message_loop.cc revision 513209b27ff55e2841eac0e4120199c23acce758
1// Copyright (c) 2010 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "base/message_loop.h" 6 7#include <algorithm> 8 9#include "base/compiler_specific.h" 10#include "base/lazy_instance.h" 11#include "base/logging.h" 12#include "base/message_pump_default.h" 13#include "base/metrics/histogram.h" 14#include "base/thread_local.h" 15 16#if defined(OS_MACOSX) 17#include "base/message_pump_mac.h" 18#endif 19#if defined(OS_POSIX) 20#include "base/message_pump_libevent.h" 21#include "base/third_party/valgrind/valgrind.h" 22#endif 23#if defined(OS_POSIX) && !defined(OS_MACOSX) 24#include "base/message_pump_glib.h" 25#endif 26#if defined(TOUCH_UI) 27#include "base/message_pump_glib_x.h" 28#endif 29 30using base::Time; 31using base::TimeDelta; 32using base::TimeTicks; 33 34namespace { 35 36// A lazily created thread local storage for quick access to a thread's message 37// loop, if one exists. This should be safe and free of static constructors. 38base::LazyInstance<base::ThreadLocalPointer<MessageLoop> > lazy_tls_ptr( 39 base::LINKER_INITIALIZED); 40 41// Logical events for Histogram profiling. Run with -message-loop-histogrammer 42// to get an accounting of messages and actions taken on each thread. 43const int kTaskRunEvent = 0x1; 44const int kTimerEvent = 0x2; 45 46// Provide range of message IDs for use in histogramming and debug display. 47const int kLeastNonZeroMessageId = 1; 48const int kMaxMessageId = 1099; 49const int kNumberOfDistinctMessagesDisplayed = 1100; 50 51// Provide a macro that takes an expression (such as a constant, or macro 52// constant) and creates a pair to initalize an array of pairs. In this case, 53// our pair consists of the expressions value, and the "stringized" version 54// of the expression (i.e., the exrpression put in quotes). For example, if 55// we have: 56// #define FOO 2 57// #define BAR 5 58// then the following: 59// VALUE_TO_NUMBER_AND_NAME(FOO + BAR) 60// will expand to: 61// {7, "FOO + BAR"} 62// We use the resulting array as an argument to our histogram, which reads the 63// number as a bucket identifier, and proceeds to use the corresponding name 64// in the pair (i.e., the quoted string) when printing out a histogram. 65#define VALUE_TO_NUMBER_AND_NAME(name) {name, #name}, 66 67const base::LinearHistogram::DescriptionPair event_descriptions_[] = { 68 // Provide some pretty print capability in our histogram for our internal 69 // messages. 70 71 // A few events we handle (kindred to messages), and used to profile actions. 72 VALUE_TO_NUMBER_AND_NAME(kTaskRunEvent) 73 VALUE_TO_NUMBER_AND_NAME(kTimerEvent) 74 75 {-1, NULL} // The list must be null terminated, per API to histogram. 76}; 77 78bool enable_histogrammer_ = false; 79 80} // namespace 81 82//------------------------------------------------------------------------------ 83 84#if defined(OS_WIN) 85 86// Upon a SEH exception in this thread, it restores the original unhandled 87// exception filter. 88static int SEHFilter(LPTOP_LEVEL_EXCEPTION_FILTER old_filter) { 89 ::SetUnhandledExceptionFilter(old_filter); 90 return EXCEPTION_CONTINUE_SEARCH; 91} 92 93// Retrieves a pointer to the current unhandled exception filter. There 94// is no standalone getter method. 95static LPTOP_LEVEL_EXCEPTION_FILTER GetTopSEHFilter() { 96 LPTOP_LEVEL_EXCEPTION_FILTER top_filter = NULL; 97 top_filter = ::SetUnhandledExceptionFilter(0); 98 ::SetUnhandledExceptionFilter(top_filter); 99 return top_filter; 100} 101 102#endif // defined(OS_WIN) 103 104//------------------------------------------------------------------------------ 105 106MessageLoop::TaskObserver::TaskObserver() { 107} 108 109MessageLoop::TaskObserver::~TaskObserver() { 110} 111 112MessageLoop::DestructionObserver::~DestructionObserver() { 113} 114 115//------------------------------------------------------------------------------ 116 117// static 118MessageLoop* MessageLoop::current() { 119 // TODO(darin): sadly, we cannot enable this yet since people call us even 120 // when they have no intention of using us. 121 // DCHECK(loop) << "Ouch, did you forget to initialize me?"; 122 return lazy_tls_ptr.Pointer()->Get(); 123} 124 125MessageLoop::MessageLoop(Type type) 126 : type_(type), 127 nestable_tasks_allowed_(true), 128 exception_restoration_(false), 129 state_(NULL), 130 next_sequence_num_(0) { 131 DCHECK(!current()) << "should only have one message loop per thread"; 132 lazy_tls_ptr.Pointer()->Set(this); 133 134// TODO(rvargas): Get rid of the OS guards. 135#if defined(OS_WIN) 136#define MESSAGE_PUMP_UI new base::MessagePumpForUI() 137#define MESSAGE_PUMP_IO new base::MessagePumpForIO() 138#elif defined(OS_MACOSX) 139#define MESSAGE_PUMP_UI base::MessagePumpMac::Create() 140#define MESSAGE_PUMP_IO new base::MessagePumpLibevent() 141<<<<<<< HEAD 142#elif defined(ANDROID) 143#define MESSAGE_PUMP_UI new base::MessagePumpDefault() 144======= 145#elif defined(TOUCH_UI) 146// TODO(sadrul): enable the new message pump when ready 147#define MESSAGE_PUMP_UI new base::MessagePumpForUI() 148>>>>>>> chromium.org at r65505 149#define MESSAGE_PUMP_IO new base::MessagePumpLibevent() 150#elif defined(OS_POSIX) // POSIX but not MACOSX. 151#define MESSAGE_PUMP_UI new base::MessagePumpForUI() 152#define MESSAGE_PUMP_IO new base::MessagePumpLibevent() 153#else 154#error Not implemented 155#endif 156 157 if (type_ == TYPE_UI) { 158 pump_ = MESSAGE_PUMP_UI; 159 } else if (type_ == TYPE_IO) { 160 pump_ = MESSAGE_PUMP_IO; 161 } else { 162 DCHECK_EQ(TYPE_DEFAULT, type_); 163 pump_ = new base::MessagePumpDefault(); 164 } 165} 166 167MessageLoop::~MessageLoop() { 168 DCHECK(this == current()); 169 170 // Let interested parties have one last shot at accessing this. 171 FOR_EACH_OBSERVER(DestructionObserver, destruction_observers_, 172 WillDestroyCurrentMessageLoop()); 173 174 DCHECK(!state_); 175 176 // Clean up any unprocessed tasks, but take care: deleting a task could 177 // result in the addition of more tasks (e.g., via DeleteSoon). We set a 178 // limit on the number of times we will allow a deleted task to generate more 179 // tasks. Normally, we should only pass through this loop once or twice. If 180 // we end up hitting the loop limit, then it is probably due to one task that 181 // is being stubborn. Inspect the queues to see who is left. 182 bool did_work; 183 for (int i = 0; i < 100; ++i) { 184 DeletePendingTasks(); 185 ReloadWorkQueue(); 186 // If we end up with empty queues, then break out of the loop. 187 did_work = DeletePendingTasks(); 188 if (!did_work) 189 break; 190 } 191 DCHECK(!did_work); 192 193 // OK, now make it so that no one can find us. 194 lazy_tls_ptr.Pointer()->Set(NULL); 195} 196 197void MessageLoop::AddDestructionObserver( 198 DestructionObserver* destruction_observer) { 199 DCHECK(this == current()); 200 destruction_observers_.AddObserver(destruction_observer); 201} 202 203void MessageLoop::RemoveDestructionObserver( 204 DestructionObserver* destruction_observer) { 205 DCHECK(this == current()); 206 destruction_observers_.RemoveObserver(destruction_observer); 207} 208 209void MessageLoop::AddTaskObserver(TaskObserver* task_observer) { 210 DCHECK_EQ(this, current()); 211 task_observers_.AddObserver(task_observer); 212} 213 214void MessageLoop::RemoveTaskObserver(TaskObserver* task_observer) { 215 DCHECK_EQ(this, current()); 216 task_observers_.RemoveObserver(task_observer); 217} 218 219void MessageLoop::Run() { 220 AutoRunState save_state(this); 221 RunHandler(); 222} 223 224void MessageLoop::RunAllPending() { 225 AutoRunState save_state(this); 226 state_->quit_received = true; // Means run until we would otherwise block. 227 RunHandler(); 228} 229 230// Runs the loop in two different SEH modes: 231// enable_SEH_restoration_ = false : any unhandled exception goes to the last 232// one that calls SetUnhandledExceptionFilter(). 233// enable_SEH_restoration_ = true : any unhandled exception goes to the filter 234// that was existed before the loop was run. 235void MessageLoop::RunHandler() { 236#if defined(OS_WIN) 237 if (exception_restoration_) { 238 RunInternalInSEHFrame(); 239 return; 240 } 241#endif 242 243 RunInternal(); 244} 245//------------------------------------------------------------------------------ 246#if defined(OS_WIN) 247__declspec(noinline) void MessageLoop::RunInternalInSEHFrame() { 248 LPTOP_LEVEL_EXCEPTION_FILTER current_filter = GetTopSEHFilter(); 249 __try { 250 RunInternal(); 251 } __except(SEHFilter(current_filter)) { 252 } 253 return; 254} 255#endif 256//------------------------------------------------------------------------------ 257 258void MessageLoop::RunInternal() { 259 DCHECK(this == current()); 260 261#ifndef ANDROID 262 StartHistogrammer(); 263#endif 264 265#if !defined(OS_MACOSX) 266 if (state_->dispatcher && type() == TYPE_UI) { 267 static_cast<base::MessagePumpForUI*>(pump_.get())-> 268 RunWithDispatcher(this, state_->dispatcher); 269 return; 270 } 271#endif 272 273 pump_->Run(this); 274} 275 276//------------------------------------------------------------------------------ 277// Wrapper functions for use in above message loop framework. 278 279bool MessageLoop::ProcessNextDelayedNonNestableTask() { 280 if (state_->run_depth != 1) 281 return false; 282 283 if (deferred_non_nestable_work_queue_.empty()) 284 return false; 285 286 Task* task = deferred_non_nestable_work_queue_.front().task; 287 deferred_non_nestable_work_queue_.pop(); 288 289 RunTask(task); 290 return true; 291} 292 293//------------------------------------------------------------------------------ 294 295void MessageLoop::Quit() { 296 DCHECK(current() == this); 297 if (state_) { 298 state_->quit_received = true; 299 } else { 300 NOTREACHED() << "Must be inside Run to call Quit"; 301 } 302} 303 304void MessageLoop::QuitNow() { 305 DCHECK(current() == this); 306 if (state_) { 307 pump_->Quit(); 308 } else { 309 NOTREACHED() << "Must be inside Run to call Quit"; 310 } 311} 312 313void MessageLoop::PostTask( 314 const tracked_objects::Location& from_here, Task* task) { 315 PostTask_Helper(from_here, task, 0, true); 316} 317 318void MessageLoop::PostDelayedTask( 319 const tracked_objects::Location& from_here, Task* task, int64 delay_ms) { 320 PostTask_Helper(from_here, task, delay_ms, true); 321} 322 323void MessageLoop::PostNonNestableTask( 324 const tracked_objects::Location& from_here, Task* task) { 325 PostTask_Helper(from_here, task, 0, false); 326} 327 328void MessageLoop::PostNonNestableDelayedTask( 329 const tracked_objects::Location& from_here, Task* task, int64 delay_ms) { 330 PostTask_Helper(from_here, task, delay_ms, false); 331} 332 333// Possibly called on a background thread! 334void MessageLoop::PostTask_Helper( 335 const tracked_objects::Location& from_here, Task* task, int64 delay_ms, 336 bool nestable) { 337 task->SetBirthPlace(from_here); 338 339 PendingTask pending_task(task, nestable); 340 341 if (delay_ms > 0) { 342 pending_task.delayed_run_time = 343 TimeTicks::Now() + TimeDelta::FromMilliseconds(delay_ms); 344 345#if defined(OS_WIN) 346 if (high_resolution_timer_expiration_.is_null()) { 347 // Windows timers are granular to 15.6ms. If we only set high-res 348 // timers for those under 15.6ms, then a 18ms timer ticks at ~32ms, 349 // which as a percentage is pretty inaccurate. So enable high 350 // res timers for any timer which is within 2x of the granularity. 351 // This is a tradeoff between accuracy and power management. 352 bool needs_high_res_timers = 353 delay_ms < (2 * Time::kMinLowResolutionThresholdMs); 354 if (needs_high_res_timers) { 355 Time::ActivateHighResolutionTimer(true); 356 high_resolution_timer_expiration_ = TimeTicks::Now() + 357 TimeDelta::FromMilliseconds(kHighResolutionTimerModeLeaseTimeMs); 358 } 359 } 360#endif 361 } else { 362 DCHECK_EQ(delay_ms, 0) << "delay should not be negative"; 363 } 364 365#if defined(OS_WIN) 366 if (!high_resolution_timer_expiration_.is_null()) { 367 if (TimeTicks::Now() > high_resolution_timer_expiration_) { 368 Time::ActivateHighResolutionTimer(false); 369 high_resolution_timer_expiration_ = TimeTicks(); 370 } 371 } 372#endif 373 374 // Warning: Don't try to short-circuit, and handle this thread's tasks more 375 // directly, as it could starve handling of foreign threads. Put every task 376 // into this queue. 377 378 scoped_refptr<base::MessagePump> pump; 379 { 380 AutoLock locked(incoming_queue_lock_); 381 382 bool was_empty = incoming_queue_.empty(); 383 incoming_queue_.push(pending_task); 384 if (!was_empty) 385 return; // Someone else should have started the sub-pump. 386 387 pump = pump_; 388 } 389 // Since the incoming_queue_ may contain a task that destroys this message 390 // loop, we cannot exit incoming_queue_lock_ until we are done with |this|. 391 // We use a stack-based reference to the message pump so that we can call 392 // ScheduleWork outside of incoming_queue_lock_. 393 394 pump->ScheduleWork(); 395} 396 397void MessageLoop::SetNestableTasksAllowed(bool allowed) { 398 if (nestable_tasks_allowed_ != allowed) { 399 nestable_tasks_allowed_ = allowed; 400 if (!nestable_tasks_allowed_) 401 return; 402 // Start the native pump if we are not already pumping. 403 pump_->ScheduleWork(); 404 } 405} 406 407bool MessageLoop::NestableTasksAllowed() const { 408 return nestable_tasks_allowed_; 409} 410 411bool MessageLoop::IsNested() { 412 return state_->run_depth > 1; 413} 414 415//------------------------------------------------------------------------------ 416 417void MessageLoop::RunTask(Task* task) { 418 DCHECK(nestable_tasks_allowed_); 419 // Execute the task and assume the worst: It is probably not reentrant. 420 nestable_tasks_allowed_ = false; 421 422 HistogramEvent(kTaskRunEvent); 423 FOR_EACH_OBSERVER(TaskObserver, task_observers_, 424 WillProcessTask(task)); 425 task->Run(); 426 FOR_EACH_OBSERVER(TaskObserver, task_observers_, DidProcessTask(task)); 427 delete task; 428 429 nestable_tasks_allowed_ = true; 430} 431 432bool MessageLoop::DeferOrRunPendingTask(const PendingTask& pending_task) { 433 if (pending_task.nestable || state_->run_depth == 1) { 434 RunTask(pending_task.task); 435 // Show that we ran a task (Note: a new one might arrive as a 436 // consequence!). 437 return true; 438 } 439 440 // We couldn't run the task now because we're in a nested message loop 441 // and the task isn't nestable. 442 deferred_non_nestable_work_queue_.push(pending_task); 443 return false; 444} 445 446void MessageLoop::AddToDelayedWorkQueue(const PendingTask& pending_task) { 447 // Move to the delayed work queue. Initialize the sequence number 448 // before inserting into the delayed_work_queue_. The sequence number 449 // is used to faciliate FIFO sorting when two tasks have the same 450 // delayed_run_time value. 451 PendingTask new_pending_task(pending_task); 452 new_pending_task.sequence_num = next_sequence_num_++; 453 delayed_work_queue_.push(new_pending_task); 454} 455 456void MessageLoop::ReloadWorkQueue() { 457 // We can improve performance of our loading tasks from incoming_queue_ to 458 // work_queue_ by waiting until the last minute (work_queue_ is empty) to 459 // load. That reduces the number of locks-per-task significantly when our 460 // queues get large. 461 if (!work_queue_.empty()) 462 return; // Wait till we *really* need to lock and load. 463 464 // Acquire all we can from the inter-thread queue with one lock acquisition. 465 { 466 AutoLock lock(incoming_queue_lock_); 467 if (incoming_queue_.empty()) 468 return; 469 incoming_queue_.Swap(&work_queue_); // Constant time 470 DCHECK(incoming_queue_.empty()); 471 } 472} 473 474bool MessageLoop::DeletePendingTasks() { 475 bool did_work = !work_queue_.empty(); 476 while (!work_queue_.empty()) { 477 PendingTask pending_task = work_queue_.front(); 478 work_queue_.pop(); 479 if (!pending_task.delayed_run_time.is_null()) { 480 // We want to delete delayed tasks in the same order in which they would 481 // normally be deleted in case of any funny dependencies between delayed 482 // tasks. 483 AddToDelayedWorkQueue(pending_task); 484 } else { 485 // TODO(darin): Delete all tasks once it is safe to do so. 486 // Until it is totally safe, just do it when running Purify or 487 // Valgrind. 488#if defined(PURIFY) || defined(USE_HEAPCHECKER) 489 delete pending_task.task; 490#elif defined(OS_POSIX) 491 if (RUNNING_ON_VALGRIND) 492 delete pending_task.task; 493#endif // defined(OS_POSIX) 494 } 495 } 496 did_work |= !deferred_non_nestable_work_queue_.empty(); 497 while (!deferred_non_nestable_work_queue_.empty()) { 498 // TODO(darin): Delete all tasks once it is safe to do so. 499 // Until it is totaly safe, only delete them under Purify and Valgrind. 500 Task* task = NULL; 501#if defined(PURIFY) || defined(USE_HEAPCHECKER) 502 task = deferred_non_nestable_work_queue_.front().task; 503#elif defined(OS_POSIX) 504 if (RUNNING_ON_VALGRIND) 505 task = deferred_non_nestable_work_queue_.front().task; 506#endif 507 deferred_non_nestable_work_queue_.pop(); 508 if (task) 509 delete task; 510 } 511 did_work |= !delayed_work_queue_.empty(); 512 while (!delayed_work_queue_.empty()) { 513 Task* task = delayed_work_queue_.top().task; 514 delayed_work_queue_.pop(); 515 delete task; 516 } 517 return did_work; 518} 519 520bool MessageLoop::DoWork() { 521 if (!nestable_tasks_allowed_) { 522 // Task can't be executed right now. 523 return false; 524 } 525 526 for (;;) { 527 ReloadWorkQueue(); 528 if (work_queue_.empty()) 529 break; 530 531 // Execute oldest task. 532 do { 533 PendingTask pending_task = work_queue_.front(); 534 work_queue_.pop(); 535 if (!pending_task.delayed_run_time.is_null()) { 536 AddToDelayedWorkQueue(pending_task); 537 // If we changed the topmost task, then it is time to re-schedule. 538 if (delayed_work_queue_.top().task == pending_task.task) 539 pump_->ScheduleDelayedWork(pending_task.delayed_run_time); 540 } else { 541 if (DeferOrRunPendingTask(pending_task)) 542 return true; 543 } 544 } while (!work_queue_.empty()); 545 } 546 547 // Nothing happened. 548 return false; 549} 550 551bool MessageLoop::DoDelayedWork(base::TimeTicks* next_delayed_work_time) { 552 if (!nestable_tasks_allowed_ || delayed_work_queue_.empty()) { 553 recent_time_ = *next_delayed_work_time = TimeTicks(); 554 return false; 555 } 556 557 // When we "fall behind," there will be a lot of tasks in the delayed work 558 // queue that are ready to run. To increase efficiency when we fall behind, 559 // we will only call Time::Now() intermittently, and then process all tasks 560 // that are ready to run before calling it again. As a result, the more we 561 // fall behind (and have a lot of ready-to-run delayed tasks), the more 562 // efficient we'll be at handling the tasks. 563 564 TimeTicks next_run_time = delayed_work_queue_.top().delayed_run_time; 565 if (next_run_time > recent_time_) { 566 recent_time_ = TimeTicks::Now(); // Get a better view of Now(); 567 if (next_run_time > recent_time_) { 568 *next_delayed_work_time = next_run_time; 569 return false; 570 } 571 } 572 573 PendingTask pending_task = delayed_work_queue_.top(); 574 delayed_work_queue_.pop(); 575 576 if (!delayed_work_queue_.empty()) 577 *next_delayed_work_time = delayed_work_queue_.top().delayed_run_time; 578 579 return DeferOrRunPendingTask(pending_task); 580} 581 582bool MessageLoop::DoIdleWork() { 583 if (ProcessNextDelayedNonNestableTask()) 584 return true; 585 586 if (state_->quit_received) 587 pump_->Quit(); 588 589 return false; 590} 591 592//------------------------------------------------------------------------------ 593// MessageLoop::AutoRunState 594 595MessageLoop::AutoRunState::AutoRunState(MessageLoop* loop) : loop_(loop) { 596 // Make the loop reference us. 597 previous_state_ = loop_->state_; 598 if (previous_state_) { 599 run_depth = previous_state_->run_depth + 1; 600 } else { 601 run_depth = 1; 602 } 603 loop_->state_ = this; 604 605 // Initialize the other fields: 606 quit_received = false; 607#if !defined(OS_MACOSX) 608 dispatcher = NULL; 609#endif 610} 611 612MessageLoop::AutoRunState::~AutoRunState() { 613 loop_->state_ = previous_state_; 614} 615 616//------------------------------------------------------------------------------ 617// MessageLoop::PendingTask 618 619bool MessageLoop::PendingTask::operator<(const PendingTask& other) const { 620 // Since the top of a priority queue is defined as the "greatest" element, we 621 // need to invert the comparison here. We want the smaller time to be at the 622 // top of the heap. 623 624 if (delayed_run_time < other.delayed_run_time) 625 return false; 626 627 if (delayed_run_time > other.delayed_run_time) 628 return true; 629 630 // If the times happen to match, then we use the sequence number to decide. 631 // Compare the difference to support integer roll-over. 632 return (sequence_num - other.sequence_num) > 0; 633} 634 635//------------------------------------------------------------------------------ 636// Method and data for histogramming events and actions taken by each instance 637// on each thread. 638 639// static 640void MessageLoop::EnableHistogrammer(bool enable) { 641 enable_histogrammer_ = enable; 642} 643 644void MessageLoop::StartHistogrammer() { 645 if (enable_histogrammer_ && !message_histogram_.get() 646 && base::StatisticsRecorder::WasStarted()) { 647 DCHECK(!thread_name_.empty()); 648 message_histogram_ = base::LinearHistogram::FactoryGet( 649 "MsgLoop:" + thread_name_, 650 kLeastNonZeroMessageId, kMaxMessageId, 651 kNumberOfDistinctMessagesDisplayed, 652 message_histogram_->kHexRangePrintingFlag); 653 message_histogram_->SetRangeDescriptions(event_descriptions_); 654 } 655} 656 657void MessageLoop::HistogramEvent(int event) { 658 if (message_histogram_.get()) 659 message_histogram_->Add(event); 660} 661 662//------------------------------------------------------------------------------ 663// MessageLoopForUI 664 665#if defined(OS_WIN) 666void MessageLoopForUI::DidProcessMessage(const MSG& message) { 667 pump_win()->DidProcessMessage(message); 668} 669#endif // defined(OS_WIN) 670 671#if !defined(OS_MACOSX) && !defined(ANDROID) 672void MessageLoopForUI::AddObserver(Observer* observer) { 673 pump_ui()->AddObserver(observer); 674} 675 676void MessageLoopForUI::RemoveObserver(Observer* observer) { 677 pump_ui()->RemoveObserver(observer); 678} 679 680void MessageLoopForUI::Run(Dispatcher* dispatcher) { 681 AutoRunState save_state(this); 682 state_->dispatcher = dispatcher; 683 RunHandler(); 684} 685#endif // !defined(OS_MACOSX) 686 687//------------------------------------------------------------------------------ 688// MessageLoopForIO 689 690#if defined(OS_WIN) 691 692void MessageLoopForIO::RegisterIOHandler(HANDLE file, IOHandler* handler) { 693 pump_io()->RegisterIOHandler(file, handler); 694} 695 696bool MessageLoopForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) { 697 return pump_io()->WaitForIOCompletion(timeout, filter); 698} 699 700#elif defined(OS_POSIX) 701 702bool MessageLoopForIO::WatchFileDescriptor(int fd, 703 bool persistent, 704 Mode mode, 705 FileDescriptorWatcher *controller, 706 Watcher *delegate) { 707 return pump_libevent()->WatchFileDescriptor( 708 fd, 709 persistent, 710 static_cast<base::MessagePumpLibevent::Mode>(mode), 711 controller, 712 delegate); 713} 714 715#endif 716