| // 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 a Go protocol |
| // buffer package. |
| package main |
| |
| import ( |
| "bytes" |
| "compress/gzip" |
| "crypto/sha256" |
| "encoding/hex" |
| "fmt" |
| "strconv" |
| "strings" |
| |
| "github.com/golang/protobuf/proto" |
| descpb "github.com/golang/protobuf/protoc-gen-go/descriptor" |
| "google.golang.org/proto/protogen" |
| ) |
| |
| func main() { |
| protogen.Run(func(gen *protogen.Plugin) error { |
| for _, f := range gen.Files { |
| if !f.Generate { |
| continue |
| } |
| genFile(gen, f) |
| } |
| return nil |
| }) |
| } |
| |
| type File struct { |
| *protogen.File |
| locationMap map[string][]*descpb.SourceCodeInfo_Location |
| } |
| |
| func genFile(gen *protogen.Plugin, file *protogen.File) { |
| f := &File{ |
| File: file, |
| locationMap: make(map[string][]*descpb.SourceCodeInfo_Location), |
| } |
| for _, loc := range file.Proto.GetSourceCodeInfo().GetLocation() { |
| key := pathKey(loc.Path) |
| f.locationMap[key] = append(f.locationMap[key], loc) |
| } |
| |
| g := gen.NewGeneratedFile(f.GeneratedFilenamePrefix+".pb.go", f.GoImportPath) |
| g.P("// Code generated by protoc-gen-go. DO NOT EDIT.") |
| g.P("// source: ", f.Desc.Path()) |
| g.P() |
| const filePackageField = 2 // FileDescriptorProto.package |
| genComment(g, f, []int32{filePackageField}) |
| g.P() |
| g.P("package ", f.GoPackageName) |
| g.P() |
| |
| for _, message := range f.Messages { |
| genMessage(gen, g, f, message) |
| } |
| |
| genFileDescriptor(gen, g, f) |
| } |
| |
| func genFileDescriptor(gen *protogen.Plugin, g *protogen.GeneratedFile, f *File) { |
| // Determine the name of the var holding the file descriptor: |
| // |
| // fileDescriptor_<hash of filename> |
| filenameHash := sha256.Sum256([]byte(f.Desc.Path())) |
| varName := fmt.Sprintf("fileDescriptor_%s", hex.EncodeToString(filenameHash[:8])) |
| |
| // Trim the source_code_info from the descriptor. |
| // Marshal and gzip it. |
| descProto := proto.Clone(f.Proto).(*descpb.FileDescriptorProto) |
| descProto.SourceCodeInfo = nil |
| b, err := proto.Marshal(descProto) |
| if err != nil { |
| gen.Error(err) |
| return |
| } |
| var buf bytes.Buffer |
| w, _ := gzip.NewWriterLevel(&buf, gzip.BestCompression) |
| w.Write(b) |
| w.Close() |
| b = buf.Bytes() |
| |
| g.P("func init() { proto.RegisterFile(", strconv.Quote(f.Desc.Path()), ", ", varName, ") }") |
| g.P() |
| g.P("var ", varName, " = []byte{") |
| g.P("// ", len(b), " bytes of a gzipped FileDescriptorProto") |
| for len(b) > 0 { |
| n := 16 |
| if n > len(b) { |
| n = len(b) |
| } |
| |
| s := "" |
| for _, c := range b[:n] { |
| s += fmt.Sprintf("0x%02x,", c) |
| } |
| g.P(s) |
| |
| b = b[n:] |
| } |
| g.P("}") |
| g.P() |
| } |
| |
| func genMessage(gen *protogen.Plugin, g *protogen.GeneratedFile, f *File, message *protogen.Message) { |
| genComment(g, f, message.Path) |
| g.P("type ", message.GoIdent, " struct {") |
| g.P("}") |
| g.P() |
| |
| for _, nested := range message.Messages { |
| genMessage(gen, g, f, nested) |
| } |
| } |
| |
| func genComment(g *protogen.GeneratedFile, f *File, path []int32) { |
| for _, loc := range f.locationMap[pathKey(path)] { |
| if loc.LeadingComments == nil { |
| continue |
| } |
| for _, line := range strings.Split(strings.TrimSuffix(loc.GetLeadingComments(), "\n"), "\n") { |
| g.P("//", line) |
| } |
| return |
| } |
| } |
| |
| // pathKey converts a location path to a string suitable for use as a map key. |
| func pathKey(path []int32) string { |
| var buf []byte |
| for i, x := range path { |
| if i != 0 { |
| buf = append(buf, ',') |
| } |
| buf = strconv.AppendInt(buf, int64(x), 10) |
| } |
| return string(buf) |
| } |