Fix possible crash in glyph cache when deleting and creating contexts

The freeResource(), used in the glyph cache as a notifier of when the
owner context of the cache disappears, is never called if the context
is in a group with other contexts that share its resources. This
implements a second notifier function instead which can be used to
invalidate the glyph cache when its context is destroyed.

Task-number: QTBUG-22324
Reviewed-by: Samuel

1 files changed, 4 insertions, 0 deletions

diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
index 83ca06d..1a8bb0b 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
@@ -144,6 +144,10 @@ public:
 
     void clear();
 
+    void contextDeleted(const QGLContext *context) {
+        if (ctx == context)
+            ctx = 0;
+    }
     void freeResource(void *) { ctx = 0; }
 
 private: