do not ignore errors, return NULL instead (moz#874315)

In the quartz backend there are occasional errors where returning NULL
can be used to signal that an error has occured.

Mozilla bug #874315.
(cherry picked from commit 6fec51990e90901ebafbb872a9e618cb70d17911)

1 files changed, 28 insertions, 9 deletions

diff --git a/src/cairo-quartz-surface.c b/src/cairo-quartz-surface.c
index 48e57d5e2..5b57d2810 100644
--- a/src/cairo-quartz-surface.c
+++ b/src/cairo-quartz-surface.c
@@ -437,17 +437,23 @@ _cairo_quartz_surface_to_quartz (cairo_surface_t *target, cairo_surface_t *pat_s
 	cairo_surface_t *ref_type = target;
 	cairo_surface_t *new_surf = NULL;
 	cairo_rectangle_int16_t rect;
+	cairo_status_t status;
+
 	if (ref_type == NULL)
 	    ref_type = cairo_quartz_surface_create (CAIRO_FORMAT_ARGB32, 1, 1);
 
-	_cairo_surface_get_extents (pat_surf, &rect);
+	status = _cairo_surface_get_extents (pat_surf, &rect);
+	if (status)
+	    return NULL;
 
-	_cairo_surface_clone_similar (ref_type, pat_surf, rect.x, rect.y,
+	status = _cairo_surface_clone_similar (ref_type, pat_surf, rect.x, rect.y,
 				      rect.width, rect.height, &new_surf);
-
 	if (target == NULL)
 	    cairo_surface_destroy(ref_type);
 
+        if (status)
+	    return NULL;
+
 	quartz_surf = (cairo_quartz_surface_t *) new_surf;
     } else {
 	/* If it's a quartz surface, we can try to see if it's a CGBitmapContext;
@@ -455,7 +461,6 @@ _cairo_quartz_surface_to_quartz (cairo_surface_t *target, cairo_surface_t *pat_s
 	 */
 	cairo_surface_reference (pat_surf);
 	quartz_surf = (cairo_quartz_surface_t*) pat_surf;
-
     }
 
     return quartz_surf;
@@ -468,10 +473,15 @@ SurfacePatternDrawFunc (void *info, CGContextRef context)
     cairo_surface_pattern_t *spat = (cairo_surface_pattern_t *) info;
     cairo_surface_t *pat_surf = spat->surface;
 
-    cairo_quartz_surface_t *quartz_surf = _cairo_quartz_surface_to_quartz (NULL, pat_surf);
-    CGImageRef img = CGBitmapContextCreateImage (quartz_surf->cgContext);
+    cairo_quartz_surface_t *quartz_surf;
+    CGImageRef img;
     CGRect imageBounds;
 
+    quartz_surf = _cairo_quartz_surface_to_quartz (NULL, pat_surf);
+    if (!quartz_surf)
+	return;
+
+    img = CGBitmapContextCreateImage (quartz_surf->cgContext);
     if (!img) {
 	// ... give up.
 	ND((stderr, "CGBitmapContextCreateImage failed\n"));
@@ -554,6 +564,7 @@ _cairo_quartz_cairo_repeating_surface_pattern_to_quartz (cairo_quartz_surface_t
 			      (CGFunctionReleaseInfoCallback) cairo_pattern_destroy };
     CGPatternRef cgpat;
     float rw, rh;
+    cairo_status_t status;
 
     cairo_pattern_union_t *snap_pattern = NULL;
     cairo_pattern_t *target_pattern = abspat;
@@ -566,7 +577,10 @@ _cairo_quartz_cairo_repeating_surface_pattern_to_quartz (cairo_quartz_surface_t
     spat = (cairo_surface_pattern_t *) abspat;
     pat_surf = spat->surface;
 
-    _cairo_surface_get_extents (pat_surf, &extents);
+    status = _cairo_surface_get_extents (pat_surf, &extents);
+    if (status)
+	return NULL;
+
     pbounds.origin.x = 0;
     pbounds.origin.y = 0;
 
@@ -672,12 +686,17 @@ _cairo_quartz_setup_source (cairo_quartz_surface_t *surface,
     {
 	    cairo_surface_pattern_t *spat = (cairo_surface_pattern_t *) source;
 	    cairo_surface_t *pat_surf = spat->surface;
-	    cairo_quartz_surface_t *quartz_surf = _cairo_quartz_surface_to_quartz ((cairo_surface_t *) surface, pat_surf);
-	    CGImageRef img = CGBitmapContextCreateImage (quartz_surf->cgContext);
+	    cairo_quartz_surface_t *quartz_surf;
+	    CGImageRef img;
 	    cairo_matrix_t m = spat->base.matrix;
 	    cairo_rectangle_int16_t extents;
 	    cairo_status_t status;
 
+	    quartz_surf = _cairo_quartz_surface_to_quartz ((cairo_surface_t *) surface, pat_surf);
+	    if (!quartz_surf)
+		return DO_UNSUPPORTED;
+
+	    img = CGBitmapContextCreateImage (quartz_surf->cgContext);
 	    if (!img)
 		return DO_UNSUPPORTED;