grpc/src/compiler/cpp_generator.cc

/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * 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.
 *
 */

#include <map>

#include "src/compiler/cpp_generator.h"

#include <sstream>

namespace grpc_cpp_generator {
namespace {

template <class T>
grpc::string as_string(T x) {
  std::ostringstream out;
  out << x;
  return out.str();
}

grpc::string FilenameIdentifier(const grpc::string &filename) {
  grpc::string result;
  for (unsigned i = 0; i < filename.size(); i++) {
    char c = filename[i];
    if (isalnum(c)) {
      result.push_back(c);
    } else {
      static char hex[] = "0123456789abcdef";
      result.push_back('_');
      result.push_back(hex[(c >> 4) & 0xf]);
      result.push_back(hex[c & 0xf]);
    }
  }
  return result;
}
}  // namespace

template<class T, size_t N>
T *array_end(T (&array)[N]) { return array + N; }

void PrintIncludes(Printer *printer, const std::vector<grpc::string>& headers, const Parameters &params) {
  std::map<grpc::string, grpc::string> vars;

  vars["l"] = params.use_system_headers ? '<' : '"';
  vars["r"] = params.use_system_headers ? '>' : '"';

  auto& s = params.grpc_search_path;
  if (!s.empty()) {
    vars["l"] += s;
    if (s[s.size()-1] != '/') {
      vars["l"] += '/';
    }
  }

  for (auto i = headers.begin(); i != headers.end(); i++) {
    vars["h"] = *i;
    printer->Print(vars, "#include $l$$h$$r$\n");
  }
}

grpc::string GetHeaderPrologue(File *file, const Parameters & /*params*/) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;

    vars["filename"] = file->filename();
    vars["filename_identifier"] = FilenameIdentifier(file->filename());
    vars["filename_base"] = file->filename_without_ext();
    vars["message_header_ext"] = file->message_header_ext();

    printer->Print(vars, "// Generated by the gRPC protobuf plugin.\n");
    printer->Print(vars,
                  "// If you make any local change, they will be lost.\n");
    printer->Print(vars, "// source: $filename$\n");
    grpc::string leading_comments = file->GetLeadingComments();
    if (!leading_comments.empty()) {
      printer->Print(vars, "// Original file comments:\n");
      printer->Print(leading_comments.c_str());
    }
    printer->Print(vars, "#ifndef GRPC_$filename_identifier$__INCLUDED\n");
    printer->Print(vars, "#define GRPC_$filename_identifier$__INCLUDED\n");
    printer->Print(vars, "\n");
    printer->Print(vars, "#include \"$filename_base$$message_header_ext$\"\n");
    printer->Print(vars, "\n");
  }
  return output;
}

grpc::string GetHeaderIncludes(File *file,
                               const Parameters &params) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;

    static const char *headers_strs[] = {
      "grpc++/impl/codegen/async_stream.h",
      "grpc++/impl/codegen/async_unary_call.h",
      "grpc++/impl/codegen/fc_unary.h",
      "grpc++/impl/codegen/method_handler_impl.h",
      "grpc++/impl/codegen/proto_utils.h",
      "grpc++/impl/codegen/rpc_method.h",
      "grpc++/impl/codegen/service_type.h",
      "grpc++/impl/codegen/status.h",
      "grpc++/impl/codegen/stub_options.h",
      "grpc++/impl/codegen/sync_stream.h"
    };
    std::vector<grpc::string> headers(headers_strs, array_end(headers_strs));
    PrintIncludes(printer.get(), headers, params);
    printer->Print(vars, "\n");
    printer->Print(vars, "namespace grpc {\n");
    printer->Print(vars, "class CompletionQueue;\n");
    printer->Print(vars, "class Channel;\n");
    printer->Print(vars, "class RpcService;\n");
    printer->Print(vars, "class ServerCompletionQueue;\n");
    printer->Print(vars, "class ServerContext;\n");
    printer->Print(vars, "}  // namespace grpc\n\n");

    if (!file->package().empty()) {
      std::vector<grpc::string> parts = file->package_parts();

      for (auto part = parts.begin(); part != parts.end(); part++) {
        vars["part"] = *part;
        printer->Print(vars, "namespace $part$ {\n");
      }
      printer->Print(vars, "\n");
    }
  }
  return output;
}

void PrintHeaderClientMethodInterfaces(
    Printer *printer, const Method *method,
    std::map<grpc::string, grpc::string> *vars, bool is_public) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();

  if (is_public) {
    if (method->NoStreaming()) {
      printer->Print(
          *vars,
          "virtual ::grpc::Status $Method$(::grpc::ClientContext* context, "
          "const $Request$& request, $Response$* response) = 0;\n");
      printer->Print(*vars,
                     "std::unique_ptr< "
                     "::grpc::ClientAsyncResponseReaderInterface< $Response$>> "
                     "Async$Method$(::grpc::ClientContext* context, "
                     "const $Request$& request, "
                     "::grpc::CompletionQueue* cq) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientAsyncResponseReaderInterface< $Response$>>("
                     "Async$Method$Raw(context, request, cq));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->ClientOnlyStreaming()) {
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientWriterInterface< $Request$>>"
          " $Method$("
          "::grpc::ClientContext* context, $Response$* response) {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< ::grpc::ClientWriterInterface< $Request$>>"
          "($Method$Raw(context, response));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientAsyncWriterInterface< $Request$>>"
          " Async$Method$(::grpc::ClientContext* context, $Response$* "
          "response, "
          "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientAsyncWriterInterface< $Request$>>("
                     "Async$Method$Raw(context, response, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->ServerOnlyStreaming()) {
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientReaderInterface< $Response$>>"
          " $Method$(::grpc::ClientContext* context, const $Request$& request)"
          " {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< ::grpc::ClientReaderInterface< $Response$>>"
          "($Method$Raw(context, request));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientAsyncReaderInterface< $Response$>> "
          "Async$Method$("
          "::grpc::ClientContext* context, const $Request$& request, "
          "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientAsyncReaderInterface< $Response$>>("
                     "Async$Method$Raw(context, request, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->BidiStreaming()) {
      printer->Print(*vars,
                     "std::unique_ptr< ::grpc::ClientReaderWriterInterface< "
                     "$Request$, $Response$>> "
                     "$Method$(::grpc::ClientContext* context) {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< "
          "::grpc::ClientReaderWriterInterface< $Request$, $Response$>>("
          "$Method$Raw(context));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(
          *vars,
          "std::unique_ptr< "
          "::grpc::ClientAsyncReaderWriterInterface< $Request$, $Response$>> "
          "Async$Method$(::grpc::ClientContext* context, "
          "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< "
          "::grpc::ClientAsyncReaderWriterInterface< $Request$, $Response$>>("
          "Async$Method$Raw(context, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    }
  } else {
    if (method->NoStreaming()) {
      printer->Print(
          *vars,
          "virtual ::grpc::ClientAsyncResponseReaderInterface< $Response$>* "
          "Async$Method$Raw(::grpc::ClientContext* context, "
          "const $Request$& request, "
          "::grpc::CompletionQueue* cq) = 0;\n");
    } else if (method->ClientOnlyStreaming()) {
      printer->Print(
          *vars,
          "virtual ::grpc::ClientWriterInterface< $Request$>*"
          " $Method$Raw("
          "::grpc::ClientContext* context, $Response$* response) = 0;\n");
      printer->Print(*vars,
                     "virtual ::grpc::ClientAsyncWriterInterface< $Request$>*"
                     " Async$Method$Raw(::grpc::ClientContext* context, "
                     "$Response$* response, "
                     "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
    } else if (method->ServerOnlyStreaming()) {
      printer->Print(
          *vars,
          "virtual ::grpc::ClientReaderInterface< $Response$>* $Method$Raw("
          "::grpc::ClientContext* context, const $Request$& request) = 0;\n");
      printer->Print(
          *vars,
          "virtual ::grpc::ClientAsyncReaderInterface< $Response$>* "
          "Async$Method$Raw("
          "::grpc::ClientContext* context, const $Request$& request, "
          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
    } else if (method->BidiStreaming()) {
      printer->Print(*vars,
                     "virtual ::grpc::ClientReaderWriterInterface< $Request$, "
                     "$Response$>* "
                     "$Method$Raw(::grpc::ClientContext* context) = 0;\n");
      printer->Print(*vars,
                     "virtual ::grpc::ClientAsyncReaderWriterInterface< "
                     "$Request$, $Response$>* "
                     "Async$Method$Raw(::grpc::ClientContext* context, "
                     "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
    }
  }
}

void PrintHeaderClientMethod(Printer *printer,
                             const Method *method,
                             std::map<grpc::string, grpc::string> *vars,
                             bool is_public) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  if (is_public) {
    if (method->NoStreaming()) {
      printer->Print(
          *vars,
          "::grpc::Status $Method$(::grpc::ClientContext* context, "
          "const $Request$& request, $Response$* response) GRPC_OVERRIDE;\n");
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientAsyncResponseReader< $Response$>> "
          "Async$Method$(::grpc::ClientContext* context, "
          "const $Request$& request, "
          "::grpc::CompletionQueue* cq) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientAsyncResponseReader< $Response$>>("
                     "Async$Method$Raw(context, request, cq));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->ClientOnlyStreaming()) {
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientWriter< $Request$>>"
          " $Method$("
          "::grpc::ClientContext* context, $Response$* response) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< ::grpc::ClientWriter< $Request$>>"
                     "($Method$Raw(context, response));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(*vars,
                     "std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>>"
                     " Async$Method$(::grpc::ClientContext* context, "
                     "$Response$* response, "
                     "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>>("
          "Async$Method$Raw(context, response, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->ServerOnlyStreaming()) {
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientReader< $Response$>>"
          " $Method$(::grpc::ClientContext* context, const $Request$& request)"
          " {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< ::grpc::ClientReader< $Response$>>"
          "($Method$Raw(context, request));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>> "
          "Async$Method$("
          "::grpc::ClientContext* context, const $Request$& request, "
          "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(
          *vars,
          "return std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>>("
          "Async$Method$Raw(context, request, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    } else if (method->BidiStreaming()) {
      printer->Print(
          *vars,
          "std::unique_ptr< ::grpc::ClientReaderWriter< $Request$, $Response$>>"
          " $Method$(::grpc::ClientContext* context) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientReaderWriter< $Request$, $Response$>>("
                     "$Method$Raw(context));\n");
      printer->Outdent();
      printer->Print("}\n");
      printer->Print(*vars,
                     "std::unique_ptr<  ::grpc::ClientAsyncReaderWriter< "
                     "$Request$, $Response$>> "
                     "Async$Method$(::grpc::ClientContext* context, "
                     "::grpc::CompletionQueue* cq, void* tag) {\n");
      printer->Indent();
      printer->Print(*vars,
                     "return std::unique_ptr< "
                     "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>>("
                     "Async$Method$Raw(context, cq, tag));\n");
      printer->Outdent();
      printer->Print("}\n");
    }
  } else {
    if (method->NoStreaming()) {
      printer->Print(*vars,
                     "::grpc::ClientAsyncResponseReader< $Response$>* "
                     "Async$Method$Raw(::grpc::ClientContext* context, "
                     "const $Request$& request, "
                     "::grpc::CompletionQueue* cq) GRPC_OVERRIDE;\n");
    } else if (method->ClientOnlyStreaming()) {
      printer->Print(*vars,
                     "::grpc::ClientWriter< $Request$>* $Method$Raw("
                     "::grpc::ClientContext* context, $Response$* response) "
                     "GRPC_OVERRIDE;\n");
      printer->Print(
          *vars,
          "::grpc::ClientAsyncWriter< $Request$>* Async$Method$Raw("
          "::grpc::ClientContext* context, $Response$* response, "
          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
    } else if (method->ServerOnlyStreaming()) {
      printer->Print(*vars,
                     "::grpc::ClientReader< $Response$>* $Method$Raw("
                     "::grpc::ClientContext* context, const $Request$& request)"
                     " GRPC_OVERRIDE;\n");
      printer->Print(
          *vars,
          "::grpc::ClientAsyncReader< $Response$>* Async$Method$Raw("
          "::grpc::ClientContext* context, const $Request$& request, "
          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
    } else if (method->BidiStreaming()) {
      printer->Print(
          *vars,
          "::grpc::ClientReaderWriter< $Request$, $Response$>* "
          "$Method$Raw(::grpc::ClientContext* context) GRPC_OVERRIDE;\n");
      printer->Print(
          *vars,
          "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>* "
          "Async$Method$Raw(::grpc::ClientContext* context, "
          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
    }
  }
}

void PrintHeaderClientMethodData(Printer *printer, const Method *method,
                                 std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  printer->Print(*vars, "const ::grpc::RpcMethod rpcmethod_$Method$_;\n");
}

void PrintHeaderServerMethodSync(Printer *printer, const Method *method,
                                 std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  printer->Print(method->GetLeadingComments().c_str());
  if (method->NoStreaming()) {
    printer->Print(*vars,
                   "virtual ::grpc::Status $Method$("
                   "::grpc::ServerContext* context, const $Request$* request, "
                   "$Response$* response);\n");
  } else if (method->ClientOnlyStreaming()) {
    printer->Print(*vars,
                   "virtual ::grpc::Status $Method$("
                   "::grpc::ServerContext* context, "
                   "::grpc::ServerReader< $Request$>* reader, "
                   "$Response$* response);\n");
  } else if (method->ServerOnlyStreaming()) {
    printer->Print(*vars,
                   "virtual ::grpc::Status $Method$("
                   "::grpc::ServerContext* context, const $Request$* request, "
                   "::grpc::ServerWriter< $Response$>* writer);\n");
  } else if (method->BidiStreaming()) {
    printer->Print(
        *vars,
        "virtual ::grpc::Status $Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerReaderWriter< $Response$, $Request$>* stream);"
        "\n");
  }
  printer->Print(method->GetTrailingComments().c_str());
}

void PrintHeaderServerMethodAsync(
    Printer *printer,
    const Method *method,
    std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  printer->Print(*vars, "template <class BaseClass>\n");
  printer->Print(*vars,
                 "class WithAsyncMethod_$Method$ : public BaseClass {\n");
  printer->Print(
      " private:\n"
      "  void BaseClassMustBeDerivedFromService(const Service *service) {}\n");
  printer->Print(" public:\n");
  printer->Indent();
  printer->Print(*vars,
                 "WithAsyncMethod_$Method$() {\n"
                 "  ::grpc::Service::MarkMethodAsync($Idx$);\n"
                 "}\n");
  printer->Print(*vars,
                 "~WithAsyncMethod_$Method$() GRPC_OVERRIDE {\n"
                 "  BaseClassMustBeDerivedFromService(this);\n"
                 "}\n");
  if (method->NoStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, const $Request$* request, "
        "$Response$* response) GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
    printer->Print(
        *vars,
        "void Request$Method$("
        "::grpc::ServerContext* context, $Request$* request, "
        "::grpc::ServerAsyncResponseWriter< $Response$>* response, "
        "::grpc::CompletionQueue* new_call_cq, "
        "::grpc::ServerCompletionQueue* notification_cq, void *tag) {\n");
    printer->Print(*vars,
                   "  ::grpc::Service::RequestAsyncUnary($Idx$, context, "
                   "request, response, new_call_cq, notification_cq, tag);\n");
    printer->Print("}\n");
  } else if (method->ClientOnlyStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerReader< $Request$>* reader, "
        "$Response$* response) GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
    printer->Print(
        *vars,
        "void Request$Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerAsyncReader< $Response$, $Request$>* reader, "
        "::grpc::CompletionQueue* new_call_cq, "
        "::grpc::ServerCompletionQueue* notification_cq, void *tag) {\n");
    printer->Print(*vars,
                   "  ::grpc::Service::RequestAsyncClientStreaming($Idx$, "
                   "context, reader, new_call_cq, notification_cq, tag);\n");
    printer->Print("}\n");
  } else if (method->ServerOnlyStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, const $Request$* request, "
        "::grpc::ServerWriter< $Response$>* writer) GRPC_FINAL GRPC_OVERRIDE "
        "{\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
    printer->Print(
        *vars,
        "void Request$Method$("
        "::grpc::ServerContext* context, $Request$* request, "
        "::grpc::ServerAsyncWriter< $Response$>* writer, "
        "::grpc::CompletionQueue* new_call_cq, "
        "::grpc::ServerCompletionQueue* notification_cq, void *tag) {\n");
    printer->Print(
        *vars,
        "  ::grpc::Service::RequestAsyncServerStreaming($Idx$, "
        "context, request, writer, new_call_cq, notification_cq, tag);\n");
    printer->Print("}\n");
  } else if (method->BidiStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerReaderWriter< $Response$, $Request$>* stream) "
        "GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
    printer->Print(
        *vars,
        "void Request$Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerAsyncReaderWriter< $Response$, $Request$>* stream, "
        "::grpc::CompletionQueue* new_call_cq, "
        "::grpc::ServerCompletionQueue* notification_cq, void *tag) {\n");
    printer->Print(*vars,
                   "  ::grpc::Service::RequestAsyncBidiStreaming($Idx$, "
                   "context, stream, new_call_cq, notification_cq, tag);\n");
    printer->Print("}\n");
  }
  printer->Outdent();
  printer->Print(*vars, "};\n");
}

void PrintHeaderServerMethodFCUnary(
    Printer *printer,
    const Method *method,
    std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  if (method->NoStreaming()) {
    printer->Print(*vars, "template <class BaseClass>\n");
    printer->Print(*vars,
		   "class WithFCUnaryMethod_$Method$ : public BaseClass {\n");
    printer->Print(
      " private:\n"
      "  void BaseClassMustBeDerivedFromService(const Service *service) {}\n");
    printer->Print(" public:\n");
    printer->Indent();
    printer->Print(*vars,
		   "WithFCUnaryMethod_$Method$() {\n"
		   "  ::grpc::Status (*fn)(::grpc::ServerContext*, ::grpc::FCUnary< $Request$,$Response$>*) = this->WithFCUnaryMethod_$Method$<BaseClass>::$Method$;\n"
		   "  ::grpc::Service::MarkMethodFCUnary($Idx$,\n"
		   "    new ::grpc::FCUnaryMethodHandler<Service, "
		   "$Request$, "
		   "$Response$>(fn, this));\n"
		   "}\n");
    printer->Print(*vars,
		   "~WithFCUnaryMethod_$Method$() GRPC_OVERRIDE {\n"
		   "  BaseClassMustBeDerivedFromService(this);\n"
		   "}\n");
    printer->Print(
        *vars,
        "// disable regular version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, const $Request$* request, "
        "$Response$* response) GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
    printer->Print(
        *vars,
        "// replace default version of this method with FCUnary\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, ::grpc::FCUnary< $Request$,$Response$>* fc_unary)"
        " GRPC_FINAL GRPC_OVERRIDE;\n");
    printer->Outdent();
    printer->Print(*vars, "};\n");
  }
}

void PrintHeaderServerMethodGeneric(
    Printer *printer,
    const Method *method,
    std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  printer->Print(*vars, "template <class BaseClass>\n");
  printer->Print(*vars,
                 "class WithGenericMethod_$Method$ : public BaseClass {\n");
  printer->Print(
      " private:\n"
      "  void BaseClassMustBeDerivedFromService(const Service *service) {}\n");
  printer->Print(" public:\n");
  printer->Indent();
  printer->Print(*vars,
                 "WithGenericMethod_$Method$() {\n"
                 "  ::grpc::Service::MarkMethodGeneric($Idx$);\n"
                 "}\n");
  printer->Print(*vars,
                 "~WithGenericMethod_$Method$() GRPC_OVERRIDE {\n"
                 "  BaseClassMustBeDerivedFromService(this);\n"
                 "}\n");
  if (method->NoStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, const $Request$* request, "
        "$Response$* response) GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
  } else if (method->ClientOnlyStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerReader< $Request$>* reader, "
        "$Response$* response) GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
  } else if (method->ServerOnlyStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, const $Request$* request, "
        "::grpc::ServerWriter< $Response$>* writer) GRPC_FINAL GRPC_OVERRIDE "
        "{\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
  } else if (method->BidiStreaming()) {
    printer->Print(
        *vars,
        "// disable synchronous version of this method\n"
        "::grpc::Status $Method$("
        "::grpc::ServerContext* context, "
        "::grpc::ServerReaderWriter< $Response$, $Request$>* stream) "
        "GRPC_FINAL GRPC_OVERRIDE {\n"
        "  abort();\n"
        "  return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, \"\");\n"
        "}\n");
  }
  printer->Outdent();
  printer->Print(*vars, "};\n");
}

void PrintHeaderService(Printer *printer,
                        const Service *service,
                        std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Service"] = service->name();

  printer->Print(service->GetLeadingComments().c_str());
  printer->Print(*vars,
                 "class $Service$ GRPC_FINAL {\n"
                 " public:\n");
  printer->Indent();

  // Client side
  printer->Print(
      "class StubInterface {\n"
      " public:\n");
  printer->Indent();
  printer->Print("virtual ~StubInterface() {}\n");
  for (int i = 0; i < service->method_count(); ++i) {
    printer->Print(service->method(i)->GetLeadingComments().c_str());
    PrintHeaderClientMethodInterfaces(printer, service->method(i).get(), vars, true);
    printer->Print(service->method(i)->GetTrailingComments().c_str());
  }
  printer->Outdent();
  printer->Print("private:\n");
  printer->Indent();
  for (int i = 0; i < service->method_count(); ++i) {
    PrintHeaderClientMethodInterfaces(printer, service->method(i).get(), vars, false);
  }
  printer->Outdent();
  printer->Print("};\n");
  printer->Print(
      "class Stub GRPC_FINAL : public StubInterface"
      " {\n public:\n");
  printer->Indent();
  printer->Print("Stub(const std::shared_ptr< ::grpc::ChannelInterface>& channel);\n");
  for (int i = 0; i < service->method_count(); ++i) {
    PrintHeaderClientMethod(printer, service->method(i).get(), vars, true);
  }
  printer->Outdent();
  printer->Print("\n private:\n");
  printer->Indent();
  printer->Print("std::shared_ptr< ::grpc::ChannelInterface> channel_;\n");
  for (int i = 0; i < service->method_count(); ++i) {
    PrintHeaderClientMethod(printer, service->method(i).get(), vars, false);
  }
  for (int i = 0; i < service->method_count(); ++i) {
    PrintHeaderClientMethodData(printer, service->method(i).get(), vars);
  }
  printer->Outdent();
  printer->Print("};\n");
  printer->Print(
      "static std::unique_ptr<Stub> NewStub(const std::shared_ptr< "
      "::grpc::ChannelInterface>& channel, "
      "const ::grpc::StubOptions& options = ::grpc::StubOptions());\n");

  printer->Print("\n");

  // Server side - base
  printer->Print(
      "class Service : public ::grpc::Service {\n"
      " public:\n");
  printer->Indent();
  printer->Print("Service();\n");
  printer->Print("virtual ~Service();\n");
  for (int i = 0; i < service->method_count(); ++i) {
    PrintHeaderServerMethodSync(printer, service->method(i).get(), vars);
  }
  printer->Outdent();
  printer->Print("};\n");

  // Server side - Asynchronous
  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Idx"] = as_string(i);
    PrintHeaderServerMethodAsync(printer, service->method(i).get(), vars);
  }

  printer->Print("typedef ");

  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["method_name"] = service->method(i).get()->name();
    printer->Print(*vars, "WithAsyncMethod_$method_name$<");
  }
  printer->Print("Service");
  for (int i = 0; i < service->method_count(); ++i) {
    printer->Print(" >");
  }
  printer->Print(" AsyncService;\n");

  // Server side - Generic
  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Idx"] = as_string(i);
    PrintHeaderServerMethodGeneric(printer, service->method(i).get(), vars);
  }

  // Server side - FC Unary
  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Idx"] = as_string(i);
    PrintHeaderServerMethodFCUnary(printer, service->method(i).get(), vars);
  }

  printer->Outdent();
  printer->Print("};\n");
  printer->Print(service->GetTrailingComments().c_str());
}

grpc::string GetHeaderServices(File *file,
                               const Parameters &params) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;
    // Package string is empty or ends with a dot. It is used to fully qualify
    // method names.
    vars["Package"] = file->package();
    if (!file->package().empty()) {
      vars["Package"].append(".");
    }

    if (!params.services_namespace.empty()) {
      vars["services_namespace"] = params.services_namespace;
      printer->Print(vars, "\nnamespace $services_namespace$ {\n\n");
    }

    for (int i = 0; i < file->service_count(); ++i) {
      PrintHeaderService(printer.get(), file->service(i).get(), &vars);
      printer->Print("\n");
    }

    if (!params.services_namespace.empty()) {
      printer->Print(vars, "}  // namespace $services_namespace$\n\n");
    }
  }
  return output;
}

grpc::string GetHeaderEpilogue(File *file, const Parameters & /*params*/) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;

    vars["filename"] = file->filename();
    vars["filename_identifier"] = FilenameIdentifier(file->filename());

    if (!file->package().empty()) {
      std::vector<grpc::string> parts = file->package_parts();

      for (auto part = parts.rbegin(); part != parts.rend(); part++) {
        vars["part"] = *part;
        printer->Print(vars, "}  // namespace $part$\n");
      }
      printer->Print(vars, "\n");
    }

    printer->Print(vars, "\n");
    printer->Print(vars, "#endif  // GRPC_$filename_identifier$__INCLUDED\n");

    printer->Print(file->GetTrailingComments().c_str());
  }
  return output;
}

grpc::string GetSourcePrologue(File *file, const Parameters & /*params*/) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;

    vars["filename"] = file->filename();
    vars["filename_base"] = file->filename_without_ext();
    vars["message_header_ext"] = file->message_header_ext();
    vars["service_header_ext"] = file->service_header_ext();

    printer->Print(vars, "// Generated by the gRPC protobuf plugin.\n");
    printer->Print(vars,
                  "// If you make any local change, they will be lost.\n");
    printer->Print(vars, "// source: $filename$\n\n");

    printer->Print(vars, "#include \"$filename_base$$message_header_ext$\"\n");
    printer->Print(vars, "#include \"$filename_base$$service_header_ext$\"\n");
    printer->Print(vars, file->additional_headers().c_str());
    printer->Print(vars, "\n");
  }
  return output;
}

grpc::string GetSourceIncludes(File *file,
                               const Parameters &params) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;

    static const char *headers_strs[] = {
      "grpc++/impl/codegen/async_stream.h",
      "grpc++/impl/codegen/async_unary_call.h",
      "grpc++/impl/codegen/channel_interface.h",
      "grpc++/impl/codegen/client_unary_call.h",
      "grpc++/impl/codegen/fc_unary.h",
      "grpc++/impl/codegen/method_handler_impl.h",
      "grpc++/impl/codegen/rpc_service_method.h",
      "grpc++/impl/codegen/service_type.h",
      "grpc++/impl/codegen/sync_stream.h"
    };
    std::vector<grpc::string> headers(headers_strs, array_end(headers_strs));
    PrintIncludes(printer.get(), headers, params);

    if (!file->package().empty()) {
      std::vector<grpc::string> parts = file->package_parts();

      for (auto part = parts.begin(); part != parts.end(); part++) {
        vars["part"] = *part;
        printer->Print(vars, "namespace $part$ {\n");
      }
    }

    printer->Print(vars, "\n");
  }
  return output;
}

void PrintSourceClientMethod(Printer *printer,
                             const Method *method,
                             std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  if (method->NoStreaming()) {
    printer->Print(*vars,
                   "::grpc::Status $ns$$Service$::Stub::$Method$("
                   "::grpc::ClientContext* context, "
                   "const $Request$& request, $Response$* response) {\n");
    printer->Print(*vars,
                   "  return ::grpc::BlockingUnaryCall(channel_.get(), "
                   "rpcmethod_$Method$_, "
                   "context, request, response);\n"
                   "}\n\n");
    printer->Print(
        *vars,
        "::grpc::ClientAsyncResponseReader< $Response$>* "
        "$ns$$Service$::Stub::Async$Method$Raw(::grpc::ClientContext* context, "
        "const $Request$& request, "
        "::grpc::CompletionQueue* cq) {\n");
    printer->Print(*vars,
                   "  return new "
                   "::grpc::ClientAsyncResponseReader< $Response$>("
                   "channel_.get(), cq, "
                   "rpcmethod_$Method$_, "
                   "context, request);\n"
                   "}\n\n");
  } else if (method->ClientOnlyStreaming()) {
    printer->Print(*vars,
                   "::grpc::ClientWriter< $Request$>* "
                   "$ns$$Service$::Stub::$Method$Raw("
                   "::grpc::ClientContext* context, $Response$* response) {\n");
    printer->Print(*vars,
                   "  return new ::grpc::ClientWriter< $Request$>("
                   "channel_.get(), "
                   "rpcmethod_$Method$_, "
                   "context, response);\n"
                   "}\n\n");
    printer->Print(*vars,
                   "::grpc::ClientAsyncWriter< $Request$>* "
                   "$ns$$Service$::Stub::Async$Method$Raw("
                   "::grpc::ClientContext* context, $Response$* response, "
                   "::grpc::CompletionQueue* cq, void* tag) {\n");
    printer->Print(*vars,
                   "  return new ::grpc::ClientAsyncWriter< $Request$>("
                   "channel_.get(), cq, "
                   "rpcmethod_$Method$_, "
                   "context, response, tag);\n"
                   "}\n\n");
  } else if (method->ServerOnlyStreaming()) {
    printer->Print(
        *vars,
        "::grpc::ClientReader< $Response$>* "
        "$ns$$Service$::Stub::$Method$Raw("
        "::grpc::ClientContext* context, const $Request$& request) {\n");
    printer->Print(*vars,
                   "  return new ::grpc::ClientReader< $Response$>("
                   "channel_.get(), "
                   "rpcmethod_$Method$_, "
                   "context, request);\n"
                   "}\n\n");
    printer->Print(*vars,
                   "::grpc::ClientAsyncReader< $Response$>* "
                   "$ns$$Service$::Stub::Async$Method$Raw("
                   "::grpc::ClientContext* context, const $Request$& request, "
                   "::grpc::CompletionQueue* cq, void* tag) {\n");
    printer->Print(*vars,
                   "  return new ::grpc::ClientAsyncReader< $Response$>("
                   "channel_.get(), cq, "
                   "rpcmethod_$Method$_, "
                   "context, request, tag);\n"
                   "}\n\n");
  } else if (method->BidiStreaming()) {
    printer->Print(
        *vars,
        "::grpc::ClientReaderWriter< $Request$, $Response$>* "
        "$ns$$Service$::Stub::$Method$Raw(::grpc::ClientContext* context) {\n");
    printer->Print(*vars,
                   "  return new ::grpc::ClientReaderWriter< "
                   "$Request$, $Response$>("
                   "channel_.get(), "
                   "rpcmethod_$Method$_, "
                   "context);\n"
                   "}\n\n");
    printer->Print(
        *vars,
        "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>* "
        "$ns$$Service$::Stub::Async$Method$Raw(::grpc::ClientContext* context, "
        "::grpc::CompletionQueue* cq, void* tag) {\n");
    printer->Print(*vars,
                   "  return new "
                   "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>("
                   "channel_.get(), cq, "
                   "rpcmethod_$Method$_, "
                   "context, tag);\n"
                   "}\n\n");
  }
}

void PrintSourceServerMethod(Printer *printer,
                             const Method *method,
                             std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Method"] = method->name();
  (*vars)["Request"] = method->input_type_name();
  (*vars)["Response"] = method->output_type_name();
  if (method->NoStreaming()) {
    printer->Print(*vars,
                   "::grpc::Status $ns$$Service$::Service::$Method$("
                   "::grpc::ServerContext* context, "
                   "const $Request$* request, $Response$* response) {\n");
    printer->Print("  (void) context;\n");
    printer->Print("  (void) request;\n");
    printer->Print("  (void) response;\n");
    printer->Print(
        "  return ::grpc::Status("
        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
    printer->Print("}\n\n");
  } else if (method->ClientOnlyStreaming()) {
    printer->Print(*vars,
                   "::grpc::Status $ns$$Service$::Service::$Method$("
                   "::grpc::ServerContext* context, "
                   "::grpc::ServerReader< $Request$>* reader, "
                   "$Response$* response) {\n");
    printer->Print("  (void) context;\n");
    printer->Print("  (void) reader;\n");
    printer->Print("  (void) response;\n");
    printer->Print(
        "  return ::grpc::Status("
        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
    printer->Print("}\n\n");
  } else if (method->ServerOnlyStreaming()) {
    printer->Print(*vars,
                   "::grpc::Status $ns$$Service$::Service::$Method$("
                   "::grpc::ServerContext* context, "
                   "const $Request$* request, "
                   "::grpc::ServerWriter< $Response$>* writer) {\n");
    printer->Print("  (void) context;\n");
    printer->Print("  (void) request;\n");
    printer->Print("  (void) writer;\n");
    printer->Print(
        "  return ::grpc::Status("
        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
    printer->Print("}\n\n");
  } else if (method->BidiStreaming()) {
    printer->Print(*vars,
                   "::grpc::Status $ns$$Service$::Service::$Method$("
                   "::grpc::ServerContext* context, "
                   "::grpc::ServerReaderWriter< $Response$, $Request$>* "
                   "stream) {\n");
    printer->Print("  (void) context;\n");
    printer->Print("  (void) stream;\n");
    printer->Print(
        "  return ::grpc::Status("
        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
    printer->Print("}\n\n");
  }
}

void PrintSourceService(Printer *printer,
                        const Service *service,
                        std::map<grpc::string, grpc::string> *vars) {
  (*vars)["Service"] = service->name();

  printer->Print(*vars,
                 "static const char* $prefix$$Service$_method_names[] = {\n");
  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Method"] = service->method(i).get()->name();
    printer->Print(*vars, "  \"/$Package$$Service$/$Method$\",\n");
  }
  printer->Print(*vars, "};\n\n");

  printer->Print(*vars,
                 "std::unique_ptr< $ns$$Service$::Stub> $ns$$Service$::NewStub("
                 "const std::shared_ptr< ::grpc::ChannelInterface>& channel, "
                 "const ::grpc::StubOptions& options) {\n"
                 "  std::unique_ptr< $ns$$Service$::Stub> stub(new "
                 "$ns$$Service$::Stub(channel));\n"
                 "  return stub;\n"
                 "}\n\n");
  printer->Print(*vars,
                 "$ns$$Service$::Stub::Stub(const std::shared_ptr< "
                 "::grpc::ChannelInterface>& channel)\n");
  printer->Indent();
  printer->Print(": channel_(channel)");
  for (int i = 0; i < service->method_count(); ++i) {
    auto method = service->method(i);
    (*vars)["Method"] = method->name();
    (*vars)["Idx"] = as_string(i);
    if (method->NoStreaming()) {
      (*vars)["StreamingType"] = "NORMAL_RPC";
      // NOTE: There is no reason to consider FC_UNARY as a separate
      // category here since this part is setting up the client-side stub
      // and this appears as a NORMAL_RPC from the client-side.
    } else if (method->ClientOnlyStreaming()) {
      (*vars)["StreamingType"] = "CLIENT_STREAMING";
    } else if (method->ServerOnlyStreaming()) {
      (*vars)["StreamingType"] = "SERVER_STREAMING";
    } else {
      (*vars)["StreamingType"] = "BIDI_STREAMING";
    }
    printer->Print(*vars,
                   ", rpcmethod_$Method$_("
                   "$prefix$$Service$_method_names[$Idx$], "
                   "::grpc::RpcMethod::$StreamingType$, "
                   "channel"
                   ")\n");
  }
  printer->Print("{}\n\n");
  printer->Outdent();

  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Idx"] = as_string(i);
    PrintSourceClientMethod(printer, service->method(i).get(), vars);
  }

  printer->Print(*vars, "$ns$$Service$::Service::Service() {\n");
  printer->Indent();
  printer->Print(*vars, "(void)$prefix$$Service$_method_names;\n");
  for (int i = 0; i < service->method_count(); ++i) {
    auto method = service->method(i);
    (*vars)["Idx"] = as_string(i);
    (*vars)["Method"] = method->name();
    (*vars)["Request"] = method->input_type_name();
    (*vars)["Response"] = method->output_type_name();
    if (method->NoStreaming()) {
      printer->Print(
          *vars,
          "AddMethod(new ::grpc::RpcServiceMethod(\n"
          "    $prefix$$Service$_method_names[$Idx$],\n"
          "    ::grpc::RpcMethod::NORMAL_RPC,\n"
          "    new ::grpc::RpcMethodHandler< $ns$$Service$::Service, "
          "$Request$, "
          "$Response$>(\n"
          "        std::mem_fn(&$ns$$Service$::Service::$Method$), this)));\n");
    } else if (method->ClientOnlyStreaming()) {
      printer->Print(
          *vars,
          "AddMethod(new ::grpc::RpcServiceMethod(\n"
          "    $prefix$$Service$_method_names[$Idx$],\n"
          "    ::grpc::RpcMethod::CLIENT_STREAMING,\n"
          "    new ::grpc::ClientStreamingHandler< "
          "$ns$$Service$::Service, $Request$, $Response$>(\n"
          "        std::mem_fn(&$ns$$Service$::Service::$Method$), this)));\n");
    } else if (method->ServerOnlyStreaming()) {
      printer->Print(
          *vars,
          "AddMethod(new ::grpc::RpcServiceMethod(\n"
          "    $prefix$$Service$_method_names[$Idx$],\n"
          "    ::grpc::RpcMethod::SERVER_STREAMING,\n"
          "    new ::grpc::ServerStreamingHandler< "
          "$ns$$Service$::Service, $Request$, $Response$>(\n"
          "        std::mem_fn(&$ns$$Service$::Service::$Method$), this)));\n");
    } else if (method->BidiStreaming()) {
      printer->Print(
          *vars,
          "AddMethod(new ::grpc::RpcServiceMethod(\n"
          "    $prefix$$Service$_method_names[$Idx$],\n"
          "    ::grpc::RpcMethod::BIDI_STREAMING,\n"
          "    new ::grpc::BidiStreamingHandler< "
          "$ns$$Service$::Service, $Request$, $Response$>(\n"
          "        std::mem_fn(&$ns$$Service$::Service::$Method$), this)));\n");
    }
  }
  printer->Outdent();
  printer->Print(*vars, "}\n\n");
  printer->Print(*vars,
                 "$ns$$Service$::Service::~Service() {\n"
                 "}\n\n");
  for (int i = 0; i < service->method_count(); ++i) {
    (*vars)["Idx"] = as_string(i);
    PrintSourceServerMethod(printer, service->method(i).get(), vars);
  }
}

grpc::string GetSourceServices(File *file,
                               const Parameters &params) {
  grpc::string output;
  {
    // Scope the output stream so it closes and finalizes output to the string.
    auto printer = file->CreatePrinter(&output);
    std::map<grpc::string, grpc::string> vars;
    // Package string is empty or ends with a dot. It is used to fully qualify
    // method names.
    vars["Package"] = file->package();
    if (!file->package().empty()) {
      vars["Package"].append(".");
    }
    if (!params.services_namespace.empty()) {
      vars["ns"] = params.services_namespace + "::";
      vars["prefix"] = params.services_namespace;
    } else {
      vars["ns"] = "";
      vars["prefix"] = "";
    }

    for (int i = 0; i < file->service_count(); ++i) {
      PrintSourceService(printer.get(), file->service(i).get(), &vars);
      printer->Print("\n");
    }
  }
  return output;
}

grpc::string GetSourceEpilogue(File *file, const Parameters & /*params*/) {
  grpc::string temp;

  if (!file->package().empty()) {
    std::vector<grpc::string> parts = file->package_parts();

    for (auto part = parts.begin(); part != parts.end(); part++) {
      temp.append("}  // namespace ");
      temp.append(*part);
      temp.append("\n");
    }
    temp.append("\n");
  }

  return temp;
}

}  // namespace grpc_cpp_generator