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// 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.
// Package internal_gengogrpc is internal to the protobuf module.
package internal_gengogrpc
import (
"fmt"
"strconv"
"strings"
"google.golang.org/protobuf/compiler/protogen"
"google.golang.org/protobuf/types/descriptorpb"
)
const (
contextPackage = protogen.GoImportPath("context")
grpcPackage = protogen.GoImportPath("google.golang.org/grpc")
)
// GenerateFile generates a _grpc.pb.go file containing gRPC service definitions.
func GenerateFile(gen *protogen.Plugin, file *protogen.File) *protogen.GeneratedFile {
if len(file.Services) == 0 {
return nil
}
filename := file.GeneratedFilenamePrefix + "_grpc.pb.go"
g := gen.NewGeneratedFile(filename, file.GoImportPath)
g.P("// Code generated by protoc-gen-go-grpc. DO NOT EDIT.")
g.P()
g.P("package ", file.GoPackageName)
g.P()
GenerateFileContent(gen, file, g)
return g
}
// GenerateFileContent generates the gRPC service definitions, excluding the package statement.
func GenerateFileContent(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile) {
if len(file.Services) == 0 {
return
}
// TODO: Remove this. We don't need to include these references any more.
g.P("// Reference imports to suppress errors if they are not otherwise used.")
g.P("var _ ", contextPackage.Ident("Context"))
g.P("var _ ", grpcPackage.Ident("ClientConn"))
g.P()
g.P("// This is a compile-time assertion to ensure that this generated file")
g.P("// is compatible with the grpc package it is being compiled against.")
g.P("const _ = ", grpcPackage.Ident("SupportPackageIsVersion4"))
g.P()
for _, service := range file.Services {
genService(gen, file, g, service)
}
}
func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile, service *protogen.Service) {
clientName := service.GoName + "Client"
g.P("// ", clientName, " is the client API for ", service.GoName, " service.")
g.P("//")
g.P("// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.")
// Client interface.
if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
g.P("//")
g.P(deprecationComment)
}
g.Annotate(clientName, service.Location)
g.P("type ", clientName, " interface {")
for _, method := range service.Methods {
g.PrintLeadingComments(method.Location)
g.Annotate(clientName+"."+method.GoName, method.Location)
g.P(clientSignature(g, method))
}
g.P("}")
g.P()
// Client structure.
g.P("type ", unexport(clientName), " struct {")
g.P("cc *", grpcPackage.Ident("ClientConn"))
g.P("}")
g.P()
// NewClient factory.
if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
g.P(deprecationComment)
}
g.P("func New", clientName, " (cc *", grpcPackage.Ident("ClientConn"), ") ", clientName, " {")
g.P("return &", unexport(clientName), "{cc}")
g.P("}")
g.P()
var methodIndex, streamIndex int
// Client method implementations.
for _, method := range service.Methods {
if !method.Desc.IsStreamingServer() && !method.Desc.IsStreamingClient() {
// Unary RPC method
genClientMethod(gen, file, g, method, methodIndex)
methodIndex++
} else {
// Streaming RPC method
genClientMethod(gen, file, g, method, streamIndex)
streamIndex++
}
}
// Server interface.
serverType := service.GoName + "Server"
g.P("// ", serverType, " is the server API for ", service.GoName, " service.")
if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
g.P("//")
g.P(deprecationComment)
}
g.Annotate(serverType, service.Location)
g.P("type ", serverType, " interface {")
for _, method := range service.Methods {
g.PrintLeadingComments(method.Location)
g.Annotate(serverType+"."+method.GoName, method.Location)
g.P(serverSignature(g, method))
}
g.P("}")
g.P()
// Server registration.
if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
g.P(deprecationComment)
}
serviceDescVar := "_" + service.GoName + "_serviceDesc"
g.P("func Register", service.GoName, "Server(s *", grpcPackage.Ident("Server"), ", srv ", serverType, ") {")
g.P("s.RegisterService(&", serviceDescVar, `, srv)`)
g.P("}")
g.P()
// Server handler implementations.
var handlerNames []string
for _, method := range service.Methods {
hname := genServerMethod(gen, file, g, method)
handlerNames = append(handlerNames, hname)
}
// Service descriptor.
g.P("var ", serviceDescVar, " = ", grpcPackage.Ident("ServiceDesc"), " {")
g.P("ServiceName: ", strconv.Quote(string(service.Desc.FullName())), ",")
g.P("HandlerType: (*", serverType, ")(nil),")
g.P("Methods: []", grpcPackage.Ident("MethodDesc"), "{")
for i, method := range service.Methods {
if method.Desc.IsStreamingClient() || method.Desc.IsStreamingServer() {
continue
}
g.P("{")
g.P("MethodName: ", strconv.Quote(string(method.Desc.Name())), ",")
g.P("Handler: ", handlerNames[i], ",")
g.P("},")
}
g.P("},")
g.P("Streams: []", grpcPackage.Ident("StreamDesc"), "{")
for i, method := range service.Methods {
if !method.Desc.IsStreamingClient() && !method.Desc.IsStreamingServer() {
continue
}
g.P("{")
g.P("StreamName: ", strconv.Quote(string(method.Desc.Name())), ",")
g.P("Handler: ", handlerNames[i], ",")
if method.Desc.IsStreamingServer() {
g.P("ServerStreams: true,")
}
if method.Desc.IsStreamingClient() {
g.P("ClientStreams: true,")
}
g.P("},")
}
g.P("},")
g.P("Metadata: \"", file.Desc.Path(), "\",")
g.P("}")
g.P()
}
func clientSignature(g *protogen.GeneratedFile, method *protogen.Method) string {
s := method.GoName + "(ctx " + g.QualifiedGoIdent(contextPackage.Ident("Context"))
if !method.Desc.IsStreamingClient() {
s += ", in *" + g.QualifiedGoIdent(method.Input.GoIdent)
}
s += ", opts ..." + g.QualifiedGoIdent(grpcPackage.Ident("CallOption")) + ") ("
if !method.Desc.IsStreamingClient() && !method.Desc.IsStreamingServer() {
s += "*" + g.QualifiedGoIdent(method.Output.GoIdent)
} else {
s += method.Parent.GoName + "_" + method.GoName + "Client"
}
s += ", error)"
return s
}
func genClientMethod(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile, method *protogen.Method, index int) {
service := method.Parent
sname := fmt.Sprintf("/%s/%s", service.Desc.FullName(), method.Desc.Name())
if method.Desc.Options().(*descriptorpb.MethodOptions).GetDeprecated() {
g.P(deprecationComment)
}
g.P("func (c *", unexport(service.GoName), "Client) ", clientSignature(g, method), "{")
if !method.Desc.IsStreamingServer() && !method.Desc.IsStreamingClient() {
g.P("out := new(", method.Output.GoIdent, ")")
g.P(`err := c.cc.Invoke(ctx, "`, sname, `", in, out, opts...)`)
g.P("if err != nil { return nil, err }")
g.P("return out, nil")
g.P("}")
g.P()
return
}
streamType := unexport(service.GoName) + method.GoName + "Client"
serviceDescVar := "_" + service.GoName + "_serviceDesc"
g.P("stream, err := c.cc.NewStream(ctx, &", serviceDescVar, ".Streams[", index, `], "`, sname, `", opts...)`)
g.P("if err != nil { return nil, err }")
g.P("x := &", streamType, "{stream}")
if !method.Desc.IsStreamingClient() {
g.P("if err := x.ClientStream.SendMsg(in); err != nil { return nil, err }")
g.P("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }")
}
g.P("return x, nil")
g.P("}")
g.P()
genSend := method.Desc.IsStreamingClient()
genRecv := method.Desc.IsStreamingServer()
genCloseAndRecv := !method.Desc.IsStreamingServer()
// Stream auxiliary types and methods.
g.P("type ", service.GoName, "_", method.GoName, "Client interface {")
if genSend {
g.P("Send(*", method.Input.GoIdent, ") error")
}
if genRecv {
g.P("Recv() (*", method.Output.GoIdent, ", error)")
}
if genCloseAndRecv {
g.P("CloseAndRecv() (*", method.Output.GoIdent, ", error)")
}
g.P(grpcPackage.Ident("ClientStream"))
g.P("}")
g.P()
g.P("type ", streamType, " struct {")
g.P(grpcPackage.Ident("ClientStream"))
g.P("}")
g.P()
if genSend {
g.P("func (x *", streamType, ") Send(m *", method.Input.GoIdent, ") error {")
g.P("return x.ClientStream.SendMsg(m)")
g.P("}")
g.P()
}
if genRecv {
g.P("func (x *", streamType, ") Recv() (*", method.Output.GoIdent, ", error) {")
g.P("m := new(", method.Output.GoIdent, ")")
g.P("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }")
g.P("return m, nil")
g.P("}")
g.P()
}
if genCloseAndRecv {
g.P("func (x *", streamType, ") CloseAndRecv() (*", method.Output.GoIdent, ", error) {")
g.P("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }")
g.P("m := new(", method.Output.GoIdent, ")")
g.P("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }")
g.P("return m, nil")
g.P("}")
g.P()
}
}
func serverSignature(g *protogen.GeneratedFile, method *protogen.Method) string {
var reqArgs []string
ret := "error"
if !method.Desc.IsStreamingClient() && !method.Desc.IsStreamingServer() {
reqArgs = append(reqArgs, g.QualifiedGoIdent(contextPackage.Ident("Context")))
ret = "(*" + g.QualifiedGoIdent(method.Output.GoIdent) + ", error)"
}
if !method.Desc.IsStreamingClient() {
reqArgs = append(reqArgs, "*"+g.QualifiedGoIdent(method.Input.GoIdent))
}
if method.Desc.IsStreamingClient() || method.Desc.IsStreamingServer() {
reqArgs = append(reqArgs, method.Parent.GoName+"_"+method.GoName+"Server")
}
return method.GoName + "(" + strings.Join(reqArgs, ", ") + ") " + ret
}
func genServerMethod(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile, method *protogen.Method) string {
service := method.Parent
hname := fmt.Sprintf("_%s_%s_Handler", service.GoName, method.GoName)
if !method.Desc.IsStreamingClient() && !method.Desc.IsStreamingServer() {
g.P("func ", hname, "(srv interface{}, ctx ", contextPackage.Ident("Context"), ", dec func(interface{}) error, interceptor ", grpcPackage.Ident("UnaryServerInterceptor"), ") (interface{}, error) {")
g.P("in := new(", method.Input.GoIdent, ")")
g.P("if err := dec(in); err != nil { return nil, err }")
g.P("if interceptor == nil { return srv.(", service.GoName, "Server).", method.GoName, "(ctx, in) }")
g.P("info := &", grpcPackage.Ident("UnaryServerInfo"), "{")
g.P("Server: srv,")
g.P("FullMethod: ", strconv.Quote(fmt.Sprintf("/%s/%s", service.Desc.FullName(), method.GoName)), ",")
g.P("}")
g.P("handler := func(ctx ", contextPackage.Ident("Context"), ", req interface{}) (interface{}, error) {")
g.P("return srv.(", service.GoName, "Server).", method.GoName, "(ctx, req.(*", method.Input.GoIdent, "))")
g.P("}")
g.P("return interceptor(ctx, in, info, handler)")
g.P("}")
g.P()
return hname
}
streamType := unexport(service.GoName) + method.GoName + "Server"
g.P("func ", hname, "(srv interface{}, stream ", grpcPackage.Ident("ServerStream"), ") error {")
if !method.Desc.IsStreamingClient() {
g.P("m := new(", method.Input.GoIdent, ")")
g.P("if err := stream.RecvMsg(m); err != nil { return err }")
g.P("return srv.(", service.GoName, "Server).", method.GoName, "(m, &", streamType, "{stream})")
} else {
g.P("return srv.(", service.GoName, "Server).", method.GoName, "(&", streamType, "{stream})")
}
g.P("}")
g.P()
genSend := method.Desc.IsStreamingServer()
genSendAndClose := !method.Desc.IsStreamingServer()
genRecv := method.Desc.IsStreamingClient()
// Stream auxiliary types and methods.
g.P("type ", service.GoName, "_", method.GoName, "Server interface {")
if genSend {
g.P("Send(*", method.Output.GoIdent, ") error")
}
if genSendAndClose {
g.P("SendAndClose(*", method.Output.GoIdent, ") error")
}
if genRecv {
g.P("Recv() (*", method.Input.GoIdent, ", error)")
}
g.P(grpcPackage.Ident("ServerStream"))
g.P("}")
g.P()
g.P("type ", streamType, " struct {")
g.P(grpcPackage.Ident("ServerStream"))
g.P("}")
g.P()
if genSend {
g.P("func (x *", streamType, ") Send(m *", method.Output.GoIdent, ") error {")
g.P("return x.ServerStream.SendMsg(m)")
g.P("}")
g.P()
}
if genSendAndClose {
g.P("func (x *", streamType, ") SendAndClose(m *", method.Output.GoIdent, ") error {")
g.P("return x.ServerStream.SendMsg(m)")
g.P("}")
g.P()
}
if genRecv {
g.P("func (x *", streamType, ") Recv() (*", method.Input.GoIdent, ", error) {")
g.P("m := new(", method.Input.GoIdent, ")")
g.P("if err := x.ServerStream.RecvMsg(m); err != nil { return nil, err }")
g.P("return m, nil")
g.P("}")
g.P()
}
return hname
}
const deprecationComment = "// Deprecated: Do not use."
func unexport(s string) string { return strings.ToLower(s[:1]) + s[1:] }