[cairo-boilerplate-xlib] Check for NULL xrender_format before use.

Testing for XRender support (xrender_format != NULL) after
dereferencing said format doesn't work as intended.

1 files changed, 12 insertions, 4 deletions

diff --git a/boilerplate/cairo-boilerplate-xlib.c b/boilerplate/cairo-boilerplate-xlib.c
index 615fc98fa..bfdc7d082 100644
--- a/boilerplate/cairo-boilerplate-xlib.c
+++ b/boilerplate/cairo-boilerplate-xlib.c
@@ -124,13 +124,24 @@ _cairo_boilerplate_xlib_perf_create_surface (Display			*dpy,
     switch (content) {
     case CAIRO_CONTENT_COLOR_ALPHA:
 	xrender_format = XRenderFindStandardFormat (dpy, PictStandardARGB32);
+	if (xrender_format == NULL) {
+	    CAIRO_BOILERPLATE_LOG ("X server does not have the Render extension.\n");
+	    return NULL;
+	}
+
 	xtc->drawable = XCreatePixmap (dpy, DefaultRootWindow (dpy),
 				       width, height, xrender_format->depth);
 	xtc->drawable_is_pixmap = TRUE;
 	break;
+
     case CAIRO_CONTENT_COLOR:
 	visual = DefaultVisual (dpy, DefaultScreen (dpy));
 	xrender_format = XRenderFindVisualFormat (dpy, visual);
+	if (xrender_format == NULL) {
+	    CAIRO_BOILERPLATE_LOG ("X server does not have the Render extension.\n");
+	    return NULL;
+	}
+
 	attr.override_redirect = True;
 	xtc->drawable = XCreateWindow (dpy, DefaultRootWindow (dpy), 0, 0,
 				       width, height, 0, xrender_format->depth,
@@ -138,15 +149,12 @@ _cairo_boilerplate_xlib_perf_create_surface (Display			*dpy,
 	XMapWindow (dpy, xtc->drawable);
 	xtc->drawable_is_pixmap = FALSE;
 	break;
+
     case CAIRO_CONTENT_ALPHA:
     default:
 	CAIRO_BOILERPLATE_LOG ("Invalid content for xlib test: %d\n", content);
 	return NULL;
     }
-    if (xrender_format == NULL) {
-	CAIRO_BOILERPLATE_LOG ("X server does not have the Render extension.\n");
-	return NULL;
-    }
 
     return cairo_xlib_surface_create_with_xrender_format (dpy, xtc->drawable,
 							  DefaultScreenOfDisplay (dpy),