introduce a cached version of te ACL checkingmediarefactor

for iterating over media namespaces

2 files changed, 32 insertions, 1 deletions

diff --git a/inc/MediaFile.class.php b/inc/MediaFile.class.php
index 4b50497f6..91ff780ed 100644
--- a/inc/MediaFile.class.php
+++ b/inc/MediaFile.class.php
@@ -47,7 +47,7 @@ class MediaFile {
             $this->id         = cleanID($this->id);
             $this->isexternal = false;
             $this->file       = mediaFN($this->id);
-            $this->auth       = auth_quickaclcheck(getNS($this->id).':*');
+            $this->auth       = auth_quickaclcheck_cached(getNS($this->id).':*');
         }
     }
 
diff --git a/inc/auth.php b/inc/auth.php
index e224b2fb5..c67bffef1 100644
--- a/inc/auth.php
+++ b/inc/auth.php
@@ -653,6 +653,37 @@ function auth_isMember($memberlist, $user, array $groups) {
 }
 
 /**
+ * Caching wrapper around auth_quickaclcheck()
+ *
+ * This will check ACLs only once per request for the given ID. This is mostly useful when iterating over
+ * a larger list of media files in the same namespace. When in doubt, use the uncached variant!
+ *
+ * Cache is done in memory (static variable)
+ *
+ * @uthor Andreas Gohr <andi@splitbrain.org>
+ * @param  string  $id  page ID (needs to be resolved and cleaned)
+ * @return int permision level
+ */
+function auth_quickaclcheck_cached($id) {
+    /* @var Input $INPUT */
+    global $INPUT;
+    $user = $INPUT->server->str('REMOTE_USER');
+
+    // cache initialization
+    // the cache is user based even though the user should not change within a request this is
+    // an additional safe guard
+    static $aclcache = array();
+    if(!isset($aclcache[$user])) $aclcache[$user] = array();
+
+    // fill cache
+    if(!isset($aclcache[$user][$id])) {
+        $aclcache[$user][$id] = auth_quickaclcheck($id);
+    }
+
+    return $aclcache[$user][$id];
+}
+
+/**
  * Convinience function for auth_aclcheck()
  *
  * This checks the permissions for the current user