2 files changed, 34 insertions, 1 deletions

diff --git a/src/gui/image/qimagereader.cpp b/src/gui/image/qimagereader.cpp
index 2762b702b2..25b9698559 100644
--- a/src/gui/image/qimagereader.cpp
+++ b/src/gui/image/qimagereader.cpp
@@ -1074,7 +1074,7 @@ QList<QByteArray> QImageReader::supportedSubTypes() const
     \since 5.5
 
     Returns the transformation metadata of the image, including image orientation. If the format
-    does not support transformation metadata \c QImageIOHandler::Transformation_None is returned.
+    does not support transformation metadata, QImageIOHandler::TransformationNone is returned.
 
     \sa setAutoTransform(), autoTransform()
 */
diff --git a/src/gui/image/qpixmapcache.cpp b/src/gui/image/qpixmapcache.cpp
index a41ec8f35c..483d6d79a2 100644
--- a/src/gui/image/qpixmapcache.cpp
+++ b/src/gui/image/qpixmapcache.cpp
@@ -42,6 +42,8 @@
 #include "qobject.h"
 #include "qdebug.h"
 #include "qpixmapcache_p.h"
+#include "qthread.h"
+#include "qcoreapplication.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -83,6 +85,9 @@ QT_BEGIN_NAMESPACE
     with QPixmapCache} explains how to use QPixmapCache to speed up
     applications by caching the results of painting.
 
+    \note QPixmapCache is only usable from the application's main thread.
+    Access from other threads will be ignored and return failure.
+
     \sa QCache, QPixmap
 */
 
@@ -98,6 +103,14 @@ static inline int cost(const QPixmap &pixmap)
     return static_cast<int>(qBound(1LL, costKb, costMax));
 }
 
+static inline bool qt_pixmapcache_thread_test()
+{
+    if (Q_LIKELY(QCoreApplication::instance() && QThread::currentThread() == QCoreApplication::instance()->thread()))
+        return true;
+
+    return false;
+}
+
 /*!
     \class QPixmapCache::Key
     \brief The QPixmapCache::Key class can be used for efficient access
@@ -490,6 +503,8 @@ QPixmapCacheEntry::~QPixmapCacheEntry()
 
 QPixmap *QPixmapCache::find(const QString &key)
 {
+    if (!qt_pixmapcache_thread_test())
+        return nullptr;
     return pm_cache()->object(key);
 }
 
@@ -519,6 +534,8 @@ bool QPixmapCache::find(const QString &key, QPixmap &pixmap)
 
 bool QPixmapCache::find(const QString &key, QPixmap *pixmap)
 {
+    if (!qt_pixmapcache_thread_test())
+        return false;
     QPixmap *ptr = pm_cache()->object(key);
     if (ptr && pixmap)
         *pixmap = *ptr;
@@ -536,6 +553,8 @@ bool QPixmapCache::find(const QString &key, QPixmap *pixmap)
 */
 bool QPixmapCache::find(const Key &key, QPixmap *pixmap)
 {
+    if (!qt_pixmapcache_thread_test())
+        return false;
     //The key is not valid anymore, a flush happened before probably
     if (!key.d || !key.d->isValid)
         return false;
@@ -567,6 +586,8 @@ bool QPixmapCache::find(const Key &key, QPixmap *pixmap)
 
 bool QPixmapCache::insert(const QString &key, const QPixmap &pixmap)
 {
+    if (!qt_pixmapcache_thread_test())
+        return false;
     return pm_cache()->insert(key, pixmap, cost(pixmap));
 }
 
@@ -587,6 +608,8 @@ bool QPixmapCache::insert(const QString &key, const QPixmap &pixmap)
 */
 QPixmapCache::Key QPixmapCache::insert(const QPixmap &pixmap)
 {
+    if (!qt_pixmapcache_thread_test())
+        return QPixmapCache::Key();
     return pm_cache()->insert(pixmap, cost(pixmap));
 }
 
@@ -601,6 +624,8 @@ QPixmapCache::Key QPixmapCache::insert(const QPixmap &pixmap)
 */
 bool QPixmapCache::replace(const Key &key, const QPixmap &pixmap)
 {
+    if (!qt_pixmapcache_thread_test())
+        return false;
     //The key is not valid anymore, a flush happened before probably
     if (!key.d || !key.d->isValid)
         return false;
@@ -630,6 +655,8 @@ int QPixmapCache::cacheLimit()
 
 void QPixmapCache::setCacheLimit(int n)
 {
+    if (!qt_pixmapcache_thread_test())
+        return;
     pm_cache()->setMaxCost(n);
 }
 
@@ -638,6 +665,8 @@ void QPixmapCache::setCacheLimit(int n)
 */
 void QPixmapCache::remove(const QString &key)
 {
+    if (!qt_pixmapcache_thread_test())
+        return;
     pm_cache()->remove(key);
 }
 
@@ -649,6 +678,8 @@ void QPixmapCache::remove(const QString &key)
 */
 void QPixmapCache::remove(const Key &key)
 {
+    if (!qt_pixmapcache_thread_test())
+        return;
     //The key is not valid anymore, a flush happened before probably
     if (!key.d || !key.d->isValid)
         return;
@@ -661,6 +692,8 @@ void QPixmapCache::remove(const Key &key)
 
 void QPixmapCache::clear()
 {
+    if (!QCoreApplication::closingDown() && !qt_pixmapcache_thread_test())
+        return;
     QT_TRY {
         if (pm_cache.exists())
             pm_cache->clear();