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
183
184
185
186
187
188
189
190
191
192
193
194
|
<?php
/**
* Cache that uses DBA as a backend.
* Slow due to the need to constantly open and close the file to avoid holding
* writer locks. Intended for development use only, as a memcached workalike
* for systems that don't have it.
*
* @ingroup Cache
*/
class DBABagOStuff extends BagOStuff {
var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
public function __construct( $dir = false ) {
global $wgDBAhandler;
if ( $dir === false ) {
global $wgTmpDirectory;
$dir = $wgTmpDirectory;
}
$this->mFile = "$dir/mw-cache-" . wfWikiID();
$this->mFile .= '.db';
wfDebug( __CLASS__ . ": using cache file {$this->mFile}\n" );
$this->mHandler = $wgDBAhandler;
}
/**
* Encode value and expiry for storage
* @param $value
* @param $expiry
*
* @return string
*/
function encode( $value, $expiry ) {
# Convert to absolute time
$expiry = $this->convertExpiry( $expiry );
return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
}
/**
* @return array list containing value first and expiry second
*/
function decode( $blob ) {
if ( !is_string( $blob ) ) {
return array( null, 0 );
} else {
return array(
unserialize( substr( $blob, 11 ) ),
intval( substr( $blob, 0, 10 ) )
);
}
}
function getReader() {
if ( file_exists( $this->mFile ) ) {
$handle = dba_open( $this->mFile, 'rl', $this->mHandler );
} else {
$handle = $this->getWriter();
}
if ( !$handle ) {
wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
}
return $handle;
}
function getWriter() {
$handle = dba_open( $this->mFile, 'cl', $this->mHandler );
if ( !$handle ) {
wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
}
return $handle;
}
function get( $key ) {
wfProfileIn( __METHOD__ );
wfDebug( __METHOD__ . "($key)\n" );
$handle = $this->getReader();
if ( !$handle ) {
wfProfileOut( __METHOD__ );
return null;
}
$val = dba_fetch( $key, $handle );
list( $val, $expiry ) = $this->decode( $val );
# Must close ASAP because locks are held
dba_close( $handle );
if ( !is_null( $val ) && $expiry && $expiry < time() ) {
# Key is expired, delete it
$handle = $this->getWriter();
dba_delete( $key, $handle );
dba_close( $handle );
wfDebug( __METHOD__ . ": $key expired\n" );
$val = null;
}
wfProfileOut( __METHOD__ );
return $val;
}
function set( $key, $value, $exptime = 0 ) {
wfProfileIn( __METHOD__ );
wfDebug( __METHOD__ . "($key)\n" );
$blob = $this->encode( $value, $exptime );
$handle = $this->getWriter();
if ( !$handle ) {
wfProfileOut( __METHOD__ );
return false;
}
$ret = dba_replace( $key, $blob, $handle );
dba_close( $handle );
wfProfileOut( __METHOD__ );
return $ret;
}
function delete( $key, $time = 0 ) {
wfProfileIn( __METHOD__ );
wfDebug( __METHOD__ . "($key)\n" );
$handle = $this->getWriter();
if ( !$handle ) {
wfProfileOut( __METHOD__ );
return false;
}
$ret = dba_delete( $key, $handle );
dba_close( $handle );
wfProfileOut( __METHOD__ );
return $ret;
}
function add( $key, $value, $exptime = 0 ) {
wfProfileIn( __METHOD__ );
$blob = $this->encode( $value, $exptime );
$handle = $this->getWriter();
if ( !$handle ) {
wfProfileOut( __METHOD__ );
return false;
}
$ret = dba_insert( $key, $blob, $handle );
# Insert failed, check to see if it failed due to an expired key
if ( !$ret ) {
list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
if ( $expiry < time() ) {
# Yes expired, delete and try again
dba_delete( $key, $handle );
$ret = dba_insert( $key, $blob, $handle );
# This time if it failed then it will be handled by the caller like any other race
}
}
dba_close( $handle );
wfProfileOut( __METHOD__ );
return $ret;
}
function keys() {
$reader = $this->getReader();
$k1 = dba_firstkey( $reader );
if ( !$k1 ) {
return array();
}
$result[] = $k1;
while ( $key = dba_nextkey( $reader ) ) {
$result[] = $key;
}
return $result;
}
}
|
