Replace ctype=CORD with rust.blob extension field (#160)

pb-jelly-gen/codegen/codegen.py

@@ -30,7 +30,6 @@
     EnumDescriptorProto,
     EnumValueDescriptorProto,
     FieldDescriptorProto,
-    FieldOptions,
     FileDescriptorProto,
     OneofDescriptorProto,
     SourceCodeInfo,
@@ -324,7 +323,7 @@ def is_grpc_slices(self) -> bool:
     def is_blob(self) -> bool:
         return (
             self.field.type == FieldDescriptorProto.TYPE_BYTES
-            and self.field.options.ctype == FieldOptions.CORD
+            and self.field.options.Extensions[extensions_pb2.blob]
         )
 
     def is_lazy_bytes(self) -> bool:
@@ -1786,7 +1785,7 @@ def calc_impls(
 
                 # If we use a Blob type, or GRPC Slice
                 if typ == FieldDescriptorProto.TYPE_BYTES and (
-                    field.options.ctype == FieldOptions.CORD
+                    field.options.Extensions[extensions_pb2.blob]
                     or field.options.Extensions[extensions_pb2.grpc_slices]
                 ):
                     (impls_eq, impls_copy) = (False, False)  # Blob is not eq/copy

pb-jelly-gen/codegen/rust/extensions.proto

@@ -13,7 +13,10 @@ import "google/protobuf/descriptor.proto";
 extend google.protobuf.FieldOptions {
     // Generate this field in a Box as opposed to inline Option
     optional bool box_it = 50000;
+    // Generates a `Lazy<VecSlice>`
     optional bool grpc_slices = 50003;
+    // Generates a `Lazy<WrappedBlob>`
+    optional bool blob = 50010;
     // Use a different Rust type which implements `pb::Message` to represent the field.
     // All paths must be fully qualified, as in `::my_crate::full::path::to::type`.
     // This only works with proto3.

pb-jelly/src/buffer.rs

@@ -17,7 +17,7 @@
 //! of copying large buffers during serialization and deserialization.
 //!
 //! To support this, messages may contain zerocopy fields using the [`Lazy`] type.
-//! `pb-jelly-gen` may generate these using the `CORD`, `grpc_slices`, or `zero_copy` options; they
+//! `pb-jelly-gen` may generate these using the `blob`, `grpc_slices`, or `zero_copy` options; they
 //! use different underlying types, which must implement [PbBuffer], but they all behave similarly.
 //!
 //! [PbBufferReader] and a [PbBufferWriter] have the opportunity to recognize [Lazy] fields.

pb-test/proto/includes/rust/extensions.proto

@@ -13,7 +13,10 @@ import "google/protobuf/descriptor.proto";
 extend google.protobuf.FieldOptions {
     // Generate this field in a Box as opposed to inline Option
     optional bool box_it = 50000;
+    // Generates a `Lazy<VecSlice>`
     optional bool grpc_slices = 50003;
+    // Generates a `Lazy<WrappedBlob>`
+    optional bool blob = 50010;
     // Use a different Rust type which implements `pb::Message` to represent the field.
     // All paths must be fully qualified, as in `::my_crate::full::path::to::type`.
     // This only works with proto3.