Allow synchronous messages to be sent from threads other than the main thread...

chrome/common/child_thread.cc

 // Copyright (c) 2009 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 "chrome/common/child_thread.h"
 
 #include "base/string_util.h"
 #include "base/command_line.h"
 #include "chrome/common/child_process.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/plugin_messages.h"
 #include "chrome/common/socket_stream_dispatcher.h"
 #include "ipc/ipc_logging.h"
 #include "ipc/ipc_message.h"
+#include "ipc/ipc_sync_message_filter.h"
 #include "ipc/ipc_switches.h"
 #include "webkit/glue/webkit_glue.h"
 
 
 ChildThread::ChildThread() {
   channel_name_ = CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
       switches::kProcessChannelID);
   Init();
 }
 
@@ skipping 16 matching lines @@
       IPC::Channel::MODE_CLIENT, this, NULL,
       ChildProcess::current()->io_message_loop(), true,
       ChildProcess::current()->GetShutDownEvent()));
 #ifdef IPC_MESSAGE_LOG_ENABLED
   IPC::Logging::current()->SetIPCSender(this);
 #endif
 
   resource_dispatcher_.reset(new ResourceDispatcher(this));
   socket_stream_dispatcher_.reset(new SocketStreamDispatcher());
 
+  sync_message_filter_ =
+      new IPC::SyncMessageFilter(ChildProcess::current()->GetShutDownEvent());
+  channel_->AddFilter(sync_message_filter_.get());
+
   // When running in unit tests, there is already a NotificationService object.
   // Since only one can exist at a time per thread, check first.
   if (!NotificationService::current())
     notification_service_.reset(new NotificationService);
 }
 
 ChildThread::~ChildThread() {
 #ifdef IPC_MESSAGE_LOG_ENABLED
   IPC::Logging::current()->SetIPCSender(NULL);
 #endif
 
+  channel_->RemoveFilter(sync_message_filter_.get());
+
   // The ChannelProxy object caches a pointer to the IPC thread, so need to
   // reset it as it's not guaranteed to outlive this object.
   // NOTE: this also has the side-effect of not closing the main IPC channel to
   // the browser process.  This is needed because this is the signal that the
   // browser uses to know that this process has died, so we need it to be alive
   // until this process is shut down, and the OS closes the handle
   // automatically.  We used to watch the object handle on Windows to do this,
   // but it wasn't possible to do so on POSIX.
   channel_->ClearIPCMessageLoop();
 }
@@ skipping 46 matching lines @@
   if (socket_stream_dispatcher_->OnMessageReceived(msg))
     return;
 
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ChildThread, msg)
     IPC_MESSAGE_HANDLER(PluginProcessMsg_AskBeforeShutdown, OnAskBeforeShutdown)
     IPC_MESSAGE_HANDLER(PluginProcessMsg_Shutdown, OnShutdown)
 #if defined(IPC_MESSAGE_LOG_ENABLED)
     IPC_MESSAGE_HANDLER(PluginProcessMsg_SetIPCLoggingEnabled,
                         OnSetIPCLoggingEnabled)
-#endif  // IPC_MESSAGE_HANDLER
+#endif
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   if (handled)
     return;
 
   if (msg.routing_id() == MSG_ROUTING_CONTROL) {
     OnControlMessageReceived(msg);
   } else {
     router_.OnMessageReceived(msg);
@@ skipping 26 matching lines @@
     MessageLoop::current()->Quit();
     return;
   }
 
   // The child process shutdown sequence is a request response based mechanism,
   // where we send out an initial feeler request to the child process host
   // instance in the browser to verify if it's ok to shutdown the child process.
   // The browser then sends back a response if it's ok to shutdown.
   Send(new PluginProcessHostMsg_ShutdownRequest);
 }