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// Copyright (c) 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.
#include "base/message_pump_libevent.h"
#include <fcntl.h>
#include "base/logging.h"
#include "base/scoped_nsautorelease_pool.h"
#include "base/time.h"
#include "third_party/libevent/event.h"
namespace base {
// Return 0 on success
// Too small a function to bother putting in a library?
static int SetNonBlocking(int fd)
{
int flags = fcntl(fd, F_GETFL, 0);
if (-1 == flags)
flags = 0;
return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}
// Called if a byte is received on the wakeup pipe.
void MessagePumpLibevent::OnWakeup(int socket, short flags, void* context) {
base::MessagePumpLibevent* that =
static_cast<base::MessagePumpLibevent*>(context);
DCHECK(that->wakeup_pipe_out_ == socket);
// Remove and discard the wakeup byte.
char buf;
int nread = read(socket, &buf, 1);
DCHECK(nread == 1);
// Tell libevent to break out of inner loop.
event_base_loopbreak(that->event_base_);
}
MessagePumpLibevent::MessagePumpLibevent()
: keep_running_(true),
in_run_(false),
event_base_(event_base_new()),
wakeup_pipe_in_(-1),
wakeup_pipe_out_(-1) {
if (!Init())
NOTREACHED();
}
bool MessagePumpLibevent::Init() {
int fds[2];
if (pipe(fds))
return false;
if (SetNonBlocking(fds[0]))
return false;
if (SetNonBlocking(fds[1]))
return false;
wakeup_pipe_out_ = fds[0];
wakeup_pipe_in_ = fds[1];
wakeup_event_ = new event;
event_set(wakeup_event_, wakeup_pipe_out_, EV_READ | EV_PERSIST,
OnWakeup, this);
event_base_set(event_base_, wakeup_event_);
if (event_add(wakeup_event_, 0))
return false;
return true;
}
MessagePumpLibevent::~MessagePumpLibevent() {
DCHECK(wakeup_event_);
DCHECK(event_base_);
event_del(wakeup_event_);
delete wakeup_event_;
event_base_free(event_base_);
}
void MessagePumpLibevent::WatchSocket(int socket, short interest_mask,
event* e, Watcher* watcher) {
// Set current interest mask and message pump for this event
event_set(e, socket, interest_mask, OnReadinessNotification, watcher);
// Tell libevent which message pump this socket will belong to when we add it.
event_base_set(event_base_, e);
// Add this socket to the list of monitored sockets.
if (event_add(e, NULL))
NOTREACHED();
}
void MessagePumpLibevent::UnwatchSocket(event* e) {
// Remove this socket from the list of monitored sockets.
if (event_del(e))
NOTREACHED();
}
void MessagePumpLibevent::OnReadinessNotification(int socket, short flags,
void* context) {
// The given socket is ready for I/O.
// Tell the owner what kind of I/O the socket is ready for.
Watcher* watcher = static_cast<Watcher*>(context);
watcher->OnSocketReady(flags);
}
// Reentrant!
void MessagePumpLibevent::Run(Delegate* delegate) {
DCHECK(keep_running_) << "Quit must have been called outside of Run!";
bool old_in_run = in_run_;
in_run_ = true;
for (;;) {
ScopedNSAutoreleasePool autorelease_pool;
bool did_work = delegate->DoWork();
if (!keep_running_)
break;
did_work |= delegate->DoDelayedWork(&delayed_work_time_);
if (!keep_running_)
break;
if (did_work)
continue;
did_work = delegate->DoIdleWork();
if (!keep_running_)
break;
if (did_work)
continue;
// EVLOOP_ONCE tells libevent to only block once,
// but to service all pending events when it wakes up.
if (delayed_work_time_.is_null()) {
event_base_loop(event_base_, EVLOOP_ONCE);
} else {
TimeDelta delay = delayed_work_time_ - Time::Now();
if (delay > TimeDelta()) {
struct timeval poll_tv;
poll_tv.tv_sec = delay.InSeconds();
poll_tv.tv_usec = delay.InMicroseconds() % Time::kMicrosecondsPerSecond;
event_base_loopexit(event_base_, &poll_tv);
event_base_loop(event_base_, EVLOOP_ONCE);
} else {
// It looks like delayed_work_time_ indicates a time in the past, so we
// need to call DoDelayedWork now.
delayed_work_time_ = Time();
}
}
}
keep_running_ = true;
in_run_ = old_in_run;
}
void MessagePumpLibevent::Quit() {
DCHECK(in_run_);
// Tell both libevent and Run that they should break out of their loops.
keep_running_ = false;
ScheduleWork();
}
void MessagePumpLibevent::ScheduleWork() {
// Tell libevent (in a threadsafe way) that it should break out of its loop.
char buf = 0;
int nwrite = write(wakeup_pipe_in_, &buf, 1);
DCHECK(nwrite == 1);
}
void MessagePumpLibevent::ScheduleDelayedWork(const Time& delayed_work_time) {
// We know that we can't be blocked on Wait right now since this method can
// only be called on the same thread as Run, so we only need to update our
// record of how long to sleep when we do sleep.
delayed_work_time_ = delayed_work_time;
}
} // namespace base
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