1: <?php
2:
3: /**
4: * Abstract class representing Definition cache managers that implements
5: * useful common methods and is a factory.
6: * @todo Create a separate maintenance file advanced users can use to
7: * cache their custom HTMLDefinition, which can be loaded
8: * via a configuration directive
9: * @todo Implement memcached
10: */
11: abstract class HTMLPurifier_DefinitionCache
12: {
13:
14: public $type;
15:
16: /**
17: * @param $name Type of definition objects this instance of the
18: * cache will handle.
19: */
20: public function __construct($type) {
21: $this->type = $type;
22: }
23:
24: /**
25: * Generates a unique identifier for a particular configuration
26: * @param Instance of HTMLPurifier_Config
27: */
28: public function generateKey($config) {
29: return $config->version . ',' . // possibly replace with function calls
30: $config->getBatchSerial($this->type) . ',' .
31: $config->get($this->type . '.DefinitionRev');
32: }
33:
34: /**
35: * Tests whether or not a key is old with respect to the configuration's
36: * version and revision number.
37: * @param $key Key to test
38: * @param $config Instance of HTMLPurifier_Config to test against
39: */
40: public function isOld($key, $config) {
41: if (substr_count($key, ',') < 2) return true;
42: list($version, $hash, $revision) = explode(',', $key, 3);
43: $compare = version_compare($version, $config->version);
44: // version mismatch, is always old
45: if ($compare != 0) return true;
46: // versions match, ids match, check revision number
47: if (
48: $hash == $config->getBatchSerial($this->type) &&
49: $revision < $config->get($this->type . '.DefinitionRev')
50: ) return true;
51: return false;
52: }
53:
54: /**
55: * Checks if a definition's type jives with the cache's type
56: * @note Throws an error on failure
57: * @param $def Definition object to check
58: * @return Boolean true if good, false if not
59: */
60: public function checkDefType($def) {
61: if ($def->type !== $this->type) {
62: trigger_error("Cannot use definition of type {$def->type} in cache for {$this->type}");
63: return false;
64: }
65: return true;
66: }
67:
68: /**
69: * Adds a definition object to the cache
70: */
71: abstract public function add($def, $config);
72:
73: /**
74: * Unconditionally saves a definition object to the cache
75: */
76: abstract public function set($def, $config);
77:
78: /**
79: * Replace an object in the cache
80: */
81: abstract public function replace($def, $config);
82:
83: /**
84: * Retrieves a definition object from the cache
85: */
86: abstract public function get($config);
87:
88: /**
89: * Removes a definition object to the cache
90: */
91: abstract public function remove($config);
92:
93: /**
94: * Clears all objects from cache
95: */
96: abstract public function flush($config);
97:
98: /**
99: * Clears all expired (older version or revision) objects from cache
100: * @note Be carefuly implementing this method as flush. Flush must
101: * not interfere with other Definition types, and cleanup()
102: * should not be repeatedly called by userland code.
103: */
104: abstract public function cleanup($config);
105:
106: }
107:
108: // vim: et sw=4 sts=4
109: