1 files changed, 32 insertions, 58 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_wasm.cpp b/src/corelib/kernel/qeventdispatcher_wasm.cpp
index c733f46c14..73f468aae5 100644
--- a/src/corelib/kernel/qeventdispatcher_wasm.cpp
+++ b/src/corelib/kernel/qeventdispatcher_wasm.cpp
@@ -26,14 +26,16 @@ Q_LOGGING_CATEGORY(lcEventDispatcherTimers, "qt.eventdispatcher.timers");
 #define LOCK_GUARD(M)
 #endif
 
-#ifdef QT_HAVE_EMSCRIPTEN_ASYNCIFY
-
 // Emscripten asyncify currently supports one level of suspend -
 // recursion is not permitted. We track the suspend state here
 // on order to fail (more) gracefully, but we can of course only
 // track Qts own usage of asyncify.
 static bool g_is_asyncify_suspended = false;
 
+EM_JS(bool, qt_have_asyncify_js, (), {
+    return typeof Asyncify != "undefined";
+});
+
 EM_JS(void, qt_asyncify_suspend_js, (), {
     let sleepFn = (wakeUp) => {
         Module.qtAsyncifyWakeUp = wakeUp;
@@ -52,6 +54,15 @@ EM_JS(void, qt_asyncify_resume_js, (), {
     setTimeout(wakeUp);
 });
 
+// Returns true if asyncify is available.
+bool qt_have_asyncify()
+{
+    static bool have_asyncify = []{
+        return qt_have_asyncify_js();
+    }();
+    return have_asyncify;
+}
+
 // Suspends the main thread until qt_asyncify_resume() is called. Returns
 // false immediately if Qt has already suspended the main thread (recursive
 // suspend is not supported by Emscripten). Returns true (after resuming),
@@ -76,19 +87,6 @@ bool qt_asyncify_resume()
     return true;
 }
 
-// Yields control to the browser, so that it can process events. Must
-// be called on the main thread. Returns false immediately if Qt has
-// already suspended the main thread. Returns true after yielding.
-bool qt_asyncify_yield()
-{
-    if (g_is_asyncify_suspended)
-        return false;
-    emscripten_sleep(0);
-    return true;
-}
-
-#endif // QT_HAVE_EMSCRIPTEN_ASYNCIFY
-
 Q_CONSTINIT QEventDispatcherWasm *QEventDispatcherWasm::g_mainThreadEventDispatcher = nullptr;
 #if QT_CONFIG(thread)
 Q_CONSTINIT QVector<QEventDispatcherWasm *> QEventDispatcherWasm::g_secondaryThreadEventDispatchers;
@@ -198,9 +196,6 @@ bool QEventDispatcherWasm::processEvents(QEventLoop::ProcessEventsFlags flags)
             handleApplicationExec();
     }
 
-    if (!(flags & QEventLoop::ExcludeUserInputEvents))
-        pollForNativeEvents();
-
     hasPendingEvents = qGlobalPostedEventsCount() > 0;
 
     if (!hasPendingEvents && (flags & QEventLoop::WaitForMoreEvents))
@@ -373,34 +368,14 @@ void QEventDispatcherWasm::handleApplicationExec()
 
 void QEventDispatcherWasm::handleDialogExec()
 {
-#ifndef QT_HAVE_EMSCRIPTEN_ASYNCIFY
-    qWarning() << "Warning: dialog exec() is not supported on Qt for WebAssembly in this"
-               << "configuration. Please use show() instead, or enable experimental support"
-               << "for asyncify.\n"
-               << "When using exec() (without asyncify) the dialog will show, the user can interact"
-               << "with it and the appropriate signals will be emitted on close. However, the"
-               << "exec() call never returns, stack content at the time of the exec() call"
-               << "is leaked, and the exec() call may interfere with input event processing";
-    emscripten_sleep(1); // This call never returns
-#endif
+    if (!qt_have_asyncify()) {
+        qWarning() << "Warning: exec() is not supported on Qt for WebAssembly in this configuration. Please build"
+                   << "with asyncify support, or use an asynchronous API like QDialog::open()";
+        emscripten_sleep(1); // This call never returns
+    }
     // For the asyncify case we do nothing here and wait for events in wait()
 }
 
-void QEventDispatcherWasm::pollForNativeEvents()
-{
-    // Secondary thread event dispatchers do not support native events
-    if (isSecondaryThreadEventDispatcher())
-        return;
-
-#if HAVE_EMSCRIPTEN_ASYNCIFY
-    // Asyncify allows us to yield to the browser and have it process native events -
-    // but this will fail if we are recursing and are already in a yield.
-    bool didYield = qt_asyncify_yield();
-    if (!didYield)
-        qWarning("QEventDispatcherWasm::processEvents() did not asyncify process native events");
-#endif
-}
-
 // Blocks/suspends the calling thread. This is possible in two cases:
 // - Caller is a secondary thread: block on m_moreEvents
 // - Caller is the main thread and asyncify is enabled: suspend using qt_asyncify_suspend()
@@ -422,20 +397,20 @@ bool QEventDispatcherWasm::wait(int timeout)
 #endif
     Q_ASSERT(emscripten_is_main_runtime_thread());
     Q_ASSERT(isMainThreadEventDispatcher());
-#ifdef QT_HAVE_EMSCRIPTEN_ASYNCIFY
-    if (timeout > 0)
-        qWarning() << "QEventDispatcherWasm asyncify wait with timeout is not supported; timeout will be ignored"; // FIXME
-
-    bool didSuspend = qt_asyncify_suspend();
-    if (!didSuspend) {
-        qWarning("QEventDispatcherWasm: current thread is already suspended; could not asyncify wait for events");
-        return false;
+    if (qt_have_asyncify()) {
+        if (timeout > 0)
+            qWarning() << "QEventDispatcherWasm asyncify wait with timeout is not supported; timeout will be ignored"; // FIXME
+
+        bool didSuspend = qt_asyncify_suspend();
+        if (!didSuspend) {
+            qWarning("QEventDispatcherWasm: current thread is already suspended; could not asyncify wait for events");
+            return false;
+        }
+        return true;
+    } else {
+        qWarning("QEventLoop::WaitForMoreEvents is not supported on the main thread without asyncify");
+        Q_UNUSED(timeout);
     }
-    return true;
-#else
-    qWarning("QEventLoop::WaitForMoreEvents is not supported on the main thread without asyncify");
-    Q_UNUSED(timeout);
-#endif
     return false;
 }
 
@@ -453,12 +428,10 @@ bool QEventDispatcherWasm::wakeEventDispatcherThread()
     }
 #endif
     Q_ASSERT(isMainThreadEventDispatcher());
-#ifdef QT_HAVE_EMSCRIPTEN_ASYNCIFY
     if (g_is_asyncify_suspended) {
         runOnMainThread([]{ qt_asyncify_resume(); });
         return true;
     }
-#endif
     return false;
 }
 
@@ -522,6 +495,7 @@ void QEventDispatcherWasm::updateNativeTimer()
             if (m_timerId > 0) {
                 emscripten_clear_timeout(m_timerId);
                 m_timerId = 0;
+                m_timerTargetTime = 0;
             }
             return;
         }