protobuf-go/cmd/protoc-gen-go/main.go
Joe Tsai 387873dd53 all: implement support for proto3 optional semantics
In the upcoming 3.12.x release of protoc, the proto3 language will be
amended to support true presence for scalars. This CL adds support
to both the generator and runtime to support these semantics.

Newly added public API:
	protogen.Plugin.SupportedFeatures
	protoreflect.FieldDescriptor.HasPresence
	protoreflect.FieldDescriptor.HasOptionalKeyword
	protoreflect.OneofDescriptor.IsSynthetic

Change-Id: I7c86bf66d0ae56642109beb5f2132184593747ad
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/230698
Reviewed-by: Damien Neil <dneil@google.com>
2020-04-29 20:02:24 +00:00

53 lines
1.5 KiB
Go

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// The protoc-gen-go binary is a protoc plugin to generate Go code for
// both proto2 and proto3 versions of the protocol buffer language.
//
// For more information about the usage of this plugin, see:
// https://developers.google.com/protocol-buffers/docs/reference/go-generated
package main
import (
"errors"
"flag"
"fmt"
"os"
"path/filepath"
gengo "google.golang.org/protobuf/cmd/protoc-gen-go/internal_gengo"
"google.golang.org/protobuf/compiler/protogen"
"google.golang.org/protobuf/internal/version"
)
func main() {
if len(os.Args) == 2 && os.Args[1] == "--version" {
fmt.Fprintf(os.Stderr, "%v %v\n", filepath.Base(os.Args[0]), version.String())
os.Exit(1)
}
var (
flags flag.FlagSet
plugins = flags.String("plugins", "", "deprecated option")
importPrefix = flags.String("import_prefix", "", "deprecated option")
)
protogen.Options{
ParamFunc: flags.Set,
}.Run(func(gen *protogen.Plugin) error {
if *plugins != "" {
return errors.New("protoc-gen-go: plugins are not supported; use 'protoc --go-grpc_out=...' to generate gRPC")
}
if *importPrefix != "" {
return errors.New("protoc-gen-go: import_prefix is not supported")
}
for _, f := range gen.Files {
if f.Generate {
gengo.GenerateFile(gen, f)
}
}
gen.SupportedFeatures = gengo.SupportedFeatures
return nil
})
}