| Line # | Frequency | Source Line |
| 1 | | <?php |
| 2 | | // $Id: cache.inc,v 1.17 2008/01/29 11:36:06 goba Exp $ |
| 3 | | |
| 4 | | /** |
| 5 | | * Return data from the persistent cache. Data may be stored as either plain text or as serialized data. |
| 6 | | * cache_get will automatically return unserialized objects and arrays. |
| 7 | | * |
| 8 | | * @param $cid |
| 9 | | * The cache ID of the data to retrieve. |
| 10 | | * @param $table |
| 11 | | * The table $table to store the data in. Valid core values are 'cache_filter', |
| 12 | | * 'cache_menu', 'cache_page', or 'cache' for the default cache. |
| 13 | | */ |
| 14 | | function cache_get($cid, $table = 'cache') { |
| 15 | 1 | global $user; |
| 16 | | |
| 17 | | // Garbage collection necessary when enforcing a minimum cache lifetime |
| 18 | 1 | $cache_flush = variable_get('cache_flush', 0); |
| 19 | 1 | if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) { |
| 20 | | // Reset the variable immediately to prevent a meltdown in heavy load situations. |
| 21 | | variable_set('cache_flush', 0); |
| 22 | | // Time to flush old cache data |
| 23 | | db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush); |
| 24 | | } |
| 25 | | |
| 26 | 1 | $cache = db_fetch_object(db_query("SELECT data, created, headers, expire, serialized FROM {". $table ."} WHERE cid = '%s'", $cid)); |
| 27 | 1 | if (isset($cache->data)) { |
| 28 | | // If the data is permanent or we're not enforcing a minimum cache lifetime |
| 29 | | // always return the cached data. |
| 30 | 1 | if ($cache->expire == CACHE_PERMANENT || !variable_get('cache_lifetime', 0)) { |
| 31 | 1 | $cache->data = db_decode_blob($cache->data); |
| 32 | 1 | if ($cache->serialized) { |
| 33 | 1 | $cache->data = unserialize($cache->data); |
| 34 | | } |
| 35 | | } |
| 36 | | // If enforcing a minimum cache lifetime, validate that the data is |
| 37 | | // currently valid for this user before we return it by making sure the |
| 38 | | // cache entry was created before the timestamp in the current session's |
| 39 | | // cache timer. The cache variable is loaded into the $user object by |
| 40 | | // sess_read() in session.inc. |
| 41 | | else { |
| 42 | | if ($user->cache > $cache->created) { |
| 43 | | // This cache data is too old and thus not valid for us, ignore it. |
| 44 | | return 0; |
| 45 | | } |
| 46 | | else { |
| 47 | | $cache->data = db_decode_blob($cache->data); |
| 48 | | if ($cache->serialized) { |
| 49 | | $cache->data = unserialize($cache->data); |
| 50 | | } |
| 51 | | } |
| 52 | | } |
| 53 | 1 | return $cache; |
| 54 | | } |
| 55 | 1 | return 0; |
| 56 | | } |
| 57 | | |
| 58 | | /** |
| 59 | | * Store data in the persistent cache. |
| 60 | | * |
| 61 | | * The persistent cache is split up into four database |
| 62 | | * tables. Contributed modules can add additional tables. |
| 63 | | * |
| 64 | | * 'cache_page': This table stores generated pages for anonymous |
| 65 | | * users. This is the only table affected by the page cache setting on |
| 66 | | * the administrator panel. |
| 67 | | * |
| 68 | | * 'cache_menu': Stores the cachable part of the users' menus. |
| 69 | | * |
| 70 | | * 'cache_filter': Stores filtered pieces of content. This table is |
| 71 | | * periodically cleared of stale entries by cron. |
| 72 | | * |
| 73 | | * 'cache': Generic cache storage table. |
| 74 | | * |
| 75 | | * The reasons for having several tables are as follows: |
| 76 | | * |
| 77 | | * - smaller tables allow for faster selects and inserts |
| 78 | | * - we try to put fast changing cache items and rather static |
| 79 | | * ones into different tables. The effect is that only the fast |
| 80 | | * changing tables will need a lot of writes to disk. The more |
| 81 | | * static tables will also be better cachable with MySQL's query cache |
| 82 | | * |
| 83 | | * @param $cid |
| 84 | | * The cache ID of the data to store. |
| 85 | | * @param $data |
| 86 | | * The data to store in the cache. Complex data types will be automatically serialized before insertion. |
| 87 | | * Strings will be stored as plain text and not serialized. |
| 88 | | * @param $table |
| 89 | | * The table $table to store the data in. Valid core values are 'cache_filter', |
| 90 | | * 'cache_menu', 'cache_page', or 'cache'. |
| 91 | | * @param $expire |
| 92 | | * One of the following values: |
| 93 | | * - CACHE_PERMANENT: Indicates that the item should never be removed unless |
| 94 | | * explicitly told to using cache_clear_all() with a cache ID. |
| 95 | | * - CACHE_TEMPORARY: Indicates that the item should be removed at the next |
| 96 | | * general cache wipe. |
| 97 | | * - A Unix timestamp: Indicates that the item should be kept at least until |
| 98 | | * the given time, after which it behaves like CACHE_TEMPORARY. |
| 99 | | * @param $headers |
| 100 | | * A string containing HTTP header information for cached pages. |
| 101 | | */ |
| 102 | | function cache_set($cid, $data, $table = 'cache', $expire = CACHE_PERMANENT, $headers = NULL) { |
| 103 | 1 | $serialized = 0; |
| 104 | 1 | if (is_object($data) || is_array($data)) { |
| 105 | 1 | $data = serialize($data); |
| 106 | 1 | $serialized = 1; |
| 107 | | } |
| 108 | 1 | $created = time(); |
| 109 | 1 | db_query("UPDATE {". $table ."} SET data = %b, created = %d, expire = %d, headers = '%s', serialized = %d WHERE cid = '%s'", $data, $created, $expire, $headers, $serialized, $cid); |
| 110 | 1 | if (!db_affected_rows()) { |
| 111 | 1 | @db_query("INSERT INTO {". $table ."} (cid, data, created, expire, headers, serialized) VALUES ('%s', %b, %d, %d, '%s', %d)", $cid, $data, $created, $expire, $headers, $serialized); |
| 112 | | } |
| 113 | | } |
| 114 | | |
| 115 | | /** |
| 116 | | * |
| 117 | | * Expire data from the cache. If called without arguments, expirable |
| 118 | | * entries will be cleared from the cache_page and cache_block tables. |
| 119 | | * |
| 120 | | * @param $cid |
| 121 | | * If set, the cache ID to delete. Otherwise, all cache entries that can |
| 122 | | * expire are deleted. |
| 123 | | * |
| 124 | | * @param $table |
| 125 | | * If set, the table $table to delete from. Mandatory |
| 126 | | * argument if $cid is set. |
| 127 | | * |
| 128 | | * @param $wildcard |
| 129 | | * If set to TRUE, the $cid is treated as a substring |
| 130 | | * to match rather than a complete ID. The match is a right hand |
| 131 | | * match. If '*' is given as $cid, the table $table will be emptied. |
| 132 | | */ |
| 133 | | function cache_clear_all($cid = NULL, $table = NULL, $wildcard = FALSE) { |
| 134 | 1 | global $user; |
| 135 | | |
| 136 | 1 | if (!isset($cid) && !isset($table)) { |
| 137 | | // Clear the block cache first, so stale data will |
| 138 | | // not end up in the page cache. |
| 139 | 1 | cache_clear_all(NULL, 'cache_block'); |
| 140 | 1 | cache_clear_all(NULL, 'cache_page'); |
| 141 | 1 | return; |
| 142 | | } |
| 143 | | |
| 144 | 1 | if (empty($cid)) { |
| 145 | 1 | if (variable_get('cache_lifetime', 0)) { |
| 146 | | // We store the time in the current user's $user->cache variable which |
| 147 | | // will be saved into the sessions table by sess_write(). We then |
| 148 | | // simulate that the cache was flushed for this user by not returning |
| 149 | | // cached data that was cached before the timestamp. |
| 150 | | $user->cache = time(); |
| 151 | | |
| 152 | | $cache_flush = variable_get('cache_flush', 0); |
| 153 | | if ($cache_flush == 0) { |
| 154 | | // This is the first request to clear the cache, start a timer. |
| 155 | | variable_set('cache_flush', time()); |
| 156 | | } |
| 157 | | else if (time() > ($cache_flush + variable_get('cache_lifetime', 0))) { |
| 158 | | // Clear the cache for everyone, cache_flush_delay seconds have |
| 159 | | // passed since the first request to clear the cache. |
| 160 | | db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time()); |
| 161 | | variable_set('cache_flush', 0); |
| 162 | | } |
| 163 | | } |
| 164 | | else { |
| 165 | | // No minimum cache lifetime, flush all temporary cache entries now. |
| 166 | 1 | db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time()); |
| 167 | | } |
| 168 | | } |
| 169 | | else { |
| 170 | 1 | if ($wildcard) { |
| 171 | 1 | if ($cid == '*') { |
| 172 | 1 | db_query("DELETE FROM {". $table ."}"); |
| 173 | | } |
| 174 | | else { |
| 175 | 1 | db_query("DELETE FROM {". $table ."} WHERE cid LIKE '%s%%'", $cid); |
| 176 | | } |
| 177 | | } |
| 178 | | else { |
| 179 | 1 | db_query("DELETE FROM {". $table ."} WHERE cid = '%s'", $cid); |
| 180 | | } |
| 181 | | } |
| 182 | | } |
| 183 | | |