| /**************************************************************************** |
| ** |
| ** Copyright (C) 2018 The Qt Company Ltd. |
| ** Contact: https://www.qt.io/licensing/ |
| ** |
| ** This file is part of the plugins of the Qt Toolkit. |
| ** |
| ** $QT_BEGIN_LICENSE:GPL$ |
| ** Commercial License Usage |
| ** Licensees holding valid commercial Qt licenses may use this file in |
| ** accordance with the commercial license agreement provided with the |
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| ** |
| ** GNU General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU |
| ** General Public License version 3 or (at your option) any later version |
| ** approved by the KDE Free Qt Foundation. The licenses are as published by |
| ** the Free Software Foundation and appearing in the file LICENSE.GPL3 |
| ** included in the packaging of this file. Please review the following |
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| ** |
| ** $QT_END_LICENSE$ |
| ** |
| ****************************************************************************/ |
| |
| #include "qwasmeventdispatcher.h" |
| |
| #include <QtCore/qcoreapplication.h> |
| |
| #include <emscripten.h> |
| |
| #if (__EMSCRIPTEN_major__ > 1 || __EMSCRIPTEN_minor__ > 38 || __EMSCRIPTEN_minor__ == 38 && __EMSCRIPTEN_tiny__ >= 22) |
| # define EMSCRIPTEN_HAS_ASYNC_RUN_IN_MAIN_RUNTIME_THREAD |
| #endif |
| |
| #ifdef EMSCRIPTEN_HAS_ASYNC_RUN_IN_MAIN_RUNTIME_THREAD |
| #include <emscripten/threading.h> |
| #endif |
| |
| class QWasmEventDispatcherPrivate : public QEventDispatcherUNIXPrivate |
| { |
| |
| }; |
| |
| QWasmEventDispatcher *g_htmlEventDispatcher; |
| |
| QWasmEventDispatcher::QWasmEventDispatcher(QObject *parent) |
| : QUnixEventDispatcherQPA(parent) |
| { |
| |
| g_htmlEventDispatcher = this; |
| } |
| |
| QWasmEventDispatcher::~QWasmEventDispatcher() |
| { |
| g_htmlEventDispatcher = nullptr; |
| } |
| |
| bool QWasmEventDispatcher::registerRequestUpdateCallback(std::function<void(void)> callback) |
| { |
| if (!g_htmlEventDispatcher || !g_htmlEventDispatcher->m_hasMainLoop) |
| return false; |
| |
| g_htmlEventDispatcher->m_requestUpdateCallbacks.append(callback); |
| emscripten_resume_main_loop(); |
| return true; |
| } |
| |
| void QWasmEventDispatcher::maintainTimers() |
| { |
| if (!g_htmlEventDispatcher || !g_htmlEventDispatcher->m_hasMainLoop) |
| return; |
| |
| g_htmlEventDispatcher->doMaintainTimers(); |
| } |
| |
| bool QWasmEventDispatcher::processEvents(QEventLoop::ProcessEventsFlags flags) |
| { |
| // WaitForMoreEvents is not supported (except for in combination with EventLoopExec below), |
| // and we don't want the unix event dispatcher base class to attempt to wait either. |
| flags &= ~QEventLoop::WaitForMoreEvents; |
| |
| // Handle normal processEvents. |
| if (!(flags & QEventLoop::EventLoopExec)) |
| return QUnixEventDispatcherQPA::processEvents(flags); |
| |
| // Handle processEvents from QEventLoop::exec(): |
| // |
| // At this point the application has created its root objects on |
| // the stack and has called app.exec() which has called into this |
| // function via QEventLoop. |
| // |
| // The application now expects that exec() will not return until |
| // app exit time. However, the browser expects that we return |
| // control to it periodically, also after initial setup in main(). |
| |
| // EventLoopExec for nested event loops is not supported. |
| Q_ASSERT(!m_hasMainLoop); |
| m_hasMainLoop = true; |
| |
| // Call emscripten_set_main_loop_arg() with a callback which processes |
| // events. Also set simulateInfiniteLoop to true which makes emscripten |
| // return control to the browser without unwinding the C++ stack. |
| auto callback = [](void *eventDispatcher) { |
| QWasmEventDispatcher *that = static_cast<QWasmEventDispatcher *>(eventDispatcher); |
| |
| // Save and clear updateRequest callbacks so we can register new ones |
| auto requestUpdateCallbacksCopy = that->m_requestUpdateCallbacks; |
| that->m_requestUpdateCallbacks.clear(); |
| |
| // Repaint all windows |
| for (auto callback : qAsConst(requestUpdateCallbacksCopy)) |
| callback(); |
| |
| // Pause main loop if no updates were requested. Updates will be |
| // restarted again by registerRequestUpdateCallback(). |
| if (that->m_requestUpdateCallbacks.isEmpty()) |
| emscripten_pause_main_loop(); |
| |
| that->doMaintainTimers(); |
| }; |
| int fps = 0; // update using requestAnimationFrame |
| int simulateInfiniteLoop = 1; |
| emscripten_set_main_loop_arg(callback, this, fps, simulateInfiniteLoop); |
| |
| // Note: the above call never returns, not even at app exit |
| return false; |
| } |
| |
| void QWasmEventDispatcher::doMaintainTimers() |
| { |
| Q_D(QWasmEventDispatcher); |
| |
| // This functon schedules native timers in order to wake up to |
| // process events and activate Qt timers. This is done using the |
| // emscripten_async_call() API which schedules a new timer. |
| // There is unfortunately no way to cancel or update a current |
| // native timer. |
| |
| // Schedule a zero-timer to continue processing any pending events. |
| if (!m_hasZeroTimer && hasPendingEvents()) { |
| auto callback = [](void *eventDispatcher) { |
| QWasmEventDispatcher *that = static_cast<QWasmEventDispatcher *>(eventDispatcher); |
| that->m_hasZeroTimer = false; |
| that->QUnixEventDispatcherQPA::processEvents(QEventLoop::AllEvents); |
| |
| // Processing events may have posted new events or created new timers |
| that->doMaintainTimers(); |
| }; |
| |
| emscripten_async_call(callback, this, 0); |
| m_hasZeroTimer = true; |
| return; |
| } |
| |
| auto timespecToNanosec = [](timespec ts) -> uint64_t { return ts.tv_sec * 1000 + ts.tv_nsec / (1000 * 1000); }; |
| |
| // Get current time and time-to-first-Qt-timer. This polls for system |
| // time, and we use this time as the current time for the duration of this call. |
| timespec toWait; |
| bool hasTimers = d->timerList.timerWait(toWait); |
| if (!hasTimers) |
| return; // no timer needed |
| |
| uint64_t currentTime = timespecToNanosec(d->timerList.currentTime); |
| uint64_t toWaitDuration = timespecToNanosec(toWait); |
| |
| // The currently scheduled timer target is stored in m_currentTargetTime. |
| // We can re-use it if the new target is equivalent or later. |
| uint64_t newTargetTime = currentTime + toWaitDuration; |
| if (newTargetTime >= m_currentTargetTime) |
| return; // existing timer is good |
| |
| // Schedule a native timer with a callback which processes events (and timers) |
| auto callback = [](void *eventDispatcher) { |
| QWasmEventDispatcher *that = static_cast<QWasmEventDispatcher *>(eventDispatcher); |
| that->m_currentTargetTime = std::numeric_limits<uint64_t>::max(); |
| that->QUnixEventDispatcherQPA::processEvents(QEventLoop::AllEvents); |
| |
| // Processing events may have posted new events or created new timers |
| that->doMaintainTimers(); |
| }; |
| emscripten_async_call(callback, this, toWaitDuration); |
| m_currentTargetTime = newTargetTime; |
| } |
| |
| void QWasmEventDispatcher::wakeUp() |
| { |
| #ifdef EMSCRIPTEN_HAS_ASYNC_RUN_IN_MAIN_RUNTIME_THREAD |
| if (!emscripten_is_main_runtime_thread()) |
| emscripten_async_run_in_main_runtime_thread_(EM_FUNC_SIG_VI, (void*)(&QWasmEventDispatcher::mainThreadWakeUp), this); |
| #endif |
| QEventDispatcherUNIX::wakeUp(); |
| } |
| |
| void QWasmEventDispatcher::mainThreadWakeUp(void *eventDispatcher) |
| { |
| emscripten_resume_main_loop(); // Service possible requestUpdate Calls |
| static_cast<QWasmEventDispatcher *>(eventDispatcher)->processEvents(QEventLoop::AllEvents); |
| } |