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

9 files changed, 70 insertions, 28 deletions

diff --git a/src/gui/image/qbmphandler.cpp b/src/gui/image/qbmphandler.cpp
index 42e19b8..074b8f0 100644
--- a/src/gui/image/qbmphandler.cpp
+++ b/src/gui/image/qbmphandler.cpp
@@ -674,13 +674,15 @@ bool QBmpHandler::readHeader()
 
 bool QBmpHandler::canRead() const
 {
-    if (state == Ready) {
-        if (!canRead(device()))
-            return false;
+    if (state == Ready && !canRead(device()))
+        return false;
+
+    if (state != Error) {
         setFormat("bmp");
         return true;
     }
-    return state != Error;
+
+    return false;
 }
 
 bool QBmpHandler::canRead(QIODevice *device)
diff --git a/src/gui/image/qpnghandler.cpp b/src/gui/image/qpnghandler.cpp
index dd31834..2cf8222 100644
--- a/src/gui/image/qpnghandler.cpp
+++ b/src/gui/image/qpnghandler.cpp
@@ -892,13 +892,15 @@ QPngHandler::~QPngHandler()
 
 bool QPngHandler::canRead() const
 {
-    if (d->state == QPngHandlerPrivate::Ready) {
-        if (!canRead(device()))
-            return false;
+    if (d->state == QPngHandlerPrivate::Ready && !canRead(device()))
+        return false;
+
+    if (d->state != QPngHandlerPrivate::Error) {
         setFormat("png");
         return true;
     }
-    return d->state != QPngHandlerPrivate::Error;
+
+    return false;
 }
 
 bool QPngHandler::canRead(QIODevice *device)
diff --git a/src/gui/image/qppmhandler.cpp b/src/gui/image/qppmhandler.cpp
index cbbbef4..a9e796c 100644
--- a/src/gui/image/qppmhandler.cpp
+++ b/src/gui/image/qppmhandler.cpp
@@ -409,13 +409,15 @@ bool QPpmHandler::readHeader()
 
 bool QPpmHandler::canRead() const
 {
-    if (state == Ready) {
-        if (!canRead(device(), &subType))
-            return false;
+    if (state == Ready && !canRead(device(), &subType))
+        return false;
+
+    if (state != Error) {
         setFormat(subType);
         return true;
     }
-    return state != Error;
+
+    return false;
 }
 
 bool QPpmHandler::canRead(QIODevice *device, QByteArray *subType)
diff --git a/src/gui/image/qxbmhandler.cpp b/src/gui/image/qxbmhandler.cpp
index 385340a..0dd4e99 100644
--- a/src/gui/image/qxbmhandler.cpp
+++ b/src/gui/image/qxbmhandler.cpp
@@ -261,13 +261,15 @@ bool QXbmHandler::readHeader()
 
 bool QXbmHandler::canRead() const
 {
-    if (state == Ready) {
-        if (!canRead(device()))
-            return false;
+    if (state == Ready && !canRead(device()))
+        return false;
+
+    if (state != Error) {
         setFormat("xbm");
         return true;
     }
-    return state != Error;
+
+    return false;
 }
 
 bool QXbmHandler::canRead(QIODevice *device)
diff --git a/src/gui/image/qxpmhandler.cpp b/src/gui/image/qxpmhandler.cpp
index a475cd0..b97afd3 100644
--- a/src/gui/image/qxpmhandler.cpp
+++ b/src/gui/image/qxpmhandler.cpp
@@ -1225,11 +1225,15 @@ bool QXpmHandler::readImage(QImage *image)
 
 bool QXpmHandler::canRead() const
 {
-    if (state == Ready && canRead(device())) {
+    if (state == Ready && !canRead(device()))
+        return false;
+
+    if (state != Error) {
         setFormat("xpm");
         return true;
     }
-    return state != Error;
+
+    return false;
 }
 
 bool QXpmHandler::canRead(QIODevice *device)
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;
     }
diff --git a/tests/auto/qimagereader/tst_qimagereader.cpp b/tests/auto/qimagereader/tst_qimagereader.cpp
index aadee5b..7e57973 100644
--- a/tests/auto/qimagereader/tst_qimagereader.cpp
+++ b/tests/auto/qimagereader/tst_qimagereader.cpp
@@ -138,6 +138,9 @@ private slots:
     void sizeBeforeRead_data();
     void sizeBeforeRead();
 
+    void sizeBeforeFormat_data();
+    void sizeBeforeFormat();
+
     void imageFormatBeforeRead_data();
     void imageFormatBeforeRead();
 
@@ -706,6 +709,31 @@ void tst_QImageReader::sizeBeforeRead()
     QCOMPARE(size, image.size());
 }
 
+void tst_QImageReader::sizeBeforeFormat_data()
+{
+    imageFormat_data();
+}
+
+void tst_QImageReader::sizeBeforeFormat()
+{
+    QFETCH(QString, fileName);
+
+    QByteArray formatA, formatB;
+
+    {
+        QImageReader reader(prefix + fileName);
+        formatA = reader.format();
+    }
+
+    {
+        QImageReader reader(prefix + fileName);
+        QSize size = reader.size();
+        formatB = reader.format();
+    }
+
+    QCOMPARE(formatA, formatB);
+}
+
 void tst_QImageReader::imageFormatBeforeRead_data()
 {
     imageFormat_data();