protocols: add support for Serde

rust-protobuf@3 does not support Serde natively anymore.
So we need to do it by ourselves.

Signed-off-by: Tim Zhang <tim@hyper.sh>

src/libs/protocols/.gitignore

@@ -3,3 +3,4 @@ Cargo.lock
 src/*.rs
 !src/lib.rs
 !src/trans.rs
+!src/serde_config.rs

src/libs/protocols/build.rs

@@ -8,7 +8,45 @@ use std::io::{BufRead, BufReader, Read, Write};
 use std::path::Path;
 use std::process::exit;
 
-use ttrpc_codegen::{Codegen, Customize, ProtobufCustomize};
+use protobuf::{
+    descriptor::field_descriptor_proto::Type,
+    reflect::{EnumDescriptor, FieldDescriptor, MessageDescriptor, OneofDescriptor},
+};
+use ttrpc_codegen::{Codegen, Customize, ProtobufCustomize, ProtobufCustomizeCallback};
+
+struct GenSerde;
+
+impl ProtobufCustomizeCallback for GenSerde {
+    fn message(&self, _message: &MessageDescriptor) -> ProtobufCustomize {
+        ProtobufCustomize::default().before("#[cfg_attr(feature = \"with-serde\", derive(::serde::Serialize, ::serde::Deserialize))]")
+    }
+
+    fn enumeration(&self, _enum_type: &EnumDescriptor) -> ProtobufCustomize {
+        ProtobufCustomize::default().before("#[cfg_attr(feature = \"with-serde\", derive(::serde::Serialize, ::serde::Deserialize))]")
+    }
+
+    fn oneof(&self, _oneof: &OneofDescriptor) -> ProtobufCustomize {
+        ProtobufCustomize::default().before("#[cfg_attr(feature = \"with-serde\", derive(::serde::Serialize, ::serde::Deserialize))]")
+    }
+
+    fn field(&self, field: &FieldDescriptor) -> ProtobufCustomize {
+        if field.proto().type_() == Type::TYPE_ENUM {
+            ProtobufCustomize::default().before(
+                    "#[cfg_attr(feature = \"with-serde\", serde(serialize_with = \"crate::serialize_enum_or_unknown\", deserialize_with = \"crate::deserialize_enum_or_unknown\"))]",
+                )
+        } else if field.proto().type_() == Type::TYPE_MESSAGE && field.is_singular() {
+            ProtobufCustomize::default().before(
+                "#[cfg_attr(feature = \"with-serde\", serde(serialize_with = \"crate::serialize_message_field\", deserialize_with = \"crate::deserialize_message_field\"))]",
+            )
+        } else {
+            ProtobufCustomize::default()
+        }
+    }
+
+    fn special_field(&self, _message: &MessageDescriptor, _field: &str) -> ProtobufCustomize {
+        ProtobufCustomize::default().before("#[cfg_attr(feature = \"with-serde\", serde(skip))]")
+    }
+}
 
 fn replace_text_in_file(file_name: &str, from: &str, to: &str) -> Result<(), std::io::Error> {
     let mut src = File::open(file_name)?;

src/libs/protocols/src/lib.rs

@@ -17,5 +17,13 @@ pub mod health_ttrpc;
 #[cfg(feature = "async")]
 pub mod health_ttrpc_async;
 pub mod oci;
+#[cfg(feature = "with-serde")]
+mod serde_config;
 pub mod trans;
 pub mod types;
+
+#[cfg(feature = "with-serde")]
+pub use serde_config::{
+    deserialize_enum_or_unknown, deserialize_message_field, serialize_enum_or_unknown,
+    serialize_message_field,
+};

src/libs/protocols/src/serde_config.rs

@@ -0,0 +1,38 @@
+// Copyright (c) 2023 Ant Group
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+use protobuf::{EnumOrUnknown, MessageField};
+use serde::{Deserialize, Serialize};
+
+#[cfg(feature = "with-serde")]
+pub fn serialize_enum_or_unknown<E: protobuf::EnumFull, S: serde::Serializer>(
+    e: &protobuf::EnumOrUnknown<E>,
+    s: S,
+) -> Result<S::Ok, S::Error> {
+    e.value().serialize(s)
+}
+
+pub fn serialize_message_field<E: Serialize, S: serde::Serializer>(
+    e: &protobuf::MessageField<E>,
+    s: S,
+) -> Result<S::Ok, S::Error> {
+    if e.is_some() {
+        e.as_ref().unwrap().serialize(s)
+    } else {
+        s.serialize_unit()
+    }
+}
+
+pub fn deserialize_enum_or_unknown<'de, E: Deserialize<'de>, D: serde::Deserializer<'de>>(
+    d: D,
+) -> Result<protobuf::EnumOrUnknown<E>, D::Error> {
+    i32::deserialize(d).map(EnumOrUnknown::from_i32)
+}
+
+pub fn deserialize_message_field<'de, E: Deserialize<'de>, D: serde::Deserializer<'de>>(
+    d: D,
+) -> Result<protobuf::MessageField<E>, D::Error> {
+    Option::deserialize(d).map(MessageField::from_option)
+}