Separates ipc code from common (http://crbug.com/16829)

chrome/common/ipc_sync_channel.h

-// Copyright (c) 2006-2008 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 CHROME_COMMON_IPC_SYNC_SENDER_H__
-#define CHROME_COMMON_IPC_SYNC_SENDER_H__
-
-#include <string>
-#include <deque>
-
-#include "base/basictypes.h"
-#include "base/lock.h"
-#include "base/ref_counted.h"
-#include "base/waitable_event_watcher.h"
-#include "chrome/common/ipc_channel_proxy.h"
-
-namespace base {
-class WaitableEvent;
-};
-
-namespace IPC {
-
-class SyncMessage;
-class MessageReplyDeserializer;
-
-// This is similar to IPC::ChannelProxy, with the added feature of supporting
-// sending synchronous messages.
-// Note that care must be taken that the lifetime of the ipc_thread argument
-// is more than this object.  If the message loop goes away while this object
-// is running and it's used to send a message, then it will use the invalid
-// message loop pointer to proxy it to the ipc thread.
-class SyncChannel : public ChannelProxy,
-                    public base::WaitableEventWatcher::Delegate {
- public:
-  SyncChannel(const std::string& channel_id, Channel::Mode mode,
-              Channel::Listener* listener, MessageFilter* filter,
-              MessageLoop* ipc_message_loop, bool create_pipe_now,
-              base::WaitableEvent* shutdown_event);
-  ~SyncChannel();
-
-  virtual bool Send(Message* message);
-  virtual bool SendWithTimeout(Message* message, int timeout_ms);
-
-  // Whether we allow sending messages with no time-out.
-  void set_sync_messages_with_no_timeout_allowed(bool value) {
-    sync_messages_with_no_timeout_allowed_ = value;
-  }
-
- protected:
-  class ReceivedSyncMsgQueue;
-  friend class ReceivedSyncMsgQueue;
-
-  // SyncContext holds the per object data for SyncChannel, so that SyncChannel
-  // can be deleted while it's being used in a different thread.  See
-  // ChannelProxy::Context for more information.
-  class SyncContext : public Context,
-                      public base::WaitableEventWatcher::Delegate {
-   public:
-    SyncContext(Channel::Listener* listener,
-                MessageFilter* filter,
-                MessageLoop* ipc_thread,
-                base::WaitableEvent* shutdown_event);
-
-    ~SyncContext();
-
-    // Adds information about an outgoing sync message to the context so that
-    // we know how to deserialize the reply.
-    void Push(IPC::SyncMessage* sync_msg);
-
-    // Cleanly remove the top deserializer (and throw it away).  Returns the
-    // result of the Send call for that message.
-    bool Pop();
-
-    // Returns an event that's set when the send is complete, timed out or the
-    // process shut down.
-    base::WaitableEvent* GetSendDoneEvent();
-
-    // Returns an event that's set when an incoming message that's not the reply
-    // needs to get dispatched (by calling SyncContext::DispatchMessages).
-    base::WaitableEvent* GetDispatchEvent();
-
-    void DispatchMessages();
-
-    // Checks if the given message is blocking the listener thread because of a
-    // synchronous send.  If it is, the thread is unblocked and true is
-    // returned. Otherwise the function returns false.
-    bool TryToUnblockListener(const Message* msg);
-
-    // Called on the IPC thread when a sync send that runs a nested message loop
-    // times out.
-    void OnSendTimeout(int message_id);
-
-    base::WaitableEvent* shutdown_event() { return shutdown_event_; }
-
-   private:
-    // IPC::ChannelProxy methods that we override.
-
-    // Called on the listener thread.
-   virtual void Clear();
-
-    // Called on the IPC thread.
-    virtual void OnMessageReceived(const Message& msg);
-    virtual void OnChannelError();
-    virtual void OnChannelOpened();
-    virtual void OnChannelClosed();
-
-    // Cancels all pending Send calls.
-    void CancelPendingSends();
-
-    // WaitableEventWatcher::Delegate implementation.
-    virtual void OnWaitableEventSignaled(base::WaitableEvent* arg);
-
-    // When sending a synchronous message, this structure contains an object
-    // that knows how to deserialize the response.
-    struct PendingSyncMsg {
-      PendingSyncMsg(int id, IPC::MessageReplyDeserializer* d,
-                     base::WaitableEvent* e) :
-          id(id), deserializer(d), done_event(e), send_result(false) { }
-      int id;
-      IPC::MessageReplyDeserializer* deserializer;
-      base::WaitableEvent* done_event;
-      bool send_result;
-    };
-
-    typedef std::deque<PendingSyncMsg> PendingSyncMessageQueue;
-    PendingSyncMessageQueue deserializers_;
-    Lock deserializers_lock_;
-
-    scoped_refptr<ReceivedSyncMsgQueue> received_sync_msgs_;
-
-    base::WaitableEvent* shutdown_event_;
-    base::WaitableEventWatcher shutdown_watcher_;
-  };
-
- private:
-  // WaitableEventWatcher::Delegate implementation.
-  virtual void OnWaitableEventSignaled(base::WaitableEvent* arg);
-
-  SyncContext* sync_context() {
-    return reinterpret_cast<SyncContext*>(context());
-  }
-
-  // Both these functions wait for a reply, timeout or process shutdown.  The
-  // latter one also runs a nested message loop in the meantime.
-  void WaitForReply(base::WaitableEvent* pump_messages_event);
-
-  // Runs a nested message loop until a reply arrives, times out, or the process
-  // shuts down.
-  void WaitForReplyWithNestedMessageLoop();
-
-  bool sync_messages_with_no_timeout_allowed_;
-
-  // Used to signal events between the IPC and listener threads.
-  base::WaitableEventWatcher send_done_watcher_;
-  base::WaitableEventWatcher dispatch_watcher_;
-
-  DISALLOW_EVIL_CONSTRUCTORS(SyncChannel);
-};
-
-}  // namespace IPC
-
-#endif  // CHROME_COMMON_IPC_SYNC_SENDER_H__