1 files changed, 63 insertions, 7 deletions

diff --git a/includes/path.inc b/includes/path.inc
index a4659d7c0..a6abc19b9 100644
--- a/includes/path.inc
+++ b/includes/path.inc
@@ -49,6 +49,9 @@ function drupal_lookup_path($action, $path = '', $path_language = '') {
   $map = &drupal_static(__FUNCTION__, array());
   $no_src = &drupal_static(__FUNCTION__ . ':no_src', array());
   $count = &drupal_static(__FUNCTION__ . ':count');
+  $system_paths = &drupal_static(__FUNCTION__ . ':system_paths');
+  $no_aliases = &drupal_static(__FUNCTION__ . ':no_alias', array());
+  $first_call = &drupal_static(__FUNCTION__ . ':first_call', TRUE);
 
   $path_language = $path_language ? $path_language : $language->language;
 
@@ -61,19 +64,45 @@ function drupal_lookup_path($action, $path = '', $path_language = '') {
     $map = array();
     $no_src = array();
     $count = NULL;
+    $system_paths = array();
+    $no_aliases = array();
   }
   elseif ($count > 0 && $path != '') {
     if ($action == 'alias') {
+      // During the first call to drupal_lookup_path() per language, load the
+      // expected system paths for the page from cache.
+      if ($first_call) {
+        $first_call = FALSE;
+        $map[$path_language] = array();
+        // Load system paths from cache.
+        $cid = current_path();
+        if ($cache = cache_get($cid, 'cache_path')) {
+          $system_paths = $cache->data;
+          // Now fetch the aliases corresponding to these system paths.
+          // We order by ASC and overwrite array keys to ensure the correct
+          // alias is used when there are multiple aliases per path.
+          $map[$path_language] = db_query("SELECT src, dst FROM {url_alias} WHERE src IN(:system) AND language IN(:language, '') ORDER BY language ASC", array(
+            ':system' => $system_paths,
+            ':language' => $path_language
+          ))->fetchAllKeyed();
+          // Keep a record of paths with no alias to avoid querying twice.
+          $no_aliases[$path_language] = array_flip(array_diff_key($system_paths, array_keys($map[$path_language])));
+        }
+      }
+      // If the alias has already been loaded, return it.
       if (isset($map[$path_language][$path])) {
         return $map[$path_language][$path];
       }
-      // Get the most fitting result falling back with alias without language
-      $alias = db_query("SELECT dst FROM {url_alias} WHERE src = :src AND language IN(:language, '') ORDER BY language DESC", array(
-        ':src' => $path,
-        ':language' => $path_language))
-        ->fetchField();
-      $map[$path_language][$path] = $alias;
-      return $alias;
+      // For system paths which were not cached, query aliases individually.
+      else if (!isset($no_aliases[$path_language][$path])) {
+        // Get the most fitting result falling back with alias without language
+        $alias = db_query("SELECT dst FROM {url_alias} WHERE src = :src AND language IN(:language, '') ORDER BY language DESC", array(
+          ':src' => $path,
+          ':language' => $path_language
+        ))->fetchField();
+        $map[$path_language][$path] = $alias;
+        return $alias;
+      }
     }
     // Check $no_src for this $path in case we've already determined that there
     // isn't a path that has this alias
@@ -103,6 +132,33 @@ function drupal_lookup_path($action, $path = '', $path_language = '') {
 }
 
 /**
+ * Cache system paths for a page.
+ *
+ * Cache an array of the system paths available on each page. We assume
+ * that aiases will be needed for the majority of these paths during
+ * subsequent requests, and load them in a single query during
+ * drupal_lookup_path().
+ */
+function drupal_cache_system_paths() {
+  // Check if the system paths for this page were loaded from cache in this
+  // request to avoid writing to cache on every request.
+  $system_paths = &drupal_static('drupal_lookup_path:system_paths', array());
+  if (!$system_paths) {
+    // The static $map array used by drupal_lookup_path() includes all
+    // system paths for the page request.
+    $map = &drupal_static('drupal_lookup_path', array());
+
+    // Generate a cache ID (cid) specifically for this page.
+    $cid = current_path();
+    if ($paths = current($map)) {
+      $data = array_keys($paths);
+      $expire = REQUEST_TIME + (60 * 60 * 24);
+      cache_set($cid, $data, 'cache_path', $expire);
+    }
+  }
+}
+
+/**
  * Given an internal Drupal path, return the alias set by the administrator.
  *
  * If no path is provided, the function will return the alias of the current