diff options
Diffstat (limited to 'ipc/chromium/src/base/message_pump_win.cc')
| -rw-r--r-- | ipc/chromium/src/base/message_pump_win.cc | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/message_pump_win.cc b/ipc/chromium/src/base/message_pump_win.cc new file mode 100644 index 000000000..407a47065 --- /dev/null +++ b/ipc/chromium/src/base/message_pump_win.cc @@ -0,0 +1,547 @@ +/* -*- 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) 2009 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_win.h" + +#include <math.h> + +#include "base/message_loop.h" +#include "base/histogram.h" +#include "base/win_util.h" +#include "WinUtils.h" + +using base::Time; + +namespace base { + +static const wchar_t kWndClass[] = L"Chrome_MessagePumpWindow"; + +// Message sent to get an additional time slice for pumping (processing) another +// task (a series of such messages creates a continuous task pump). +static const int kMsgHaveWork = WM_USER + 1; + +//----------------------------------------------------------------------------- +// MessagePumpWin public: + +void MessagePumpWin::AddObserver(Observer* observer) { + observers_.AddObserver(observer); +} + +void MessagePumpWin::RemoveObserver(Observer* observer) { + observers_.RemoveObserver(observer); +} + +void MessagePumpWin::WillProcessMessage(const MSG& msg) { + FOR_EACH_OBSERVER(Observer, observers_, WillProcessMessage(msg)); +} + +void MessagePumpWin::DidProcessMessage(const MSG& msg) { + FOR_EACH_OBSERVER(Observer, observers_, DidProcessMessage(msg)); +} + +void MessagePumpWin::RunWithDispatcher( + Delegate* delegate, Dispatcher* dispatcher) { + RunState s; + s.delegate = delegate; + s.dispatcher = dispatcher; + s.should_quit = false; + s.run_depth = state_ ? state_->run_depth + 1 : 1; + + RunState* previous_state = state_; + state_ = &s; + + DoRunLoop(); + + state_ = previous_state; +} + +void MessagePumpWin::Quit() { + DCHECK(state_); + state_->should_quit = true; +} + +//----------------------------------------------------------------------------- +// MessagePumpWin protected: + +int MessagePumpWin::GetCurrentDelay() const { + if (delayed_work_time_.is_null()) + return -1; + + // Be careful here. TimeDelta has a precision of microseconds, but we want a + // value in milliseconds. If there are 5.5ms left, should the delay be 5 or + // 6? It should be 6 to avoid executing delayed work too early. + double timeout = + ceil((delayed_work_time_ - TimeTicks::Now()).InMillisecondsF()); + + // If this value is negative, then we need to run delayed work soon. + int delay = static_cast<int>(timeout); + if (delay < 0) + delay = 0; + + return delay; +} + +//----------------------------------------------------------------------------- +// MessagePumpForUI public: + +MessagePumpForUI::MessagePumpForUI() { + InitMessageWnd(); +} + +MessagePumpForUI::~MessagePumpForUI() { + DestroyWindow(message_hwnd_); + UnregisterClass(kWndClass, GetModuleHandle(NULL)); +} + +void MessagePumpForUI::ScheduleWork() { + if (InterlockedExchange(&have_work_, 1)) + return; // Someone else continued the pumping. + + // Make sure the MessagePump does some work for us. + PostMessage(message_hwnd_, kMsgHaveWork, reinterpret_cast<WPARAM>(this), 0); + + // In order to wake up any cross-process COM calls which may currently be + // pending on the main thread, we also have to post a UI message. + PostMessage(message_hwnd_, WM_NULL, 0, 0); +} + +void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) { + // + // We would *like* to provide high resolution timers. Windows timers using + // SetTimer() have a 10ms granularity. We have to use WM_TIMER as a wakeup + // mechanism because the application can enter modal windows loops where it + // is not running our MessageLoop; the only way to have our timers fire in + // these cases is to post messages there. + // + // To provide sub-10ms timers, we process timers directly from our run loop. + // For the common case, timers will be processed there as the run loop does + // its normal work. However, we *also* set the system timer so that WM_TIMER + // events fire. This mops up the case of timers not being able to work in + // modal message loops. It is possible for the SetTimer to pop and have no + // pending timers, because they could have already been processed by the + // run loop itself. + // + // We use a single SetTimer corresponding to the timer that will expire + // soonest. As new timers are created and destroyed, we update SetTimer. + // Getting a spurrious SetTimer event firing is benign, as we'll just be + // processing an empty timer queue. + // + delayed_work_time_ = delayed_work_time; + + int delay_msec = GetCurrentDelay(); + DCHECK(delay_msec >= 0); + if (delay_msec < USER_TIMER_MINIMUM) + delay_msec = USER_TIMER_MINIMUM; + + // Create a WM_TIMER event that will wake us up to check for any pending + // timers (in case we are running within a nested, external sub-pump). + SetTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this), delay_msec, NULL); +} + +void MessagePumpForUI::PumpOutPendingPaintMessages() { + // If we are being called outside of the context of Run, then don't try to do + // any work. + if (!state_) + return; + + // Create a mini-message-pump to force immediate processing of only Windows + // WM_PAINT messages. Don't provide an infinite loop, but do enough peeking + // to get the job done. Actual common max is 4 peeks, but we'll be a little + // safe here. + const int kMaxPeekCount = 20; + int peek_count; + for (peek_count = 0; peek_count < kMaxPeekCount; ++peek_count) { + MSG msg; + if (!PeekMessage(&msg, NULL, 0, 0, PM_REMOVE | PM_QS_PAINT)) + break; + ProcessMessageHelper(msg); + if (state_->should_quit) // Handle WM_QUIT. + break; + } + // Histogram what was really being used, to help to adjust kMaxPeekCount. + DHISTOGRAM_COUNTS("Loop.PumpOutPendingPaintMessages Peeks", peek_count); +} + +//----------------------------------------------------------------------------- +// MessagePumpForUI private: + +// static +LRESULT CALLBACK MessagePumpForUI::WndProcThunk( + HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) { + switch (message) { + case kMsgHaveWork: + reinterpret_cast<MessagePumpForUI*>(wparam)->HandleWorkMessage(); + break; + case WM_TIMER: + reinterpret_cast<MessagePumpForUI*>(wparam)->HandleTimerMessage(); + break; + } + return DefWindowProc(hwnd, message, wparam, lparam); +} + +void MessagePumpForUI::DoRunLoop() { + // IF this was just a simple PeekMessage() loop (servicing all possible work + // queues), then Windows would try to achieve the following order according + // to MSDN documentation about PeekMessage with no filter): + // * Sent messages + // * Posted messages + // * Sent messages (again) + // * WM_PAINT messages + // * WM_TIMER messages + // + // Summary: none of the above classes is starved, and sent messages has twice + // the chance of being processed (i.e., reduced service time). + + for (;;) { + // If we do any work, we may create more messages etc., and more work may + // possibly be waiting in another task group. When we (for example) + // ProcessNextWindowsMessage(), there is a good chance there are still more + // messages waiting. On the other hand, when any of these methods return + // having done no work, then it is pretty unlikely that calling them again + // quickly will find any work to do. Finally, if they all say they had no + // work, then it is a good time to consider sleeping (waiting) for more + // work. + + bool more_work_is_plausible = ProcessNextWindowsMessage(); + if (state_->should_quit) + break; + + more_work_is_plausible |= state_->delegate->DoWork(); + if (state_->should_quit) + break; + + more_work_is_plausible |= + state_->delegate->DoDelayedWork(&delayed_work_time_); + // If we did not process any delayed work, then we can assume that our + // existing WM_TIMER if any will fire when delayed work should run. We + // don't want to disturb that timer if it is already in flight. However, + // if we did do all remaining delayed work, then lets kill the WM_TIMER. + if (more_work_is_plausible && delayed_work_time_.is_null()) + KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this)); + if (state_->should_quit) + break; + + if (more_work_is_plausible) + continue; + + more_work_is_plausible = state_->delegate->DoIdleWork(); + if (state_->should_quit) + break; + + if (more_work_is_plausible) + continue; + + WaitForWork(); // Wait (sleep) until we have work to do again. + } +} + +void MessagePumpForUI::InitMessageWnd() { + HINSTANCE hinst = GetModuleHandle(NULL); + + WNDCLASSEX wc = {0}; + wc.cbSize = sizeof(wc); + wc.lpfnWndProc = WndProcThunk; + wc.hInstance = hinst; + wc.lpszClassName = kWndClass; + RegisterClassEx(&wc); + + message_hwnd_ = + CreateWindow(kWndClass, 0, 0, 0, 0, 0, 0, HWND_MESSAGE, 0, hinst, 0); + DCHECK(message_hwnd_); +} + +void MessagePumpForUI::WaitForWork() { + // Wait until a message is available, up to the time needed by the timer + // manager to fire the next set of timers. + int delay = GetCurrentDelay(); + if (delay < 0) // Negative value means no timers waiting. + delay = INFINITE; + + mozilla::widget::WinUtils::WaitForMessage(delay); +} + +void MessagePumpForUI::HandleWorkMessage() { + // If we are being called outside of the context of Run, then don't try to do + // any work. This could correspond to a MessageBox call or something of that + // sort. + if (!state_) { + // Since we handled a kMsgHaveWork message, we must still update this flag. + InterlockedExchange(&have_work_, 0); + return; + } + + // Let whatever would have run had we not been putting messages in the queue + // run now. This is an attempt to make our dummy message not starve other + // messages that may be in the Windows message queue. + ProcessPumpReplacementMessage(); + + // Now give the delegate a chance to do some work. He'll let us know if he + // needs to do more work. + if (state_->delegate->DoWork()) + ScheduleWork(); +} + +void MessagePumpForUI::HandleTimerMessage() { + KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this)); + + // If we are being called outside of the context of Run, then don't do + // anything. This could correspond to a MessageBox call or something of + // that sort. + if (!state_) + return; + + state_->delegate->DoDelayedWork(&delayed_work_time_); + if (!delayed_work_time_.is_null()) { + // A bit gratuitous to set delayed_work_time_ again, but oh well. + ScheduleDelayedWork(delayed_work_time_); + } +} + +bool MessagePumpForUI::ProcessNextWindowsMessage() { + // If there are sent messages in the queue then PeekMessage internally + // dispatches the message and returns false. We return true in this + // case to ensure that the message loop peeks again instead of calling + // MsgWaitForMultipleObjectsEx again. + bool sent_messages_in_queue = false; + DWORD queue_status = GetQueueStatus(QS_SENDMESSAGE); + if (HIWORD(queue_status) & QS_SENDMESSAGE) + sent_messages_in_queue = true; + + MSG msg; + if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) + return ProcessMessageHelper(msg); + + return sent_messages_in_queue; +} + +bool MessagePumpForUI::ProcessMessageHelper(const MSG& msg) { + if (WM_QUIT == msg.message) { + // Repost the QUIT message so that it will be retrieved by the primary + // GetMessage() loop. + state_->should_quit = true; + PostQuitMessage(static_cast<int>(msg.wParam)); + return false; + } + + // While running our main message pump, we discard kMsgHaveWork messages. + if (msg.message == kMsgHaveWork && msg.hwnd == message_hwnd_) + return ProcessPumpReplacementMessage(); + + WillProcessMessage(msg); + + if (state_->dispatcher) { + if (!state_->dispatcher->Dispatch(msg)) + state_->should_quit = true; + } else { + TranslateMessage(&msg); + DispatchMessage(&msg); + } + + DidProcessMessage(msg); + return true; +} + +bool MessagePumpForUI::ProcessPumpReplacementMessage() { + // When we encounter a kMsgHaveWork message, this method is called to peek + // and process a replacement message, such as a WM_PAINT or WM_TIMER. The + // goal is to make the kMsgHaveWork as non-intrusive as possible, even though + // a continuous stream of such messages are posted. This method carefully + // peeks a message while there is no chance for a kMsgHaveWork to be pending, + // then resets the have_work_ flag (allowing a replacement kMsgHaveWork to + // possibly be posted), and finally dispatches that peeked replacement. Note + // that the re-post of kMsgHaveWork may be asynchronous to this thread!! + + MSG msg; + bool have_message = false; + if (MessageLoop::current()->os_modal_loop()) { + // We only peek out WM_PAINT and WM_TIMER here for reasons mentioned above. + have_message = PeekMessage(&msg, NULL, WM_PAINT, WM_PAINT, PM_REMOVE) || + PeekMessage(&msg, NULL, WM_TIMER, WM_TIMER, PM_REMOVE); + } else { + have_message = (0 != PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)); + + if (have_message && msg.message == WM_NULL) + have_message = (0 != PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)); + } + + DCHECK(!have_message || kMsgHaveWork != msg.message || + msg.hwnd != message_hwnd_); + + // Since we discarded a kMsgHaveWork message, we must update the flag. + int old_have_work = InterlockedExchange(&have_work_, 0); + DCHECK(old_have_work); + + // We don't need a special time slice if we didn't have_message to process. + if (!have_message) + return false; + + // Guarantee we'll get another time slice in the case where we go into native + // windows code. This ScheduleWork() may hurt performance a tiny bit when + // tasks appear very infrequently, but when the event queue is busy, the + // kMsgHaveWork events get (percentage wise) rarer and rarer. + ScheduleWork(); + return ProcessMessageHelper(msg); +} + +//----------------------------------------------------------------------------- +// MessagePumpForIO public: + +MessagePumpForIO::MessagePumpForIO() { + port_.Set(CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1)); + DCHECK(port_.IsValid()); +} + +void MessagePumpForIO::ScheduleWork() { + if (InterlockedExchange(&have_work_, 1)) + return; // Someone else continued the pumping. + + // Make sure the MessagePump does some work for us. + BOOL ret = PostQueuedCompletionStatus(port_, 0, + reinterpret_cast<ULONG_PTR>(this), + reinterpret_cast<OVERLAPPED*>(this)); + DCHECK(ret); +} + +void MessagePumpForIO::ScheduleDelayedWork(const TimeTicks& delayed_work_time) { + // We know that we can't be blocked 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 MessagePumpForIO::RegisterIOHandler(HANDLE file_handle, + IOHandler* handler) { + ULONG_PTR key = reinterpret_cast<ULONG_PTR>(handler); + HANDLE port = CreateIoCompletionPort(file_handle, port_, key, 1); + DCHECK(port == port_.Get()); +} + +//----------------------------------------------------------------------------- +// MessagePumpForIO private: + +void MessagePumpForIO::DoRunLoop() { + for (;;) { + // If we do any work, we may create more messages etc., and more work may + // possibly be waiting in another task group. When we (for example) + // WaitForIOCompletion(), there is a good chance there are still more + // messages waiting. On the other hand, when any of these methods return + // having done no work, then it is pretty unlikely that calling them + // again quickly will find any work to do. Finally, if they all say they + // had no work, then it is a good time to consider sleeping (waiting) for + // more work. + + bool more_work_is_plausible = state_->delegate->DoWork(); + if (state_->should_quit) + break; + + more_work_is_plausible |= WaitForIOCompletion(0, NULL); + if (state_->should_quit) + break; + + more_work_is_plausible |= + state_->delegate->DoDelayedWork(&delayed_work_time_); + if (state_->should_quit) + break; + + if (more_work_is_plausible) + continue; + + more_work_is_plausible = state_->delegate->DoIdleWork(); + if (state_->should_quit) + break; + + if (more_work_is_plausible) + continue; + + WaitForWork(); // Wait (sleep) until we have work to do again. + } +} + +// Wait until IO completes, up to the time needed by the timer manager to fire +// the next set of timers. +void MessagePumpForIO::WaitForWork() { + // We do not support nested IO message loops. This is to avoid messy + // recursion problems. + DCHECK(state_->run_depth == 1) << "Cannot nest an IO message loop!"; + + int timeout = GetCurrentDelay(); + if (timeout < 0) // Negative value means no timers waiting. + timeout = INFINITE; + + WaitForIOCompletion(timeout, NULL); +} + +bool MessagePumpForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) { + IOItem item; + if (completed_io_.empty() || !MatchCompletedIOItem(filter, &item)) { + // We have to ask the system for another IO completion. + if (!GetIOItem(timeout, &item)) + return false; + + if (ProcessInternalIOItem(item)) + return true; + } + + if (item.context->handler) { + if (filter && item.handler != filter) { + // Save this item for later + completed_io_.push_back(item); + } else { + DCHECK(item.context->handler == item.handler); + item.handler->OnIOCompleted(item.context, item.bytes_transfered, + item.error); + } + } else { + // The handler must be gone by now, just cleanup the mess. + delete item.context; + } + return true; +} + +// Asks the OS for another IO completion result. +bool MessagePumpForIO::GetIOItem(DWORD timeout, IOItem* item) { + memset(item, 0, sizeof(*item)); + ULONG_PTR key = 0; + OVERLAPPED* overlapped = NULL; + if (!GetQueuedCompletionStatus(port_.Get(), &item->bytes_transfered, &key, + &overlapped, timeout)) { + if (!overlapped) + return false; // Nothing in the queue. + item->error = GetLastError(); + item->bytes_transfered = 0; + } + + item->handler = reinterpret_cast<IOHandler*>(key); + item->context = reinterpret_cast<IOContext*>(overlapped); + return true; +} + +bool MessagePumpForIO::ProcessInternalIOItem(const IOItem& item) { + if (this == reinterpret_cast<MessagePumpForIO*>(item.context) && + this == reinterpret_cast<MessagePumpForIO*>(item.handler)) { + // This is our internal completion. + DCHECK(!item.bytes_transfered); + InterlockedExchange(&have_work_, 0); + return true; + } + return false; +} + +// Returns a completion item that was previously received. +bool MessagePumpForIO::MatchCompletedIOItem(IOHandler* filter, IOItem* item) { + DCHECK(!completed_io_.empty()); + for (std::list<IOItem>::iterator it = completed_io_.begin(); + it != completed_io_.end(); ++it) { + if (!filter || it->handler == filter) { + *item = *it; + completed_io_.erase(it); + return true; + } + } + return false; +} + +} // namespace base |