initial commit

vendor/github.com/golang/protobuf/protoc-gen-go/grpc/grpc.go

@@ -0,0 +1,463 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2015 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Package grpc outputs gRPC service descriptions in Go code.
+// It runs as a plugin for the Go protocol buffer compiler plugin.
+// It is linked in to protoc-gen-go.
+package grpc
+
+import (
+	"fmt"
+	"path"
+	"strconv"
+	"strings"
+
+	pb "github.com/golang/protobuf/protoc-gen-go/descriptor"
+	"github.com/golang/protobuf/protoc-gen-go/generator"
+)
+
+// generatedCodeVersion indicates a version of the generated code.
+// It is incremented whenever an incompatibility between the generated code and
+// the grpc package is introduced; the generated code references
+// a constant, grpc.SupportPackageIsVersionN (where N is generatedCodeVersion).
+const generatedCodeVersion = 3
+
+// Paths for packages used by code generated in this file,
+// relative to the import_prefix of the generator.Generator.
+const (
+	contextPkgPath = "golang.org/x/net/context"
+	grpcPkgPath    = "google.golang.org/grpc"
+)
+
+func init() {
+	generator.RegisterPlugin(new(grpc))
+}
+
+// grpc is an implementation of the Go protocol buffer compiler's
+// plugin architecture.  It generates bindings for gRPC support.
+type grpc struct {
+	gen *generator.Generator
+}
+
+// Name returns the name of this plugin, "grpc".
+func (g *grpc) Name() string {
+	return "grpc"
+}
+
+// The names for packages imported in the generated code.
+// They may vary from the final path component of the import path
+// if the name is used by other packages.
+var (
+	contextPkg string
+	grpcPkg    string
+)
+
+// Init initializes the plugin.
+func (g *grpc) Init(gen *generator.Generator) {
+	g.gen = gen
+	contextPkg = generator.RegisterUniquePackageName("context", nil)
+	grpcPkg = generator.RegisterUniquePackageName("grpc", nil)
+}
+
+// Given a type name defined in a .proto, return its object.
+// Also record that we're using it, to guarantee the associated import.
+func (g *grpc) objectNamed(name string) generator.Object {
+	g.gen.RecordTypeUse(name)
+	return g.gen.ObjectNamed(name)
+}
+
+// Given a type name defined in a .proto, return its name as we will print it.
+func (g *grpc) typeName(str string) string {
+	return g.gen.TypeName(g.objectNamed(str))
+}
+
+// P forwards to g.gen.P.
+func (g *grpc) P(args ...interface{}) { g.gen.P(args...) }
+
+// Generate generates code for the services in the given file.
+func (g *grpc) Generate(file *generator.FileDescriptor) {
+	if len(file.FileDescriptorProto.Service) == 0 {
+		return
+	}
+
+	g.P("// Reference imports to suppress errors if they are not otherwise used.")
+	g.P("var _ ", contextPkg, ".Context")
+	g.P("var _ ", grpcPkg, ".ClientConn")
+	g.P()
+
+	// Assert version compatibility.
+	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 _ = ", grpcPkg, ".SupportPackageIsVersion", generatedCodeVersion)
+	g.P()
+
+	for i, service := range file.FileDescriptorProto.Service {
+		g.generateService(file, service, i)
+	}
+}
+
+// GenerateImports generates the import declaration for this file.
+func (g *grpc) GenerateImports(file *generator.FileDescriptor) {
+	if len(file.FileDescriptorProto.Service) == 0 {
+		return
+	}
+	g.P("import (")
+	g.P(contextPkg, " ", strconv.Quote(path.Join(g.gen.ImportPrefix, contextPkgPath)))
+	g.P(grpcPkg, " ", strconv.Quote(path.Join(g.gen.ImportPrefix, grpcPkgPath)))
+	g.P(")")
+	g.P()
+}
+
+// reservedClientName records whether a client name is reserved on the client side.
+var reservedClientName = map[string]bool{
+// TODO: do we need any in gRPC?
+}
+
+func unexport(s string) string { return strings.ToLower(s[:1]) + s[1:] }
+
+// generateService generates all the code for the named service.
+func (g *grpc) generateService(file *generator.FileDescriptor, service *pb.ServiceDescriptorProto, index int) {
+	path := fmt.Sprintf("6,%d", index) // 6 means service.
+
+	origServName := service.GetName()
+	fullServName := origServName
+	if pkg := file.GetPackage(); pkg != "" {
+		fullServName = pkg + "." + fullServName
+	}
+	servName := generator.CamelCase(origServName)
+
+	g.P()
+	g.P("// Client API for ", servName, " service")
+	g.P()
+
+	// Client interface.
+	g.P("type ", servName, "Client interface {")
+	for i, method := range service.Method {
+		g.gen.PrintComments(fmt.Sprintf("%s,2,%d", path, i)) // 2 means method in a service.
+		g.P(g.generateClientSignature(servName, method))
+	}
+	g.P("}")
+	g.P()
+
+	// Client structure.
+	g.P("type ", unexport(servName), "Client struct {")
+	g.P("cc *", grpcPkg, ".ClientConn")
+	g.P("}")
+	g.P()
+
+	// NewClient factory.
+	g.P("func New", servName, "Client (cc *", grpcPkg, ".ClientConn) ", servName, "Client {")
+	g.P("return &", unexport(servName), "Client{cc}")
+	g.P("}")
+	g.P()
+
+	var methodIndex, streamIndex int
+	serviceDescVar := "_" + servName + "_serviceDesc"
+	// Client method implementations.
+	for _, method := range service.Method {
+		var descExpr string
+		if !method.GetServerStreaming() && !method.GetClientStreaming() {
+			// Unary RPC method
+			descExpr = fmt.Sprintf("&%s.Methods[%d]", serviceDescVar, methodIndex)
+			methodIndex++
+		} else {
+			// Streaming RPC method
+			descExpr = fmt.Sprintf("&%s.Streams[%d]", serviceDescVar, streamIndex)
+			streamIndex++
+		}
+		g.generateClientMethod(servName, fullServName, serviceDescVar, method, descExpr)
+	}
+
+	g.P("// Server API for ", servName, " service")
+	g.P()
+
+	// Server interface.
+	serverType := servName + "Server"
+	g.P("type ", serverType, " interface {")
+	for i, method := range service.Method {
+		g.gen.PrintComments(fmt.Sprintf("%s,2,%d", path, i)) // 2 means method in a service.
+		g.P(g.generateServerSignature(servName, method))
+	}
+	g.P("}")
+	g.P()
+
+	// Server registration.
+	g.P("func Register", servName, "Server(s *", grpcPkg, ".Server, srv ", serverType, ") {")
+	g.P("s.RegisterService(&", serviceDescVar, `, srv)`)
+	g.P("}")
+	g.P()
+
+	// Server handler implementations.
+	var handlerNames []string
+	for _, method := range service.Method {
+		hname := g.generateServerMethod(servName, fullServName, method)
+		handlerNames = append(handlerNames, hname)
+	}
+
+	// Service descriptor.
+	g.P("var ", serviceDescVar, " = ", grpcPkg, ".ServiceDesc {")
+	g.P("ServiceName: ", strconv.Quote(fullServName), ",")
+	g.P("HandlerType: (*", serverType, ")(nil),")
+	g.P("Methods: []", grpcPkg, ".MethodDesc{")
+	for i, method := range service.Method {
+		if method.GetServerStreaming() || method.GetClientStreaming() {
+			continue
+		}
+		g.P("{")
+		g.P("MethodName: ", strconv.Quote(method.GetName()), ",")
+		g.P("Handler: ", handlerNames[i], ",")
+		g.P("},")
+	}
+	g.P("},")
+	g.P("Streams: []", grpcPkg, ".StreamDesc{")
+	for i, method := range service.Method {
+		if !method.GetServerStreaming() && !method.GetClientStreaming() {
+			continue
+		}
+		g.P("{")
+		g.P("StreamName: ", strconv.Quote(method.GetName()), ",")
+		g.P("Handler: ", handlerNames[i], ",")
+		if method.GetServerStreaming() {
+			g.P("ServerStreams: true,")
+		}
+		if method.GetClientStreaming() {
+			g.P("ClientStreams: true,")
+		}
+		g.P("},")
+	}
+	g.P("},")
+	g.P("Metadata: ", file.VarName(), ",")
+	g.P("}")
+	g.P()
+}
+
+// generateClientSignature returns the client-side signature for a method.
+func (g *grpc) generateClientSignature(servName string, method *pb.MethodDescriptorProto) string {
+	origMethName := method.GetName()
+	methName := generator.CamelCase(origMethName)
+	if reservedClientName[methName] {
+		methName += "_"
+	}
+	reqArg := ", in *" + g.typeName(method.GetInputType())
+	if method.GetClientStreaming() {
+		reqArg = ""
+	}
+	respName := "*" + g.typeName(method.GetOutputType())
+	if method.GetServerStreaming() || method.GetClientStreaming() {
+		respName = servName + "_" + generator.CamelCase(origMethName) + "Client"
+	}
+	return fmt.Sprintf("%s(ctx %s.Context%s, opts ...%s.CallOption) (%s, error)", methName, contextPkg, reqArg, grpcPkg, respName)
+}
+
+func (g *grpc) generateClientMethod(servName, fullServName, serviceDescVar string, method *pb.MethodDescriptorProto, descExpr string) {
+	sname := fmt.Sprintf("/%s/%s", fullServName, method.GetName())
+	methName := generator.CamelCase(method.GetName())
+	inType := g.typeName(method.GetInputType())
+	outType := g.typeName(method.GetOutputType())
+
+	g.P("func (c *", unexport(servName), "Client) ", g.generateClientSignature(servName, method), "{")
+	if !method.GetServerStreaming() && !method.GetClientStreaming() {
+		g.P("out := new(", outType, ")")
+		// TODO: Pass descExpr to Invoke.
+		g.P("err := ", grpcPkg, `.Invoke(ctx, "`, sname, `", in, out, c.cc, opts...)`)
+		g.P("if err != nil { return nil, err }")
+		g.P("return out, nil")
+		g.P("}")
+		g.P()
+		return
+	}
+	streamType := unexport(servName) + methName + "Client"
+	g.P("stream, err := ", grpcPkg, ".NewClientStream(ctx, ", descExpr, `, c.cc, "`, sname, `", opts...)`)
+	g.P("if err != nil { return nil, err }")
+	g.P("x := &", streamType, "{stream}")
+	if !method.GetClientStreaming() {
+		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.GetClientStreaming()
+	genRecv := method.GetServerStreaming()
+	genCloseAndRecv := !method.GetServerStreaming()
+
+	// Stream auxiliary types and methods.
+	g.P("type ", servName, "_", methName, "Client interface {")
+	if genSend {
+		g.P("Send(*", inType, ") error")
+	}
+	if genRecv {
+		g.P("Recv() (*", outType, ", error)")
+	}
+	if genCloseAndRecv {
+		g.P("CloseAndRecv() (*", outType, ", error)")
+	}
+	g.P(grpcPkg, ".ClientStream")
+	g.P("}")
+	g.P()
+
+	g.P("type ", streamType, " struct {")
+	g.P(grpcPkg, ".ClientStream")
+	g.P("}")
+	g.P()
+
+	if genSend {
+		g.P("func (x *", streamType, ") Send(m *", inType, ") error {")
+		g.P("return x.ClientStream.SendMsg(m)")
+		g.P("}")
+		g.P()
+	}
+	if genRecv {
+		g.P("func (x *", streamType, ") Recv() (*", outType, ", error) {")
+		g.P("m := new(", outType, ")")
+		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() (*", outType, ", error) {")
+		g.P("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }")
+		g.P("m := new(", outType, ")")
+		g.P("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }")
+		g.P("return m, nil")
+		g.P("}")
+		g.P()
+	}
+}
+
+// generateServerSignature returns the server-side signature for a method.
+func (g *grpc) generateServerSignature(servName string, method *pb.MethodDescriptorProto) string {
+	origMethName := method.GetName()
+	methName := generator.CamelCase(origMethName)
+	if reservedClientName[methName] {
+		methName += "_"
+	}
+
+	var reqArgs []string
+	ret := "error"
+	if !method.GetServerStreaming() && !method.GetClientStreaming() {
+		reqArgs = append(reqArgs, contextPkg+".Context")
+		ret = "(*" + g.typeName(method.GetOutputType()) + ", error)"
+	}
+	if !method.GetClientStreaming() {
+		reqArgs = append(reqArgs, "*"+g.typeName(method.GetInputType()))
+	}
+	if method.GetServerStreaming() || method.GetClientStreaming() {
+		reqArgs = append(reqArgs, servName+"_"+generator.CamelCase(origMethName)+"Server")
+	}
+
+	return methName + "(" + strings.Join(reqArgs, ", ") + ") " + ret
+}
+
+func (g *grpc) generateServerMethod(servName, fullServName string, method *pb.MethodDescriptorProto) string {
+	methName := generator.CamelCase(method.GetName())
+	hname := fmt.Sprintf("_%s_%s_Handler", servName, methName)
+	inType := g.typeName(method.GetInputType())
+	outType := g.typeName(method.GetOutputType())
+
+	if !method.GetServerStreaming() && !method.GetClientStreaming() {
+		g.P("func ", hname, "(srv interface{}, ctx ", contextPkg, ".Context, dec func(interface{}) error, interceptor ", grpcPkg, ".UnaryServerInterceptor) (interface{}, error) {")
+		g.P("in := new(", inType, ")")
+		g.P("if err := dec(in); err != nil { return nil, err }")
+		g.P("if interceptor == nil { return srv.(", servName, "Server).", methName, "(ctx, in) }")
+		g.P("info := &", grpcPkg, ".UnaryServerInfo{")
+		g.P("Server: srv,")
+		g.P("FullMethod: ", strconv.Quote(fmt.Sprintf("/%s/%s", fullServName, methName)), ",")
+		g.P("}")
+		g.P("handler := func(ctx ", contextPkg, ".Context, req interface{}) (interface{}, error) {")
+		g.P("return srv.(", servName, "Server).", methName, "(ctx, req.(*", inType, "))")
+		g.P("}")
+		g.P("return interceptor(ctx, in, info, handler)")
+		g.P("}")
+		g.P()
+		return hname
+	}
+	streamType := unexport(servName) + methName + "Server"
+	g.P("func ", hname, "(srv interface{}, stream ", grpcPkg, ".ServerStream) error {")
+	if !method.GetClientStreaming() {
+		g.P("m := new(", inType, ")")
+		g.P("if err := stream.RecvMsg(m); err != nil { return err }")
+		g.P("return srv.(", servName, "Server).", methName, "(m, &", streamType, "{stream})")
+	} else {
+		g.P("return srv.(", servName, "Server).", methName, "(&", streamType, "{stream})")
+	}
+	g.P("}")
+	g.P()
+
+	genSend := method.GetServerStreaming()
+	genSendAndClose := !method.GetServerStreaming()
+	genRecv := method.GetClientStreaming()
+
+	// Stream auxiliary types and methods.
+	g.P("type ", servName, "_", methName, "Server interface {")
+	if genSend {
+		g.P("Send(*", outType, ") error")
+	}
+	if genSendAndClose {
+		g.P("SendAndClose(*", outType, ") error")
+	}
+	if genRecv {
+		g.P("Recv() (*", inType, ", error)")
+	}
+	g.P(grpcPkg, ".ServerStream")
+	g.P("}")
+	g.P()
+
+	g.P("type ", streamType, " struct {")
+	g.P(grpcPkg, ".ServerStream")
+	g.P("}")
+	g.P()
+
+	if genSend {
+		g.P("func (x *", streamType, ") Send(m *", outType, ") error {")
+		g.P("return x.ServerStream.SendMsg(m)")
+		g.P("}")
+		g.P()
+	}
+	if genSendAndClose {
+		g.P("func (x *", streamType, ") SendAndClose(m *", outType, ") error {")
+		g.P("return x.ServerStream.SendMsg(m)")
+		g.P("}")
+		g.P()
+	}
+	if genRecv {
+		g.P("func (x *", streamType, ") Recv() (*", inType, ", error) {")
+		g.P("m := new(", inType, ")")
+		g.P("if err := x.ServerStream.RecvMsg(m); err != nil { return nil, err }")
+		g.P("return m, nil")
+		g.P("}")
+		g.P()
+	}
+
+	return hname
+}