src/mojo/embedder/embedder.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "mojo/embedder/embedder.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/logging.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "mojo/embedder/platform_support.h"
  12 #include "mojo/system/channel.h"
  13 #include "mojo/system/channel_endpoint.h"
  14 #include "mojo/system/core.h"
  15 #include "mojo/system/entrypoints.h"
  16 #include "mojo/system/message_in_transit.h"
  17 #include "mojo/system/message_pipe_dispatcher.h"
  18 #include "mojo/system/platform_handle_dispatcher.h"
  19 #include "mojo/system/raw_channel.h"
  20
  21 namespace mojo {
  22 namespace embedder {
  23
  24 // This is defined here (instead of a header file), since it's opaque to the
  25 // outside world. But we need to define it before our (internal-only) functions
  26 // that use it.
  27 struct ChannelInfo {
  28   ChannelInfo() {}
  29   ~ChannelInfo() {}
  30
  31   scoped_refptr<system::Channel> channel;
  32
  33   // May be null, in which case |DestroyChannelOnIOThread()| must be used (from
  34   // the IO thread), instead of |DestroyChannel()|.
  35   scoped_refptr<base::TaskRunner> io_thread_task_runner;
  36 };
  37
  38 namespace {
  39
  40 // Helper for |CreateChannel...()|. (Note: May return null for some failures.)
  41 scoped_refptr<system::Channel> MakeChannel(
  42     system::Core* core,
  43     ScopedPlatformHandle platform_handle,
  44     scoped_refptr<system::ChannelEndpoint> channel_endpoint) {
  45   DCHECK(platform_handle.is_valid());
  46
  47   // Create and initialize a |system::Channel|.
  48   scoped_refptr<system::Channel> channel =
  49       new system::Channel(core->platform_support());
  50   if (!channel->Init(system::RawChannel::Create(platform_handle.Pass()))) {
  51     // This is very unusual (e.g., maybe |platform_handle| was invalid or we
  52     // reached some system resource limit).
  53     LOG(ERROR) << "Channel::Init() failed";
  54     // Return null, since |Shutdown()| shouldn't be called in this case.
  55     return scoped_refptr<system::Channel>();
  56   }
  57   // Once |Init()| has succeeded, we have to return |channel| (since
  58   // |Shutdown()| will have to be called on it).
  59
  60   // Attach the endpoint.
  61   system::MessageInTransit::EndpointId endpoint_id =
  62       channel->AttachEndpoint(channel_endpoint);
  63   if (endpoint_id == system::MessageInTransit::kInvalidEndpointId) {
  64     // This means that, e.g., the other endpoint of the message pipe was closed
  65     // first. But it's not necessarily an error per se.
  66     DVLOG(2) << "Channel::AttachEndpoint() failed";
  67     return channel;
  68   }
  69   CHECK_EQ(endpoint_id, system::Channel::kBootstrapEndpointId);
  70
  71   if (!channel->RunMessagePipeEndpoint(system::Channel::kBootstrapEndpointId,
  72                                        system::Channel::kBootstrapEndpointId)) {
  73     // Currently, there's no reason for this to fail.
  74     NOTREACHED() << "Channel::RunMessagePipeEndpoint() failed";
  75     return channel;
  76   }
  77
  78   return channel;
  79 }
  80
  81 void CreateChannelHelper(
  82     system::Core* core,
  83     ScopedPlatformHandle platform_handle,
  84     scoped_ptr<ChannelInfo> channel_info,
  85     scoped_refptr<system::ChannelEndpoint> channel_endpoint,
  86     DidCreateChannelCallback callback,
  87     scoped_refptr<base::TaskRunner> callback_thread_task_runner) {
  88   channel_info->channel =
  89       MakeChannel(core, platform_handle.Pass(), channel_endpoint);
  90
  91   // Hand the channel back to the embedder.
  92   if (callback_thread_task_runner.get()) {
  93     callback_thread_task_runner->PostTask(
  94         FROM_HERE, base::Bind(callback, channel_info.release()));
  95   } else {
  96     callback.Run(channel_info.release());
  97   }
  98 }
  99
 100 }  // namespace
 101
 102 void Init(scoped_ptr<PlatformSupport> platform_support) {
 103   system::entrypoints::SetCore(new system::Core(platform_support.Pass()));
 104 }
 105
 106 // TODO(vtl): Write tests for this.
 107 ScopedMessagePipeHandle CreateChannelOnIOThread(
 108     ScopedPlatformHandle platform_handle,
 109     ChannelInfo** channel_info) {
 110   DCHECK(platform_handle.is_valid());
 111   DCHECK(channel_info);
 112
 113   scoped_refptr<system::ChannelEndpoint> channel_endpoint;
 114   scoped_refptr<system::MessagePipeDispatcher> dispatcher =
 115       system::MessagePipeDispatcher::CreateRemoteMessagePipe(&channel_endpoint);
 116
 117   system::Core* core = system::entrypoints::GetCore();
 118   DCHECK(core);
 119   ScopedMessagePipeHandle rv(
 120       MessagePipeHandle(core->AddDispatcher(dispatcher)));
 121
 122   *channel_info = new ChannelInfo();
 123   (*channel_info)->channel =
 124       MakeChannel(core, platform_handle.Pass(), channel_endpoint);
 125
 126   return rv.Pass();
 127 }
 128
 129 ScopedMessagePipeHandle CreateChannel(
 130     ScopedPlatformHandle platform_handle,
 131     scoped_refptr<base::TaskRunner> io_thread_task_runner,
 132     DidCreateChannelCallback callback,
 133     scoped_refptr<base::TaskRunner> callback_thread_task_runner) {
 134   DCHECK(platform_handle.is_valid());
 135
 136   scoped_refptr<system::ChannelEndpoint> channel_endpoint;
 137   scoped_refptr<system::MessagePipeDispatcher> dispatcher =
 138       system::MessagePipeDispatcher::CreateRemoteMessagePipe(&channel_endpoint);
 139
 140   system::Core* core = system::entrypoints::GetCore();
 141   DCHECK(core);
 142   ScopedMessagePipeHandle rv(
 143       MessagePipeHandle(core->AddDispatcher(dispatcher)));
 144
 145   scoped_ptr<ChannelInfo> channel_info(new ChannelInfo());
 146   channel_info->io_thread_task_runner = io_thread_task_runner;
 147
 148   if (rv.is_valid()) {
 149     io_thread_task_runner->PostTask(FROM_HERE,
 150                                     base::Bind(&CreateChannelHelper,
 151                                                base::Unretained(core),
 152                                                base::Passed(&platform_handle),
 153                                                base::Passed(&channel_info),
 154                                                channel_endpoint,
 155                                                callback,
 156                                                callback_thread_task_runner));
 157   } else {
 158     (callback_thread_task_runner.get() ? callback_thread_task_runner
 159                                        : io_thread_task_runner)
 160         ->PostTask(FROM_HERE, base::Bind(callback, channel_info.release()));
 161   }
 162
 163   return rv.Pass();
 164 }
 165
 166 void DestroyChannelOnIOThread(ChannelInfo* channel_info) {
 167   DCHECK(channel_info);
 168   if (!channel_info->channel.get()) {
 169     // Presumably, |Init()| on the channel failed.
 170     return;
 171   }
 172
 173   channel_info->channel->Shutdown();
 174   delete channel_info;
 175 }
 176
 177 // TODO(vtl): Write tests for this.
 178 void DestroyChannel(ChannelInfo* channel_info) {
 179   DCHECK(channel_info);
 180   DCHECK(channel_info->io_thread_task_runner.get());
 181
 182   if (!channel_info->channel.get()) {
 183     // Presumably, |Init()| on the channel failed.
 184     return;
 185   }
 186
 187   channel_info->channel->WillShutdownSoon();
 188   channel_info->io_thread_task_runner->PostTask(
 189       FROM_HERE, base::Bind(&DestroyChannelOnIOThread, channel_info));
 190 }
 191
 192 void WillDestroyChannelSoon(ChannelInfo* channel_info) {
 193   DCHECK(channel_info);
 194   channel_info->channel->WillShutdownSoon();
 195 }
 196
 197 MojoResult CreatePlatformHandleWrapper(
 198     ScopedPlatformHandle platform_handle,
 199     MojoHandle* platform_handle_wrapper_handle) {
 200   DCHECK(platform_handle_wrapper_handle);
 201
 202   scoped_refptr<system::Dispatcher> dispatcher(
 203       new system::PlatformHandleDispatcher(platform_handle.Pass()));
 204
 205   system::Core* core = system::entrypoints::GetCore();
 206   DCHECK(core);
 207   MojoHandle h = core->AddDispatcher(dispatcher);
 208   if (h == MOJO_HANDLE_INVALID) {
 209     LOG(ERROR) << "Handle table full";
 210     dispatcher->Close();
 211     return MOJO_RESULT_RESOURCE_EXHAUSTED;
 212   }
 213
 214   *platform_handle_wrapper_handle = h;
 215   return MOJO_RESULT_OK;
 216 }
 217
 218 MojoResult PassWrappedPlatformHandle(MojoHandle platform_handle_wrapper_handle,
 219                                      ScopedPlatformHandle* platform_handle) {
 220   DCHECK(platform_handle);
 221
 222   system::Core* core = system::entrypoints::GetCore();
 223   DCHECK(core);
 224   scoped_refptr<system::Dispatcher> dispatcher(
 225       core->GetDispatcher(platform_handle_wrapper_handle));
 226   if (!dispatcher.get())
 227     return MOJO_RESULT_INVALID_ARGUMENT;
 228
 229   if (dispatcher->GetType() != system::Dispatcher::kTypePlatformHandle)
 230     return MOJO_RESULT_INVALID_ARGUMENT;
 231
 232   *platform_handle =
 233       static_cast<system::PlatformHandleDispatcher*>(dispatcher.get())
 234           ->PassPlatformHandle()
 235           .Pass();
 236   return MOJO_RESULT_OK;
 237 }
 238
 239 }  // namespace embedder
 240 }  // namespace mojo