node_generator.cc

/*
 *
 * Copyright 2016, 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/config.h"
#include "src/compiler/generator_helpers.h"
#include "src/compiler/node_generator_helpers.h"

using grpc::protobuf::FileDescriptor;
using grpc::protobuf::ServiceDescriptor;
using grpc::protobuf::MethodDescriptor;
using grpc::protobuf::Descriptor;
using grpc::protobuf::io::Printer;
using grpc::protobuf::io::StringOutputStream;
using std::map;

namespace grpc_node_generator {
namespace {

// Returns the alias we assign to the module of the given .proto filename
// when importing. Copied entirely from
// github:google/protobuf/src/google/protobuf/compiler/js/js_generator.cc#L154
grpc::string ModuleAlias(const grpc::string filename) {
  // This scheme could technically cause problems if a file includes any 2 of:
  //   foo/bar_baz.proto
  //   foo_bar_baz.proto
  //   foo_bar/baz.proto
  //
  // We'll worry about this problem if/when we actually see it.  This name isn't
  // exposed to users so we can change it later if we need to.
  grpc::string basename = grpc_generator::StripProto(filename);
  basename = grpc_generator::StringReplace(basename, "-", "$");
  basename = grpc_generator::StringReplace(basename, "/", "_");
  return basename + "_pb";
}

// Given a filename like foo/bar/baz.proto, returns the corresponding JavaScript
// message file foo/bar/baz.js
grpc::string GetJSMessageFilename(const grpc::string& filename) {
  grpc::string name = filename;
  return grpc_generator::StripProto(name) + "_pb.js";
}

// Given a filename like foo/bar/baz.proto, returns the root directory
// path ../../
grpc::string GetRootPath(const grpc::string& filename) {
  size_t slashes = std::count(filename.begin(), filename.end(), '/');
  if (slashes == 0) {
    return "./";
  }
  grpc::string result = "";
  for (size_t i = 0; i < slashes; i++) {
    result += "../";
  }
  return result;
}

// Return the relative path to load to_file from the directory containing
// from_file, assuming that both paths are relative to the same directory
grpc::string GetRelativePath(const grpc::string& from_file,
                             const grpc::string& to_file) {
  return GetRootPath(from_file) + to_file;
}

/* Finds all message types used in all services in the file, and returns them
 * as a map of fully qualified message type name to message descriptor */
map<grpc::string, const Descriptor*> GetAllMessages(const FileDescriptor *file) {
  map<grpc::string, const Descriptor*> message_types;
  for (int i = 0; i < file->service_count(); i++) {
    const ServiceDescriptor* service = file->service(i);
    for (int j = 0; j < service->method_count(); j++) {
      const MethodDescriptor* method = service->method(i);
      const Descriptor* input_type = method->input_type();
      const Descriptor* output_type = method->output_type();
      message_types[input_type->name()] = input_type;
      message_types[output_type->name()] = output_type;
    }
  }
  return message_types;
}

grpc::string MessageIdentifierName(const grpc::string& name) {
  return grpc_generator::StringReplace(name, ".", "_");
}

grpc::string NodeObjectPath(const Descriptor *descriptor) {
  grpc::string module_alias = ModuleAlias(descriptor->file()->name());
  grpc::string name = descriptor->name();
  grpc_generator::StripPrefix(&name, descriptor->file()->package() + ".");
  return module_alias + "." + name;
}

// Prints out the message serializer and deserializer functions
void PrintMessageTransformer(const Descriptor *descriptor, Printer *out) {
  map<grpc::string, grpc::string> template_vars;
  template_vars["identifier_name"] = MessageIdentifierName(descriptor->name());
  template_vars["name"] = descriptor->name();
  template_vars["node_name"] = NodeObjectPath(descriptor);
  // Print the serializer
  out->Print(template_vars, "function serialize_$identifier_name$(arg) {\n");
  out->Indent();
  out->Print(template_vars, "if (!(arg instanceof $node_name$)) {\n");
  out->Indent();
  out->Print(template_vars,
             "throw new Error('Expected argument of type $name$');\n");
  out->Outdent();
  out->Print("}\n");
  out->Print("return new Buffer(arg.serializeBinary());\n");
  out->Outdent();
  out->Print("}\n");

  // Print the deserializer
  out->Print(template_vars,
             "function deserialize_$identifier_name$(buffer_arg) {\n");
  out->Indent();
  out->Print(
      template_vars,
      "return $node_name$.deserializeBinary(new Uint8Array(buffer_arg));\n");
  out->Outdent();
  out->Print("}\n");
}

void PrintMethod(const MethodDescriptor *method, Printer *out) {
  const Descriptor *input_type = method->input_type();
  const Descriptor *output_type = method->output_type();
  map<grpc::string, grpc::string> vars;
  vars["service_name"] = method->service()->full_name();
  vars["name"] = method->name();
  vars["input_type"] = NodeObjectPath(input_type);
  vars["input_type_id"] = MessageIdentifierName(input_type->name());
  vars["output_type"] = NodeObjectPath(output_type);
  vars["output_type_id"] = MessageIdentifierName(output_type->name());
  vars["client_stream"] = method->client_streaming() ? "true" : "false";
  vars["server_stream"] = method->server_streaming() ? "true" : "false";
  out->Print("{\n");
  out->Indent();
  out->Print(vars, "path: '/$service_name$/$name$',\n");
  out->Print(vars, "requestStream: $client_stream$,\n");
  out->Print(vars, "responseStream: $server_stream$,\n");
  out->Print(vars, "requestType: $input_type$,\n");
  out->Print(vars, "responseType: $output_type$,\n");
  out->Print(vars, "requestSerialize: serialize_$input_type_id$,\n");
  out->Print(vars, "requestDeserialize: deserialize_$input_type_id$,\n");
  out->Print(vars, "responseSerialize: serialize_$output_type_id$,\n");
  out->Print(vars, "responseDeserialize: deserialize_$output_type_id$,\n");
  out->Outdent();
  out->Print("}");
}

// Prints out the service descriptor object
void PrintService(const ServiceDescriptor *service, Printer *out) {
  map<grpc::string, grpc::string> template_vars;
  template_vars["name"] = service->name();
  out->Print(template_vars, "var $name$Service = exports.$name$Service = {\n");
  out->Indent();
  for (int i = 0; i < service->method_count(); i++) {
    grpc::string method_name = grpc_generator::LowercaseFirstLetter(
        service->method(i)->name());
    out->Print("$method_name$: ",
               "method_name", method_name);
    PrintMethod(service->method(i), out);
    out->Print(",\n");
  }
  out->Outdent();
  out->Print("};\n\n");
  out->Print(template_vars, "exports.$name$Client = "
             "grpc.makeGenericClientConstructor($name$Service);\n");
}

}

grpc::string GetImports(const FileDescriptor *file) {
  grpc::string output;
  {
    StringOutputStream output_stream(&output);
    Printer out(&output_stream, '$');

    if (file->service_count() == 0) {
      return output;
    }

    out.Print("var grpc = require('grpc');\n");
    if (file->message_type_count() > 0) {
      grpc::string file_path = GetRelativePath(file->name(),
                                               GetJSMessageFilename(
                                                   file->name()));
      out.Print("var $module_alias$ = require('$file_path$');\n",
                "module_alias", ModuleAlias(file->name()),
                "file_path", file_path);
    }

    for (int i = 0; i < file->dependency_count(); i++) {
      grpc::string file_path = GetRelativePath(
          file->name(), GetJSMessageFilename(file->dependency(i)->name()));
      out.Print("var $module_alias$ = require('$file_path$');\n",
                "module_alias", ModuleAlias(file->dependency(i)->name()),
                "file_path", file_path);
    }
    out.Print("\n");
  }
  return output;
}

grpc::string GetTransformers(const FileDescriptor *file) {
  grpc::string output;
  {
    StringOutputStream output_stream(&output);
    Printer out(&output_stream, '$');

    if (file->service_count() == 0) {
      return output;
    }

    map<grpc::string, const Descriptor*> messages = GetAllMessages(file);
    for (std::map<grpc::string, const Descriptor*>::iterator it =
             messages.begin();
         it != messages.end(); it++) {
      PrintMessageTransformer(it->second, &out);
    }
    out.Print("\n");
  }
  return output;
}

grpc::string GetServices(const FileDescriptor *file) {
  grpc::string output;
  {
    StringOutputStream output_stream(&output);
    Printer out(&output_stream, '$');

    if (file->service_count() == 0) {
      return output;
    }

    for (int i = 0; i < file->service_count(); i++) {
      PrintService(file->service(i), &out);
    }
  }
  return output;
}

}  // namespace grpc_node_generator