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| 1 // Copyright (c) 2012 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/message_pump_win.h" | |
| 6 | |
| 7 #include <math.h> | |
| 8 | |
| 9 #include "base/debug/trace_event.h" | |
| 10 #include "base/message_loop/message_loop.h" | |
| 11 #include "base/metrics/histogram.h" | |
| 12 #include "base/process_util.h" | |
| 13 #include "base/stringprintf.h" | |
| 14 #include "base/win/wrapped_window_proc.h" | |
| 15 | |
| 16 namespace base { | |
| 17 | |
| 18 namespace { | |
| 19 | |
| 20 enum MessageLoopProblems { | |
| 21 MESSAGE_POST_ERROR, | |
| 22 COMPLETION_POST_ERROR, | |
| 23 SET_TIMER_ERROR, | |
| 24 MESSAGE_LOOP_PROBLEM_MAX, | |
| 25 }; | |
| 26 | |
| 27 } // namespace | |
| 28 | |
| 29 static const wchar_t kWndClassFormat[] = L"Chrome_MessagePumpWindow_%p"; | |
| 30 | |
| 31 // Message sent to get an additional time slice for pumping (processing) another | |
| 32 // task (a series of such messages creates a continuous task pump). | |
| 33 static const int kMsgHaveWork = WM_USER + 1; | |
| 34 | |
| 35 //----------------------------------------------------------------------------- | |
| 36 // MessagePumpWin public: | |
| 37 | |
| 38 void MessagePumpWin::AddObserver(MessagePumpObserver* observer) { | |
| 39 observers_.AddObserver(observer); | |
| 40 } | |
| 41 | |
| 42 void MessagePumpWin::RemoveObserver(MessagePumpObserver* observer) { | |
| 43 observers_.RemoveObserver(observer); | |
| 44 } | |
| 45 | |
| 46 void MessagePumpWin::WillProcessMessage(const MSG& msg) { | |
| 47 FOR_EACH_OBSERVER(MessagePumpObserver, observers_, WillProcessEvent(msg)); | |
| 48 } | |
| 49 | |
| 50 void MessagePumpWin::DidProcessMessage(const MSG& msg) { | |
| 51 FOR_EACH_OBSERVER(MessagePumpObserver, observers_, DidProcessEvent(msg)); | |
| 52 } | |
| 53 | |
| 54 void MessagePumpWin::RunWithDispatcher( | |
| 55 Delegate* delegate, MessagePumpDispatcher* dispatcher) { | |
| 56 RunState s; | |
| 57 s.delegate = delegate; | |
| 58 s.dispatcher = dispatcher; | |
| 59 s.should_quit = false; | |
| 60 s.run_depth = state_ ? state_->run_depth + 1 : 1; | |
| 61 | |
| 62 RunState* previous_state = state_; | |
| 63 state_ = &s; | |
| 64 | |
| 65 DoRunLoop(); | |
| 66 | |
| 67 state_ = previous_state; | |
| 68 } | |
| 69 | |
| 70 void MessagePumpWin::Quit() { | |
| 71 DCHECK(state_); | |
| 72 state_->should_quit = true; | |
| 73 } | |
| 74 | |
| 75 //----------------------------------------------------------------------------- | |
| 76 // MessagePumpWin protected: | |
| 77 | |
| 78 int MessagePumpWin::GetCurrentDelay() const { | |
| 79 if (delayed_work_time_.is_null()) | |
| 80 return -1; | |
| 81 | |
| 82 // Be careful here. TimeDelta has a precision of microseconds, but we want a | |
| 83 // value in milliseconds. If there are 5.5ms left, should the delay be 5 or | |
| 84 // 6? It should be 6 to avoid executing delayed work too early. | |
| 85 double timeout = | |
| 86 ceil((delayed_work_time_ - TimeTicks::Now()).InMillisecondsF()); | |
| 87 | |
| 88 // If this value is negative, then we need to run delayed work soon. | |
| 89 int delay = static_cast<int>(timeout); | |
| 90 if (delay < 0) | |
| 91 delay = 0; | |
| 92 | |
| 93 return delay; | |
| 94 } | |
| 95 | |
| 96 //----------------------------------------------------------------------------- | |
| 97 // MessagePumpForUI public: | |
| 98 | |
| 99 MessagePumpForUI::MessagePumpForUI() | |
| 100 : atom_(0), | |
| 101 message_filter_(new MessageFilter) { | |
| 102 InitMessageWnd(); | |
| 103 } | |
| 104 | |
| 105 MessagePumpForUI::~MessagePumpForUI() { | |
| 106 DestroyWindow(message_hwnd_); | |
| 107 UnregisterClass(MAKEINTATOM(atom_), | |
| 108 GetModuleFromAddress(&WndProcThunk)); | |
| 109 } | |
| 110 | |
| 111 void MessagePumpForUI::ScheduleWork() { | |
| 112 if (InterlockedExchange(&have_work_, 1)) | |
| 113 return; // Someone else continued the pumping. | |
| 114 | |
| 115 // Make sure the MessagePump does some work for us. | |
| 116 BOOL ret = PostMessage(message_hwnd_, kMsgHaveWork, | |
| 117 reinterpret_cast<WPARAM>(this), 0); | |
| 118 if (ret) | |
| 119 return; // There was room in the Window Message queue. | |
| 120 | |
| 121 // We have failed to insert a have-work message, so there is a chance that we | |
| 122 // will starve tasks/timers while sitting in a nested message loop. Nested | |
| 123 // loops only look at Windows Message queues, and don't look at *our* task | |
| 124 // queues, etc., so we might not get a time slice in such. :-( | |
| 125 // We could abort here, but the fear is that this failure mode is plausibly | |
| 126 // common (queue is full, of about 2000 messages), so we'll do a near-graceful | |
| 127 // recovery. Nested loops are pretty transient (we think), so this will | |
| 128 // probably be recoverable. | |
| 129 InterlockedExchange(&have_work_, 0); // Clarify that we didn't really insert. | |
| 130 UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", MESSAGE_POST_ERROR, | |
| 131 MESSAGE_LOOP_PROBLEM_MAX); | |
| 132 } | |
| 133 | |
| 134 void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) { | |
| 135 // | |
| 136 // We would *like* to provide high resolution timers. Windows timers using | |
| 137 // SetTimer() have a 10ms granularity. We have to use WM_TIMER as a wakeup | |
| 138 // mechanism because the application can enter modal windows loops where it | |
| 139 // is not running our MessageLoop; the only way to have our timers fire in | |
| 140 // these cases is to post messages there. | |
| 141 // | |
| 142 // To provide sub-10ms timers, we process timers directly from our run loop. | |
| 143 // For the common case, timers will be processed there as the run loop does | |
| 144 // its normal work. However, we *also* set the system timer so that WM_TIMER | |
| 145 // events fire. This mops up the case of timers not being able to work in | |
| 146 // modal message loops. It is possible for the SetTimer to pop and have no | |
| 147 // pending timers, because they could have already been processed by the | |
| 148 // run loop itself. | |
| 149 // | |
| 150 // We use a single SetTimer corresponding to the timer that will expire | |
| 151 // soonest. As new timers are created and destroyed, we update SetTimer. | |
| 152 // Getting a spurrious SetTimer event firing is benign, as we'll just be | |
| 153 // processing an empty timer queue. | |
| 154 // | |
| 155 delayed_work_time_ = delayed_work_time; | |
| 156 | |
| 157 int delay_msec = GetCurrentDelay(); | |
| 158 DCHECK_GE(delay_msec, 0); | |
| 159 if (delay_msec < USER_TIMER_MINIMUM) | |
| 160 delay_msec = USER_TIMER_MINIMUM; | |
| 161 | |
| 162 // Create a WM_TIMER event that will wake us up to check for any pending | |
| 163 // timers (in case we are running within a nested, external sub-pump). | |
| 164 BOOL ret = SetTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this), | |
| 165 delay_msec, NULL); | |
| 166 if (ret) | |
| 167 return; | |
| 168 // If we can't set timers, we are in big trouble... but cross our fingers for | |
| 169 // now. | |
| 170 // TODO(jar): If we don't see this error, use a CHECK() here instead. | |
| 171 UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", SET_TIMER_ERROR, | |
| 172 MESSAGE_LOOP_PROBLEM_MAX); | |
| 173 } | |
| 174 | |
| 175 void MessagePumpForUI::PumpOutPendingPaintMessages() { | |
| 176 // If we are being called outside of the context of Run, then don't try to do | |
| 177 // any work. | |
| 178 if (!state_) | |
| 179 return; | |
| 180 | |
| 181 // Create a mini-message-pump to force immediate processing of only Windows | |
| 182 // WM_PAINT messages. Don't provide an infinite loop, but do enough peeking | |
| 183 // to get the job done. Actual common max is 4 peeks, but we'll be a little | |
| 184 // safe here. | |
| 185 const int kMaxPeekCount = 20; | |
| 186 int peek_count; | |
| 187 for (peek_count = 0; peek_count < kMaxPeekCount; ++peek_count) { | |
| 188 MSG msg; | |
| 189 if (!PeekMessage(&msg, NULL, 0, 0, PM_REMOVE | PM_QS_PAINT)) | |
| 190 break; | |
| 191 ProcessMessageHelper(msg); | |
| 192 if (state_->should_quit) // Handle WM_QUIT. | |
| 193 break; | |
| 194 } | |
| 195 // Histogram what was really being used, to help to adjust kMaxPeekCount. | |
| 196 DHISTOGRAM_COUNTS("Loop.PumpOutPendingPaintMessages Peeks", peek_count); | |
| 197 } | |
| 198 | |
| 199 //----------------------------------------------------------------------------- | |
| 200 // MessagePumpForUI private: | |
| 201 | |
| 202 // static | |
| 203 LRESULT CALLBACK MessagePumpForUI::WndProcThunk( | |
| 204 HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) { | |
| 205 switch (message) { | |
| 206 case kMsgHaveWork: | |
| 207 reinterpret_cast<MessagePumpForUI*>(wparam)->HandleWorkMessage(); | |
| 208 break; | |
| 209 case WM_TIMER: | |
| 210 reinterpret_cast<MessagePumpForUI*>(wparam)->HandleTimerMessage(); | |
| 211 break; | |
| 212 } | |
| 213 return DefWindowProc(hwnd, message, wparam, lparam); | |
| 214 } | |
| 215 | |
| 216 void MessagePumpForUI::DoRunLoop() { | |
| 217 // IF this was just a simple PeekMessage() loop (servicing all possible work | |
| 218 // queues), then Windows would try to achieve the following order according | |
| 219 // to MSDN documentation about PeekMessage with no filter): | |
| 220 // * Sent messages | |
| 221 // * Posted messages | |
| 222 // * Sent messages (again) | |
| 223 // * WM_PAINT messages | |
| 224 // * WM_TIMER messages | |
| 225 // | |
| 226 // Summary: none of the above classes is starved, and sent messages has twice | |
| 227 // the chance of being processed (i.e., reduced service time). | |
| 228 | |
| 229 for (;;) { | |
| 230 // If we do any work, we may create more messages etc., and more work may | |
| 231 // possibly be waiting in another task group. When we (for example) | |
| 232 // ProcessNextWindowsMessage(), there is a good chance there are still more | |
| 233 // messages waiting. On the other hand, when any of these methods return | |
| 234 // having done no work, then it is pretty unlikely that calling them again | |
| 235 // quickly will find any work to do. Finally, if they all say they had no | |
| 236 // work, then it is a good time to consider sleeping (waiting) for more | |
| 237 // work. | |
| 238 | |
| 239 bool more_work_is_plausible = ProcessNextWindowsMessage(); | |
| 240 if (state_->should_quit) | |
| 241 break; | |
| 242 | |
| 243 more_work_is_plausible |= state_->delegate->DoWork(); | |
| 244 if (state_->should_quit) | |
| 245 break; | |
| 246 | |
| 247 more_work_is_plausible |= | |
| 248 state_->delegate->DoDelayedWork(&delayed_work_time_); | |
| 249 // If we did not process any delayed work, then we can assume that our | |
| 250 // existing WM_TIMER if any will fire when delayed work should run. We | |
| 251 // don't want to disturb that timer if it is already in flight. However, | |
| 252 // if we did do all remaining delayed work, then lets kill the WM_TIMER. | |
| 253 if (more_work_is_plausible && delayed_work_time_.is_null()) | |
| 254 KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this)); | |
| 255 if (state_->should_quit) | |
| 256 break; | |
| 257 | |
| 258 if (more_work_is_plausible) | |
| 259 continue; | |
| 260 | |
| 261 more_work_is_plausible = state_->delegate->DoIdleWork(); | |
| 262 if (state_->should_quit) | |
| 263 break; | |
| 264 | |
| 265 if (more_work_is_plausible) | |
| 266 continue; | |
| 267 | |
| 268 WaitForWork(); // Wait (sleep) until we have work to do again. | |
| 269 } | |
| 270 } | |
| 271 | |
| 272 void MessagePumpForUI::InitMessageWnd() { | |
| 273 // Generate a unique window class name. | |
| 274 string16 class_name = StringPrintf(kWndClassFormat, this); | |
| 275 | |
| 276 HINSTANCE instance = GetModuleFromAddress(&WndProcThunk); | |
| 277 WNDCLASSEX wc = {0}; | |
| 278 wc.cbSize = sizeof(wc); | |
| 279 wc.lpfnWndProc = base::win::WrappedWindowProc<WndProcThunk>; | |
| 280 wc.hInstance = instance; | |
| 281 wc.lpszClassName = class_name.c_str(); | |
| 282 atom_ = RegisterClassEx(&wc); | |
| 283 DCHECK(atom_); | |
| 284 | |
| 285 message_hwnd_ = CreateWindow(MAKEINTATOM(atom_), 0, 0, 0, 0, 0, 0, | |
| 286 HWND_MESSAGE, 0, instance, 0); | |
| 287 DCHECK(message_hwnd_); | |
| 288 } | |
| 289 | |
| 290 void MessagePumpForUI::WaitForWork() { | |
| 291 // Wait until a message is available, up to the time needed by the timer | |
| 292 // manager to fire the next set of timers. | |
| 293 int delay = GetCurrentDelay(); | |
| 294 if (delay < 0) // Negative value means no timers waiting. | |
| 295 delay = INFINITE; | |
| 296 | |
| 297 DWORD result; | |
| 298 result = MsgWaitForMultipleObjectsEx(0, NULL, delay, QS_ALLINPUT, | |
| 299 MWMO_INPUTAVAILABLE); | |
| 300 | |
| 301 if (WAIT_OBJECT_0 == result) { | |
| 302 // A WM_* message is available. | |
| 303 // If a parent child relationship exists between windows across threads | |
| 304 // then their thread inputs are implicitly attached. | |
| 305 // This causes the MsgWaitForMultipleObjectsEx API to return indicating | |
| 306 // that messages are ready for processing (Specifically, mouse messages | |
| 307 // intended for the child window may appear if the child window has | |
| 308 // capture). | |
| 309 // The subsequent PeekMessages call may fail to return any messages thus | |
| 310 // causing us to enter a tight loop at times. | |
| 311 // The WaitMessage call below is a workaround to give the child window | |
| 312 // some time to process its input messages. | |
| 313 MSG msg = {0}; | |
| 314 DWORD queue_status = GetQueueStatus(QS_MOUSE); | |
| 315 if (HIWORD(queue_status) & QS_MOUSE && | |
| 316 !PeekMessage(&msg, NULL, WM_MOUSEFIRST, WM_MOUSELAST, PM_NOREMOVE)) { | |
| 317 WaitMessage(); | |
| 318 } | |
| 319 return; | |
| 320 } | |
| 321 | |
| 322 DCHECK_NE(WAIT_FAILED, result) << GetLastError(); | |
| 323 } | |
| 324 | |
| 325 void MessagePumpForUI::HandleWorkMessage() { | |
| 326 // If we are being called outside of the context of Run, then don't try to do | |
| 327 // any work. This could correspond to a MessageBox call or something of that | |
| 328 // sort. | |
| 329 if (!state_) { | |
| 330 // Since we handled a kMsgHaveWork message, we must still update this flag. | |
| 331 InterlockedExchange(&have_work_, 0); | |
| 332 return; | |
| 333 } | |
| 334 | |
| 335 // Let whatever would have run had we not been putting messages in the queue | |
| 336 // run now. This is an attempt to make our dummy message not starve other | |
| 337 // messages that may be in the Windows message queue. | |
| 338 ProcessPumpReplacementMessage(); | |
| 339 | |
| 340 // Now give the delegate a chance to do some work. He'll let us know if he | |
| 341 // needs to do more work. | |
| 342 if (state_->delegate->DoWork()) | |
| 343 ScheduleWork(); | |
| 344 } | |
| 345 | |
| 346 void MessagePumpForUI::HandleTimerMessage() { | |
| 347 KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this)); | |
| 348 | |
| 349 // If we are being called outside of the context of Run, then don't do | |
| 350 // anything. This could correspond to a MessageBox call or something of | |
| 351 // that sort. | |
| 352 if (!state_) | |
| 353 return; | |
| 354 | |
| 355 state_->delegate->DoDelayedWork(&delayed_work_time_); | |
| 356 if (!delayed_work_time_.is_null()) { | |
| 357 // A bit gratuitous to set delayed_work_time_ again, but oh well. | |
| 358 ScheduleDelayedWork(delayed_work_time_); | |
| 359 } | |
| 360 } | |
| 361 | |
| 362 bool MessagePumpForUI::ProcessNextWindowsMessage() { | |
| 363 // If there are sent messages in the queue then PeekMessage internally | |
| 364 // dispatches the message and returns false. We return true in this | |
| 365 // case to ensure that the message loop peeks again instead of calling | |
| 366 // MsgWaitForMultipleObjectsEx again. | |
| 367 bool sent_messages_in_queue = false; | |
| 368 DWORD queue_status = GetQueueStatus(QS_SENDMESSAGE); | |
| 369 if (HIWORD(queue_status) & QS_SENDMESSAGE) | |
| 370 sent_messages_in_queue = true; | |
| 371 | |
| 372 MSG msg; | |
| 373 if (message_filter_->DoPeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) | |
| 374 return ProcessMessageHelper(msg); | |
| 375 | |
| 376 return sent_messages_in_queue; | |
| 377 } | |
| 378 | |
| 379 bool MessagePumpForUI::ProcessMessageHelper(const MSG& msg) { | |
| 380 TRACE_EVENT1("base", "MessagePumpForUI::ProcessMessageHelper", | |
| 381 "message", msg.message); | |
| 382 if (WM_QUIT == msg.message) { | |
| 383 // Repost the QUIT message so that it will be retrieved by the primary | |
| 384 // GetMessage() loop. | |
| 385 state_->should_quit = true; | |
| 386 PostQuitMessage(static_cast<int>(msg.wParam)); | |
| 387 return false; | |
| 388 } | |
| 389 | |
| 390 // While running our main message pump, we discard kMsgHaveWork messages. | |
| 391 if (msg.message == kMsgHaveWork && msg.hwnd == message_hwnd_) | |
| 392 return ProcessPumpReplacementMessage(); | |
| 393 | |
| 394 if (CallMsgFilter(const_cast<MSG*>(&msg), kMessageFilterCode)) | |
| 395 return true; | |
| 396 | |
| 397 WillProcessMessage(msg); | |
| 398 | |
| 399 if (!message_filter_->ProcessMessage(msg)) { | |
| 400 if (state_->dispatcher) { | |
| 401 if (!state_->dispatcher->Dispatch(msg)) | |
| 402 state_->should_quit = true; | |
| 403 } else { | |
| 404 TranslateMessage(&msg); | |
| 405 DispatchMessage(&msg); | |
| 406 } | |
| 407 } | |
| 408 | |
| 409 DidProcessMessage(msg); | |
| 410 return true; | |
| 411 } | |
| 412 | |
| 413 bool MessagePumpForUI::ProcessPumpReplacementMessage() { | |
| 414 // When we encounter a kMsgHaveWork message, this method is called to peek | |
| 415 // and process a replacement message, such as a WM_PAINT or WM_TIMER. The | |
| 416 // goal is to make the kMsgHaveWork as non-intrusive as possible, even though | |
| 417 // a continuous stream of such messages are posted. This method carefully | |
| 418 // peeks a message while there is no chance for a kMsgHaveWork to be pending, | |
| 419 // then resets the have_work_ flag (allowing a replacement kMsgHaveWork to | |
| 420 // possibly be posted), and finally dispatches that peeked replacement. Note | |
| 421 // that the re-post of kMsgHaveWork may be asynchronous to this thread!! | |
| 422 | |
| 423 bool have_message = false; | |
| 424 MSG msg; | |
| 425 // We should not process all window messages if we are in the context of an | |
| 426 // OS modal loop, i.e. in the context of a windows API call like MessageBox. | |
| 427 // This is to ensure that these messages are peeked out by the OS modal loop. | |
| 428 if (MessageLoop::current()->os_modal_loop()) { | |
| 429 // We only peek out WM_PAINT and WM_TIMER here for reasons mentioned above. | |
| 430 have_message = PeekMessage(&msg, NULL, WM_PAINT, WM_PAINT, PM_REMOVE) || | |
| 431 PeekMessage(&msg, NULL, WM_TIMER, WM_TIMER, PM_REMOVE); | |
| 432 } else { | |
| 433 have_message = !!message_filter_->DoPeekMessage(&msg, NULL, 0, 0, | |
| 434 PM_REMOVE); | |
| 435 } | |
| 436 | |
| 437 DCHECK(!have_message || kMsgHaveWork != msg.message || | |
| 438 msg.hwnd != message_hwnd_); | |
| 439 | |
| 440 // Since we discarded a kMsgHaveWork message, we must update the flag. | |
| 441 int old_have_work = InterlockedExchange(&have_work_, 0); | |
| 442 DCHECK(old_have_work); | |
| 443 | |
| 444 // We don't need a special time slice if we didn't have_message to process. | |
| 445 if (!have_message) | |
| 446 return false; | |
| 447 | |
| 448 // Guarantee we'll get another time slice in the case where we go into native | |
| 449 // windows code. This ScheduleWork() may hurt performance a tiny bit when | |
| 450 // tasks appear very infrequently, but when the event queue is busy, the | |
| 451 // kMsgHaveWork events get (percentage wise) rarer and rarer. | |
| 452 ScheduleWork(); | |
| 453 return ProcessMessageHelper(msg); | |
| 454 } | |
| 455 | |
| 456 void MessagePumpForUI::SetMessageFilter( | |
| 457 scoped_ptr<MessageFilter> message_filter) { | |
| 458 message_filter_ = message_filter.Pass(); | |
| 459 } | |
| 460 | |
| 461 //----------------------------------------------------------------------------- | |
| 462 // MessagePumpForIO public: | |
| 463 | |
| 464 MessagePumpForIO::MessagePumpForIO() { | |
| 465 port_.Set(CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, NULL, 1)); | |
| 466 DCHECK(port_.IsValid()); | |
| 467 } | |
| 468 | |
| 469 void MessagePumpForIO::ScheduleWork() { | |
| 470 if (InterlockedExchange(&have_work_, 1)) | |
| 471 return; // Someone else continued the pumping. | |
| 472 | |
| 473 // Make sure the MessagePump does some work for us. | |
| 474 BOOL ret = PostQueuedCompletionStatus(port_, 0, | |
| 475 reinterpret_cast<ULONG_PTR>(this), | |
| 476 reinterpret_cast<OVERLAPPED*>(this)); | |
| 477 if (ret) | |
| 478 return; // Post worked perfectly. | |
| 479 | |
| 480 // See comment in MessagePumpForUI::ScheduleWork() for this error recovery. | |
| 481 InterlockedExchange(&have_work_, 0); // Clarify that we didn't succeed. | |
| 482 UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", COMPLETION_POST_ERROR, | |
| 483 MESSAGE_LOOP_PROBLEM_MAX); | |
| 484 } | |
| 485 | |
| 486 void MessagePumpForIO::ScheduleDelayedWork(const TimeTicks& delayed_work_time) { | |
| 487 // We know that we can't be blocked right now since this method can only be | |
| 488 // called on the same thread as Run, so we only need to update our record of | |
| 489 // how long to sleep when we do sleep. | |
| 490 delayed_work_time_ = delayed_work_time; | |
| 491 } | |
| 492 | |
| 493 void MessagePumpForIO::RegisterIOHandler(HANDLE file_handle, | |
| 494 IOHandler* handler) { | |
| 495 ULONG_PTR key = HandlerToKey(handler, true); | |
| 496 HANDLE port = CreateIoCompletionPort(file_handle, port_, key, 1); | |
| 497 DPCHECK(port); | |
| 498 } | |
| 499 | |
| 500 bool MessagePumpForIO::RegisterJobObject(HANDLE job_handle, | |
| 501 IOHandler* handler) { | |
| 502 // Job object notifications use the OVERLAPPED pointer to carry the message | |
| 503 // data. Mark the completion key correspondingly, so we will not try to | |
| 504 // convert OVERLAPPED* to IOContext*. | |
| 505 ULONG_PTR key = HandlerToKey(handler, false); | |
| 506 JOBOBJECT_ASSOCIATE_COMPLETION_PORT info; | |
| 507 info.CompletionKey = reinterpret_cast<void*>(key); | |
| 508 info.CompletionPort = port_; | |
| 509 return SetInformationJobObject(job_handle, | |
| 510 JobObjectAssociateCompletionPortInformation, | |
| 511 &info, | |
| 512 sizeof(info)) != FALSE; | |
| 513 } | |
| 514 | |
| 515 //----------------------------------------------------------------------------- | |
| 516 // MessagePumpForIO private: | |
| 517 | |
| 518 void MessagePumpForIO::DoRunLoop() { | |
| 519 for (;;) { | |
| 520 // If we do any work, we may create more messages etc., and more work may | |
| 521 // possibly be waiting in another task group. When we (for example) | |
| 522 // WaitForIOCompletion(), there is a good chance there are still more | |
| 523 // messages waiting. On the other hand, when any of these methods return | |
| 524 // having done no work, then it is pretty unlikely that calling them | |
| 525 // again quickly will find any work to do. Finally, if they all say they | |
| 526 // had no work, then it is a good time to consider sleeping (waiting) for | |
| 527 // more work. | |
| 528 | |
| 529 bool more_work_is_plausible = state_->delegate->DoWork(); | |
| 530 if (state_->should_quit) | |
| 531 break; | |
| 532 | |
| 533 more_work_is_plausible |= WaitForIOCompletion(0, NULL); | |
| 534 if (state_->should_quit) | |
| 535 break; | |
| 536 | |
| 537 more_work_is_plausible |= | |
| 538 state_->delegate->DoDelayedWork(&delayed_work_time_); | |
| 539 if (state_->should_quit) | |
| 540 break; | |
| 541 | |
| 542 if (more_work_is_plausible) | |
| 543 continue; | |
| 544 | |
| 545 more_work_is_plausible = state_->delegate->DoIdleWork(); | |
| 546 if (state_->should_quit) | |
| 547 break; | |
| 548 | |
| 549 if (more_work_is_plausible) | |
| 550 continue; | |
| 551 | |
| 552 WaitForWork(); // Wait (sleep) until we have work to do again. | |
| 553 } | |
| 554 } | |
| 555 | |
| 556 // Wait until IO completes, up to the time needed by the timer manager to fire | |
| 557 // the next set of timers. | |
| 558 void MessagePumpForIO::WaitForWork() { | |
| 559 // We do not support nested IO message loops. This is to avoid messy | |
| 560 // recursion problems. | |
| 561 DCHECK_EQ(1, state_->run_depth) << "Cannot nest an IO message loop!"; | |
| 562 | |
| 563 int timeout = GetCurrentDelay(); | |
| 564 if (timeout < 0) // Negative value means no timers waiting. | |
| 565 timeout = INFINITE; | |
| 566 | |
| 567 WaitForIOCompletion(timeout, NULL); | |
| 568 } | |
| 569 | |
| 570 bool MessagePumpForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) { | |
| 571 IOItem item; | |
| 572 if (completed_io_.empty() || !MatchCompletedIOItem(filter, &item)) { | |
| 573 // We have to ask the system for another IO completion. | |
| 574 if (!GetIOItem(timeout, &item)) | |
| 575 return false; | |
| 576 | |
| 577 if (ProcessInternalIOItem(item)) | |
| 578 return true; | |
| 579 } | |
| 580 | |
| 581 // If |item.has_valid_io_context| is false then |item.context| does not point | |
| 582 // to a context structure, and so should not be dereferenced, although it may | |
| 583 // still hold valid non-pointer data. | |
| 584 if (!item.has_valid_io_context || item.context->handler) { | |
| 585 if (filter && item.handler != filter) { | |
| 586 // Save this item for later | |
| 587 completed_io_.push_back(item); | |
| 588 } else { | |
| 589 DCHECK(!item.has_valid_io_context || | |
| 590 (item.context->handler == item.handler)); | |
| 591 WillProcessIOEvent(); | |
| 592 item.handler->OnIOCompleted(item.context, item.bytes_transfered, | |
| 593 item.error); | |
| 594 DidProcessIOEvent(); | |
| 595 } | |
| 596 } else { | |
| 597 // The handler must be gone by now, just cleanup the mess. | |
| 598 delete item.context; | |
| 599 } | |
| 600 return true; | |
| 601 } | |
| 602 | |
| 603 // Asks the OS for another IO completion result. | |
| 604 bool MessagePumpForIO::GetIOItem(DWORD timeout, IOItem* item) { | |
| 605 memset(item, 0, sizeof(*item)); | |
| 606 ULONG_PTR key = NULL; | |
| 607 OVERLAPPED* overlapped = NULL; | |
| 608 if (!GetQueuedCompletionStatus(port_.Get(), &item->bytes_transfered, &key, | |
| 609 &overlapped, timeout)) { | |
| 610 if (!overlapped) | |
| 611 return false; // Nothing in the queue. | |
| 612 item->error = GetLastError(); | |
| 613 item->bytes_transfered = 0; | |
| 614 } | |
| 615 | |
| 616 item->handler = KeyToHandler(key, &item->has_valid_io_context); | |
| 617 item->context = reinterpret_cast<IOContext*>(overlapped); | |
| 618 return true; | |
| 619 } | |
| 620 | |
| 621 bool MessagePumpForIO::ProcessInternalIOItem(const IOItem& item) { | |
| 622 if (this == reinterpret_cast<MessagePumpForIO*>(item.context) && | |
| 623 this == reinterpret_cast<MessagePumpForIO*>(item.handler)) { | |
| 624 // This is our internal completion. | |
| 625 DCHECK(!item.bytes_transfered); | |
| 626 InterlockedExchange(&have_work_, 0); | |
| 627 return true; | |
| 628 } | |
| 629 return false; | |
| 630 } | |
| 631 | |
| 632 // Returns a completion item that was previously received. | |
| 633 bool MessagePumpForIO::MatchCompletedIOItem(IOHandler* filter, IOItem* item) { | |
| 634 DCHECK(!completed_io_.empty()); | |
| 635 for (std::list<IOItem>::iterator it = completed_io_.begin(); | |
| 636 it != completed_io_.end(); ++it) { | |
| 637 if (!filter || it->handler == filter) { | |
| 638 *item = *it; | |
| 639 completed_io_.erase(it); | |
| 640 return true; | |
| 641 } | |
| 642 } | |
| 643 return false; | |
| 644 } | |
| 645 | |
| 646 void MessagePumpForIO::AddIOObserver(IOObserver *obs) { | |
| 647 io_observers_.AddObserver(obs); | |
| 648 } | |
| 649 | |
| 650 void MessagePumpForIO::RemoveIOObserver(IOObserver *obs) { | |
| 651 io_observers_.RemoveObserver(obs); | |
| 652 } | |
| 653 | |
| 654 void MessagePumpForIO::WillProcessIOEvent() { | |
| 655 FOR_EACH_OBSERVER(IOObserver, io_observers_, WillProcessIOEvent()); | |
| 656 } | |
| 657 | |
| 658 void MessagePumpForIO::DidProcessIOEvent() { | |
| 659 FOR_EACH_OBSERVER(IOObserver, io_observers_, DidProcessIOEvent()); | |
| 660 } | |
| 661 | |
| 662 // static | |
| 663 ULONG_PTR MessagePumpForIO::HandlerToKey(IOHandler* handler, | |
| 664 bool has_valid_io_context) { | |
| 665 ULONG_PTR key = reinterpret_cast<ULONG_PTR>(handler); | |
| 666 | |
| 667 // |IOHandler| is at least pointer-size aligned, so the lowest two bits are | |
| 668 // always cleared. We use the lowest bit to distinguish completion keys with | |
| 669 // and without the associated |IOContext|. | |
| 670 DCHECK((key & 1) == 0); | |
| 671 | |
| 672 // Mark the completion key as context-less. | |
| 673 if (!has_valid_io_context) | |
| 674 key = key | 1; | |
| 675 return key; | |
| 676 } | |
| 677 | |
| 678 // static | |
| 679 MessagePumpForIO::IOHandler* MessagePumpForIO::KeyToHandler( | |
| 680 ULONG_PTR key, | |
| 681 bool* has_valid_io_context) { | |
| 682 *has_valid_io_context = ((key & 1) == 0); | |
| 683 return reinterpret_cast<IOHandler*>(key & ~static_cast<ULONG_PTR>(1)); | |
| 684 } | |
| 685 | |
| 686 } // namespace base | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 16897005:
Revert 206507 "Move message_pump to base/message_loop." (Closed)
Base URL: svn://svn.chromium.org/chrome/