Introduce centralized means of checking for asyncify

The new function has an advantage of not requring EM_JS.

Change-Id: Ib9ad0e6b59cfe2e6864697a14b5cfdb39f62af2d
Reviewed-by: David Skoland <david.skoland@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/corelib/kernel/qeventdispatcher_wasm.cpp

@@ -7,6 +7,7 @@
 #include <QtCore/qcoreapplication.h>
 #include <QtCore/qthread.h>
 #include <QtCore/qsocketnotifier.h>
+#include <QtCore/private/qstdweb_p.h>
 
 #include "emscripten.h"
 #include <emscripten/html5.h>
@@ -34,9 +35,10 @@ static bool g_is_asyncify_suspended = false;
 
 #if defined(QT_STATIC)
 
-EM_JS(bool, qt_have_asyncify_js, (), {
+static bool useAsyncify()
-    return typeof Asyncify != "undefined";
+{
-});
+    return qstdweb::haveAsyncify();
+}
 
 EM_JS(void, qt_asyncify_suspend_js, (), {
     let sleepFn = (wakeUp) => {
@@ -60,7 +62,7 @@ EM_JS(void, qt_asyncify_resume_js, (), {
 
 // EM_JS is not supported for side modules; disable asyncify
 
-bool qt_have_asyncify_js()
+static bool useAsyncify()
 {
     return false;
 }
@@ -77,15 +79,6 @@ void qt_asyncify_resume_js()
 
 #endif // defined(QT_STATIC)
 
-// 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),
@@ -391,7 +384,7 @@ void QEventDispatcherWasm::handleApplicationExec()
 
 void QEventDispatcherWasm::handleDialogExec()
 {
-    if (!qt_have_asyncify()) {
+    if (!useAsyncify()) {
         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
@@ -420,7 +413,7 @@ bool QEventDispatcherWasm::wait(int timeout)
 #endif
     Q_ASSERT(emscripten_is_main_runtime_thread());
     Q_ASSERT(isMainThreadEventDispatcher());
-    if (qt_have_asyncify()) {
+    if (useAsyncify()) {
         if (timeout > 0)
             qWarning() << "QEventDispatcherWasm asyncify wait with timeout is not supported; timeout will be ignored"; // FIXME
 

src/corelib/platform/wasm/qstdweb.cpp

@@ -667,6 +667,12 @@ namespace Promise {
     }
 }
 
+bool haveAsyncify()
+{
+    static bool HaveAsyncify = !emscripten::val::global("Asyncify").isUndefined();
+    return HaveAsyncify;
+}
+
 } // namespace qstdweb
 
 QT_END_NAMESPACE

src/corelib/platform/wasm/qstdweb_p.h

@@ -189,6 +189,8 @@ namespace qstdweb {
         static emscripten::val savedWindow = emscripten::val::global("window");
         return savedWindow;
     }
+
+    bool haveAsyncify();
 }
 
 QT_END_NAMESPACE

tests/manual/wasm/eventloop/eventloop_auto/CMakeLists.txt

@@ -7,6 +7,7 @@ qt_internal_add_manual_test(eventloop_auto
         ../../qtwasmtestlib/qtwasmtestlib.cpp
     LIBRARIES
         Qt::Core
+        Qt::CorePrivate
 )
 
 add_custom_command(
@@ -28,6 +29,7 @@ qt_internal_add_manual_test(eventloop_auto_asyncify
         ../../qtwasmtestlib/qtwasmtestlib.cpp
     LIBRARIES
         Qt::Core
+        Qt::CorePrivate
 )
 
 target_link_options(eventloop_auto_asyncify PRIVATE -sASYNCIFY -Os)

tests/manual/wasm/eventloop/eventloop_auto/main.cpp

@@ -7,6 +7,7 @@
 #include <QtCore/QObject>
 #include <QtCore/QThread>
 #include <QtCore/QTimer>
+#include <QtCore/private/qstdweb_p.h>
 
 #include <qtwasmtestlib.h>
 
@@ -14,10 +15,6 @@
 
 const int timerTimeout = 10;
 
-EM_JS(bool, have_asyncify, (), {
-    return typeof Asyncify != "undefined";
-});
-
 class WasmEventDispatcherTest: public QObject
 {
     Q_OBJECT
@@ -242,7 +239,7 @@ void WasmEventDispatcherTest::timerSecondaryThread()
 // Post an event to the main thread and asyncify wait for it
 void WasmEventDispatcherTest::postEventAsyncify()
 {
-    if (!have_asyncify()) {
+    if (!qstdweb::haveAsyncify()) {
         QtWasmTest::completeTestFunction(QtWasmTest::TestResult::Skip, "requires asyncify");
         return;
     }
@@ -259,7 +256,7 @@ void WasmEventDispatcherTest::postEventAsyncify()
 // Create a timer on the main thread and asyncify wait for it
 void WasmEventDispatcherTest::timerAsyncify()
 {
-    if (!have_asyncify()) {
+    if (!qstdweb::haveAsyncify()) {
         QtWasmTest::completeTestFunction(QtWasmTest::TestResult::Skip, "requires asyncify");
         return;
     }
@@ -276,7 +273,7 @@ void WasmEventDispatcherTest::timerAsyncify()
 // Asyncify wait in a loop
 void WasmEventDispatcherTest::postEventAsyncifyLoop()
 {
-    if (!have_asyncify()) {
+    if (!qstdweb::haveAsyncify()) {
         QtWasmTest::completeTestFunction(QtWasmTest::TestResult::Skip, "requires asyncify");
         return;
     }
@@ -296,7 +293,7 @@ void WasmEventDispatcherTest::postEventAsyncifyLoop()
 // Asyncify wait for QThread::wait() / pthread_join()
 void WasmEventDispatcherTest::threadAsyncifyWait()
 {
-    if (!have_asyncify())
+    if (!qstdweb::haveAsyncify())
         QtWasmTest::completeTestFunction(QtWasmTest::TestResult::Skip, "requires asyncify");
 
     const int threadCount = 15;