Force completion of asynchronously loaded components.

[ChangeLog][QtQuick][QQmlComponent] Synchronously complete the loading of a
Asynchronous QQmlComponent, if a PreferSynchronous QQmlComponent is created
for the same url (given that this url does support synchronous loading).

Change-Id: I3291d0569a69bac2aeb4815f1068a426ef2707ef
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index e860b8e0fa..408f17ffde 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -1612,6 +1612,20 @@ QQmlTypeData *QQmlTypeLoader::getType(const QUrl &url, Mode mode)
         } else {
             QQmlTypeLoader::load(typeData, mode);
         }
+    } else if ((mode == PreferSynchronous) && QQmlFile::isSynchronous(url)) {
+        // this was started Asynchronous, but we need to force Synchronous
+        // completion now (if at all possible with this type of URL).
+
+        if (!m_thread->isThisThread()) {
+            // this only works when called directly from the UI thread, but not
+            // when recursively called on the QML thread via resolveTypes()
+
+            while (!typeData->isCompleteOrError()) {
+                unlock();
+                m_thread->waitForNextMessage();
+                lock();
+            }
+        }
     }
 
     typeData->addref();