Mojo: Add the ability to hook up a channel to the embedder API.

mojo/system/embedder.cc

 // Copyright 2014 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 "mojo/system/embedder.h"
 
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "mojo/system/channel.h"
 #include "mojo/system/core_impl.h"
+#include "mojo/system/local_message_pipe_endpoint.h"
+#include "mojo/system/message_pipe.h"
+#include "mojo/system/message_pipe_dispatcher.h"
+#include "mojo/system/proxy_message_pipe_endpoint.h"
 
 namespace mojo {
+
+namespace embedder {
+
+struct ChannelInfo {
+  scoped_refptr<system::Channel> channel;
+};
+
+}  // namespace embedder
+
+// Have helpers in the |system| namespace, to avoid saying "system::" all over
+// the place.
+namespace system {
+namespace {
+
+void CreateChannelOnIOThread(
+    ScopedPlatformHandle platform_handle,
+    scoped_refptr<MessagePipe> message_pipe,
+    embedder::DidCreateChannelOnIOThreadCallback callback) {
+  CHECK(platform_handle.is_valid());
+
+  scoped_ptr<embedder::ChannelInfo> channel_info(new embedder::ChannelInfo);
+
+  // Create and initialize |Channel|.
+  channel_info->channel = new Channel();
+  bool success = channel_info->channel->Init(platform_handle.Pass());
+  DCHECK(success);
+
+  // Attach the message pipe endpoint.
+  MessageInTransit::EndpointId endpoint_id =
+      channel_info->channel->AttachMessagePipeEndpoint(message_pipe, 1);
+  DCHECK_EQ(endpoint_id, Channel::kBootstrapEndpointId);
+  channel_info->channel->RunMessagePipeEndpoint(Channel::kBootstrapEndpointId,
+                                                Channel::kBootstrapEndpointId);
+
+  // Hand the channel back to the embedder.
+  callback.Run(channel_info.release());
+}
+
+MojoHandle CreateChannelHelper(
+    ScopedPlatformHandle platform_handle,
+    scoped_refptr<base::TaskRunner> io_thread_task_runner,
+    embedder::DidCreateChannelOnIOThreadCallback callback) {
+  DCHECK(platform_handle.is_valid());
+
+  scoped_refptr<MessagePipe> message_pipe(new MessagePipe(
+      scoped_ptr<MessagePipeEndpoint>(new LocalMessagePipeEndpoint()),
+      scoped_ptr<MessagePipeEndpoint>(new ProxyMessagePipeEndpoint())));
+  scoped_refptr<MessagePipeDispatcher> dispatcher(new MessagePipeDispatcher());
+  dispatcher->Init(message_pipe, 0);
+
+  CoreImpl* core_impl = static_cast<CoreImpl*>(Core::Get());
+  DCHECK(core_impl);
+  MojoHandle rv = core_impl->AddDispatcher(dispatcher);
+  // TODO(vtl): Do we properly handle the failure case here?
+  if (rv != MOJO_HANDLE_INVALID) {
+    io_thread_task_runner->PostTask(FROM_HERE,
+                                    base::Bind(&CreateChannelOnIOThread,
+                                               base::Passed(&platform_handle),
+                                               message_pipe,
+                                               callback));
+  }
+  return rv;
+}
+
+}  // namespace
+}  // namespace system
+
 namespace embedder {
 
 void Init() {
   Core::Init(new system::CoreImpl());
 }
 
+MojoHandle CreateChannel(
+    system::ScopedPlatformHandle platform_handle,
+    scoped_refptr<base::TaskRunner> io_thread_task_runner,
+    DidCreateChannelOnIOThreadCallback callback) {
+  return system::CreateChannelHelper(platform_handle.Pass(),
+                                     io_thread_task_runner,
+                                     callback);
+}
+
+void DestroyChannelOnIOThread(ChannelInfo* channel_info) {
+  DCHECK(channel_info);
+  DCHECK(channel_info->channel.get());
+  channel_info->channel->Shutdown();
+  delete channel_info;
+}
+
 }  // namespace embedder
 }  // namespace mojo