src/svgtiny_css.c: add user handler function

This function needs to be passed to dom_node_set_user_data() in
set_libcss_node_data(), but we couldn't implement it before our
css_select_handler was defined, because it passes the address of
that select handler to css_libcss_node_data_handler().

diff --git a/src/svgtiny_css.c b/src/svgtiny_css.c
index 76b01d196abdd6c0fe4a72dc9987555e5922fdc4..a5a75214a57239d3bbfb150768dc1611531007ae 100644 (file)
--- a/src/svgtiny_css.c
+++ b/src/svgtiny_css.c
@@ -1860,6 +1860,57 @@ css_error ua_default_for_property(void *pw, uint32_t property,
 }
 
 
+/**
+ * A "user handler" function that we pass to dom_node_set_user_data()
+ * in set_libcss_node_data(). The set_libcss_node_data() documentation
+ * says that if the node (on which data is set) is is deleted or
+ * cloned, or if its ancestors are modified, then we must call
+ * css_libcss_node_data_handler() on the user data. This function
+ * basically just checks to see which DOM event has happened and
+ * calls css_libcss_node_data_handler() when any of those criteria
+ * are met.
+ */
+static void svgtiny_dom_user_data_handler(dom_node_operation operation,
+       dom_string *key, void *data, struct dom_node *src,
+       struct dom_node *dst)
+{
+       /* We only care about the userdata that is identified by our
+        * userdata key. Unfortunately I see no obvious way to obtain
+        * the copy of the userdata key that is already interned in
+        * svgtiny_strings.h; so we duplicate it here (ugh). */
+       dom_string *str;
+       dom_string_create((const uint8_t *)"_libcss_user_data", 17, &str);
+       if (dom_string_isequal(str,key) == false || data == NULL) {
+               /* Wrong key, or no data */
+               return;
+       }
+
+       /* Check the DOM operation, and make the corresponding call to
+        * css_libcss_node_data_handler(). No error handling is done.
+        */
+       switch (operation) {
+               case DOM_NODE_CLONED:
+                       css_libcss_node_data_handler(&svgtiny_select_handler,
+                                               CSS_NODE_CLONED,
+                                               NULL, src, dst, data);
+                       break;
+               case DOM_NODE_RENAMED:
+                       css_libcss_node_data_handler(&svgtiny_select_handler,
+                                               CSS_NODE_MODIFIED,
+                                               NULL, src, NULL, data);
+                       break;
+               case DOM_NODE_IMPORTED:
+               case DOM_NODE_ADOPTED:
+               case DOM_NODE_DELETED:
+                       css_libcss_node_data_handler(&svgtiny_select_handler,
+                                               CSS_NODE_DELETED,
+                                               NULL, src, NULL, data);
+               default:
+                       /* Our list of cases should have been exhaustive */
+                       assert(false);
+       }
+}
+
 /**
  * Store libcss data on a node
  *