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// 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 BASE_MESSAGE_PUMP_LIBEVENT_H_
#define BASE_MESSAGE_PUMP_LIBEVENT_H_
#include "base/message_pump.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 MessagePumpLibevent : public MessagePump {
public:
// Used with WatchObject to asynchronously monitor the I/O readiness of a
// socket.
class Watcher {
public:
virtual ~Watcher() {}
// Called from MessageLoop::Run when a ready socket is detected.
virtual void OnSocketReady(short eventmask) = 0;
};
MessagePumpLibevent();
virtual ~MessagePumpLibevent();
// Have the current thread's message loop watch for a ready socket.
// Caller must provide a struct event for this socket for libevent's use.
// The event and interest_mask fields are defined in libevent.
// Returns true on success.
// TODO(dkegel): hide libevent better; abstraction still too leaky
// TODO(dkegel): better error handing
// TODO(dkegel): switch to edge-triggered readiness notification
void WatchSocket(int socket, short interest_mask, event* e, Watcher*);
// Stop watching a socket.
// Event was previously initialized by WatchSocket.
void UnwatchSocket(event* e);
// MessagePump methods:
virtual void Run(Delegate* delegate);
virtual void Quit();
virtual void ScheduleWork();
virtual void ScheduleDelayedWork(const Time& delayed_work_time);
private:
// Risky part of constructor. Returns true on success.
bool Init();
// This flag is set to false when Run should return.
bool keep_running_;
// This flag is set when inside Run.
bool in_run_;
// The time at which we should call DoDelayedWork.
Time 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_;
// Called by libevent to tell us a registered socket is ready
static void OnReadinessNotification(int socket, 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);
// ... 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_;
DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent);
};
} // namespace base
#endif // BASE_MESSAGE_PUMP_LIBEVENT_H_
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