--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/web/drupal/includes/cache.inc Fri Aug 21 16:26:26 2009 +0000
@@ -0,0 +1,183 @@
+<?php
+// $Id: cache.inc,v 1.17.2.2 2009/05/26 08:10:33 goba Exp $
+
+/**
+ * Return data from the persistent cache. Data may be stored as either plain text or as serialized data.
+ * cache_get will automatically return unserialized objects and arrays.
+ *
+ * @param $cid
+ * The cache ID of the data to retrieve.
+ * @param $table
+ * The table $table to store the data in. Valid core values are 'cache_filter',
+ * 'cache_menu', 'cache_page', or 'cache' for the default cache.
+ */
+function cache_get($cid, $table = 'cache') {
+ global $user;
+
+ // Garbage collection necessary when enforcing a minimum cache lifetime
+ $cache_flush = variable_get('cache_flush_'. $table, 0);
+ if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) {
+ // Reset the variable immediately to prevent a meltdown in heavy load situations.
+ variable_set('cache_flush_'. $table, 0);
+ // Time to flush old cache data
+ db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush);
+ }
+
+ $cache = db_fetch_object(db_query("SELECT data, created, headers, expire, serialized FROM {". $table ."} WHERE cid = '%s'", $cid));
+ if (isset($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 ($cache->serialized) {
+ $cache->data = unserialize($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;
+ }
+ else {
+ $cache->data = db_decode_blob($cache->data);
+ if ($cache->serialized) {
+ $cache->data = unserialize($cache->data);
+ }
+ }
+ }
+ return $cache;
+ }
+ return 0;
+}
+
+/**
+ * Store data in the persistent cache.
+ *
+ * The persistent cache is split up into four database
+ * tables. Contributed modules can add additional tables.
+ *
+ * 'cache_page': This table stores generated pages for anonymous
+ * users. This is the only table affected by the page cache setting on
+ * the administrator panel.
+ *
+ * 'cache_menu': Stores the cachable part of the users' menus.
+ *
+ * 'cache_filter': Stores filtered pieces of content. This table is
+ * periodically cleared of stale entries by cron.
+ *
+ * 'cache': Generic cache storage table.
+ *
+ * The reasons for having several tables are as follows:
+ *
+ * - smaller tables allow for faster selects and inserts
+ * - we try to put fast changing cache items and rather static
+ * ones into different tables. The effect is that only the fast
+ * changing tables will need a lot of writes to disk. The more
+ * static tables will also be better cachable with MySQL's query cache
+ *
+ * @param $cid
+ * The cache ID of the data to store.
+ * @param $data
+ * The data to store in the cache. Complex data types will be automatically serialized before insertion.
+ * Strings will be stored as plain text and not serialized.
+ * @param $table
+ * The table $table to store the data in. Valid core values are 'cache_filter',
+ * 'cache_menu', 'cache_page', or 'cache'.
+ * @param $expire
+ * One of the following values:
+ * - CACHE_PERMANENT: Indicates that the item should never be removed unless
+ * explicitly told to using cache_clear_all() with a cache ID.
+ * - CACHE_TEMPORARY: Indicates that the item should be removed at the next
+ * general cache wipe.
+ * - A Unix timestamp: Indicates that the item should be kept at least until
+ * the given time, after which it behaves like CACHE_TEMPORARY.
+ * @param $headers
+ * A string containing HTTP header information for cached pages.
+ */
+function cache_set($cid, $data, $table = 'cache', $expire = CACHE_PERMANENT, $headers = NULL) {
+ $serialized = 0;
+ if (is_object($data) || is_array($data)) {
+ $data = serialize($data);
+ $serialized = 1;
+ }
+ $created = time();
+ db_query("UPDATE {". $table ."} SET data = %b, created = %d, expire = %d, headers = '%s', serialized = %d WHERE cid = '%s'", $data, $created, $expire, $headers, $serialized, $cid);
+ if (!db_affected_rows()) {
+ @db_query("INSERT INTO {". $table ."} (cid, data, created, expire, headers, serialized) VALUES ('%s', %b, %d, %d, '%s', %d)", $cid, $data, $created, $expire, $headers, $serialized);
+ }
+}
+
+/**
+ *
+ * Expire data from the cache. If called without arguments, expirable
+ * entries will be cleared from the cache_page and cache_block tables.
+ *
+ * @param $cid
+ * If set, the cache ID to delete. Otherwise, all cache entries that can
+ * expire are deleted.
+ *
+ * @param $table
+ * If set, the table $table to delete from. Mandatory
+ * argument if $cid is set.
+ *
+ * @param $wildcard
+ * If set to TRUE, the $cid is treated as a substring
+ * to match rather than a complete ID. The match is a right hand
+ * match. If '*' is given as $cid, the table $table will be emptied.
+ */
+function cache_clear_all($cid = NULL, $table = NULL, $wildcard = FALSE) {
+ global $user;
+
+ if (!isset($cid) && !isset($table)) {
+ // Clear the block cache first, so stale data will
+ // not end up in the page cache.
+ cache_clear_all(NULL, 'cache_block');
+ cache_clear_all(NULL, 'cache_page');
+ return;
+ }
+
+ if (empty($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_'. $table, 0);
+ if ($cache_flush == 0) {
+ // This is the first request to clear the cache, start a timer.
+ variable_set('cache_flush_'. $table, time());
+ }
+ else if (time() > ($cache_flush + variable_get('cache_lifetime', 0))) {
+ // Clear the cache for everyone, cache_lifetime seconds have
+ // passed since the first request to clear the cache.
+ db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
+ variable_set('cache_flush_'. $table, 0);
+ }
+ }
+ else {
+ // No minimum cache lifetime, flush all temporary cache entries now.
+ db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
+ }
+ }
+ else {
+ if ($wildcard) {
+ if ($cid == '*') {
+ db_query("DELETE FROM {". $table ."}");
+ }
+ else {
+ db_query("DELETE FROM {". $table ."} WHERE cid LIKE '%s%%'", $cid);
+ }
+ }
+ else {
+ db_query("DELETE FROM {". $table ."} WHERE cid = '%s'", $cid);
+ }
+ }
+}
+