Componentize html_viewer's MessagePort

components/html_viewer/web_message_port_channel_impl.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/html_viewer/web_message_port_channel_impl.h"
-
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/strings/string16.h"
-#include "third_party/WebKit/public/platform/WebMessagePortChannelClient.h"
-#include "third_party/WebKit/public/platform/WebString.h"
-#include "third_party/mojo/src/mojo/public/cpp/system/message_pipe.h"
-
-using blink::WebMessagePortChannel;
-using blink::WebMessagePortChannelArray;
-using blink::WebMessagePortChannelClient;
-using blink::WebString;
-
-namespace html_viewer {
-
-void WebMessagePortChannelImpl::CreatePair(
-    blink::WebMessagePortChannel** channel1,
-    blink::WebMessagePortChannel** channel2) {
-  mojo::ScopedMessagePipeHandle pipe1;
-  mojo::ScopedMessagePipeHandle pipe2;
-  MojoResult result = mojo::CreateMessagePipe(nullptr, &pipe1, &pipe2);
-  if (result != MOJO_RESULT_OK) {
-    NOTREACHED();
-    return;
-  }
-
-  *channel1 = new WebMessagePortChannelImpl(pipe1.Pass());;
-  *channel2 = new WebMessagePortChannelImpl(pipe2.Pass());
-}
-
-WebMessagePortChannelImpl::WebMessagePortChannelImpl(
-    mojo::ScopedMessagePipeHandle pipe)
-    : client_(nullptr), pipe_(pipe.Pass()) {
-  WaitForNextMessage();
-}
-
-WebMessagePortChannelImpl::~WebMessagePortChannelImpl() {
-}
-
-void WebMessagePortChannelImpl::setClient(WebMessagePortChannelClient* client) {
-  client_ = client;
-}
-
-void WebMessagePortChannelImpl::destroy() {
-  setClient(nullptr);
-  delete this;
-}
-
-void WebMessagePortChannelImpl::postMessage(
-    const WebString& message_as_string,
-    WebMessagePortChannelArray* channels) {
-  base::string16 string = message_as_string;
-
-  std::vector<MojoHandle> handles;
-  if (channels) {
-    for (size_t i = 0; i < channels->size(); ++i) {
-      WebMessagePortChannelImpl* channel =
-          static_cast<WebMessagePortChannelImpl*>((*channels)[i]);
-      handles.push_back(channel->pipe_.release().value());
-      channel->handle_watcher_.Stop();
-    }
-    delete channels;
-  }
-
-  uint32_t num_handles = static_cast<uint32_t>(handles.size());
-  MojoHandle* handles_ptr = handles.empty() ? nullptr : &handles[0];
-
-  MojoResult result = MojoWriteMessage(
-      pipe_.get().value(), string.c_str(),
-      static_cast<uint32_t>(string.length() * sizeof(base::char16)),
-      handles_ptr, num_handles, MOJO_WRITE_MESSAGE_FLAG_NONE);
-  DCHECK_EQ(MOJO_RESULT_OK, result);
-}
-
-bool WebMessagePortChannelImpl::tryGetMessage(
-    WebString* message,
-    WebMessagePortChannelArray& channels) {
-  uint32_t num_bytes = 0;
-  uint32_t num_handles = 0;
-  MojoResult result = MojoReadMessage(
-      pipe_.get().value(), nullptr, &num_bytes, nullptr, &num_handles,
-      MOJO_READ_MESSAGE_FLAG_NONE);
-  if (result != MOJO_RESULT_RESOURCE_EXHAUSTED)
-    return false;
-
-  base::string16 message16;
-  CHECK(num_bytes % sizeof(base::char16) == 0);
-  message16.resize(num_bytes / sizeof(base::char16));
-  std::vector<MojoHandle> handles;
-  handles.resize(num_handles);
-
-  MojoHandle* handles_ptr = handles.empty() ? nullptr : &handles[0];
-  result = MojoReadMessage(
-      pipe_.get().value(), &message16[0], &num_bytes, handles_ptr, &num_handles,
-      MOJO_READ_MESSAGE_FLAG_NONE);
-  if (result != MOJO_RESULT_OK) {
-    NOTREACHED();
-    return false;
-  }
-
-  *message = message16;
-  WebMessagePortChannelArray ports(handles.size());
-  for (size_t i = 0; i < handles.size(); ++i) {
-    mojo::MessagePipeHandle mph(handles[i]);
-    mojo::ScopedMessagePipeHandle handle(mph);
-    ports[i] = new WebMessagePortChannelImpl(handle.Pass());
-  }
-  channels = ports;
-  return true;
-}
-
-void WebMessagePortChannelImpl::WaitForNextMessage() {
-  handle_watcher_.Start(
-      pipe_.get(),
-      MOJO_HANDLE_SIGNAL_READABLE,
-      MOJO_DEADLINE_INDEFINITE,
-      base::Bind(&WebMessagePortChannelImpl::OnMessageAvailable,
-                 base::Unretained(this)));
-}
-
-void WebMessagePortChannelImpl::OnMessageAvailable(MojoResult result) {
-  DCHECK_EQ(MOJO_RESULT_OK, result);
-  client_->messageAvailable();
-  WaitForNextMessage();
-}
-
-}  // namespace html_viewer