Fixed QImageReader::format() inconsistency.

If state is set to ReadHeader before canRead() then setFormat("png")
never gets called. We should make sure that setFormat() gets set
whenever canRead() returns true.

Task-number: QTBUG-2263
Reviewed-by: Kent Hansen

3 files changed, 12 insertions, 10 deletions

diff --git a/src/plugins/imageformats/gif/qgifhandler.cpp b/src/plugins/imageformats/gif/qgifhandler.cpp
index 8abc2d1..5e2157e 100644
--- a/src/plugins/imageformats/gif/qgifhandler.cpp
+++ b/src/plugins/imageformats/gif/qgifhandler.cpp
@@ -1061,12 +1061,12 @@ bool QGifHandler::imageIsComing() const
 
 bool QGifHandler::canRead() const
 {
-    if (!nextDelay && canRead(device())) {
+    if (!nextDelay && canRead(device()) || imageIsComing()) {
         setFormat("gif");
         return true;
     }
 
-    return imageIsComing();
+    return false;
 }
 
 bool QGifHandler::canRead(QIODevice *device)
diff --git a/src/plugins/imageformats/jpeg/qjpeghandler.cpp b/src/plugins/imageformats/jpeg/qjpeghandler.cpp
index 72dde15..60e7cce 100644
--- a/src/plugins/imageformats/jpeg/qjpeghandler.cpp
+++ b/src/plugins/imageformats/jpeg/qjpeghandler.cpp
@@ -802,13 +802,15 @@ QJpegHandler::~QJpegHandler()
 
 bool QJpegHandler::canRead() const
 {
-    if(d->state == QJpegHandlerPrivate::Ready) {
-        if (!canRead(device()))
-            return false;
+    if(d->state == QJpegHandlerPrivate::Ready && !canRead(device()))
+        return false;
+
+    if (d->state != QJpegHandlerPrivate::Error) {
         setFormat("jpeg");
         return true;
     }
-    return d->state != QJpegHandlerPrivate::Error;
+
+    return false;
 }
 
 bool QJpegHandler::canRead(QIODevice *device)
diff --git a/src/plugins/imageformats/mng/qmnghandler.cpp b/src/plugins/imageformats/mng/qmnghandler.cpp
index d408e6c..c134fd6 100644
--- a/src/plugins/imageformats/mng/qmnghandler.cpp
+++ b/src/plugins/imageformats/mng/qmnghandler.cpp
@@ -381,10 +381,10 @@ QMngHandler::~QMngHandler()
 bool QMngHandler::canRead() const
 {
     Q_D(const QMngHandler);
-    if (!d->haveReadNone)
-	return (!d->haveReadAll || (d->haveReadAll && (d->nextIndex < d->frameCount)));
-
-    if (canRead(device())) {
+    if ((!d->haveReadNone
+         && (!d->haveReadAll || (d->haveReadAll && (d->nextIndex < d->frameCount))))
+        || canRead(device()))
+    {
         setFormat("mng");
         return true;
     }