gstate: Set an error status when restoring a push_group

cairo_push_group (cr) followed by cairo_restore (cr) should put cr in
an error status of CAIRO_STATUS_INVALID_RESTORE.

Fixes group-state.

1 files changed, 11 insertions, 15 deletions

diff --git a/src/cairo.c b/src/cairo.c
index b87274a2..73dbaeef 100644
--- a/src/cairo.c
+++ b/src/cairo.c
@@ -585,6 +585,11 @@ cairo_restore (cairo_t *cr)
     if (unlikely (cr->status))
 	return;
 
+    if (unlikely (_cairo_gstate_is_group (cr->gstate))) {
+	_cairo_set_error (cr, _cairo_error (CAIRO_STATUS_INVALID_RESTORE));
+	return;
+    }
+
     status = _cairo_gstate_restore (&cr->gstate, &cr->gstate_freelist);
     if (unlikely (status))
 	_cairo_set_error (cr, status);
@@ -754,7 +759,7 @@ slim_hidden_def(cairo_push_group_with_content);
 cairo_pattern_t *
 cairo_pop_group (cairo_t *cr)
 {
-    cairo_surface_t *group_surface, *parent_target;
+    cairo_surface_t *group_surface;
     cairo_pattern_t *group_pattern;
     cairo_matrix_t group_matrix, device_transform_matrix;
     cairo_status_t status;
@@ -762,27 +767,18 @@ cairo_pop_group (cairo_t *cr)
     if (unlikely (cr->status))
 	return _cairo_pattern_create_in_error (cr->status);
 
-    /* Grab the active surfaces */
-    group_surface = _cairo_gstate_get_target (cr->gstate);
-    parent_target = _cairo_gstate_get_parent_target (cr->gstate);
-
     /* Verify that we are at the right nesting level */
-    if (parent_target == NULL) {
+    if (unlikely (! _cairo_gstate_is_group (cr->gstate))) {
 	_cairo_set_error (cr, CAIRO_STATUS_INVALID_POP_GROUP);
 	return _cairo_pattern_create_in_error (CAIRO_STATUS_INVALID_POP_GROUP);
     }
 
-    /* We need to save group_surface before we restore; we don't need
-     * to reference parent_target and original_target, since the
-     * gstate will still hold refs to them once we restore. */
+    /* Get a reference to the active surface before restoring */
+    group_surface = _cairo_gstate_get_target (cr->gstate);
     group_surface = cairo_surface_reference (group_surface);
 
-    cairo_restore (cr);
-
-    if (unlikely (cr->status)) {
-	group_pattern = _cairo_pattern_create_in_error (cr->status);
-	goto done;
-    }
+    status = _cairo_gstate_restore (&cr->gstate, &cr->gstate_freelist);
+    assert (status == CAIRO_STATUS_SUCCESS);
 
     group_pattern = cairo_pattern_create_for_surface (group_surface);
     status = group_pattern->status;