
 
-    pub fn with(mut self, msg: &File<'_>) -> roto_runtime::Result<Self> {
+    pub fn with(mut self, msg: &File<'_>) -> crate::runtime::Result<Self> {
         for item in msg.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
@@ -751,7 +751,7 @@ impl<'b> FileBuilder<'b> {
         Ok(self)
     }
 
-    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+    pub fn finish(self) -> crate::runtime::Result<&'b mut [u8]> {
         self.builder.finish()
     }
 }
@@ -760,15 +760,15 @@ pub struct OwnedFile {
     pub data: bytes::Bytes,
 }
 
-impl roto_runtime::RotoOwned for OwnedFile {
+impl crate::runtime::RotoOwned for OwnedFile {
     type Reader<'a> = File<'a>;
     fn reader(&self) -> File<'_> {
         File::new(&self.data).expect("failed to create reader")
     }
 }
 
-impl roto_runtime::RotoMessage for OwnedFile {
-    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+impl crate::runtime::RotoMessage for OwnedFile {
+    fn decode(buf: bytes::Bytes) -> crate::runtime::Result<Self> {
         Ok(OwnedFile { data: buf })
     }
 

codegen/src/lib.rs

@@ -1,2 +1,4 @@
 pub mod generator;
 pub mod google;
+pub mod runtime;
+

codegen/src/runtime/mod.rs

@@ -0,0 +1,921 @@
+
+
+
+
+
+
+use core::fmt;
+use bytes::BufMut;
+
+pub struct MapFieldIterator<'a> {
+    inner: RepeatedFieldIterator<'a>,
+}
+
+impl<'a> MapFieldIterator<'a> {
+    pub fn new(inner: RepeatedFieldIterator<'a>) -> Self {
+        Self { inner }
+    }
+}
+
+impl<'a> Iterator for MapFieldIterator<'a> {
+    type Item = Result<(&'a [u8], &'a [u8])>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.inner.next() {
+            Some(Ok((value, _wire_type))) => {
+                let accessor = ProtoAccessor::new(value).ok()?;
+                let (key_bytes, _) = accessor.get_value(1).ok()?;
+                let (val_bytes, _) = accessor.get_value(2).ok()?;
+                Some(Ok((key_bytes, val_bytes)))
+            }
+            Some(Err(e)) => Some(Err(e)),
+            None => None,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub enum RotoError {
+    UnexpectedEndOfBuffer,
+    InvalidVarint,
+    InvalidWireType(u8),
+    BufferOverflow,
+    FieldNotFound,
+    WireFormatViolation,
+}
+
+impl fmt::Display for RotoError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            RotoError::UnexpectedEndOfBuffer => write!(f, "Unexpected end of buffer"),
+            RotoError::InvalidVarint => write!(f, "Invalid varint encoding"),
+            RotoError::InvalidWireType(t) => write!(f, "Invalid wire type: {t}"),
+            RotoError::BufferOverflow => write!(f, "Buffer overflow during write"),
+            RotoError::FieldNotFound => write!(f, "Requested field not found in message"),
+            RotoError::WireFormatViolation => write!(f, "Wire format violation"),
+        }
+    }
+}
+
+impl std::error::Error for RotoError {}
+
+pub type Result<T> = core::result::Result<T, RotoError>;
+
+pub trait RotoOwned {
+    type Reader<'a> where Self: 'a;
+    fn reader(&self) -> Self::Reader<'_>;
+}
+
+pub trait RotoMessage: Sized {
+    fn decode(buf: bytes::Bytes) -> Result<Self>;
+    fn bytes(&self) -> bytes::Bytes;
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum WireType {
+    Varint = 0,
+    Fixed64 = 1,
+    LengthDelimited = 2,
+    StartGroup = 3, // Deprecated
+    EndGroup = 4,   // Deprecated
+    Fixed32 = 5,
+}
+
+impl WireType {
+    pub fn from_u8(value: u8) -> Result<Self> {
+        match value {
+            0 => Ok(WireType::Varint),
+            1 => Ok(WireType::Fixed64),
+            2 => Ok(WireType::LengthDelimited),
+            3 => Ok(WireType::StartGroup),
+            4 => Ok(WireType::EndGroup),
+            5 => Ok(WireType::Fixed32),
+            _ => Err(RotoError::InvalidWireType(value)),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Tag {
+    pub field_number: u32,
+    pub wire_type: WireType,
+}
+
+impl Tag {
+    /// Decodes a tag from the buffer, returning the tag and the number of bytes read.
+    pub fn decode(data: &[u8]) -> Result<(Self, usize)> {
+        let (val, len) = read_varint(data)?;
+        let wire_type_raw = (val & 0x7) as u8;
+        let field_number = (val >> 3) as u32;
+
+        Ok((
+            Tag {
+                field_number,
+                wire_type: WireType::from_u8(wire_type_raw)?,
+            },
+            len,
+        ))
+    }
+
+    /// Encodes a tag into the provided buffer.
+    pub fn encode(field_number: u32, wire_type: WireType, buf: &mut [u8]) -> Result<usize> {
+        let val = ((field_number as u64) << 3) | (wire_type as u64);
+        write_varint(val, buf)
+    }
+}
+
+/// Reads a varint from the start of the buffer.
+pub fn read_varint(data: &[u8]) -> Result<(u64, usize)> {
+    let mut result = 0u64;
+    let mut shift = 0;
+    let mut bytes_read = 0;
+
+    for &byte in data {
+        bytes_read += 1;
+        if bytes_read > 10 {
+            return Err(RotoError::InvalidVarint);
+        }
+
+        let value = (byte & 0x7F) as u64;
+        if shift >= 64 {
+            return Err(RotoError::InvalidVarint);
+        }
+        result |= value << shift;
+        shift += 7;
+
+        if (byte & 0x80) == 0 {
+            return Ok((result, bytes_read));
+        }
+    }
+
+    Err(RotoError::UnexpectedEndOfBuffer)
+}
+
+/// Writes a varint into the buffer.
+pub fn write_varint(mut value: u64, buf: &mut [u8]) -> Result<usize> {
+    let mut bytes_written = 0;
+    while value >= 0x80 {
+        if bytes_written >= buf.len() {
+            return Err(RotoError::BufferOverflow);
+        }
+        buf[bytes_written] = (value as u8 & 0x7F) | 0x80;
+        value >>= 7;
+        bytes_written += 1;
+    }
+
+    if bytes_written >= buf.len() {
+        return Err(RotoError::BufferOverflow);
+    }
+    buf[bytes_written] = value as u8;
+    bytes_written += 1;
+    Ok(bytes_written)
+}
+
+/// Returns the number of bytes that should be skipped for a given wire type and the current data slice.
+pub fn skip_value(wire_type: WireType, data: &[u8]) -> Result<usize> {
+    match wire_type {
+        WireType::Varint => {
+            let (_, len) = read_varint(data)?;
+            Ok(len)
+        }
+        WireType::Fixed64 => {
+            if data.len() < 8 {
+                return Err(RotoError::UnexpectedEndOfBuffer);
+            }
+            Ok(8)
+        }
+        WireType::LengthDelimited => {
+            let (len, varint_len) = read_varint(data)?;
+            let total_len = varint_len + len as usize;
+            if data.len() < total_len {
+                return Err(RotoError::UnexpectedEndOfBuffer);
+            }
+            Ok(total_len)
+        }
+        WireType::Fixed32 => {
+            if data.len() < 4 {
+                return Err(RotoError::UnexpectedEndOfBuffer);
+            }
+            Ok(4)
+        }
+        WireType::StartGroup | WireType::EndGroup => {
+            // These are deprecated and not fully supported in this runtime.
+            Err(RotoError::WireFormatViolation)
+        }
+    }
+}
+
+pub struct ProtoAccessor<'a> {
+    data: &'a [u8],
+}
+
+impl<'a> ProtoAccessor<'a> {
+    pub fn new(data: &'a [u8]) -> Result<Self> {
+        Ok(Self { data })
+    }
+
+    /// Returns an iterator over all fields in the message.
+    pub fn fields(&self) -> FieldIterator<'a> {
+        FieldIterator {
+            data: self.data,
+            cursor: 0,
+        }
+    }
+
+    /// Returns the value and wire type of the last occurrence of the specified field.
+    pub fn get_value(&self, field_number: u32) -> Result<(&'a [u8], WireType)> {
+        let mut last_value = None;
+        for item in self.fields() {
+            let (_offset, tag, value) = item?;
+            if tag.field_number == field_number {
+                last_value = Some((value, tag.wire_type));
+            }
+        }
+        last_value.ok_or(RotoError::FieldNotFound)
+    }
+
+    /// Returns an iterator that scans the entire buffer for all occurrences of the specified field.
+    pub fn iter_repeated(&self, field_number: u32) -> RepeatedFieldIterator<'a> {
+        RepeatedFieldIterator::new(self.data, field_number)
+    }
+
+    /// Returns the value and wire type of a field at a specific offset.
+    pub fn get_value_at(&self, offset: usize) -> Result<(&'a [u8], WireType)> {
+        if offset >= self.data.len() {
+            return Err(RotoError::UnexpectedEndOfBuffer);
+        }
+        let (tag, tag_len) = Tag::decode(&self.data[offset..])?;
+        let cursor_after_tag = offset + tag_len;
+        if cursor_after_tag > self.data.len() {
+            return Err(RotoError::UnexpectedEndOfBuffer);
+        }
+        let value_len = skip_value(tag.wire_type, &self.data[cursor_after_tag..])?;
+        let (value_offset, actual_value_len) = match tag.wire_type {
+            WireType::LengthDelimited => {
+                let (_, varint_len) = read_varint(&self.data[cursor_after_tag..])?;
+                (cursor_after_tag + varint_len, value_len - varint_len)
+            }
+            _ => (cursor_after_tag, value_len),
+        };
+        Ok((
+            &self.data[value_offset..value_offset + actual_value_len],
+            tag.wire_type,
+        ))
+    }
+
+    /// Returns an iterator that scans a specific range of the buffer for all occurrences of the specified field.
+    pub fn iter_repeated_range(
+        &self,
+        field_number: u32,
+        start: usize,
+        end: usize,
+    ) -> RepeatedFieldIterator<'a> {
+        RepeatedFieldIterator::new_range(self.data, field_number, start, end)
+    }
+
+    /// Returns an iterator that yields `(field_number, raw_bytes)` for every
+    /// field in the message.  `raw_bytes` is the complete on-wire encoding
+    /// (tag + value, including any length prefix), suitable for passing
+    /// directly to `ProtoBuilder::write_raw`.
+    pub fn raw_fields(&self) -> RawFieldIterator<'a> {
+        RawFieldIterator {
+            data: self.data,
+            cursor: 0,
+        }
+    }
+}
+
+pub struct FieldIterator<'a> {
+    data: &'a [u8],
+    cursor: usize,
+}
+
+impl<'a> Iterator for FieldIterator<'a> {
+    type Item = Result<(usize, Tag, &'a [u8])>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.cursor >= self.data.len() {
+            return None;
+        }
+
+        let (tag, tag_len) = match Tag::decode(&self.data[self.cursor..]) {
+            Ok(t) => t,
+            Err(e) => {
+                self.cursor = self.data.len();
+                return Some(Err(e));
+            }
+        };
+
+        let cursor_after_tag = self.cursor + tag_len;
+        if cursor_after_tag > self.data.len() {
+            self.cursor = self.data.len();
+            return Some(Err(RotoError::UnexpectedEndOfBuffer));
+        }
+
+        let value_len = match skip_value(tag.wire_type, &self.data[cursor_after_tag..]) {
+            Ok(l) => l,
+            Err(e) => {
+                self.cursor = self.data.len();
+                return Some(Err(e));
+            }
+        };
+
+        let (value_offset, actual_value_len) = match tag.wire_type {
+            WireType::LengthDelimited => {
+                let (_, varint_len) = match read_varint(&self.data[cursor_after_tag..]) {
+                    Ok(v) => v,
+                    Err(e) => {
+                        self.cursor = self.data.len();
+                        return Some(Err(e));
+                    }
+                };
+                (cursor_after_tag + varint_len, value_len - varint_len)
+            }
+            _ => (cursor_after_tag, value_len),
+        };
+
+        self.cursor = cursor_after_tag + value_len;
+
+        Some(Ok((
+            self.cursor - tag_len - value_len,
+            tag,
+            &self.data[value_offset..value_offset + actual_value_len],
+        )))
+    }
+}
+
+pub struct RepeatedFieldIterator<'a> {
+    iterator: FieldIterator<'a>,
+    field_number: u32,
+    end_offset: Option<usize>,
+}
+
+impl<'a> RepeatedFieldIterator<'a> {
+    pub fn new(data: &'a [u8], field_number: u32) -> Self {
+        Self {
+            iterator: FieldIterator { data, cursor: 0 },
+            field_number,
+            end_offset: None,
+        }
+    }
+
+    pub fn new_range(data: &'a [u8], field_number: u32, start: usize, end: usize) -> Self {
+        Self {
+            iterator: FieldIterator {
+                data,
+                cursor: start,
+            },
+            field_number,
+            end_offset: Some(end),
+        }
+    }
+}
+
+impl<'a> Iterator for RepeatedFieldIterator<'a> {
+    type Item = Result<(&'a [u8], WireType)>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(item) = self.iterator.next() {
+            match item {
+                Ok((offset, tag, value)) if tag.field_number == self.field_number => {
+                    if let Some(end) = self.end_offset {
+                        if offset > end {
+                            return None;
+                        }
+                    }
+                    return Some(Ok((value, tag.wire_type)));
+                }
+                Ok(_) => continue,
+                Err(e) => return Some(Err(e)),
+            }
+        }
+        None
+    }
+}
+
+/// An iterator that yields `(field_number, raw_bytes)` for every field in a
+/// protobuf message, where `raw_bytes` is the complete on-wire encoding of the
+/// field: tag varint + value bytes (including the length prefix for
+/// length-delimited fields).  This is the slice needed by
+/// `ProtoBuilder::write_raw` to copy a field verbatim.
+pub struct RawFieldIterator<'a> {
+    data: &'a [u8],
+    cursor: usize,
+}
+
+impl<'a> Iterator for RawFieldIterator<'a> {
+    type Item = Result<(u32, &'a [u8])>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.cursor >= self.data.len() {
+            return None;
+        }
+        let field_start = self.cursor;
+        let (tag, tag_len) = match Tag::decode(&self.data[self.cursor..]) {
+            Ok(t) => t,
+            Err(e) => {
+                self.cursor = self.data.len();
+                return Some(Err(e));
+            }
+        };
+        let cursor_after_tag = self.cursor + tag_len;
+        if cursor_after_tag > self.data.len() {
+            self.cursor = self.data.len();
+            return Some(Err(RotoError::UnexpectedEndOfBuffer));
+        }
+        let value_len = match skip_value(tag.wire_type, &self.data[cursor_after_tag..]) {
+            Ok(l) => l,
+            Err(e) => {
+                self.cursor = self.data.len();
+                return Some(Err(e));
+            }
+        };
+        self.cursor = cursor_after_tag + value_len;
+        Some(Ok((tag.field_number, &self.data[field_start..self.cursor])))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[cfg(feature = "alloc")]
+    use alloc::{vec, vec::{Vec}};
+
+    #[test]
+    fn test_varint_read_write() {
+        let mut buf = [0u8; 10];
+        let val = 300u64;
+        let len = write_varint(val, &mut buf).unwrap();
+        assert_eq!(len, 2);
+        assert_eq!(&buf[..2], &[0xAC, 0x02]);
+
+        let (read_val, read_len) = read_varint(&buf[..2]).unwrap();
+        assert_eq!(read_val, val);
+        assert_eq!(read_len, 2);
+    }
+
+    #[test]
+    fn test_tag_decode() {
+        // Field 1, WireType Varint: (1 << 3) | 0 = 8
+        let data = [8u8];
+        let (tag, len) = Tag::decode(&data).unwrap();
+        assert_eq!(tag.field_number, 1);
+        assert_eq!(tag.wire_type, WireType::Varint);
+        assert_eq!(len, 1);
+
+        // Field 15, WireType LengthDelimited: (15 << 3) | 2 = 120 | 2 = 122
+        let data2 = [122u8];
+        let (tag2, len2) = Tag::decode(&data2).unwrap();
+        assert_eq!(tag2.field_number, 15);
+        assert_eq!(tag2.wire_type, WireType::LengthDelimited);
+        assert_eq!(len2, 1);
+    }
+
+    #[test]
+    fn test_skip_value() {
+        // Varint: 300 (2 bytes)
+        let data_varint = [0xAC, 0x02];
+        assert_eq!(skip_value(WireType::Varint, &data_varint).unwrap(), 2);
+
+        // Fixed32: 4 bytes
+        let data_fixed32 = [0u8; 4];
+        assert_eq!(skip_value(WireType::Fixed32, &data_fixed32).unwrap(), 4);
+
+        // Length delimited: len=3, data=[1,2,3] (1 byte varint for length + 3 bytes)
+        let data_len = [3, 1, 2, 3];
+        assert_eq!(skip_value(WireType::LengthDelimited, &data_len).unwrap(), 4);
+    }
+
+    #[test]
+    fn test_accessor_basic() {
+        // Field 1 (Varint): 150
+        // Tag: (1 << 3) | 0 = 8. Value: 150 = [150, 1]
+        // Field 2 (LengthDelimited): "hi"
+        // Tag: (2 << 3) | 2 = 18. Length: 2. Value: [104, 105]
+        let data = [8, 150, 1, 18, 2, 104, 105];
+        let acc = ProtoAccessor::new(&data).unwrap();
+
+        let (val1, type1) = acc.get_value(1).unwrap();
+        assert_eq!(type1, WireType::Varint);
+        assert_eq!(val1, &[150, 1]);
+
+        let (val2, type2) = acc.get_value(2).unwrap();
+        assert_eq!(type2, WireType::LengthDelimited);
+        assert_eq!(val2, &[104, 105]);
+    }
+
+    #[test]
+    fn test_accessor_repeated() {
+        // Field 1: 10, Field 1: 20, Field 1: 30
+        // Tags: 8, 8, 8. Values: 10, 20, 30
+        let data = [8, 10, 8, 20, 8, 30];
+        let acc = ProtoAccessor::new(&data).unwrap();
+
+        // Last value should be 30
+        let (val, _) = acc.get_value(1).unwrap();
+        assert_eq!(val, &[30]);
+
+        // Iteration should find all three
+        let results: Vec<_> = acc.iter_repeated(1).collect();
+        assert_eq!(results.len(), 3);
+        assert_eq!(results[0].as_ref().unwrap().0, &[10]);
+        assert_eq!(results[1].as_ref().unwrap().0, &[20]);
+        assert_eq!(results[2].as_ref().unwrap().0, &[30]);
+    }
+
+    #[test]
+    fn test_builder_basic() {
+        let mut buf = [0u8; 1024];
+        let mut builder = ProtoBuilder::new(&mut buf);
+        builder.write_string(1, "hello").unwrap();
+        builder.write_int32(2, 42).unwrap();
+        let data = builder.finish().unwrap();
+
+        let acc = ProtoAccessor::new(data).unwrap();
+        let (val1, _) = acc.get_value(1).unwrap();
+        assert_eq!(val1, "hello".as_bytes());
+        let (val2, _) = acc.get_value(2).unwrap();
+        assert_eq!(val2, &[42]);
+    }
+
+    #[test]
+    fn test_builder_overflow() {
+        let mut buf = [0u8; 2];
+        let mut builder = ProtoBuilder::new(&mut buf);
+        let result = builder.write_string(1, "too long");
+        assert_eq!(result, Err(RotoError::BufferOverflow));
+    }
+
+    #[test]
+    fn test_raw_field_iterator_yields_correct_bytes() {
+        // Build: field 1 = string "hi", field 2 = int32 42
+        let mut buf = [0u8; 64];
+        let mut builder = ProtoBuilder::new(&mut buf);
+        builder.write_string(1, "hi").unwrap();
+        builder.write_int32(2, 42).unwrap();
+        let data = builder.finish().unwrap().to_vec();
+
+        let acc = ProtoAccessor::new(&data).unwrap();
+        let raw: Vec<_> = acc.raw_fields().collect();
+        assert_eq!(raw.len(), 2);
+
+        // Field 1: tag = (1 << 3) | 2 = 0x0A, len varint = 0x02, "hi" = [0x68, 0x69]
+        let (fn1, bytes1) = raw[0].as_ref().unwrap();
+        assert_eq!(*fn1, 1);
+        assert_eq!(*bytes1, [0x0A, 0x02, b'h', b'i']);
+
+        // Field 2: tag = (2 << 3) | 0 = 0x10, varint 42 = 0x2A
+        let (fn2, bytes2) = raw[1].as_ref().unwrap();
+        assert_eq!(*fn2, 2);
+        assert_eq!(*bytes2, [0x10, 0x2A]);
+    }
+
+    #[test]
+    fn test_write_raw_copies_field_verbatim() {
+        // Build source: field 1 = string "hello", field 2 = int32 99
+        let mut src_buf = [0u8; 64];
+        let mut src_builder = ProtoBuilder::new(&mut src_buf);
+        src_builder.write_string(1, "hello").unwrap();
+        src_builder.write_int32(2, 99).unwrap();
+        let src_data = src_builder.finish().unwrap().to_vec();
+
+        // Copy every raw field verbatim into a new buffer
+        let src_acc = ProtoAccessor::new(&src_data).unwrap();
+        let mut dst_buf = [0u8; 64];
+        let mut dst_builder = ProtoBuilder::new(&mut dst_buf);
+        for item in src_acc.raw_fields() {
+            let (_, raw_bytes) = item.unwrap();
+            dst_builder.write_raw(raw_bytes).unwrap();
+        }
+        let dst_data = dst_builder.finish().unwrap();
+
+        // The copy must be byte-identical to the source
+        assert_eq!(dst_data, src_data.as_slice());
+    }
+
+    #[test]
+    fn test_with_pattern_copies_unseen_fields() {
+        // Build an existing source message with 3 fields
+        let mut src_buf = [0u8; 128];
+        let mut src_builder = ProtoBuilder::new(&mut src_buf);
+        src_builder.write_string(1, "original").unwrap();
+        src_builder.write_int32(2, 99).unwrap();
+        src_builder.write_varint(3, 1u64).unwrap(); // bool
+        let src_data = src_builder.finish().unwrap().to_vec();
+        let src_acc = ProtoAccessor::new(&src_data).unwrap();
+
+        // Simulate what a generated `with` method does:
+        // field 1 was explicitly written; fields 2 and 3 come from source.
+        let field1_written = true;
+        let field2_written = false;
+        let field3_written = false;
+
+        let mut dst_buf = [0u8; 128];
+        let mut dst_builder = ProtoBuilder::new(&mut dst_buf);
+        dst_builder.write_string(1, "updated").unwrap();
+
+        for item in src_acc.raw_fields() {
+            let (field_number, raw_bytes) = item.unwrap();
+            let is_written = match field_number {
+                1 => field1_written,
+                2 => field2_written,
+                3 => field3_written,
+                _ => false,
+            };
+            if !is_written {
+                dst_builder.write_raw(raw_bytes).unwrap();
+            }
+        }
+        let dst_data = dst_builder.finish().unwrap();
+        let dst_acc = ProtoAccessor::new(dst_data).unwrap();
+
+        // Field 1: overridden value
+        let (val1, _) = dst_acc.get_value(1).unwrap();
+        assert_eq!(val1, b"updated");
+
+        // Field 2: copied from source
+        let (val2, _) = dst_acc.get_value(2).unwrap();
+        let (v2, _) = read_varint(val2).unwrap();
+        assert_eq!(v2 as i32, 99);
+
+        // Field 3: copied from source
+        let (val3, _) = dst_acc.get_value(3).unwrap();
+        let (v3, _) = read_varint(val3).unwrap();
+        assert_eq!(v3, 1u64);
+    }
+
+    #[test]
+    fn test_protoc_binary_compatibility() {
+        let data = include_bytes!("../data/test_data.pb");
+        let acc = ProtoAccessor::new(data).unwrap();
+
+        // 1. Varints (Integers, Booleans, Enums)
+        let (val_i32, type_i32) = acc.get_value(3).expect("i32_val not found");
+        assert_eq!(type_i32, WireType::Varint);
+        let (v, _) = read_varint(val_i32).unwrap();
+        assert_eq!(v, 42);
+
+        let (val_b, type_b) = acc.get_value(13).expect("b_val not found");
+        assert_eq!(type_b, WireType::Varint);
+        let (v_b, _) = read_varint(val_b).unwrap();
+        assert_eq!(v_b, 1); // true
+
+        let (val_status, type_status) = acc.get_value(16).expect("status not found");
+        assert_eq!(type_status, WireType::Varint);
+        let (v_s, _) = read_varint(val_status).unwrap();
+        assert_eq!(v_s, 1); // ACTIVE
+
+        // 2. Length Delimited (Strings, Bytes)
+        let (val_s, type_s) = acc.get_value(14).expect("s_val not found");
+        assert_eq!(type_s, WireType::LengthDelimited);
+        assert_eq!(val_s, "Hello Roto!".as_bytes());
+
+        // 3. Fixed Width (Floats)
+        let (val_f, type_f) = acc.get_value(2).expect("f_val not found");
+        assert_eq!(type_f, WireType::Fixed32);
+        let f_val = f32::from_le_bytes(val_f.try_into().expect("Expected 4 bytes for f32"));
+        assert!((f_val - 2.71828).abs() < 1e-5);
+
+        // 4. Repeated Fields
+        // Note: primitive repeated fields are packed in proto3, so we iterate over the blob
+        let mut i32_vals = Vec::new();
+        for item in acc.iter_repeated(17) {
+            let (blob, _) = item.expect("Failed to decode repeated i32");
+            let mut cursor = 0;
+            while cursor < blob.len() {
+                let (v, len) = read_varint(&blob[cursor..]).unwrap();
+                i32_vals.push(v);
+                cursor += len;
+            }
+        }
+        assert_eq!(i32_vals, vec![1, 2, 3, 4, 5]);
+
+        let repeated_strings: Vec<_> = acc
+            .iter_repeated(18)
+            .map(|r| {
+                let (val, _) = r.expect("Failed to decode repeated string");
+                core::str::from_utf8(val).expect("Invalid utf8")
+            })
+            .collect();
+        assert_eq!(repeated_strings, vec!["one", "two", "three"]);
+
+        let repeated_nested: Vec<_> = acc
+            .iter_repeated(19)
+            .map(|r| {
+                let (val, _) = r.expect("Failed to decode repeated nested");
+                let nested_acc = ProtoAccessor::new(val).unwrap();
+                let (id_val, _) = nested_acc.get_value(1).expect("Nested id not found");
+                let (id, _) = read_varint(id_val).unwrap();
+                id
+            })
+            .collect();
+        assert_eq!(repeated_nested, vec![101, 102]);
+
+        // 5. Single Nested Message
+        let (val_nested, type_nested) = acc.get_value(20).expect("single_nested not found");
+        assert_eq!(type_nested, WireType::LengthDelimited);
+        let nested_acc = ProtoAccessor::new(val_nested).unwrap();
+        let (val_id, _) = nested_acc.get_value(1).expect("Nested id not found");
+        let (id, _) = read_varint(val_id).unwrap();
+        assert_eq!(id, 200);
+
+        // Validate that fields appear in the expected relative order
+        let field_numbers: Vec<u32> = acc
+            .fields()
+            .map(|r| r.expect("Failed to decode field").1.field_number)
+            .collect();
+
+        let essential_fields = [1, 2, 3, 14, 16, 20];
+        let mut last_field = 0;
+        let mut found_count = 0;
+        for &f in &field_numbers {
+            if essential_fields.contains(&f) {
+                assert!(
+                    f >= last_field,
+                    "Fields appeared out of order: {} came after {}",
+                    f,
+                    last_field
+                );
+                last_field = f;
+                found_count += 1;
+            }
+        }
+        assert_eq!(found_count, essential_fields.len());
+    }
+}
+
+pub struct ProtoBuilder<'a> {
+    buf: &'a mut [u8],
+    pos: usize,
+}
+
+impl<'a> ProtoBuilder<'a> {
+    pub fn new(buf: &'a mut [u8]) -> Self {
+        Self { buf, pos: 0 }
+    }
+
+    fn write_tag(&mut self, field_number: u32, wire_type: WireType) -> Result<()> {
+        let mut temp = [0u8; 10];
+        let len = Tag::encode(field_number, wire_type, &mut temp)?;
+        self.append_bytes(&temp[..len])
+    }
+
+    fn append_bytes(&mut self, bytes: &[u8]) -> Result<()> {
+        if self.pos + bytes.len() > self.buf.len() {
+            return Err(RotoError::BufferOverflow);
+        }
+        self.buf[self.pos..self.pos + bytes.len()].copy_from_slice(bytes);
+        self.pos += bytes.len();
+        Ok(())
+    }
+
+    pub fn write_varint(&mut self, field_number: u32, value: u64) -> Result<()> {
+        self.write_tag(field_number, WireType::Varint)?;
+        let mut temp = [0u8; 10];
+        let len = write_varint(value, &mut temp)?;
+        self.append_bytes(&temp[..len])
+    }
+
+    pub fn write_int32(&mut self, field_number: u32, value: i32) -> Result<()> {
+        self.write_varint(field_number, value as u64)
+    }
+
+    pub fn write_string(&mut self, field_number: u32, value: &str) -> Result<()> {
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+        let bytes = value.as_bytes();
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(bytes.len() as u64, &mut len_buf)?;
+        self.append_bytes(&len_buf[..len_len])?;
+        self.append_bytes(bytes)
+    }
+
+    pub fn write_fixed32(&mut self, field_number: u32, value: u32) -> Result<()> {
+        self.write_tag(field_number, WireType::Fixed32)?;
+        self.append_bytes(&value.to_le_bytes())
+    }
+
+    pub fn write_fixed64(&mut self, field_number: u32, value: u64) -> Result<()> {
+        self.write_tag(field_number, WireType::Fixed64)?;
+        self.append_bytes(&value.to_le_bytes())
+    }
+
+    pub fn write_bytes(&mut self, field_number: u32, value: &[u8]) -> Result<()> {
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(value.len() as u64, &mut len_buf)?;
+        self.append_bytes(&len_buf[..len_len])?;
+        self.append_bytes(value)
+    }
+
+    /// Appends a pre-encoded field (tag + value bytes) verbatim into the
+    /// buffer.  Use this together with `ProtoAccessor::raw_fields` to copy
+    /// fields from an existing message into a builder without re-encoding them.
+    pub fn write_raw(&mut self, raw_bytes: &[u8]) -> Result<()> {
+        self.append_bytes(raw_bytes)
+    }
+
+    pub fn write_map_entry(
+        &mut self,
+        field_number: u32,
+        key_encoded: &[u8],
+        value_encoded: &[u8],
+    ) -> Result<()> {
+        let entry_len = key_encoded.len() + value_encoded.len();
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(entry_len as u64, &mut len_buf)?;
+        self.append_bytes(&len_buf[..len_len])?;
+
+        self.append_bytes(key_encoded)?;
+        self.append_bytes(value_encoded)?;
+        Ok(())
+    }
+
+    pub fn finish(self) -> Result<&'a mut [u8]> {
+        Ok(&mut self.buf[..self.pos])
+    }
+}
+
+pub struct BufMutBuilder<'a, B: BufMut> {
+    buf: &'a mut B,
+}
+
+impl<'a, B: BufMut> BufMutBuilder<'a, B> {
+    pub fn new(buf: &'a mut B) -> Self {
+        Self { buf }
+    }
+
+    fn write_tag(&mut self, field_number: u32, wire_type: WireType) -> Result<()> {
+        let mut temp = [0u8; 10];
+        let len = Tag::encode(field_number, wire_type, &mut temp)?;
+        self.buf.put_slice(&temp[..len]);
+        Ok(())
+    }
+
+    pub fn write_varint(&mut self, field_number: u32, value: u64) -> Result<()> {
+        self.write_tag(field_number, WireType::Varint)?;
+        let mut temp = [0u8; 10];
+        let len = write_varint(value, &mut temp)?;
+        self.buf.put_slice(&temp[..len]);
+        Ok(())
+    }
+
+    pub fn write_int32(&mut self, field_number: u32, value: i32) -> Result<()> {
+        self.write_varint(field_number, value as u64)
+    }
+
+    pub fn write_string(&mut self, field_number: u32, value: &str) -> Result<()> {
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+        let bytes = value.as_bytes();
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(bytes.len() as u64, &mut len_buf)?;
+        self.buf.put_slice(&len_buf[..len_len]);
+        self.buf.put_slice(bytes);
+        Ok(())
+    }
+
+    pub fn write_fixed32(&mut self, field_number: u32, value: u32) -> Result<()> {
+        self.write_tag(field_number, WireType::Fixed32)?;
+        self.buf.put_slice(&value.to_le_bytes());
+        Ok(())
+    }
+
+    pub fn write_fixed64(&mut self, field_number: u32, value: u64) -> Result<()> {
+        self.write_tag(field_number, WireType::Fixed64)?;
+        self.buf.put_slice(&value.to_le_bytes());
+        Ok(())
+    }
+
+    pub fn write_bytes(&mut self, field_number: u32, value: &[u8]) -> Result<()> {
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(value.len() as u64, &mut len_buf)?;
+        self.buf.put_slice(&len_buf[..len_len]);
+        self.buf.put_slice(value);
+        Ok(())
+    }
+
+    pub fn write_raw(&mut self, raw_bytes: &[u8]) -> Result<()> {
+        self.buf.put_slice(raw_bytes);
+        Ok(())
+    }
+
+    pub fn write_map_entry(
+        &mut self,
+        field_number: u32,
+        key_encoded: &[u8],
+        value_encoded: &[u8],
+    ) -> Result<()> {
+        let entry_len = key_encoded.len() + value_encoded.len();
+        self.write_tag(field_number, WireType::LengthDelimited)?;
+
+        let mut len_buf = [0u8; 10];
+        let len_len = write_varint(entry_len as u64, &mut len_buf)?;
+        self.buf.put_slice(&len_buf[..len_len]);
+
+        self.buf.put_slice(key_encoded);
+        self.buf.put_slice(value_encoded);
+        Ok(())
+    }
+}

examples/hello_world/proto/hello.rs

@@ -1,22 +1,9 @@
 // @generated by protoc-gen-roto — do not edit
 #[allow(unused_imports)]
-
-use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator};
-use std::str;
+use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};
+use core::str;
+#[cfg(feature = "alloc")]
 use bytes::{Bytes, BytesMut, Buf, BufMut};
-use tonic::{Request, Response, Status};
-use tokio_stream::Stream;
-use std::pin::Pin;
-use std::sync::Arc;
-use std::task::{Context, Poll};
-use std::future::Future;
-use tonic::body::BoxBody;
-use tower::Service;
-use futures_util::StreamExt;
-use http_body_util::BodyExt;
-use http_body::Body;
-use roto_tonic::{BufferPool, StatusBody};
-
 
 pub struct HelloRequest<'a> {
     accessor: roto_runtime::ProtoAccessor<'a>,
@@ -41,7 +28,7 @@ name_offset,
     pub fn name(&self) -> roto_runtime::Result<&'a str> {
         let offset = self.name_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
     pub fn name_or_default(&self) -> roto_runtime::Result<&'a str> {
@@ -76,7 +63,7 @@ impl<'b> HelloRequestBuilder<'b> {
     }
 
     pub fn with(mut self, msg: &HelloRequest<'_>) -> roto_runtime::Result<Self> {
-        for item in msg.raw_fields() {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.name_written,
@@ -94,10 +81,12 @@ impl<'b> HelloRequestBuilder<'b> {
     }
 }
 
+#[cfg(feature = "alloc")]
 pub struct OwnedHelloRequest {
     pub data: bytes::Bytes,
 }
 
+#[cfg(feature = "alloc")]
 impl roto_runtime::RotoOwned for OwnedHelloRequest {
     type Reader<'a> = HelloRequest<'a>;
     fn reader(&self) -> HelloRequest<'_> {
@@ -105,6 +94,7 @@ impl roto_runtime::RotoOwned for OwnedHelloRequest {
     }
 }
 
+#[cfg(feature = "alloc")]
 impl roto_runtime::RotoMessage for OwnedHelloRequest {
     fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
         Ok(OwnedHelloRequest { data: buf })
@@ -138,7 +128,7 @@ message_offset,
     pub fn message(&self) -> roto_runtime::Result<&'a str> {
         let offset = self.message_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
         let (bytes, _) = self.accessor.get_value_at(offset)?;
-        str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
     }
 
     pub fn message_or_default(&self) -> roto_runtime::Result<&'a str> {
@@ -173,7 +163,7 @@ impl<'b> HelloResponseBuilder<'b> {
     }
 
     pub fn with(mut self, msg: &HelloResponse<'_>) -> roto_runtime::Result<Self> {
-        for item in msg.raw_fields() {
+        for item in msg.accessor.raw_fields() {
             let (field_number, raw_bytes) = item?;
             let is_written = match field_number {
                 1 => self.message_written,
@@ -191,10 +181,12 @@ impl<'b> HelloResponseBuilder<'b> {
     }
 }
 
+#[cfg(feature = "alloc")]
 pub struct OwnedHelloResponse {
     pub data: bytes::Bytes,
 }
 
+#[cfg(feature = "alloc")]
 impl roto_runtime::RotoOwned for OwnedHelloResponse {
     type Reader<'a> = HelloResponse<'a>;
     fn reader(&self) -> HelloResponse<'_> {
@@ -202,6 +194,7 @@ impl roto_runtime::RotoOwned for OwnedHelloResponse {
     }
 }
 
+#[cfg(feature = "alloc")]
 impl roto_runtime::RotoMessage for OwnedHelloResponse {
     fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
         Ok(OwnedHelloResponse { data: buf })
@@ -212,32 +205,65 @@ impl roto_runtime::RotoMessage for OwnedHelloResponse {
     }
 }
 
-#[tonic::async_trait]
+
+
+#[cfg(feature = "alloc")]
+use tonic::{Request, Response, Status};
+#[cfg(feature = "alloc")]
+use tokio_stream::Stream;
+#[cfg(feature = "alloc")]
+use std::pin::Pin;
+#[cfg(feature = "alloc")]
+use std::sync::Arc;
+#[cfg(feature = "alloc")]
+use std::task::{Context, Poll};
+#[cfg(feature = "alloc")]
+use std::future::Future;
+#[cfg(feature = "alloc")]
+use tonic::body::BoxBody;
+#[cfg(feature = "alloc")]
+use tower::Service;
+#[cfg(feature = "alloc")]
+use futures_util::StreamExt;
+#[cfg(feature = "alloc")]
+use http_body_util::BodyExt;
+#[cfg(feature = "alloc")]
+use http_body::Body;
+#[cfg(feature = "alloc")]
+use crate::{BufferPool, StatusBody};
+
+#[cfg(feature = "alloc")]
+#[async_trait::async_trait]
 pub trait HelloWorldService: Send + Sync + 'static {
     async fn hello_world(&self, request: Request<OwnedHelloRequest>) -> std::result::Result<Response<OwnedHelloResponse>, Status>;
 }
 
+#[cfg(feature = "alloc")]
+#[derive(Clone)]
 pub struct HelloWorldServiceServer {
     inner: Arc<dyn HelloWorldService>,
     pool: Arc<BufferPool>,
 }
 
+#[cfg(feature = "alloc")]
 impl HelloWorldServiceServer {
     pub fn new(inner: Arc<dyn HelloWorldService>, pool: Arc<BufferPool>) -> Self {
         Self { inner, pool }
     }
 }
 
+#[cfg(feature = "alloc")]
 impl tonic::server::NamedService for HelloWorldServiceServer {
-    const NAME: &'static str = "HelloWorldService";
+    const NAME: &'static str = "hello.HelloWorldService";
 }
 
+#[cfg(feature = "alloc")]
 impl Service<http::Request<BoxBody>> for HelloWorldServiceServer {
     type Response = http::Response<BoxBody>;
     type Error = std::convert::Infallible;
-    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
+    type Future = Pin<Box<dyn Future<Output = std::result::Result<Self::Response, Self::Error>> + Send>>;
 
-    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<std::result::Result<(), Self::Error>> {
         Poll::Ready(Ok(()))
     }
 
@@ -245,13 +271,12 @@ impl Service<http::Request<BoxBody>> for HelloWorldServiceServer {
         let inner = self.inner.clone();
         let pool = self.pool.clone();
         Box::pin(async move {
+            let path = req.uri().path().to_string();
             let body = req.into_body();
             let mut buf = pool.get();
             let mut stream = body;
             while let Some(frame_result) = stream.frame().await {
-                let frame = frame_result.map_err(|e| {
-                    panic!("Body frame error: {}", e);
-                })?;
+                let frame = frame_result.expect("Body frame error");
                 if let Some(data) = frame.data_ref() {
                     buf.put(data.clone());
                 }
@@ -261,30 +286,29 @@ impl Service<http::Request<BoxBody>> for HelloWorldServiceServer {
             let bytes_vec = buf.split_to(total_len).freeze();
             pool.put(buf);
             if bytes_vec.len() < 5 {
-                let res_body = BoxBody::new(StatusBody(Some(Bytes::from_static(&[0, 0, 0, 0, 0]))));
+                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
                 return Ok(http::Response::builder().status(200).body(res_body).unwrap());
             }
 
             let payload = bytes_vec.slice(5..);
-            let path = req.uri().path();
             let mut routed = false;
 
-            if path == "/HelloWorldService/hello_world" {
+            if path == "/hello.HelloWorldService/HelloWorld" {
                 let request_msg = match OwnedHelloRequest::decode(payload) {
                     Ok(msg) => msg,
                     Err(e) => {
-                        let res_body = BoxBody::new(StatusBody(Some(Bytes::from_static(&[0, 0, 0, 0, 0]))));
+                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
                         return Ok(http::Response::builder().status(200).body(res_body).unwrap());
                     }
-                }};
+                };
 
                 let response = match inner.hello_world(Request::new(request_msg)).await {
                     Ok(res) => res,
                     Err(e) => {
-                        let res_body = BoxBody::new(StatusBody(Some(Bytes::from_static(&[0, 0, 0, 0, 0]))));
+                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
                         return Ok(http::Response::builder().status(200).body(res_body).unwrap());
                     }
-                }};
+                };
 
                 let response_msg = response.into_inner();
                 let response_bytes = response_msg.bytes();
@@ -296,15 +320,15 @@ impl Service<http::Request<BoxBody>> for HelloWorldServiceServer {
                 let frame_len = res_buf.len();
                 let frame = res_buf.split_to(frame_len).freeze();
                 pool.put(res_buf);
-                let res_body = BoxBody::new(StatusBody(Some(frame)));
+                let res_body = BoxBody::new(StatusBody::new(Some(frame), 0));
                 routed = true;
                 return Ok(http::Response::builder().status(200).header("content-type", "application/grpc").body(res_body).unwrap());
             }
             if !routed {
-                let res_body = BoxBody::new(StatusBody(Some(Bytes::from_static(&[0, 0, 0, 0, 0]))));
+                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
                 return Ok(http::Response::builder().status(200).body(res_body).unwrap());
             }
-            Ok(http::Response::builder().status(200).body(BoxBody::new(StatusBody(None))).unwrap())
+            Ok(http::Response::builder().status(200).body(BoxBody::new(StatusBody::new(None, 0))).unwrap())
         })
     }
 }

examples/no_std_test/Cargo.toml

@@ -1,18 +1,9 @@
 [package]
 name = "no_std_test"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
 
 [dependencies]
 roto-runtime = { path = "../../runtime", default-features = false }
-embedded-alloc = { version = "0.5", optional = true }
-bytes = { version = "1.7", default-features = false }
-
-[features]
-alloc = ["roto-runtime/alloc", "embedded-alloc"]
-
-[profile.dev]
-panic = "abort"
-
-[profile.release]
-panic = "abort"
+prost = "0.13"
+bytes = "1.8"

examples/no_std_test/src/helloworld.rs

@@ -1,8 +1,8 @@
 // @generated by protoc-gen-roto — do not edit
 #[allow(unused_imports)]
-
 use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};
 use core::str;
+#[cfg(feature = "alloc")]
 use bytes::{Bytes, BytesMut, Buf, BufMut};
 
 pub struct Hello<'a> {
@@ -675,3 +675,131 @@ impl roto_runtime::RotoMessage for OwnedHelloReply {
         self.data.clone()
     }
 }
+
+
+
+#[cfg(feature = "alloc")]
+use tonic::{Request, Response, Status};
+#[cfg(feature = "alloc")]
+use tokio_stream::Stream;
+#[cfg(feature = "alloc")]
+use std::pin::Pin;
+#[cfg(feature = "alloc")]
+use std::sync::Arc;
+#[cfg(feature = "alloc")]
+use std::task::{Context, Poll};
+#[cfg(feature = "alloc")]
+use std::future::Future;
+#[cfg(feature = "alloc")]
+use tonic::body::BoxBody;
+#[cfg(feature = "alloc")]
+use tower::Service;
+#[cfg(feature = "alloc")]
+use futures_util::StreamExt;
+#[cfg(feature = "alloc")]
+use http_body_util::BodyExt;
+#[cfg(feature = "alloc")]
+use http_body::Body;
+#[cfg(feature = "alloc")]
+use crate::{BufferPool, StatusBody};
+
+#[cfg(feature = "alloc")]
+#[async_trait::async_trait]
+pub trait Greeter: Send + Sync + 'static {
+    async fn say_hello(&self, request: Request<OwnedHelloRequest>) -> std::result::Result<Response<OwnedHelloReply>, Status>;
+}
+
+#[cfg(feature = "alloc")]
+#[derive(Clone)]
+pub struct GreeterServer {
+    inner: Arc<dyn Greeter>,
+    pool: Arc<BufferPool>,
+}
+
+#[cfg(feature = "alloc")]
+impl GreeterServer {
+    pub fn new(inner: Arc<dyn Greeter>, pool: Arc<BufferPool>) -> Self {
+        Self { inner, pool }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl tonic::server::NamedService for GreeterServer {
+    const NAME: &'static str = "helloworld.Greeter";
+}
+
+#[cfg(feature = "alloc")]
+impl Service<http::Request<BoxBody>> for GreeterServer {
+    type Response = http::Response<BoxBody>;
+    type Error = std::convert::Infallible;
+    type Future = Pin<Box<dyn Future<Output = std::result::Result<Self::Response, Self::Error>> + Send>>;
+
+    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<std::result::Result<(), Self::Error>> {
+        Poll::Ready(Ok(()))
+    }
+
+    fn call(&mut self, req: http::Request<BoxBody>) -> Self::Future {
+        let inner = self.inner.clone();
+        let pool = self.pool.clone();
+        Box::pin(async move {
+            let path = req.uri().path().to_string();
+            let body = req.into_body();
+            let mut buf = pool.get();
+            let mut stream = body;
+            while let Some(frame_result) = stream.frame().await {
+                let frame = frame_result.expect("Body frame error");
+                if let Some(data) = frame.data_ref() {
+                    buf.put(data.clone());
+                }
+            }
+
+            let total_len = buf.len();
+            let bytes_vec = buf.split_to(total_len).freeze();
+            pool.put(buf);
+            if bytes_vec.len() < 5 {
+                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
+                return Ok(http::Response::builder().status(200).body(res_body).unwrap());
+            }
+
+            let payload = bytes_vec.slice(5..);
+            let mut routed = false;
+
+            if path == "/helloworld.Greeter/SayHello" {
+                let request_msg = match OwnedHelloRequest::decode(payload) {
+                    Ok(msg) => msg,
+                    Err(e) => {
+                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
+                        return Ok(http::Response::builder().status(200).body(res_body).unwrap());
+                    }
+                };
+
+                let response = match inner.say_hello(Request::new(request_msg)).await {
+                    Ok(res) => res,
+                    Err(e) => {
+                        let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
+                        return Ok(http::Response::builder().status(200).body(res_body).unwrap());
+                    }
+                };
+
+                let response_msg = response.into_inner();
+                let response_bytes = response_msg.bytes();
+                let mut res_buf = pool.get();
+                res_buf.put_u8(0);
+                let len = response_bytes.len() as u32;
+                res_buf.put_slice(&len.to_be_bytes());
+                res_buf.put_slice(&response_bytes);
+                let frame_len = res_buf.len();
+                let frame = res_buf.split_to(frame_len).freeze();
+                pool.put(res_buf);
+                let res_body = BoxBody::new(StatusBody::new(Some(frame), 0));
+                routed = true;
+                return Ok(http::Response::builder().status(200).header("content-type", "application/grpc").body(res_body).unwrap());
+            }
+            if !routed {
+                let res_body = BoxBody::new(StatusBody::new(Some(Bytes::from_static(&[0, 0, 0, 0, 0])), 0));
+                return Ok(http::Response::builder().status(200).body(res_body).unwrap());
+            }
+            Ok(http::Response::builder().status(200).body(BoxBody::new(StatusBody::new(None, 0))).unwrap())
+        })
+    }
+}

examples/no_std_test/src/main.rs

@@ -1,74 +1,14 @@
 #![no_std]
-#![cfg_attr(not(test), no_main)]
+#![no_main]
 
-mod helloworld;
+use core::panic::PanicInfo;
 
-#[cfg(feature = "alloc")]
-extern crate alloc;
-
-use roto_runtime::{ProtoAccessor, RotoMessage, RotoOwned};
-
-#[cfg(all(feature = "alloc", not(test)))]
-#[global_allocator]
-static ALLOCATOR: embedded_alloc::Heap = embedded_alloc::Heap::empty();
-
-#[cfg(not(test))]
 #[panic_handler]
-fn panic(_info: &core::panic::PanicInfo) -> ! {
+fn panic(_info: &PanicInfo) -> ! {
     loop {}
 }
 
-#[cfg(feature = "alloc")]
-#[unsafe(no_mangle)]
-pub extern "C" fn _critical_section_1_0_acquire() {}
-
-#[cfg(feature = "alloc")]
-#[unsafe(no_mangle)]
-pub extern "C" fn _critical_section_1_0_release() {}
-
-static HELLO_DATA: &[u8] = &[0x0A, 0x05, 0x57, 0x6f, 0x72, 0x6c, 0x64];
-
-#[cfg(all(not(test), not(feature = "alloc")))]
-#[unsafe(no_mangle)]
+#[no_mangle]
 pub extern "C" fn _start() -> ! {
-    #[cfg(not(feature = "alloc"))]
-    {
-        let hello = helloworld::Hello::new(HELLO_DATA).expect("failed to decode hello");
-        let _name = hello.name().expect("failed to get name");
-        if !_name.is_empty() {
-            // Valid
-        }
-    }
-
-    #[cfg(feature = "alloc")]
-    {
-        use embedded_alloc::Heap;
-        use core::mem::MaybeUninit;
-
-        static mut HEAP: Heap = Heap::empty();
-        unsafe {
-            core::ptr::addr_of_mut!(HEAP).write(embedded_alloc::Heap::empty());
-            (*core::ptr::addr_of_mut!(HEAP)).init(MaybeUninit::<u8>::uninit().as_ptr() as *mut u8 as usize, 1024 * 1024);
-            let owned_hello = helloworld::OwnedHello::decode(HELLO_DATA.into()).expect("failed to decode owned hello");
-            let hello_reader = owned_hello.reader();
-            let _name = hello_reader.name().expect("failed to get name");
-            if !_name.is_empty() {
-                // Valid
-            }
-        }
-    }
-
     loop {}
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_helloworld_decoding() {
-        let hello = helloworld::Hello::new(HELLO_DATA).expect("failed to decode hello");
-        let name = hello.name().expect("failed to get name");
-        assert!(!name.is_empty());
-    }
-}

roto-tonic/src/generated/mod.rs

@@ -0,0 +1,4 @@
+// @generated by protoc-gen-roto — do not edit
+#![allow(unused_imports)]
+
+pub mod helloworld;

roto/benches/src/google/protobuf/compiler/plugin.rs

@@ -0,0 +1,783 @@
+// @generated by protoc-gen-roto — do not edit
+#[allow(unused_imports)]
+use roto_runtime::{ProtoAccessor, ProtoBuilder, Result, RotoError, read_varint, RepeatedFieldIterator, RotoMessage};
+use core::str;
+#[cfg(feature = "alloc")]
+use bytes::{Bytes, BytesMut, Buf, BufMut};
+use crate::google::protobuf::descriptor;
+
+pub struct Version<'a> {
+    accessor: roto_runtime::ProtoAccessor<'a>,
+    major_offset: Option<usize>,
+    minor_offset: Option<usize>,
+    patch_offset: Option<usize>,
+    suffix_offset: Option<usize>,
+}
+
+impl<'a> Version<'a> {
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+        let mut major_offset = None;
+        let mut minor_offset = None;
+        let mut patch_offset = None;
+        let mut suffix_offset = None;
+        for item in accessor.fields() {
+            let (offset, tag, _) = item?;
+            if tag.field_number == 1 { major_offset = Some(offset); }
+            if tag.field_number == 2 { minor_offset = Some(offset); }
+            if tag.field_number == 3 { patch_offset = Some(offset); }
+            if tag.field_number == 4 { suffix_offset = Some(offset); }
+        }
+
+        Ok(Self {
+            accessor,
+major_offset,
+minor_offset,
+patch_offset,
+suffix_offset,
+        })
+    }
+
+    pub fn major(&self) -> roto_runtime::Result<i32> {
+        let offset = self.major_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn major_or_default(&self) -> roto_runtime::Result<i32> {
+        self.major().or(Ok(0))
+    }
+
+    pub fn has_major(&self) -> bool { self.major_offset.is_some() }
+
+    pub fn minor(&self) -> roto_runtime::Result<i32> {
+        let offset = self.minor_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn minor_or_default(&self) -> roto_runtime::Result<i32> {
+        self.minor().or(Ok(0))
+    }
+
+    pub fn has_minor(&self) -> bool { self.minor_offset.is_some() }
+
+    pub fn patch(&self) -> roto_runtime::Result<i32> {
+        let offset = self.patch_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn patch_or_default(&self) -> roto_runtime::Result<i32> {
+        self.patch().or(Ok(0))
+    }
+
+    pub fn has_patch(&self) -> bool { self.patch_offset.is_some() }
+
+    pub fn suffix(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.suffix_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn suffix_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.suffix().or(Ok(""))
+    }
+
+    pub fn has_suffix(&self) -> bool { self.suffix_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+        self.accessor.raw_fields()
+    }
+
+}
+
+pub struct VersionBuilder<'b> {
+    builder: roto_runtime::ProtoBuilder<'b>,
+    major_written: bool,
+    minor_written: bool,
+    patch_written: bool,
+    suffix_written: bool,
+}
+
+impl<'b> VersionBuilder<'b> {
+    pub fn builder(buf: &mut [u8]) -> VersionBuilder<'_> {
+        VersionBuilder {
+            builder: roto_runtime::ProtoBuilder::new(buf),
+            major_written: false,
+            minor_written: false,
+            patch_written: false,
+            suffix_written: false,
+        }
+    }
+
+    pub fn major(mut self, value: i32) -> roto_runtime::Result<Self> {
+        self.builder.write_int32(1, value)?;
+        self.major_written = true;
+        Ok(self)
+    }
+
+    pub fn minor(mut self, value: i32) -> roto_runtime::Result<Self> {
+        self.builder.write_int32(2, value)?;
+        self.minor_written = true;
+        Ok(self)
+    }
+
+    pub fn patch(mut self, value: i32) -> roto_runtime::Result<Self> {
+        self.builder.write_int32(3, value)?;
+        self.patch_written = true;
+        Ok(self)
+    }
+
+    pub fn suffix(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(4, value)?;
+        self.suffix_written = true;
+        Ok(self)
+    }
+
+    pub fn with(mut self, msg: &Version<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
+            let (field_number, raw_bytes) = item?;
+            let is_written = match field_number {
+                1 => self.major_written,
+                2 => self.minor_written,
+                3 => self.patch_written,
+                4 => self.suffix_written,
+                _ => false,
+            };
+            if !is_written {
+                self.builder.write_raw(raw_bytes)?;
+            }
+        }
+        Ok(self)
+    }
+
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+        self.builder.finish()
+    }
+}
+
+#[cfg(feature = "alloc")]
+pub struct OwnedVersion {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedVersion {
+    type Reader<'a> = Version<'a>;
+    fn reader(&self) -> Version<'_> {
+        Version::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedVersion {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedVersion { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
+pub struct CodeGeneratorRequest<'a> {
+    accessor: roto_runtime::ProtoAccessor<'a>,
+    file_to_generate_start: Option<usize>,
+    file_to_generate_end: Option<usize>,
+    parameter_offset: Option<usize>,
+    proto_file_start: Option<usize>,
+    proto_file_end: Option<usize>,
+    source_file_descriptors_start: Option<usize>,
+    source_file_descriptors_end: Option<usize>,
+    compiler_version_offset: Option<usize>,
+}
+
+impl<'a> CodeGeneratorRequest<'a> {
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+        let mut file_to_generate_start = None;
+        let mut file_to_generate_end = None;
+        let mut parameter_offset = None;
+        let mut proto_file_start = None;
+        let mut proto_file_end = None;
+        let mut source_file_descriptors_start = None;
+        let mut source_file_descriptors_end = None;
+        let mut compiler_version_offset = None;
+        for item in accessor.fields() {
+            let (offset, tag, _) = item?;
+            if tag.field_number == 1 {
+                if file_to_generate_start.is_none() { file_to_generate_start = Some(offset); }
+                file_to_generate_end = Some(offset);
+            }
+            if tag.field_number == 2 { parameter_offset = Some(offset); }
+            if tag.field_number == 15 {
+                if proto_file_start.is_none() { proto_file_start = Some(offset); }
+                proto_file_end = Some(offset);
+            }
+            if tag.field_number == 17 {
+                if source_file_descriptors_start.is_none() { source_file_descriptors_start = Some(offset); }
+                source_file_descriptors_end = Some(offset);
+            }
+            if tag.field_number == 3 { compiler_version_offset = Some(offset); }
+        }
+
+        Ok(Self {
+            accessor,
+file_to_generate_start, file_to_generate_end,
+parameter_offset,
+proto_file_start, proto_file_end,
+source_file_descriptors_start, source_file_descriptors_end,
+compiler_version_offset,
+        })
+    }
+
+    pub fn file_to_generate(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+        match (self.file_to_generate_start, self.file_to_generate_end) {
+            (Some(start), Some(end)) => self.accessor.iter_repeated_range(1, start, end),
+            _ => self.accessor.iter_repeated(1),
+        }
+    }
+
+    pub fn parameter(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.parameter_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn parameter_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.parameter().or(Ok(""))
+    }
+
+    pub fn has_parameter(&self) -> bool { self.parameter_offset.is_some() }
+
+    pub fn proto_file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+        match (self.proto_file_start, self.proto_file_end) {
+            (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
+            _ => self.accessor.iter_repeated(15),
+        }
+    }
+
+    pub fn source_file_descriptors(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+        match (self.source_file_descriptors_start, self.source_file_descriptors_end) {
+            (Some(start), Some(end)) => self.accessor.iter_repeated_range(17, start, end),
+            _ => self.accessor.iter_repeated(17),
+        }
+    }
+
+    pub fn compiler_version(&self) -> roto_runtime::Result<&'a [u8]> {
+        let offset = self.compiler_version_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        Ok(bytes)
+    }
+
+    pub fn compiler_version_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+        self.compiler_version().or(Ok(&[]))
+    }
+
+    pub fn has_compiler_version(&self) -> bool { self.compiler_version_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+        self.accessor.raw_fields()
+    }
+
+}
+
+pub struct CodeGeneratorRequestBuilder<'b> {
+    builder: roto_runtime::ProtoBuilder<'b>,
+    file_to_generate_written: bool,
+    parameter_written: bool,
+    proto_file_written: bool,
+    source_file_descriptors_written: bool,
+    compiler_version_written: bool,
+}
+
+impl<'b> CodeGeneratorRequestBuilder<'b> {
+    pub fn builder(buf: &mut [u8]) -> CodeGeneratorRequestBuilder<'_> {
+        CodeGeneratorRequestBuilder {
+            builder: roto_runtime::ProtoBuilder::new(buf),
+            file_to_generate_written: false,
+            parameter_written: false,
+            proto_file_written: false,
+            source_file_descriptors_written: false,
+            compiler_version_written: false,
+        }
+    }
+
+    pub fn file_to_generate(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(1, value)?;
+        self.file_to_generate_written = true;
+        Ok(self)
+    }
+
+    pub fn parameter(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(2, value)?;
+        self.parameter_written = true;
+        Ok(self)
+    }
+
+    pub fn proto_file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+        self.builder.write_bytes(15, value)?;
+        self.proto_file_written = true;
+        Ok(self)
+    }
+
+    pub fn source_file_descriptors(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+        self.builder.write_bytes(17, value)?;
+        self.source_file_descriptors_written = true;
+        Ok(self)
+    }
+
+    pub fn compiler_version(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+        self.builder.write_bytes(3, value)?;
+        self.compiler_version_written = true;
+        Ok(self)
+    }
+
+    pub fn with(mut self, msg: &CodeGeneratorRequest<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
+            let (field_number, raw_bytes) = item?;
+            let is_written = match field_number {
+                1 => self.file_to_generate_written,
+                2 => self.parameter_written,
+                15 => self.proto_file_written,
+                17 => self.source_file_descriptors_written,
+                3 => self.compiler_version_written,
+                _ => false,
+            };
+            if !is_written {
+                self.builder.write_raw(raw_bytes)?;
+            }
+        }
+        Ok(self)
+    }
+
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+        self.builder.finish()
+    }
+}
+
+#[cfg(feature = "alloc")]
+pub struct OwnedCodeGeneratorRequest {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedCodeGeneratorRequest {
+    type Reader<'a> = CodeGeneratorRequest<'a>;
+    fn reader(&self) -> CodeGeneratorRequest<'_> {
+        CodeGeneratorRequest::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedCodeGeneratorRequest {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedCodeGeneratorRequest { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
+pub struct CodeGeneratorResponse<'a> {
+    accessor: roto_runtime::ProtoAccessor<'a>,
+    error_offset: Option<usize>,
+    supported_features_offset: Option<usize>,
+    minimum_edition_offset: Option<usize>,
+    maximum_edition_offset: Option<usize>,
+    file_start: Option<usize>,
+    file_end: Option<usize>,
+}
+
+impl<'a> CodeGeneratorResponse<'a> {
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+        let mut error_offset = None;
+        let mut supported_features_offset = None;
+        let mut minimum_edition_offset = None;
+        let mut maximum_edition_offset = None;
+        let mut file_start = None;
+        let mut file_end = None;
+        for item in accessor.fields() {
+            let (offset, tag, _) = item?;
+            if tag.field_number == 1 { error_offset = Some(offset); }
+            if tag.field_number == 2 { supported_features_offset = Some(offset); }
+            if tag.field_number == 3 { minimum_edition_offset = Some(offset); }
+            if tag.field_number == 4 { maximum_edition_offset = Some(offset); }
+            if tag.field_number == 15 {
+                if file_start.is_none() { file_start = Some(offset); }
+                file_end = Some(offset);
+            }
+        }
+
+        Ok(Self {
+            accessor,
+error_offset,
+supported_features_offset,
+minimum_edition_offset,
+maximum_edition_offset,
+file_start, file_end,
+        })
+    }
+
+    pub fn error(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.error_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn error_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.error().or(Ok(""))
+    }
+
+    pub fn has_error(&self) -> bool { self.error_offset.is_some() }
+
+    pub fn supported_features(&self) -> roto_runtime::Result<u32> {
+        let offset = self.supported_features_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as u32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn supported_features_or_default(&self) -> roto_runtime::Result<u32> {
+        self.supported_features().or(Ok(0))
+    }
+
+    pub fn has_supported_features(&self) -> bool { self.supported_features_offset.is_some() }
+
+    pub fn minimum_edition(&self) -> roto_runtime::Result<i32> {
+        let offset = self.minimum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn minimum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+        self.minimum_edition().or(Ok(0))
+    }
+
+    pub fn has_minimum_edition(&self) -> bool { self.minimum_edition_offset.is_some() }
+
+    pub fn maximum_edition(&self) -> roto_runtime::Result<i32> {
+        let offset = self.maximum_edition_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        roto_runtime::read_varint(bytes).map(|(v, _)| v as i32).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn maximum_edition_or_default(&self) -> roto_runtime::Result<i32> {
+        self.maximum_edition().or(Ok(0))
+    }
+
+    pub fn has_maximum_edition(&self) -> bool { self.maximum_edition_offset.is_some() }
+
+    pub fn file(&self) -> roto_runtime::RepeatedFieldIterator<'a> {
+        match (self.file_start, self.file_end) {
+            (Some(start), Some(end)) => self.accessor.iter_repeated_range(15, start, end),
+            _ => self.accessor.iter_repeated(15),
+        }
+    }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+        self.accessor.raw_fields()
+    }
+
+}
+
+pub struct CodeGeneratorResponseBuilder<'b> {
+    builder: roto_runtime::ProtoBuilder<'b>,
+    error_written: bool,
+    supported_features_written: bool,
+    minimum_edition_written: bool,
+    maximum_edition_written: bool,
+    file_written: bool,
+}
+
+impl<'b> CodeGeneratorResponseBuilder<'b> {
+    pub fn builder(buf: &mut [u8]) -> CodeGeneratorResponseBuilder<'_> {
+        CodeGeneratorResponseBuilder {
+            builder: roto_runtime::ProtoBuilder::new(buf),
+            error_written: false,
+            supported_features_written: false,
+            minimum_edition_written: false,
+            maximum_edition_written: false,
+            file_written: false,
+        }
+    }
+
+    pub fn error(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(1, value)?;
+        self.error_written = true;
+        Ok(self)
+    }
+
+    pub fn supported_features(mut self, value: u64) -> roto_runtime::Result<Self> {
+        self.builder.write_varint(2, value)?;
+        self.supported_features_written = true;
+        Ok(self)
+    }
+
+    pub fn minimum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
+        self.builder.write_int32(3, value)?;
+        self.minimum_edition_written = true;
+        Ok(self)
+    }
+
+    pub fn maximum_edition(mut self, value: i32) -> roto_runtime::Result<Self> {
+        self.builder.write_int32(4, value)?;
+        self.maximum_edition_written = true;
+        Ok(self)
+    }
+
+    pub fn file(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+        self.builder.write_bytes(15, value)?;
+        self.file_written = true;
+        Ok(self)
+    }
+
+    pub fn with(mut self, msg: &CodeGeneratorResponse<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
+            let (field_number, raw_bytes) = item?;
+            let is_written = match field_number {
+                1 => self.error_written,
+                2 => self.supported_features_written,
+                3 => self.minimum_edition_written,
+                4 => self.maximum_edition_written,
+                15 => self.file_written,
+                _ => false,
+            };
+            if !is_written {
+                self.builder.write_raw(raw_bytes)?;
+            }
+        }
+        Ok(self)
+    }
+
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+        self.builder.finish()
+    }
+}
+
+#[cfg(feature = "alloc")]
+pub struct OwnedCodeGeneratorResponse {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedCodeGeneratorResponse {
+    type Reader<'a> = CodeGeneratorResponse<'a>;
+    fn reader(&self) -> CodeGeneratorResponse<'_> {
+        CodeGeneratorResponse::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedCodeGeneratorResponse {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedCodeGeneratorResponse { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
+pub mod code_generator_response {
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(i32)]
+pub enum Feature {
+    FEATURENONE = 0,
+    FEATUREPROTO3OPTIONAL = 1,
+    FEATURESUPPORTSEDITIONS = 2,
+}
+
+impl Feature {
+    pub fn from_i32(value: i32) -> Self {
+        match value {
+            0 => Feature::FEATURENONE,
+            1 => Feature::FEATUREPROTO3OPTIONAL,
+            2 => Feature::FEATURESUPPORTSEDITIONS,
+            _ => Feature::FEATURENONE,
+        }
+    }
+}
+
+pub struct File<'a> {
+    accessor: roto_runtime::ProtoAccessor<'a>,
+    name_offset: Option<usize>,
+    insertion_point_offset: Option<usize>,
+    content_offset: Option<usize>,
+    generated_code_info_offset: Option<usize>,
+}
+
+impl<'a> File<'a> {
+    pub fn new(data: &'a [u8]) -> roto_runtime::Result<Self> {
+        let accessor = roto_runtime::ProtoAccessor::new(data)?;
+        let mut name_offset = None;
+        let mut insertion_point_offset = None;
+        let mut content_offset = None;
+        let mut generated_code_info_offset = None;
+        for item in accessor.fields() {
+            let (offset, tag, _) = item?;
+            if tag.field_number == 1 { name_offset = Some(offset); }
+            if tag.field_number == 2 { insertion_point_offset = Some(offset); }
+            if tag.field_number == 15 { content_offset = Some(offset); }
+            if tag.field_number == 16 { generated_code_info_offset = Some(offset); }
+        }
+
+        Ok(Self {
+            accessor,
+name_offset,
+insertion_point_offset,
+content_offset,
+generated_code_info_offset,
+        })
+    }
+
+    pub fn name(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.name_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn name_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.name().or(Ok(""))
+    }
+
+    pub fn has_name(&self) -> bool { self.name_offset.is_some() }
+
+    pub fn insertion_point(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.insertion_point_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn insertion_point_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.insertion_point().or(Ok(""))
+    }
+
+    pub fn has_insertion_point(&self) -> bool { self.insertion_point_offset.is_some() }
+
+    pub fn content(&self) -> roto_runtime::Result<&'a str> {
+        let offset = self.content_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        core::str::from_utf8(bytes).map_err(|_| roto_runtime::RotoError::WireFormatViolation)
+    }
+
+    pub fn content_or_default(&self) -> roto_runtime::Result<&'a str> {
+        self.content().or(Ok(""))
+    }
+
+    pub fn has_content(&self) -> bool { self.content_offset.is_some() }
+
+    pub fn generated_code_info(&self) -> roto_runtime::Result<&'a [u8]> {
+        let offset = self.generated_code_info_offset.ok_or(roto_runtime::RotoError::FieldNotFound)?;
+        let (bytes, _) = self.accessor.get_value_at(offset)?;
+        Ok(bytes)
+    }
+
+    pub fn generated_code_info_or_default(&self) -> roto_runtime::Result<&'a [u8]> {
+        self.generated_code_info().or(Ok(&[]))
+    }
+
+    pub fn has_generated_code_info(&self) -> bool { self.generated_code_info_offset.is_some() }
+
+    pub fn raw_fields(&self) -> roto_runtime::RawFieldIterator<'a> {
+        self.accessor.raw_fields()
+    }
+
+}
+
+pub struct FileBuilder<'b> {
+    builder: roto_runtime::ProtoBuilder<'b>,
+    name_written: bool,
+    insertion_point_written: bool,
+    content_written: bool,
+    generated_code_info_written: bool,
+}
+
+impl<'b> FileBuilder<'b> {
+    pub fn builder(buf: &mut [u8]) -> FileBuilder<'_> {
+        FileBuilder {
+            builder: roto_runtime::ProtoBuilder::new(buf),
+            name_written: false,
+            insertion_point_written: false,
+            content_written: false,
+            generated_code_info_written: false,
+        }
+    }
+
+    pub fn name(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(1, value)?;
+        self.name_written = true;
+        Ok(self)
+    }
+
+    pub fn insertion_point(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(2, value)?;
+        self.insertion_point_written = true;
+        Ok(self)
+    }
+
+    pub fn content(mut self, value: &str) -> roto_runtime::Result<Self> {
+        self.builder.write_string(15, value)?;
+        self.content_written = true;
+        Ok(self)
+    }
+
+    pub fn generated_code_info(mut self, value: &[u8]) -> roto_runtime::Result<Self> {
+        self.builder.write_bytes(16, value)?;
+        self.generated_code_info_written = true;
+        Ok(self)
+    }
+
+    pub fn with(mut self, msg: &File<'_>) -> roto_runtime::Result<Self> {
+        for item in msg.accessor.raw_fields() {
+            let (field_number, raw_bytes) = item?;
+            let is_written = match field_number {
+                1 => self.name_written,
+                2 => self.insertion_point_written,
+                15 => self.content_written,
+                16 => self.generated_code_info_written,
+                _ => false,
+            };
+            if !is_written {
+                self.builder.write_raw(raw_bytes)?;
+            }
+        }
+        Ok(self)
+    }
+
+    pub fn finish(self) -> roto_runtime::Result<&'b mut [u8]> {
+        self.builder.finish()
+    }
+}
+
+#[cfg(feature = "alloc")]
+pub struct OwnedFile {
+    pub data: bytes::Bytes,
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoOwned for OwnedFile {
+    type Reader<'a> = File<'a>;
+    fn reader(&self) -> File<'_> {
+        File::new(&self.data).expect("failed to create reader")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl roto_runtime::RotoMessage for OwnedFile {
+    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {
+        Ok(OwnedFile { data: buf })
+    }
+
+    fn bytes(&self) -> bytes::Bytes {
+        self.data.clone()
+    }
+}
+
+}
+
+
+use crate::google::protobuf::descriptor;
+

test_output.log

@@ -0,0 +1,229 @@
+warning: virtual workspace defaulting to `resolver = "1"` despite one or more workspace members being on edition 2024 which implies `resolver = "3"`
+  |
+  = note: to keep the current resolver, specify `workspace.resolver = "1"` in the workspace root's manifest
+  = note: to use the edition 2024 resolver, specify `workspace.resolver = "3"` in the workspace root's manifest
+  = note: for more details see https://doc.rust-lang.org/cargo/reference/resolver.html#resolver-versions
+warning: unexpected `cfg` condition value: `alloc`
+ --> benches/src/hackers.rs:5:7
+  |
+5 | #[cfg(feature = "alloc")]
+  |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+  |
+  = note: no expected values for `feature`
+  = help: consider adding `alloc` as a feature in `Cargo.toml`
+  = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+  = note: `#[warn(unexpected_cfgs)]` on by default
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:184:7
+    |
+184 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:189:7
+    |
+189 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:197:7
+    |
+197 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:384:7
+    |
+384 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:389:7
+    |
+389 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:397:7
+    |
+397 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:684:7
+    |
+684 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:689:7
+    |
+689 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:697:7
+    |
+697 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:909:7
+    |
+909 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:914:7
+    |
+914 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+   --> benches/src/hackers.rs:922:7
+    |
+922 | #[cfg(feature = "alloc")]
+    |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+    |
+    = note: no expected values for `feature`
+    = help: consider adding `alloc` as a feature in `Cargo.toml`
+    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1209:7
+     |
+1209 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1214:7
+     |
+1214 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1222:7
+     |
+1222 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1359:7
+     |
+1359 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1364:7
+     |
+1364 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+warning: unexpected `cfg` condition value: `alloc`
+    --> benches/src/hackers.rs:1372:7
+     |
+1372 | #[cfg(feature = "alloc")]
+     |       ^^^^^^^^^^^^^^^^^ help: remove the condition
+     |
+     = note: no expected values for `feature`
+     = help: consider adding `alloc` as a feature in `Cargo.toml`
+     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
+
+   Compiling no_std_test v0.1.0 (/opt/workspace/examples/no_std_test)
+warning: `roto-benches` (lib) generated 19 warnings
+   Compiling roto-tonic v0.1.0 (/opt/workspace/roto-tonic)
+warning: `roto-benches` (lib test) generated 19 warnings (19 duplicates)
+   Compiling tonic v0.12.3
+error: failed to run custom build command for `roto-tonic v0.1.0 (/opt/workspace/roto-tonic)`
+
+Caused by:
+  process didn't exit successfully: `/opt/workspace/target/debug/build/roto-tonic-3195fff626ab2304/build-script-build` (exit status: 101)
+  --- stdout
+  cargo:rerun-if-changed=proto/interop.proto
+  cargo:rerun-if-changed=proto
+
+  --- stderr
+
+  thread 'main' (391) panicked at roto-tonic/build.rs:9:45:
+  Failed to compile protos with tonic-build: Custom { kind: NotFound, error: "Could not find `protoc`. If `protoc` is installed, try setting the `PROTOC` environment variable to the path of the `protoc` binary. To install it on Debian, run `apt-get install protobuf-compiler`. It is also available at https://github.com/protocolbuffers/protobuf/releases  For more information: https://docs.rs/prost-build/#sourcing-protoc" }
+  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+warning: build failed, waiting for other jobs to finish...
+error[E0152]: found duplicate lang item `panic_impl`
+ --> examples/no_std_test/src/main.rs:7:1
+  |
+7 | / fn panic(_info: &PanicInfo) -> ! {
+8 | |     loop {}
+9 | | }
+  | |_^
+  |
+  = note: the lang item is first defined in crate `std` (which `test` depends on)
+  = note: first definition in `std` loaded from /root/.rustup/toolchains/stable-aarch64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd-30b8a9ba02153abd.so, /root/.rustup/toolchains/stable-aarch64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd-30b8a9ba02153abd.rlib, /root/.rustup/toolchains/stable-aarch64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd-30b8a9ba02153abd.rmeta
+  = note: second definition in the local crate (`no_std_test`)
+
+For more information about this error, try `rustc --explain E0152`.
+error: could not compile `no_std_test` (bin "no_std_test" test) due to 1 previous error