Move message_pump to base/message_loop.

base/message_pump_libevent.h

-// Copyright (c) 2012 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_MESSAGE_PUMP_LIBEVENT_H_
-#define BASE_MESSAGE_PUMP_LIBEVENT_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/memory/weak_ptr.h"
-#include "base/message_pump.h"
-#include "base/observer_list.h"
-#include "base/threading/thread_checker.h"
-#include "base/time.h"
-
-// Declare structs we need from libevent.h rather than including it
-struct event_base;
-struct event;
-
-namespace base {
-
-// Class to monitor sockets and issue callbacks when sockets are ready for I/O
-// TODO(dkegel): add support for background file IO somehow
-class BASE_EXPORT MessagePumpLibevent : public MessagePump {
- public:
-  class IOObserver {
-   public:
-    IOObserver() {}
-
-    // An IOObserver is an object that receives IO notifications from the
-    // MessagePump.
-    //
-    // NOTE: An IOObserver implementation should be extremely fast!
-    virtual void WillProcessIOEvent() = 0;
-    virtual void DidProcessIOEvent() = 0;
-
-   protected:
-    virtual ~IOObserver() {}
-  };
-
-  // Used with WatchFileDescriptor to asynchronously monitor the I/O readiness
-  // of a file descriptor.
-  class Watcher {
-   public:
-    // Called from MessageLoop::Run when an FD can be read from/written to
-    // without blocking
-    virtual void OnFileCanReadWithoutBlocking(int fd) = 0;
-    virtual void OnFileCanWriteWithoutBlocking(int fd) = 0;
-
-   protected:
-    virtual ~Watcher() {}
-  };
-
-  // Object returned by WatchFileDescriptor to manage further watching.
-  class FileDescriptorWatcher {
-   public:
-    FileDescriptorWatcher();
-    ~FileDescriptorWatcher();  // Implicitly calls StopWatchingFileDescriptor.
-
-    // NOTE: These methods aren't called StartWatching()/StopWatching() to
-    // avoid confusion with the win32 ObjectWatcher class.
-
-    // Stop watching the FD, always safe to call.  No-op if there's nothing
-    // to do.
-    bool StopWatchingFileDescriptor();
-
-   private:
-    friend class MessagePumpLibevent;
-    friend class MessagePumpLibeventTest;
-
-    // Called by MessagePumpLibevent, ownership of |e| is transferred to this
-    // object.
-    void Init(event* e);
-
-    // Used by MessagePumpLibevent to take ownership of event_.
-    event* ReleaseEvent();
-
-    void set_pump(MessagePumpLibevent* pump) { pump_ = pump; }
-    MessagePumpLibevent* pump() const { return pump_; }
-
-    void set_watcher(Watcher* watcher) { watcher_ = watcher; }
-
-    void OnFileCanReadWithoutBlocking(int fd, MessagePumpLibevent* pump);
-    void OnFileCanWriteWithoutBlocking(int fd, MessagePumpLibevent* pump);
-
-    event* event_;
-    MessagePumpLibevent* pump_;
-    Watcher* watcher_;
-    base::WeakPtrFactory<FileDescriptorWatcher> weak_factory_;
-
-    DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcher);
-  };
-
-  enum Mode {
-    WATCH_READ = 1 << 0,
-    WATCH_WRITE = 1 << 1,
-    WATCH_READ_WRITE = WATCH_READ | WATCH_WRITE
-  };
-
-  MessagePumpLibevent();
-
-  // Have the current thread's message loop watch for a a situation in which
-  // reading/writing to the FD can be performed without blocking.
-  // Callers must provide a preallocated FileDescriptorWatcher object which
-  // can later be used to manage the lifetime of this event.
-  // If a FileDescriptorWatcher is passed in which is already attached to
-  // an event, then the effect is cumulative i.e. after the call |controller|
-  // will watch both the previous event and the new one.
-  // If an error occurs while calling this method in a cumulative fashion, the
-  // event previously attached to |controller| is aborted.
-  // Returns true on success.
-  // Must be called on the same thread the message_pump is running on.
-  // TODO(dkegel): switch to edge-triggered readiness notification
-  bool WatchFileDescriptor(int fd,
-                           bool persistent,
-                           int mode,
-                           FileDescriptorWatcher *controller,
-                           Watcher *delegate);
-
-  void AddIOObserver(IOObserver* obs);
-  void RemoveIOObserver(IOObserver* obs);
-
-  // MessagePump methods:
-  virtual void Run(Delegate* delegate) OVERRIDE;
-  virtual void Quit() OVERRIDE;
-  virtual void ScheduleWork() OVERRIDE;
-  virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
-
- protected:
-  virtual ~MessagePumpLibevent();
-
- private:
-  friend class MessagePumpLibeventTest;
-
-  void WillProcessIOEvent();
-  void DidProcessIOEvent();
-
-  // Risky part of constructor.  Returns true on success.
-  bool Init();
-
-  // Called by libevent to tell us a registered FD can be read/written to.
-  static void OnLibeventNotification(int fd, short flags,
-                                     void* context);
-
-  // Unix pipe used to implement ScheduleWork()
-  // ... callback; called by libevent inside Run() when pipe is ready to read
-  static void OnWakeup(int socket, short flags, void* context);
-
-  // This flag is set to false when Run should return.
-  bool keep_running_;
-
-  // This flag is set when inside Run.
-  bool in_run_;
-
-  // This flag is set if libevent has processed I/O events.
-  bool processed_io_events_;
-
-  // The time at which we should call DoDelayedWork.
-  TimeTicks delayed_work_time_;
-
-  // Libevent dispatcher.  Watches all sockets registered with it, and sends
-  // readiness callbacks when a socket is ready for I/O.
-  event_base* event_base_;
-
-  // ... write end; ScheduleWork() writes a single byte to it
-  int wakeup_pipe_in_;
-  // ... read end; OnWakeup reads it and then breaks Run() out of its sleep
-  int wakeup_pipe_out_;
-  // ... libevent wrapper for read end
-  event* wakeup_event_;
-
-  ObserverList<IOObserver> io_observers_;
-  ThreadChecker watch_file_descriptor_caller_checker_;
-  DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent);
-};
-
-}  // namespace base
-
-#endif  // BASE_MESSAGE_PUMP_LIBEVENT_H_