QMimeDatabase: fix performance regression when using the internal XML

That XML was parsed over and over again, because the QMimeXMLProvider
was re-created instead of re-used.

Change-Id: I07ff005d3f238afc1490b69a58cf4815e67d418c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 354ea7bd963b3c54b4b15d28a595bf836a78de07)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/corelib/mimetypes/qmimeprovider.cpp b/src/corelib/mimetypes/qmimeprovider.cpp
index a28c43a4ad..dbe90b136a 100644
--- a/src/corelib/mimetypes/qmimeprovider.cpp
+++ b/src/corelib/mimetypes/qmimeprovider.cpp
@@ -167,6 +167,11 @@ bool QMimeBinaryProvider::isValid()
     return m_cacheFile != nullptr;
 }
 
+bool QMimeBinaryProvider::isInternalDatabase() const
+{
+    return false;
+}
+
 // Position of the "list offsets" values, at the beginning of the mime.cache file
 enum {
     PosAliasListOffset = 4,
@@ -691,6 +696,11 @@ bool QMimeXMLProvider::isValid()
     return true;
 }
 
+bool QMimeXMLProvider::isInternalDatabase() const
+{
+    return m_directory == internalMimeFileName();
+}
+
 QMimeType QMimeXMLProvider::mimeTypeForName(const QString &name)
 {
     return m_nameMimeTypeMap.value(name);