Android: Add runOnAndroidThreadSync

This is a convenient function which waits (timoutMS) for the runnable to be executed.

Change-Id: I2c0f262d3795c29961e8182b7ffc35a2c6f8a1f6
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

src/corelib/kernel/qjnihelpers.cpp

@@ -41,6 +41,7 @@
 #include "qmutex.h"
 #include "qlist.h"
 #include "qsemaphore.h"
+#include "qsharedpointer.h"
 #include "qvector.h"
 #include <QtCore/qrunnable.h>
 
@@ -338,6 +339,16 @@ void QtAndroidPrivate::runOnAndroidThread(const QtAndroidPrivate::Runnable &runn
         env->CallStaticVoidMethod(g_jNativeClass, g_runPendingCppRunnablesMethodID);
 }
 
+void QtAndroidPrivate::runOnAndroidThreadSync(const QtAndroidPrivate::Runnable &runnable, JNIEnv *env, int timeoutMs)
+{
+    QSharedPointer<QSemaphore> sem(new QSemaphore);
+    runOnAndroidThread([&runnable, sem]{
+        runnable();
+        sem->release();
+    }, env);
+    sem->tryAcquire(1, timeoutMs);
+}
+
 void QtAndroidPrivate::registerGenericMotionEventListener(QtAndroidPrivate::GenericMotionEventListener *listener)
 {
     QMutexLocker locker(&g_genericMotionEventListeners()->mutex);

src/corelib/kernel/qjnihelpers_p.h

@@ -105,6 +105,7 @@ namespace QtAndroidPrivate
     jobject classLoader();
     Q_CORE_EXPORT jint androidSdkVersion();
     Q_CORE_EXPORT void runOnAndroidThread(const Runnable &runnable, JNIEnv *env);
+    Q_CORE_EXPORT void runOnAndroidThreadSync(const Runnable &runnable, JNIEnv *env, int timeoutMs = INT_MAX);
     Q_CORE_EXPORT void runOnUiThread(QRunnable *runnable, JNIEnv *env);
 
     Q_CORE_EXPORT void handleActivityResult(jint requestCode, jint resultCode, jobject data);