1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
<?php
// $Id$
/**
* 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
$cache_flush = variable_get('cache_flush', 0);
if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) {
// Time to flush old cache data
db_query("DELETE FROM {". $table ."} 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, 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();
$cache_flush = variable_get('cache_flush', 0);
if ($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 {". $table ."} 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 {". $table ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
}
}
else {
if ($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);
}
}
}
|
