Index: database/updates.inc
===================================================================
RCS file: /cvs/drupal/drupal/database/updates.inc,v
retrieving revision 1.234
diff -u -r1.234 updates.inc
--- database/updates.inc	29 May 2006 16:04:41 -0000	1.234
+++ database/updates.inc	31 May 2006 20:36:38 -0000
@@ -146,8 +146,8 @@
 
   }
 
-  // Flush the menu cache:
-  cache_clear_all('menu:', TRUE);
+  // Invalidate any cached menu items.
+  variable_set('menu-cache-time', time());
 
   return $ret;
 }
Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.99
diff -u -r1.99 bootstrap.inc
--- includes/bootstrap.inc	7 May 2006 00:08:36 -0000	1.99
+++ includes/bootstrap.inc	31 May 2006 20:36:39 -0000
@@ -6,11 +6,16 @@
  * Functions that need to be loaded on every Drupal request.
  */
 
+define('SECONDS_IN_ONE_DAY', 86400);    // (60 * 60 * 24 = 86400)
+
 define('CACHE_PERMANENT', 0);
 define('CACHE_TEMPORARY', -1);
 
-define('CACHE_DISABLED', 0);
-define('CACHE_ENABLED', 1);
+define('CACHE_METHOD_NONE', 0);
+define('CACHE_METHOD_DATABASE', 1);
+define('CACHE_METHOD_MEMCACHED', 2);
+define('CACHE_HEADERS', '_HEADERS');
+define('CACHE_MISS', 0);
 
 define('WATCHDOG_NOTICE', 0);
 define('WATCHDOG_WARNING', 1);
@@ -150,6 +155,9 @@
  */
 function conf_init() {
   global $db_url, $db_prefix, $base_url, $base_path, $base_root, $conf;
+  global $cache_mode, $memcached_options, $memcache;
+
+  $cache_mode = CACHE_METHOD_DATABASE;
   $conf = array();
   require_once './'. conf_path() .'/settings.php';
 
@@ -176,6 +184,30 @@
       $base_path = '/';
     }
   }
+
+  // Setup access to memcached.
+  if ($cache_mode == CACHE_METHOD_MEMCACHED) {
+    if ((array_key_exists('servers', (is_array($memcached_options) ? $memcached_options : array())))) {
+      $serverlist = $memcached_options['servers'];
+      foreach ($serverlist as $server) {
+        list($server, $port) = explode(':', $server);
+        if (!isset($memcache)) {
+          $memcache = new Memcache;
+          if (isset($memcached_options['persist']) and ($memcached_options['persist'])) {
+            // Use a persistent connection.
+            $memcache->pconnect($server, $port);
+          } else {
+            // Don't use a persistent connection.
+            $memcache->connect($server, $port);
+          }
+        }
+        else {
+          $memcache->addServer($server, $port);
+        }
+      }
+    }    
+  }
+
 }
 
 /**
@@ -311,42 +343,91 @@
  *
  * @param $key
  *   The cache ID of the data to retrieve.
+ * @param $expired
+ *   The optional timestamp for which we ignore any cached values
+ *   prior to it.
  */
-function cache_get($key) {
-  global $user;
+function cache_get($key, $expired = 0) {
+  global $user, $cache_mode, $memcache;
 
-  // Garbage collection necessary when enforcing a minimum cache lifetime
-  $cache_flush = variable_get('cache_flush', 0);
-  if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) {
-    // Time to flush old cache data
-    db_query("DELETE FROM {cache} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush);
-    variable_set('cache_flush', 0);
-  }
-
-  $cache = db_fetch_object(db_query("SELECT data, created, headers, expire FROM {cache} WHERE cid = '%s'", $key));
-  if (isset($cache->data)) {
-    // If the data is permanent or we're not enforcing a minimum cache lifetime
-    // always return the cached data.
-    if ($cache->expire == CACHE_PERMANENT || !variable_get('cache_lifetime', 0)) {
-      $cache->data = db_decode_blob($cache->data);
-    }
-    // If enforcing a minimum cache lifetime, validate that the data is
-    // currently valid for this user before we return it by making sure the
-    // cache entry was created before the timestamp in the current session's
-    // cache timer. The cache variable is loaded into the $user object by
-    // sess_read() in session.inc.
-    else {
-      if ($user->cache > $cache->created) {
-        // This cache data is too old and thus not valid for us, ignore it.
-        return 0;
+  switch ($cache_mode) {
+
+    case CACHE_METHOD_NONE:
+      return CACHE_MISS;
+      break;
+
+    case CACHE_METHOD_DATABASE:
+
+      // Garbage collection necessary when enforcing a minimum cache lifetime
+      $cache_flush = variable_get('cache_flush', 0);
+      if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) {
+        // Time to flush old cache data
+        db_query("DELETE FROM {cache} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush);
+        variable_set('cache_flush', 0);
       }
-      else {
-        $cache->data = db_decode_blob($cache->data);
+
+      $cache = db_fetch_object(db_query("SELECT data, created, headers, expire FROM {cache} WHERE cid = '%s'", $key));
+      if (isset($cache->data)) {
+        // If the data is permanent or we're not enforcing a minimum cache lifetime
+        // always return the cached data.
+        if ($cache->expire == CACHE_PERMANENT || !variable_get('cache_lifetime', 0)) {
+          $cache->data = db_decode_blob($cache->data);
+        }
+        // If enforcing a minimum cache lifetime, validate that the data is
+        // currently valid for this user before we return it by making sure the
+        // cache entry was created before the timestamp in the current session's
+        // cache timer. The cache variable is loaded into the $user object by
+        // sess_read() in session.inc.
+        else {
+          if ($user->cache > $cache->created) {
+            // This cache data is too old and thus not valid for us, ignore it.
+            return CACHE_MISS;
+          } elseif ($expired > $cache->created) {
+            return CACHE_MISS;
+          } else {
+            $cache->data = db_decode_blob($cache->data);
+          }
+        }
+        return $cache;
       }
-    }
-    return $cache;
+      return CACHE_MISS;
+      break;
+
+    case CACHE_METHOD_MEMCACHED:
+      // memcached will handle expiration for us, so if we get a 
+      // result back, count it as valid.
+      if (isset($memcache)) {
+        $keyheaders = $key . CACHE_HEADERS;
+        $cached = $memcache->get( array($key, $keyheaders) );
+        if (isset($cached[$key])) {
+          // Build our return object.
+          $cachedata = $cached[$key];
+          $cache = new stdClass();
+          $cache->data = ''; 
+          $cache->created = 0;
+          $cache->expire = $expired;
+          $cache->header = '';
+          // Check for a created timestamp;
+          if (isset($cachedata['created'])) {
+            $cache->created = $cachedata['created'];
+          }
+          // Check if this item is still valid.
+          if ($cache->created > $cache->expire) {
+            if (isset($cachedata['data'])) {
+              $cache->data = $cachedata['data'];
+            }
+            // Check for a cached header.
+            if (isset($cached[$keyheaders])) {
+              $cache->header = $cached[$keyheaders];
+            }
+            return $cache;
+          }
+        }
+      }  
+      return CACHE_MISS;
+      break;
   }
-  return 0;
+
 }
 
 /**
@@ -368,12 +449,55 @@
  *   A string containing HTTP header information for cached pages.
  */
 function cache_set($cid, $data, $expire = CACHE_PERMANENT, $headers = NULL) {
-  db_lock_table('cache');
-  db_query("UPDATE {cache} SET data = %b, created = %d, expire = %d, headers = '%s' WHERE cid = '%s'", $data, time(), $expire, $headers, $cid);
-  if (!db_affected_rows()) {
-    @db_query("INSERT INTO {cache} (cid, data, created, expire, headers) VALUES ('%s', %b, %d, %d, '%s')", $cid, $data, time(), $expire, $headers);
+  global $cache_mode, $memcache;
+
+  switch ($cache_mode) {
+
+    case CACHE_METHOD_NONE:
+      break;
+
+    case CACHE_METHOD_DATABASE:
+
+      db_lock_table('cache');
+      db_query("UPDATE {cache} SET data = %b, created = %d, expire = %d, headers = '%s' WHERE cid = '%s'", $data, time(), $expire, $headers, $cid);
+      if (!db_affected_rows()) {
+        @db_query("INSERT INTO {cache} (cid, data, created, expire, headers) VALUES ('%s', %b, %d, %d, '%s')", $cid, $data, time(), $expire, $headers);
+      }
+      db_unlock_tables();
+      break;
+
+    case CACHE_METHOD_MEMCACHED:
+    
+      if (isset($memcache)) {
+        // Determine the timeout as used by memcached.
+        $time = 0;
+        switch ($expire) {
+          case CACHE_PERMANENT:
+            $time = 0;
+            break;
+          case CACHE_TEMPORARY:
+            $life = variable_get('cache_lifetime', 0);
+            if ($life == 0) {
+              $time = 0;               // treat it as CACHE_PERMANENT
+            } else {
+              $time = time() + $life;  // set the expire time to now + lifetime
+            }
+            break;
+          default:
+            $time = $expire;           // use supplied expire time
+            break;
+        }
+        // Unconditionally set the data, this will update any old values.
+        $cachedata = array( 'data' => $data, 'created' => time() );
+        $memcache->set($cid, $cachedata, 0, $time);
+        if (isset($headers)) {
+          $memcache->set($cid . CACHE_HEADERS, $headers, 0, $time);
+        }
+      }
+      break;
+
   }
-  db_unlock_tables();
+
 }
 
 /**
@@ -388,41 +512,57 @@
  *   complete ID.
  */
 function cache_clear_all($cid = NULL, $wildcard = false) {
-  global $user;
+  global $user, $cache_mode, $memcache;
 
-  if (empty($cid)) {
-    if (variable_get('cache_lifetime', 0)) {
-      // We store the time in the current user's $user->cache variable which
-      // will be saved into the sessions table by sess_write(). We then
-      // simulate that the cache was flushed for this user by not returning
-      // cached data that was cached before the timestamp.
-      $user->cache = time();
+  switch ($cache_mode) {
 
-      $cache_flush = variable_get('cache_flush', 0);
-      if ($cache_flush == 0) {
-        // This is the first request to clear the cache, start a timer.
-        variable_set('cache_flush', time());
-      }
-      else if (time() > ($cache_flush + variable_get('cache_lifetime', 0))) {
-        // Clear the cache for everyone, cache_flush_delay seconds have
-        // passed since the first request to clear the cache.
-        db_query("DELETE FROM {cache} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
-        variable_set('cache_flush', 0);
+    case CACHE_METHOD_NONE:
+      break;
+
+    case CACHE_METHOD_DATABASE:
+      if (empty($cid)) {
+        if (variable_get('cache_lifetime', 0)) {
+          // We store the time in the current user's $user->cache variable which
+          // will be saved into the sessions table by sess_write(). We then
+          // simulate that the cache was flushed for this user by not returning
+          // cached data that was cached before the timestamp.
+          $user->cache = time();
+
+          $cache_flush = variable_get('cache_flush', 0);
+          if ($cache_flush == 0) {
+            // This is the first request to clear the cache, start a timer.
+            variable_set('cache_flush', time());
+          }
+          else if (time() > ($cache_flush + variable_get('cache_lifetime', 0))) {
+            // Clear the cache for everyone, cache_flush_delay seconds have
+            // passed since the first request to clear the cache.
+            db_query("DELETE FROM {cache} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
+            variable_set('cache_flush', 0);
+          }
+        }
+        else {
+          // No minimum cache lifetime, flush all temporary cache entries now.
+          db_query("DELETE FROM {cache} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
+        }
       }
-    }
-    else {
-      // No minimum cache lifetime, flush all temporary cache entries now.
-      db_query("DELETE FROM {cache} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
-    }
-  }
-  else {
-    if ($wildcard) {
-      db_query("DELETE FROM {cache} WHERE cid LIKE '%%%s%%'", $cid);
-    }
-    else {
-      db_query("DELETE FROM {cache} WHERE cid = '%s'", $cid);
-    }
+      else {
+        db_query("DELETE FROM {cache} WHERE cid = '%s'", $cid);
+      }
+      break;
+      
+    case CACHE_METHOD_MEMCACHED:
+      // We don't need to flush everything since memcached handles that for us.
+      // We can still purge specific values when requested.
+      if (isset($memcache)) {
+        if (isset($cid)) {
+          $memcache->delete($cid);
+          $memcache->delete($cid . CACHE_HEADERS);
+        }
+      }
+      break;
+
   }
+
 }
 
 /**
@@ -796,3 +936,4 @@
   unicode_check();
   $theme = '';
 }
+
Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.122
diff -u -r1.122 menu.inc
--- includes/menu.inc	21 May 2006 09:18:47 -0000	1.122
+++ includes/menu.inc	31 May 2006 20:36:40 -0000
@@ -204,16 +204,16 @@
 
   if (!isset($_menu['items'])) {
     // _menu_build() may indirectly call this function, so prevent infinite loops.
-    $_menu['items'] = array();
 
     $cid = "menu:$user->uid:$locale";
-    if ($cached = cache_get($cid)) {
+    if ($cached = cache_get($cid, variable_get('menu-cache-time', 0))) {
       $_menu = unserialize($cached->data);
     }
-    else {
+    
+    if (!isset($_menu['items'])) {
       _menu_build();
       // Cache the menu structure for this user, to expire after one day.
-      cache_set($cid, serialize($_menu), time() + (60 * 60 * 24));
+      cache_set($cid, serialize($_menu), $time + SECONDS_IN_ONE_DAY);
     }
 
     // Make sure items that cannot be cached are added.
@@ -586,8 +586,8 @@
 function menu_rebuild() {
   // Clear the page cache, so that changed menus are reflected for anonymous users.
   cache_clear_all();
-  // Also clear the menu cache.
-  cache_clear_all('menu:', TRUE);
+  // Invalidate any cached menu items.
+  variable_set('menu-cache-time', time());
 
   _menu_build();
 
Index: modules/filter.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/filter.module,v
retrieving revision 1.124
diff -u -r1.124 filter.module
--- modules/filter.module	7 May 2006 00:08:36 -0000	1.124
+++ modules/filter.module	31 May 2006 20:36:41 -0000
@@ -383,7 +383,9 @@
   db_query("UPDATE {comments} SET format = %d WHERE format = %d", $default, $form_values['format']);
   db_query("UPDATE {boxes} SET format = %d WHERE format = %d", $default, $form_values['format']);
 
-  cache_clear_all('filter:'. $form_values['format'], true);
+  // Invalidate any cached filters.
+  variable_set('filter-cache-time', time());
+
   drupal_set_message(t('Deleted input format %format.', array('%format' => theme('placeholder', $form_values['name']))));
 
   return 'admin/filters';
@@ -522,7 +524,8 @@
 
   db_query("UPDATE {filter_formats} SET cache = %d, name='%s', roles = '%s' WHERE format = %d", $cache, $name, $roles, $format);
 
-  cache_clear_all('filter:'. $format, true);
+  // Invalidate any cached filters.
+  variable_set('filter-cache-time', time());
 
   // If a new filter was added, return to the main list of filters. Otherwise, stay on edit filter page to show new changes.
   if ($new) {
@@ -580,7 +583,8 @@
   }
   drupal_set_message(t('The filter ordering has been saved.'));
 
-  cache_clear_all('filter:'. $form_values['format'], true);
+  // Invalidate any cached filters.
+  variable_set('filter-cache-time', time());
 }
 
 /**
@@ -745,7 +749,7 @@
 
     // Check for a cached version of this piece of text.
     $id = 'filter:'. $format .':'. md5($text);
-    if ($cached = cache_get($id)) {
+    if ($cached = cache_get($id, variable_get('filter-cache-time', 0))) {
       return $cached->data;
     }
 
@@ -771,7 +775,7 @@
 
     // Store in cache with a minimum expiration time of 1 day.
     if ($cache) {
-      cache_set($id, $text, time() + (60 * 60 * 24));
+      cache_set($id, $text, time() + SECONDS_IN_ONE_DAY);
     }
   }
   else {
Index: modules/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user.module,v
retrieving revision 1.626
diff -u -r1.626 user.module
--- modules/user.module	29 May 2006 13:02:14 -0000	1.626
+++ modules/user.module	31 May 2006 20:36:43 -0000
@@ -1438,8 +1438,8 @@
   unset($form_values['_account'], $form_values['submit'], $form_values['delete'], $form_values['form_id'], $form_values['_category']);
   user_module_invoke('submit', $form_values, $account, $category);
   user_save($account, $form_values, $category);
-  // Delete that user's menu cache.
-  cache_clear_all('menu:'. $account->uid, TRUE);
+  // Invalidate any cached menu items.
+  variable_set('menu-cache-time', time());
   drupal_set_message(t('The changes have been saved.'));
   return 'user/'. $account->uid;
 }
Index: sites/default/settings.php
===================================================================
RCS file: /cvs/drupal/drupal/sites/default/settings.php,v
retrieving revision 1.28
diff -u -r1.28 settings.php
--- sites/default/settings.php	7 May 2006 00:08:36 -0000	1.28
+++ sites/default/settings.php	31 May 2006 20:36:43 -0000
@@ -147,3 +147,30 @@
 #   'anonymous' => 'Visitor'
 # );
 
+
+/**
+ * Set caching preference.
+ * Choose one of the following cache methods.
+ *
+ * CACHE_METHOD_NONE = 0
+ * CACHE_METHOD_DATABASE = 1
+ * CACHE_METHOD_MEMCACHED = 2
+ */
+$cache_mode = CACHE_METHOD_DATABASE;
+
+/**
+ * When using CACHE_METHOD_MEMCACHED, uncomment and adjust
+ * the following settings.
+ *
+ * $memcached_options = array(
+ *      'servers' => array( '127.0.0.1:11212' ),
+ *        // Add additional servers as need.
+ *      'persist' => true
+ *        // Establish a persistant connection to the cache server.
+ * );
+ */
+#$memcached_options = array(
+#	'servers' => array( '127.0.0.1:11211' ),
+#        'persist' => true 
+#);
+