Refactor ChildProcess and related classes to create a framework outside of br...

base/mp/mp_child_thread.h

+// Copyright (c) 2010 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.
+
+#ifndef BASE_MP_CHILD_THREAD_H_
+#define BASE_MP_CHILD_THREAD_H_
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "base/mp/message_router.h"
+#include "ipc/ipc_sync_channel.h"
+#include "ipc/ipc_message.h"
+
+namespace IPC {
+class SyncMessageFilter;
+}
+
+namespace base {
+
+// The main thread of a child process derives from this class.
+class MpChildThread : public IPC::Channel::Listener,
+                      public IPC::Message::Sender {
+ public:
+  // Creates the thread.
+  MpChildThread();
+  // Used for single-process mode.
+  explicit MpChildThread(const std::string& channel_name);
+  virtual ~MpChildThread();
+
+  // IPC::Message::Sender implementation:
+  virtual bool Send(IPC::Message* msg);
+
+  // IPC::Channel::Listener implementation:
+  virtual void OnMessageReceived(const IPC::Message& msg);
+
+  // See documentation on MessageRouter for AddRoute and RemoveRoute
+  void AddRoute(int32 routing_id, IPC::Channel::Listener* listener);
+  void RemoveRoute(int32 routing_id);
+
+  IPC::Channel::Listener* ResolveRoute(int32 routing_id);
+
+  // Safe to call on any thread, as long as it's guaranteed that the thread's
+  // lifetime is less than the main thread.
+  IPC::SyncMessageFilter* sync_message_filter() { return sync_message_filter_; }
+
+  MessageLoop* message_loop() { return message_loop_; }
+
+  // Returns the one child thread.
+  static MpChildThread* current();
+
+ protected:
+  friend class MpChildProcess;
+
+  // Called when the process refcount is 0.
+  void OnProcessFinalRelease();
+
+  virtual void OnControlMessageReceived(const IPC::Message& msg) { }
+  virtual void OnAskBeforeShutdown();
+  virtual void OnShutdown();
+
+#ifdef IPC_MESSAGE_LOG_ENABLED
+  virtual void OnSetIPCLoggingEnabled(bool enable);
+#endif
+
+  IPC::SyncChannel* channel() { return channel_.get(); }
+
+  void set_on_channel_error_called(bool on_channel_error_called) {
+    on_channel_error_called_ = on_channel_error_called;
+  }
+
+ private:
+  void Init();
+
+  // IPC::Channel::Listener implementation:
+  virtual void OnChannelError();
+
+  std::string channel_name_;
+  scoped_ptr<IPC::SyncChannel> channel_;
+
+  // Allows threads other than the main thread to send sync messages.
+  scoped_refptr<IPC::SyncMessageFilter> sync_message_filter_;
+
+  // Implements message routing functionality to the consumers of MpChildThread.
+  MessageRouter router_;
+
+  // If true, checks with the parent process before shutdown.  This avoids race
+  // conditions if the process refcount is 0 but there's an IPC message inflight
+  // that would addref it.
+  bool check_with_parent_before_shutdown_;
+
+  // The OnChannelError() callback was invoked - the channel is dead, don't
+  // attempt to communicate.
+  bool on_channel_error_called_;
+
+  MessageLoop* message_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(MpChildThread);
+};
+
+}  // namespace base
+
+#endif  // BASE_MP_CHILD_THREAD_H_