1 files changed, 24 insertions, 2 deletions
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php b/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
index c116f93df..6a1b0b08e 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
@@ -4,7 +4,21 @@
  * Chainable filters for custom URI processing.
  *
  * These filters can perform custom actions on a URI filter object,
- * including transformation or blacklisting.
+ * including transformation or blacklisting.  A filter named Foo
+ * must have a corresponding configuration directive %URI.Foo,
+ * unless always_load is specified to be true.
+ *
+ * The following contexts may be available while URIFilters are being
+ * processed:
+ *
+ *      - EmbeddedURI: true if URI is an embedded resource that will
+ *        be loaded automatically on page load
+ *      - CurrentToken: a reference to the token that is currently
+ *        being processed
+ *      - CurrentAttr: the name of the attribute that is currently being
+ *        processed
+ *      - CurrentCSSProperty: the name of the CSS property that is
+ *        currently being processed (if applicable)
  *
  * @warning This filter is called before scheme object validation occurs.
  *          Make sure, if you require a specific scheme object, you
@@ -25,7 +39,15 @@ abstract class HTMLPurifier_URIFilter
     public $post = false;
 
     /**
-     * Performs initialization for the filter
+     * True if this filter should always be loaded (this permits
+     * a filter to be named Foo without the corresponding %URI.Foo
+     * directive existing.)
+     */
+    public $always_load = false;
+
+    /**
+     * Performs initialization for the filter.  If the filter returns
+     * false, this means that it shouldn't be considered active.
      */
     public function prepare($config) {return true;}