QSvgIconEngine::addFile(): Use QMimeDatabase to determine file type

Introduce an enumeration to describe the file type and use
QMimeDatbase to determine the type. This will detect SVG files
also in the case resource aliases without suffixes are used.
As a drive by, do not pass compressed SVG files
to QPixmap when QT_NO_COMPRESS is defined, as this likely
results in garbage.

Task-number: QTBUG-55388
Change-Id: Ib8bafca60e9238412a5c7edf560d487e512b8fd0
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

1 files changed, 38 insertions, 18 deletions

diff --git a/src/plugins/iconengines/svgiconengine/qsvgiconengine.cpp b/src/plugins/iconengines/svgiconengine/qsvgiconengine.cpp
index 713f2ad..1342c0b 100644
--- a/src/plugins/iconengines/svgiconengine/qsvgiconengine.cpp
+++ b/src/plugins/iconengines/svgiconengine/qsvgiconengine.cpp
@@ -45,6 +45,8 @@
 #include "qsvgrenderer.h"
 #include "qpixmapcache.h"
 #include "qfileinfo.h"
+#include <qmimedatabase.h>
+#include <qmimetype.h>
 #include <QAtomicInt>
 #include "qdebug.h"
 #include <private/qguiapplication_p.h>
@@ -201,31 +203,49 @@ void QSvgIconEngine::addPixmap(const QPixmap &pixmap, QIcon::Mode mode,
     d->addedPixmaps->insert(d->hashKey(mode, state), pixmap);
 }
 
+enum FileType { OtherFile, SvgFile, CompressedSvgFile };
+
+static FileType fileType(const QFileInfo &fi)
+{
+    const QString &abs = fi.absoluteFilePath();
+    if (abs.endsWith(QLatin1String(".svg"), Qt::CaseInsensitive))
+        return SvgFile;
+    if (abs.endsWith(QLatin1String(".svgz"), Qt::CaseInsensitive)
+        || abs.endsWith(QLatin1String(".svg.gz"), Qt::CaseInsensitive)) {
+        return CompressedSvgFile;
+    }
+#ifndef QT_NO_MIMETYPE
+    const QString &mimeTypeName = QMimeDatabase().mimeTypeForFile(fi).name();
+    if (mimeTypeName == QLatin1String("image/svg+xml"))
+        return SvgFile;
+    if (mimeTypeName == QLatin1String("image/svg+xml-compressed"))
+        return CompressedSvgFile;
+#endif // !QT_NO_MIMETYPE
+    return OtherFile;
+}
 
 void QSvgIconEngine::addFile(const QString &fileName, const QSize &,
                              QIcon::Mode mode, QIcon::State state)
 {
     if (!fileName.isEmpty()) {
-        QString abs = fileName;
-        if (fileName.at(0) != QLatin1Char(':'))
-            abs = QFileInfo(fileName).absoluteFilePath();
-        if (abs.endsWith(QLatin1String(".svg"), Qt::CaseInsensitive)
+         const QFileInfo fi(fileName);
+         const QString abs = fi.absoluteFilePath();
+         const FileType type = fileType(fi);
 #ifndef QT_NO_COMPRESS
-                || abs.endsWith(QLatin1String(".svgz"), Qt::CaseInsensitive)
-                || abs.endsWith(QLatin1String(".svg.gz"), Qt::CaseInsensitive)
+         if (type == SvgFile || type == CompressedSvgFile) {
+#else
+         if (type == SvgFile) {
 #endif
-            )
-        {
-            QSvgRenderer renderer(abs);
-            if (renderer.isValid()) {
-                d->stepSerialNum();
-                d->svgFiles.insert(d->hashKey(mode, state), abs);
-            }
-        } else {
-            QPixmap pm(abs);
-            if (!pm.isNull())
-                addPixmap(pm, mode, state);
-        }
+             QSvgRenderer renderer(abs);
+             if (renderer.isValid()) {
+                 d->stepSerialNum();
+                 d->svgFiles.insert(d->hashKey(mode, state), abs);
+             }
+         } else if (type == OtherFile) {
+             QPixmap pm(abs);
+             if (!pm.isNull())
+                 addPixmap(pm, mode, state);
+         }
     }
 }