MediaWiki  master
MapCacheLRU.php
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1 <?php
24 
39  private $cache = [];
41  private $timestamps = [];
43  private $epoch;
44 
46  private $maxCacheKeys;
47 
50 
52  const RANK_TOP = 1.0;
53 
55  const SIMPLE = 0;
57  const FIELDS = 1;
58 
63  public function __construct( $maxKeys ) {
64  Assert::parameterType( 'integer', $maxKeys, '$maxKeys' );
65  Assert::parameter( $maxKeys > 0, '$maxKeys', 'must be above zero' );
66 
67  $this->maxCacheKeys = $maxKeys;
68  // Use the current time as the default "as of" timestamp of entries
69  $this->epoch = $this->getCurrentTime();
70  }
71 
78  public static function newFromArray( array $values, $maxKeys ) {
79  $mapCache = new self( $maxKeys );
80  $mapCache->cache = ( count( $values ) > $maxKeys )
81  ? array_slice( $values, -$maxKeys, null, true )
82  : $values;
83 
84  return $mapCache;
85  }
86 
91  public function toArray() {
92  return $this->cache;
93  }
94 
110  public function set( $key, $value, $rank = self::RANK_TOP ) {
111  if ( $this->has( $key ) ) {
112  $this->ping( $key );
113  } elseif ( count( $this->cache ) >= $this->maxCacheKeys ) {
114  reset( $this->cache );
115  $evictKey = key( $this->cache );
116  unset( $this->cache[$evictKey] );
117  unset( $this->timestamps[$evictKey] );
118  }
119 
120  if ( $rank < 1.0 && $rank > 0 ) {
121  $offset = intval( $rank * count( $this->cache ) );
122  $this->cache = array_slice( $this->cache, 0, $offset, true )
123  + [ $key => $value ]
124  + array_slice( $this->cache, $offset, null, true );
125  } else {
126  $this->cache[$key] = $value;
127  }
128 
129  $this->timestamps[$key] = [
130  self::SIMPLE => $this->getCurrentTime(),
131  self::FIELDS => []
132  ];
133  }
134 
143  public function has( $key, $maxAge = INF ) {
144  if ( !is_int( $key ) && !is_string( $key ) ) {
145  throw new UnexpectedValueException(
146  __METHOD__ . ': invalid key; must be string or integer.' );
147  }
148 
149  if ( !array_key_exists( $key, $this->cache ) ) {
150  return false;
151  }
152 
153  return ( $maxAge <= 0 || $this->getAge( $key ) <= $maxAge );
154  }
155 
168  public function get( $key, $maxAge = INF, $default = null ) {
169  if ( !$this->has( $key, $maxAge ) ) {
170  return $default;
171  }
172 
173  $this->ping( $key );
174 
175  return $this->cache[$key];
176  }
177 
184  public function setField( $key, $field, $value, $initRank = self::RANK_TOP ) {
185  if ( $this->has( $key ) ) {
186  $this->ping( $key );
187  } else {
188  $this->set( $key, [], $initRank );
189  }
190 
191  if ( !is_int( $field ) && !is_string( $field ) ) {
192  throw new UnexpectedValueException(
193  __METHOD__ . ": invalid field for '$key'; must be string or integer." );
194  }
195 
196  if ( !is_array( $this->cache[$key] ) ) {
197  $type = gettype( $this->cache[$key] );
198 
199  throw new UnexpectedValueException( "The value of '$key' ($type) is not an array." );
200  }
201 
202  $this->cache[$key][$field] = $value;
203  $this->timestamps[$key][self::FIELDS][$field] = $this->getCurrentTime();
204  }
205 
213  public function hasField( $key, $field, $maxAge = INF ) {
214  $value = $this->get( $key );
215 
216  if ( !is_int( $field ) && !is_string( $field ) ) {
217  throw new UnexpectedValueException(
218  __METHOD__ . ": invalid field for '$key'; must be string or integer." );
219  }
220 
221  if ( !is_array( $value ) || !array_key_exists( $field, $value ) ) {
222  return false;
223  }
224 
225  return ( $maxAge <= 0 || $this->getAge( $key, $field ) <= $maxAge );
226  }
227 
235  public function getField( $key, $field, $maxAge = INF ) {
236  if ( !$this->hasField( $key, $field, $maxAge ) ) {
237  return null;
238  }
239 
240  return $this->cache[$key][$field];
241  }
242 
247  public function getAllKeys() {
248  return array_keys( $this->cache );
249  }
250 
264  public function getWithSetCallback(
265  $key, callable $callback, $rank = self::RANK_TOP, $maxAge = INF
266  ) {
267  if ( $this->has( $key, $maxAge ) ) {
268  $value = $this->get( $key );
269  } else {
270  $value = call_user_func( $callback );
271  if ( $value !== false ) {
272  $this->set( $key, $value, $rank );
273  }
274  }
275 
276  return $value;
277  }
278 
285  public function clear( $keys = null ) {
286  if ( func_num_args() == 0 ) {
287  $this->cache = [];
288  $this->timestamps = [];
289  } else {
290  foreach ( (array)$keys as $key ) {
291  unset( $this->cache[$key] );
292  unset( $this->timestamps[$key] );
293  }
294  }
295  }
296 
303  public function getMaxSize() {
304  return $this->maxCacheKeys;
305  }
306 
315  public function setMaxSize( $maxKeys ) {
316  Assert::parameterType( 'integer', $maxKeys, '$maxKeys' );
317  Assert::parameter( $maxKeys > 0, '$maxKeys', 'must be above zero' );
318 
319  $this->maxCacheKeys = $maxKeys;
320  while ( count( $this->cache ) > $this->maxCacheKeys ) {
321  reset( $this->cache );
322  $evictKey = key( $this->cache );
323  unset( $this->cache[$evictKey] );
324  unset( $this->timestamps[$evictKey] );
325  }
326  }
327 
333  private function ping( $key ) {
334  $item = $this->cache[$key];
335  unset( $this->cache[$key] );
336  $this->cache[$key] = $item;
337  }
338 
344  private function getAge( $key, $field = null ) {
345  if ( $field !== null ) {
346  $mtime = $this->timestamps[$key][self::FIELDS][$field] ?? $this->epoch;
347  } else {
348  $mtime = $this->timestamps[$key][self::SIMPLE] ?? $this->epoch;
349  }
350 
351  return ( $this->getCurrentTime() - $mtime );
352  }
353 
354  public function serialize() {
355  return serialize( [
356  'entries' => $this->cache,
357  'timestamps' => $this->timestamps
358  ] );
359  }
360 
361  public function unserialize( $serialized ) {
362  $data = unserialize( $serialized );
363  $this->cache = $data['entries'] ?? [];
364  $this->timestamps = $data['timestamps'] ?? [];
365  $this->epoch = $this->getCurrentTime();
366  }
367 
372  protected function getCurrentTime() {
373  return $this->wallClockOverride ?: microtime( true );
374  }
375 
380  public function setMockTime( &$time ) {
381  $this->wallClockOverride =& $time;
382  }
383 }
getField( $key, $field, $maxAge=INF)
clear( $keys=null)
Clear one or several cache entries, or all cache entries.
__construct( $maxKeys)
Definition: MapCacheLRU.php:63
hasField( $key, $field, $maxAge=INF)
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
$value
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Definition: hooks.txt:2138
see documentation in includes Linker php for Linker::makeImageLink & $time
Definition: hooks.txt:1780
array $timestamps
Map of (key => (UNIX timestamp, (field => UNIX timestamp)))
Definition: MapCacheLRU.php:41
you have access to all of the normal MediaWiki so you can get a DB use the cache
Definition: maintenance.txt:52
ping( $key)
Push an entry to the top of the cache.
getWithSetCallback( $key, callable $callback, $rank=self::RANK_TOP, $maxAge=INF)
Get an item with the given key, producing and setting it if not found.
has( $key, $maxAge=INF)
Check if a key exists.
float null $wallClockOverride
Definition: MapCacheLRU.php:49
array $cache
Map of (key => value)
Definition: MapCacheLRU.php:39
getAge( $key, $field=null)
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not null
Definition: hooks.txt:767
unserialize( $serialized)
int $maxCacheKeys
Max number of entries.
Definition: MapCacheLRU.php:46
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
setField( $key, $field, $value, $initRank=self::RANK_TOP)
static newFromArray(array $values, $maxKeys)
Definition: MapCacheLRU.php:78
setMaxSize( $maxKeys)
Resize the maximum number of cache entries, removing older entries as needed.
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
getMaxSize()
Get the maximum number of keys allowed.
setMockTime(&$time)
foreach( $res as $row) $serialized
float $epoch
Default entry timestamp if not specified.
Definition: MapCacheLRU.php:43