Mirror of roytam1's UXP fork just in case Moonchild and Tobin decide to go after him
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// 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 <errno.h>
#include <fcntl.h>
#if defined(OS_SOLARIS)
#include <sys/stat.h>
#endif
#if defined(ANDROID) || defined(OS_POSIX)
#include <unistd.h>
#endif
#include "eintr_wrapper.h"
#include "base/logging.h"
#include "base/scoped_nsautorelease_pool.h"
#include "base/time.h"
#include "nsDependentSubstring.h"
#include "event.h"
#include "mozilla/UniquePtr.h"
// This macro checks that the _EVENT_SIZEOF_* constants defined in
// ipc/chromiume/src/third_party/<platform>/event2/event-config.h are correct.
#if defined(_EVENT_SIZEOF_SHORT)
#define CHECK_EVENT_SIZEOF(TYPE, type) \
static_assert(_EVENT_SIZEOF_##TYPE == sizeof(type), \
"bad _EVENT_SIZEOF_"#TYPE);
#elif defined(EVENT__SIZEOF_SHORT)
#define CHECK_EVENT_SIZEOF(TYPE, type) \
static_assert(EVENT__SIZEOF_##TYPE == sizeof(type), \
"bad EVENT__SIZEOF_"#TYPE);
#else
#error Cannot find libevent type sizes
#endif
CHECK_EVENT_SIZEOF(LONG, long);
CHECK_EVENT_SIZEOF(LONG_LONG, long long);
CHECK_EVENT_SIZEOF(PTHREAD_T, pthread_t);
CHECK_EVENT_SIZEOF(SHORT, short);
CHECK_EVENT_SIZEOF(SIZE_T, size_t);
CHECK_EVENT_SIZEOF(VOID_P, void*);
// Lifecycle of struct event
// Libevent uses two main data structures:
// struct event_base (of which there is one per message pump), and
// struct event (of which there is roughly one per socket).
// The socket's struct event is created in
// MessagePumpLibevent::WatchFileDescriptor(),
// is owned by the FileDescriptorWatcher, and is destroyed in
// StopWatchingFileDescriptor().
// It is moved into and out of lists in struct event_base by
// the libevent functions event_add() and event_del().
//
// TODO(dkegel):
// At the moment bad things happen if a FileDescriptorWatcher
// is active after its MessagePumpLibevent has been destroyed.
// See MessageLoopTest.FileDescriptorWatcherOutlivesMessageLoop
// Not clear yet whether that situation occurs in practice,
// but if it does, we need to fix it.
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 (flags == -1)
flags = 0;
return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}
MessagePumpLibevent::FileDescriptorWatcher::FileDescriptorWatcher()
: is_persistent_(false),
event_(NULL) {
}
MessagePumpLibevent::FileDescriptorWatcher::~FileDescriptorWatcher() {
if (event_) {
StopWatchingFileDescriptor();
}
}
void MessagePumpLibevent::FileDescriptorWatcher::Init(event *e,
bool is_persistent) {
DCHECK(e);
DCHECK(event_ == NULL);
is_persistent_ = is_persistent;
event_ = e;
}
event *MessagePumpLibevent::FileDescriptorWatcher::ReleaseEvent() {
struct event *e = event_;
event_ = NULL;
return e;
}
bool MessagePumpLibevent::FileDescriptorWatcher::StopWatchingFileDescriptor() {
event* e = ReleaseEvent();
if (e == NULL)
return true;
// event_del() is a no-op if the event isn't active.
int rv = event_del(e);
delete e;
return (rv == 0);
}
// 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 = HANDLE_EINTR(read(socket, &buf, 1));
DCHECK_EQ(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)) {
DLOG(ERROR) << "pipe() failed, errno: " << errno;
return false;
}
if (SetNonBlocking(fds[0])) {
DLOG(ERROR) << "SetNonBlocking for pipe fd[0] failed, errno: " << errno;
return false;
}
if (SetNonBlocking(fds[1])) {
DLOG(ERROR) << "SetNonBlocking for pipe fd[1] failed, errno: " << errno;
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_;
if (wakeup_pipe_in_ >= 0)
close(wakeup_pipe_in_);
if (wakeup_pipe_out_ >= 0)
close(wakeup_pipe_out_);
event_base_free(event_base_);
}
bool MessagePumpLibevent::WatchFileDescriptor(int fd,
bool persistent,
Mode mode,
FileDescriptorWatcher *controller,
Watcher *delegate) {
DCHECK(fd > 0);
DCHECK(controller);
DCHECK(delegate);
DCHECK(mode == WATCH_READ || mode == WATCH_WRITE || mode == WATCH_READ_WRITE);
int event_mask = persistent ? EV_PERSIST : 0;
if ((mode & WATCH_READ) != 0) {
event_mask |= EV_READ;
}
if ((mode & WATCH_WRITE) != 0) {
event_mask |= EV_WRITE;
}
// |should_delete_event| is true if we're modifying an event that's currently
// active in |controller|.
// If we're modifying an existing event and there's an error then we need to
// tell libevent to clean it up via event_delete() before returning.
bool should_delete_event = true;
mozilla::UniquePtr<event> evt(controller->ReleaseEvent());
if (evt.get() == NULL) {
should_delete_event = false;
// Ownership is transferred to the controller.
evt = mozilla::MakeUnique<event>();
} else {
// It's illegal to use this function to listen on 2 separate fds with the
// same |controller|.
if (EVENT_FD(evt.get()) != fd) {
NOTREACHED() << "FDs don't match" << EVENT_FD(evt.get()) << "!=" << fd;
return false;
}
// Make sure we don't pick up any funky internal libevent masks.
int old_interest_mask = evt.get()->ev_events &
(EV_READ | EV_WRITE | EV_PERSIST);
// Combine old/new event masks.
event_mask |= old_interest_mask;
// Must disarm the event before we can reuse it.
event_del(evt.get());
}
// Set current interest mask and message pump for this event.
event_set(evt.get(), fd, event_mask, OnLibeventNotification,
delegate);
// Tell libevent which message pump this socket will belong to when we add it.
if (event_base_set(event_base_, evt.get()) != 0) {
if (should_delete_event) {
event_del(evt.get());
}
return false;
}
// Add this socket to the list of monitored sockets.
if (event_add(evt.get(), NULL) != 0) {
if (should_delete_event) {
event_del(evt.get());
}
return false;
}
// Transfer ownership of evt to controller.
controller->Init(evt.release(), persistent);
return true;
}
void MessagePumpLibevent::OnLibeventNotification(int fd, short flags,
void* context) {
Watcher* watcher = static_cast<Watcher*>(context);
if (flags & EV_WRITE) {
watcher->OnFileCanWriteWithoutBlocking(fd);
}
if (flags & EV_READ) {
watcher->OnFileCanReadWithoutBlocking(fd);
}
}
MessagePumpLibevent::SignalEvent::SignalEvent() :
event_(NULL)
{
}
MessagePumpLibevent::SignalEvent::~SignalEvent()
{
if (event_) {
StopCatching();
}
}
void
MessagePumpLibevent::SignalEvent::Init(event *e)
{
DCHECK(e);
DCHECK(event_ == NULL);
event_ = e;
}
bool
MessagePumpLibevent::SignalEvent::StopCatching()
{
// XXX/cjones: this code could be shared with
// FileDescriptorWatcher. ironic that libevent is "more"
// object-oriented than this C++
event* e = ReleaseEvent();
if (e == NULL)
return true;
// event_del() is a no-op if the event isn't active.
int rv = event_del(e);
delete e;
return (rv == 0);
}
event *
MessagePumpLibevent::SignalEvent::ReleaseEvent()
{
event *e = event_;
event_ = NULL;
return e;
}
bool
MessagePumpLibevent::CatchSignal(int sig,
SignalEvent* sigevent,
SignalWatcher* delegate)
{
DCHECK(sig > 0);
DCHECK(sigevent);
DCHECK(delegate);
// TODO if we want to support re-using SignalEvents, this code needs
// to jump through the same hoops as WatchFileDescriptor(). Not
// needed at present
DCHECK(NULL == sigevent->event_);
mozilla::UniquePtr<event> evt = mozilla::MakeUnique<event>();
signal_set(evt.get(), sig, OnLibeventSignalNotification, delegate);
if (event_base_set(event_base_, evt.get()))
return false;
if (signal_add(evt.get(), NULL))
return false;
// Transfer ownership of evt to controller.
sigevent->Init(evt.release());
return true;
}
void
MessagePumpLibevent::OnLibeventSignalNotification(int sig, short flags,
void* context)
{
DCHECK(sig > 0);
DCHECK(EV_SIGNAL == flags);
DCHECK(context);
reinterpret_cast<SignalWatcher*>(context)->OnSignal(sig);
}
// 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_ - TimeTicks::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_ = TimeTicks();
}
}
}
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 = HANDLE_EINTR(write(wakeup_pipe_in_, &buf, 1));
DCHECK(nwrite == 1 || errno == EAGAIN)
<< "[nwrite:" << nwrite << "] [errno:" << errno << "]";
}
void MessagePumpLibevent::ScheduleDelayedWork(
const TimeTicks& 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;
}
void LineWatcher::OnFileCanReadWithoutBlocking(int aFd)
{
ssize_t length = 0;
while (true) {
length = read(aFd, mReceiveBuffer.get(), mBufferSize - mReceivedIndex);
DCHECK(length <= ssize_t(mBufferSize - mReceivedIndex));
if (length <= 0) {
if (length < 0) {
if (errno == EINTR) {
continue; // retry system call when interrupted
}
if (errno == EAGAIN || errno == EWOULDBLOCK) {
return; // no data available: return and re-poll
}
DLOG(ERROR) << "Can't read from fd, error " << errno;
} else {
DLOG(ERROR) << "End of file";
}
// At this point, assume that we can't actually access
// the socket anymore, and indicate an error.
OnError();
mReceivedIndex = 0;
return;
}
while (length-- > 0) {
DCHECK(mReceivedIndex < mBufferSize);
if (mReceiveBuffer[mReceivedIndex] == mTerminator) {
nsDependentCSubstring message(mReceiveBuffer.get(), mReceivedIndex);
OnLineRead(aFd, message);
if (length > 0) {
DCHECK(mReceivedIndex < (mBufferSize - 1));
memmove(&mReceiveBuffer[0], &mReceiveBuffer[mReceivedIndex + 1], length);
}
mReceivedIndex = 0;
} else {
mReceivedIndex++;
}
}
}
}
} // namespace base