1 files changed, 53 insertions, 18 deletions

diff --git a/library/HTMLPurifier/AttrDef/HTML/ID.php b/library/HTMLPurifier/AttrDef/HTML/ID.php
index 81d03762d..3d86efb44 100644
--- a/library/HTMLPurifier/AttrDef/HTML/ID.php
+++ b/library/HTMLPurifier/AttrDef/HTML/ID.php
@@ -12,42 +12,77 @@
 class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
 {
 
-    // ref functionality disabled, since we also have to verify
-    // whether or not the ID it refers to exists
-
-    public function validate($id, $config, $context) {
+    // selector is NOT a valid thing to use for IDREFs, because IDREFs
+    // *must* target IDs that exist, whereas selector #ids do not.
+
+    /**
+     * Determines whether or not we're validating an ID in a CSS
+     * selector context.
+     * @type bool
+     */
+    protected $selector;
+
+    /**
+     * @param bool $selector
+     */
+    public function __construct($selector = false)
+    {
+        $this->selector = $selector;
+    }
 
-        if (!$config->get('Attr.EnableID')) return false;
+    /**
+     * @param string $id
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return bool|string
+     */
+    public function validate($id, $config, $context)
+    {
+        if (!$this->selector && !$config->get('Attr.EnableID')) {
+            return false;
+        }
 
         $id = trim($id); // trim it first
 
-        if ($id === '') return false;
+        if ($id === '') {
+            return false;
+        }
 
         $prefix = $config->get('Attr.IDPrefix');
         if ($prefix !== '') {
             $prefix .= $config->get('Attr.IDPrefixLocal');
             // prevent re-appending the prefix
-            if (strpos($id, $prefix) !== 0) $id = $prefix . $id;
+            if (strpos($id, $prefix) !== 0) {
+                $id = $prefix . $id;
+            }
         } elseif ($config->get('Attr.IDPrefixLocal') !== '') {
-            trigger_error('%Attr.IDPrefixLocal cannot be used unless '.
-                '%Attr.IDPrefix is set', E_USER_WARNING);
+            trigger_error(
+                '%Attr.IDPrefixLocal cannot be used unless ' .
+                '%Attr.IDPrefix is set',
+                E_USER_WARNING
+            );
         }
 
-        //if (!$this->ref) {
+        if (!$this->selector) {
             $id_accumulator =& $context->get('IDAccumulator');
-            if (isset($id_accumulator->ids[$id])) return false;
-        //}
+            if (isset($id_accumulator->ids[$id])) {
+                return false;
+            }
+        }
 
         // we purposely avoid using regex, hopefully this is faster
 
         if (ctype_alpha($id)) {
             $result = true;
         } else {
-            if (!ctype_alpha(@$id[0])) return false;
-            $trim = trim( // primitive style of regexps, I suppose
+            if (!ctype_alpha(@$id[0])) {
+                return false;
+            }
+            // primitive style of regexps, I suppose
+            $trim = trim(
                 $id,
                 'A..Za..z0..9:-._'
-              );
+            );
             $result = ($trim === '');
         }
 
@@ -56,15 +91,15 @@ class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
             return false;
         }
 
-        if (/*!$this->ref && */$result) $id_accumulator->add($id);
+        if (!$this->selector && $result) {
+            $id_accumulator->add($id);
+        }
 
         // if no change was made to the ID, return the result
         // else, return the new id if stripping whitespace made it
         //     valid, or return false.
         return $result ? $id : false;
-
     }
-
 }
 
 // vim: et sw=4 sts=4