Crate buffa_codegen 

Shared code generation logic for buffa.

This crate takes protobuf descriptors (google.protobuf.FileDescriptorProto, decoded from binary FileDescriptorSet data) and emits Rust source code that uses the buffa runtime.

It is used by:

• protoc-gen-buffa (protoc plugin)
• buffa-build (build.rs integration)

Architecture

The code generator is intentionally decoupled from how descriptors are obtained. It receives fully-resolved FileDescriptorProtos and produces Rust source strings. This means:

• It doesn’t parse .proto files.
• It doesn’t invoke protoc.
• It doesn’t do import resolution or name linking.

All of that is handled upstream (by protoc, buf, or a future parser).

Modules

context

Code generation context and descriptor-to-Rust mapping state.

idents

Rust identifier and path construction helpers.

Structs

AliasConflict

One CamelCase collision: a target identifier and the proto value names that would all convert onto it.

CodeGenConfig

Configuration for code generation.

FeatureGateNames

Crate feature names used by the gated impls, customizable per impl kind.

GeneratedFile

One generated output file.

Enums

BytesRepr

The Rust type a proto bytes field maps to in generated owned structs.

CodeGenError

Code generation error.

CodeGenWarning

A non-fatal diagnostic produced during code generation.

EnumTypeOverride

Supported values for FeatureOverride::EnumType.

FeatureOverride

A path-scoped protobuf editions feature override, applied by mutating the parsed descriptors before generation (see feature_overrides).

GeneratedFileKind

Kind of GeneratedFile.

IncludeMode

How generate_module_tree emits include! paths.

MapRepr

The owned Rust collection a proto map<K, V> field maps to in generated owned structs.

PointerRepr

The owned smart pointer a singular message field’s buffa::MessageField wraps in generated owned structs.

ReflectMode

How much reflection support generated types get.

RepeatedRepr

The owned Rust collection a proto repeated field maps to in generated owned structs.

StringRepr

The Rust type a proto string field maps to in generated owned structs.

Constants

ALLOW_LINTS

Lints suppressed on generated code at module boundaries.

ELEMENT_MEMORY_LIMIT_ENV

Environment variable overriding the element-memory bound buffa’s tooling applies when decoding a descriptor set.

ELEMENT_MEMORY_LIMIT_OPT

Plugin option, settable in the protoc/buf parameter string, that sets the element-memory bound used to decode the request carrying it.

TOOLING_ELEMENT_MEMORY_LIMIT

Element-memory bound buffa’s build tooling applies to a descriptor set — the protoc plugins to a CodeGeneratorRequest, buffa-build to a FileDescriptorSet.

Functions

allow_lints_attr

Render ALLOW_LINTS as a #[allow(…)] attribute token stream.

apply_companions

Merge downstream Companion files into the per-package stitcher produced by generate.

decode_failure

Describe a failure to decode a descriptor set, naming the override when the element-memory bound is what rejected it.

decode_request

Decode a CodeGeneratorRequest from a protoc plugin’s stdin.

element_memory_limit_opt

Find element_memory_limit=<value> in a protoc plugin parameter string.

generate

Generate Rust source files from a set of file descriptors.

generate_module_tree

Generate a module tree that assembles per-package .mod.rs files into nested pub mod blocks matching the protobuf package hierarchy.

generate_with_diagnostics

normalize_exclude_package

Normalize and validate one exclude_package option value: trim whitespace, strip the optional leading dot, reject an empty result or a value with empty components (buf.validate., buf..validate) — those could never match a real package, so a typo would otherwise be a silent no-op.

package_is_excluded

Returns true if package is covered by any entry in excludes.

package_to_filename

Convert a proto package name to its file_per_package output filename.

package_to_mod_filename

Convert a proto package name to its .mod.rs stitcher filename.

peek_request_parameter

Read CodeGeneratorRequest.parameter (field 2) straight off the wire, without decoding the request.

proto_path_to_stem

Convert a .proto file path to its content-file stem.

tooling_decode_options

Decode options for a descriptor set produced by the caller’s own build, honouring ELEMENT_MEMORY_LIMIT_ENV.