powered-cache / includes / dropins / apcu-object-cache.php

apcu-object-cache.php in Powered Cache – Caching and Optimization for WordPress – Easily Improve PageSpeed & Web Vitals Score 2.0.2, at includes/dropins/apcu-object-cache.php

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1	<?php
2
3	/**
4	* APCu drop-in
5	*
6	* @link https://github.com/l3rady/WordPress-APCu-Object-Cache
7	*/
8
9	if ( ! function_exists( 'apcu_add' ) ) {
10	return;
11	}
12	// Stop direct access
13	defined( 'ABSPATH' ) or exit;
14
15
16	/**
17	* Adds data to the cache, if the cache key does not already exist.
18	*
19	* @param int\|string $key The cache key to use for retrieval later
20	* @param mixed $data The data to add to the cache store
21	* @param string $group The group to add the cache to
22	* @param int $expire When the cache data should be expired
23	*
24	* @return bool False if cache key and group already exist, true on success
25	*/
26	function wp_cache_add( $key, $data, $group = 'default', $expire = 0 ) {
27	return WP_Object_Cache::instance()->add( $key, $data, $group, $expire );
28	}
29
30
31	/**
32	* Closes the cache.
33	*
34	* This function has ceased to do anything since WordPress 2.5. The
35	* functionality was removed along with the rest of the persistent cache. This
36	* does not mean that plugins can't implement this function when they need to
37	* make sure that the cache is cleaned up after WordPress no longer needs it.
38	*
39	* @return bool Always returns True
40	*/
41	function wp_cache_close() {
42	return true;
43	}
44
45
46	/**
47	* Decrement numeric cache item's value
48	*
49	* @param int\|string $key The cache key to increment
50	* @param int $offset The amount by which to decrement the item's value. Default is 1.
51	* @param string $group The group the key is in.
52	*
53	* @return false\|int False on failure, the item's new value on success.
54	*/
55	function wp_cache_decr( $key, $offset = 1, $group = 'default' ) {
56	return WP_Object_Cache::instance()->decr( $key, $offset, $group );
57	}
58
59
60	/**
61	* Removes the cache contents matching key and group.
62	*
63	* @param int\|string $key What the contents in the cache are called
64	* @param string $group Where the cache contents are grouped
65	*
66	* @return bool True on successful removal, false on failure
67	*/
68	function wp_cache_delete( $key, $group = 'default' ) {
69	return WP_Object_Cache::instance()->delete( $key, $group );
70	}
71
72
73	/**
74	* Removes all cache items.
75	*
76	* @return bool False on failure, true on success
77	*/
78	function wp_cache_flush() {
79	return WP_Object_Cache::instance()->flush();
80	}
81
82
83	/**
84	* Retrieves the cache contents from the cache by key and group.
85	*
86	* @param int\|string $key What the contents in the cache are called
87	* @param string $group Where the cache contents are grouped
88	* @param bool $force Does nothing with APCu object cache
89	* @param bool &$found Whether key was found in the cache. Disambiguates a return of false, a storable value.
90	*
91	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
92	*/
93	function wp_cache_get( $key, $group = 'default', $force = false, &$found = null ) {
94	return WP_Object_Cache::instance()->get( $key, $group, $force, $found );
95	}
96
97
98	/**
99	* Retrieve multiple values from cache.
100	*
101	* Gets multiple values from cache, including across multiple groups
102	*
103	* Usage: array( 'group0' => array( 'key0', 'key1', 'key2', ), 'group1' => array( 'key0' ) )
104	*
105	* @param array $groups Array of groups and keys to retrieve
106	*
107	* @return array Array of cached values as
108	* array( 'group0' => array( 'key0' => 'value0', 'key1' => 'value1', 'key2' => 'value2', ) )
109	* Non-existent keys are not returned.
110	*/
111	function wp_cache_get_multi( $groups ) {
112	return WP_Object_Cache::instance()->get_multi( $groups );
113	}
114
115
116	/**
117	* Increment numeric cache item's value
118	*
119	* @param int\|string $key The cache key to increment
120	* @param int $offset The amount by which to increment the item's value. Default is 1.
121	* @param string $group The group the key is in.
122	*
123	* @return false\|int False on failure, the item's new value on success.
124	*/
125	function wp_cache_incr( $key, $offset = 1, $group = 'default' ) {
126	return WP_Object_Cache::instance()->incr( $key, $offset, $group );
127	}
128
129
130	/**
131	* Sets up Object Cache Global and assigns it.
132	*
133	* @global WP_Object_Cache $wp_object_cache WordPress Object Cache
134	*/
135	function wp_cache_init() {
136	$GLOBALS['wp_object_cache'] = WP_Object_Cache::instance();
137	}
138
139
140	/**
141	* Replaces the contents of the cache with new data.
142	*
143	* @param int\|string $key What to call the contents in the cache
144	* @param mixed $data The contents to store in the cache
145	* @param string $group Where to group the cache contents
146	* @param int $expire When to expire the cache contents
147	*
148	* @return bool False if not exists, true if contents were replaced
149	*/
150	function wp_cache_replace( $key, $data, $group = 'default', $expire = 0 ) {
151	return WP_Object_Cache::instance()->replace( $key, $data, $group, $expire );
152	}
153
154
155	/**
156	* Saves the data to the cache.
157	*
158	* @param int\|string $key What to call the contents in the cache
159	* @param mixed $data The contents to store in the cache
160	* @param string $group Where to group the cache contents
161	* @param int $expire When to expire the cache contents
162	*
163	* @return bool False on failure, true on success
164	*/
165	function wp_cache_set( $key, $data, $group = 'default', $expire = 0 ) {
166	return WP_Object_Cache::instance()->set( $key, $data, $group, $expire );
167	}
168
169
170	/**
171	* Switch the internal blog id.
172	*
173	* This changes the blog id used to create keys in blog specific groups.
174	*
175	* @param int $blog_id Blog ID
176	*/
177	function wp_cache_switch_to_blog( $blog_id ) {
178	WP_Object_Cache::instance()->switch_to_blog( $blog_id );
179	}
180
181
182	/**
183	* Adds a group or set of groups to the list of global groups.
184	*
185	* @param string\|array $groups A group or an array of groups to add
186	*/
187	function wp_cache_add_global_groups( $groups ) {
188	WP_Object_Cache::instance()->add_global_groups( $groups );
189	}
190
191
192	/**
193	* Adds a group or set of groups to the list of non-persistent groups.
194	*
195	* @param string\|array $groups A group or an array of groups to add
196	*/
197	function wp_cache_add_non_persistent_groups( $groups ) {
198	WP_Object_Cache::instance()->add_non_persistent_groups( $groups );
199	}
200
201
202	/**
203	* Function was depreciated and now does nothing
204	*
205	* @return bool Always returns false
206	*/
207	function wp_cache_reset() {
208	_deprecated_function( __FUNCTION__, '3.5', 'wp_cache_switch_to_blog()' );
209
210	return false;
211	}
212
213
214	/**
215	* Invalidate a site's object cache
216	*
217	* @param mixed $sites Sites ID's that want flushing.
218	* Don't pass a site to flush current site
219	*
220	* @return bool
221	*/
222	function wp_cache_flush_site( $sites = null ) {
223	return WP_Object_Cache::instance()->flush_sites( $sites );
224	}
225
226
227	/**
228	* Invalidate a groups object cache
229	*
230	* @param mixed $groups A group or an array of groups to invalidate
231	*
232	* @return bool
233	*/
234	function wp_cache_flush_group( $groups = 'default' ) {
235	return WP_Object_Cache::instance()->flush_groups( $groups );
236	}
237
238
239	/**
240	* WordPress APCu Object Cache Backend
241	*
242	* The WordPress Object Cache is used to save on trips to the database. The
243	* APCu Object Cache stores all of the cache data to APCu and makes the cache
244	* contents available by using a key, which is used to name and later retrieve
245	* the cache contents.
246	*/
247	class WP_Object_Cache {
248
249	/**
250	* @var string MD5 hash of the current installation ABSPATH
251	*/
252	private $abspath;
253
254	/**
255	* @var bool Stores if APCu is available.
256	*/
257	private $apcu_available;
258
259	/**
260	* @var int The sites current blog ID. This only
261	* differs if running a multi-site installations
262	*/
263	private $blog_prefix;
264
265	/**
266	* @var int Keeps count of how many times the
267	* cache was successfully received from APCu
268	*/
269	public $cache_hits = 0;
270
271	/**
272	* @var int Keeps count of how many times the
273	* cache was not successfully received from APCu
274	*/
275	public $cache_misses = 0;
276
277	/**
278	* @var array Holds a list of cache groups that are
279	* shared across all sites in a multi-site installation
280	*/
281	private $global_groups = [];
282
283	/**
284	* @var array Holds an array of versions of the retrieved groups
285	*/
286	private $group_versions = [];
287
288	/**
289	* @var bool True if the current installation is a multi-site
290	*/
291	private $multi_site;
292
293	/**
294	* @var array Holds cache that is to be non persistent
295	*/
296	private $non_persistent_cache = [];
297
298	/**
299	* @var array Holds a list of cache groups that are not to be saved to APCu
300	*/
301	private $non_persistent_groups = [];
302
303	/**
304	* @var array
305	*/
306	private $local_cache = [];
307
308	/**
309	* @var array Holds an array of versions of the retrieved sites
310	*/
311	private $site_versions = [];
312
313	private static $instance;
314
315	/**
316	* Singleton. Return instance of WP_Object_Cache
317	*
318	* @return WP_Object_Cache
319	*/
320	public static function instance() {
321	if ( self::$instance === null ) {
322	self::$instance = new WP_Object_Cache();
323	}
324
325	return self::$instance;
326	}
327
328	/**
329	* __clone not allowed
330	*/
331	private function __clone() {
332	}
333
334	/**
335	* Direct access to __construct not allowed.
336	*/
337	private function __construct() {
338	global $blog_id;
339
340	if ( ! defined( 'WP_APCU_KEY_SALT' ) ) {
341	/**
342	* Set in config if you are using some sort of shared
343	* config where ABSPATH is the same on all sites
344	*/
345	define( 'WP_APCU_KEY_SALT', 'wp' );
346	}
347
348	/**
349	* define('WP_APCU_LOCAL_CACHE', false) to disable local
350	* array cache and force all cache to be returned from APCu
351	*/
352	if ( ! defined( 'WP_APCU_LOCAL_CACHE' ) ) {
353	define( 'WP_APCU_LOCAL_CACHE', true );
354	}
355
356	$this->abspath = md5( ABSPATH );
357	$this->apcu_available = ( extension_loaded( 'apcu' ) && ini_get( 'apc.enabled' ) );
358	$this->multi_site = is_multisite();
359	$this->blog_prefix = $this->multi_site ? $blog_id : 1;
360	}
361
362	/**
363	* Adds data to the cache, if the cache key does not already exist.
364	*
365	* @param int\|string $key The cache key to use for retrieval later
366	* @param mixed $var The data to add to the cache store
367	* @param string $group The group to add the cache to
368	* @param int $ttl When the cache data should be expired
369	*
370	* @return bool False if cache key and group already exist, true on success
371	*/
372	public function add( $key, $var, $group = 'default', $ttl = 0 ) {
373	if ( wp_suspend_cache_addition() ) {
374	return false;
375	}
376
377	$key = $this->_key( $key, $group );
378
379	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
380	return $this->_add_np( $key, $var );
381	}
382
383	return $this->_add( $key, $var, $ttl );
384	}
385
386	/**
387	* Adds data to APCu cache, if the cache key does not already exist.
388	*
389	* @param string $key The cache key to use for retrieval later
390	* @param mixed $var The data to add to the cache store
391	* @param int $ttl When the cache data should be expired
392	*
393	* @return bool False if cache key and group already exist, true on success
394	*/
395	private function _add( $key, $var, $ttl ) {
396	if ( apcu_add( $key, $var, max( (int) $ttl, 0 ) ) ) {
397	if ( WP_APCU_LOCAL_CACHE ) {
398	$this->local_cache[ $key ] = is_object( $var ) ? clone $var : $var;
399	}
400
401	return true;
402	}
403
404	return false;
405	}
406
407	/**
408	* Adds data to non persistent cache, if the cache key does not already exist.
409	*
410	* @param string $key The cache key to use for retrieval later
411	* @param mixed $var The data to add to the cache store
412	*
413	* @return bool False if cache key and group already exist, true on success
414	*/
415	private function _add_np( $key, $var ) {
416	if ( $this->_exists_np( $key ) ) {
417	return false;
418	}
419
420	return $this->_set_np( $key, $var );
421	}
422
423	/**
424	* Sets the list of global groups.
425	*
426	* @param string\|array $groups List of groups that are global.
427	*/
428	public function add_global_groups( $groups ) {
429	foreach ( (array) $groups as $group ) {
430	$this->global_groups[ $group ] = true;
431	}
432	}
433
434	/**
435	* Sets the list of non persistent groups.
436	*
437	* @param string\|array $groups List of groups that are non persistent.
438	*/
439	public function add_non_persistent_groups( $groups ) {
440	foreach ( (array) $groups as $group ) {
441	$this->non_persistent_groups[ $group ] = true;
442	}
443	}
444
445	/**
446	* Decrement numeric cache item's value
447	*
448	* @param int\|string $key The cache key to increment
449	* @param int $offset The amount by which to decrement the item's value. Default is 1.
450	* @param string $group The group the key is in.
451	*
452	* @return false\|int False on failure, the item's new value on success.
453	*/
454	public function decr( $key, $offset = 1, $group = 'default' ) {
455	$key = $this->_key( $key, $group );
456
457	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
458	return $this->_decr_np( $key, $offset );
459	}
460
461	return $this->_decr( $key, $offset );
462	}
463
464	/**
465	* Decrement numeric APCu cache item's value
466	*
467	* @param string $key The cache key to increment
468	* @param int $offset The amount by which to decrement the item's value. Default is 1.
469	*
470	* @return false\|int False on failure, the item's new value on success.
471	*/
472	private function _decr( $key, $offset ) {
473	$this->_get( $key, $success );
474	if ( ! $success ) {
475	return false;
476	}
477
478	$value = apcu_dec( $key, max( (int) $offset, 0 ) );
479	if ( $value !== false && WP_APCU_LOCAL_CACHE ) {
480	$this->local_cache[ $key ] = $value;
481	}
482
483	return $value;
484	}
485
486	/**
487	* Decrement numeric non persistent cache item's value
488	*
489	* @param string $key The cache key to increment
490	* @param int $offset The amount by which to decrement the item's value. Default is 1.
491	*
492	* @return false\|int False on failure, the item's new value on success.
493	*/
494	private function _decr_np( $key, $offset ) {
495	if ( ! $this->_exists_np( $key ) ) {
496	return false;
497	}
498
499	$offset = max( (int) $offset, 0 );
500	$var = $this->_get_np( $key );
501	$var = is_numeric( $var ) ? $var : 0;
502	$var -= $offset;
503
504	return $this->_set_np( $key, $var );
505	}
506
507	/**
508	* Remove the contents of the cache key in the group
509	*
510	* If the cache key does not exist in the group, then nothing will happen.
511	*
512	* @param int\|string $key What the contents in the cache are called
513	* @param string $group Where the cache contents are grouped
514	* @param bool $deprecated Deprecated.
515	*
516	* @return bool False if the contents weren't deleted and true on success
517	*/
518	public function delete( $key, $group = 'default', $deprecated = false ) {
519	$key = $this->_key( $key, $group );
520
521	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
522	return $this->_delete_np( $key );
523	}
524
525	return $this->_delete( $key );
526	}
527
528	/**
529	* Remove the contents of the APCu cache key in the group
530	*
531	* If the cache key does not exist in the group, then nothing will happen.
532	*
533	* @param string $key What the contents in the cache are called
534	*
535	* @return bool False if the contents weren't deleted and true on success
536	*/
537	private function _delete( $key ) {
538	unset( $this->local_cache[ $key ] );
539
540	return apcu_delete( $key );
541	}
542
543	/**
544	* Remove the contents of the non persistent cache key in the group
545	*
546	* If the cache key does not exist in the group, then nothing will happen.
547	*
548	* @param string $key What the contents in the cache are called
549	*
550	* @return bool False if the contents weren't deleted and true on success
551	*/
552	private function _delete_np( $key ) {
553	if ( array_key_exists( $key, $this->non_persistent_cache ) ) {
554	unset( $this->non_persistent_cache[ $key ] );
555
556	return true;
557	}
558
559	return false;
560	}
561
562	/**
563	* Checks if the cached non persistent key exists
564	*
565	* @param string $key What the contents in the cache are called
566	*
567	* @return bool True if cache key exists else false
568	*/
569	private function _exists_np( $key ) {
570	return array_key_exists( $key, $this->non_persistent_cache );
571	}
572
573	/**
574	* Clears the object cache of all data
575	*
576	* @return bool Always returns true
577	*/
578	public function flush() {
579	$this->non_persistent_cache = [];
580
581	if ( WP_APCU_LOCAL_CACHE ) {
582	$this->local_cache = [];
583	}
584
585	if ( $this->apcu_available ) {
586	apcu_clear_cache();
587	}
588
589	return true;
590	}
591
592	/**
593	* Invalidate a groups object cache
594	*
595	* @param mixed $groups A group or an array of groups to invalidate
596	*
597	* @return bool
598	*/
599	public function flush_groups( $groups ) {
600	$groups = (array) $groups;
601
602	if ( empty( $groups ) ) {
603	return false;
604	}
605
606	foreach ( $groups as $group ) {
607	$version = $this->_get_group_cache_version( $group );
608	$this->_set_group_cache_version( $group, $version + 1 );
609	}
610
611	return true;
612	}
613
614	/**
615	* Invalidate a site's object cache
616	*
617	* @param mixed $sites Sites ID's that want flushing.
618	* Don't pass a site to flush current site
619	*
620	* @return bool
621	*/
622	public function flush_sites( $sites ) {
623	$sites = (array) $sites;
624
625	if ( empty( $sites ) ) {
626	$sites = [ $this->blog_prefix ];
627	}
628
629	// Add global groups (site 0) to be flushed.
630	if ( ! in_array( 0, $sites, false ) ) {
631	$sites[] = 0;
632	}
633
634	foreach ( $sites as $site ) {
635	$version = $this->_get_site_cache_version( $site );
636	$this->_set_site_cache_version( $site, $version + 1 );
637	}
638
639	return true;
640	}
641
642	/**
643	* Retrieves the cache contents, if it exists
644	*
645	* The contents will be first attempted to be retrieved by searching by the
646	* key in the cache key. If the cache is hit (success) then the contents
647	* are returned.
648	*
649	* On failure, the number of cache misses will be incremented.
650	*
651	* @param int\|string $key What the contents in the cache are called
652	* @param string $group Where the cache contents are grouped
653	* @param bool $force Not used.
654	* @param bool &$success
655	*
656	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
657	*/
658	public function get( $key, $group = 'default', $force = false, &$success = null ) {
659	$key = $this->_key( $key, $group );
660
661	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
662	$var = $this->_get_np( $key, $success );
663	} else {
664	$var = $this->_get( $key, $success );
665	}
666
667	if ( $success ) {
668	$this->cache_hits ++;
669	} else {
670	$this->cache_misses ++;
671	}
672
673	return $var;
674	}
675
676	/**
677	* Retrieves the APCu cache contents, if it exists
678	*
679	* @param string $key What the contents in the cache are called
680	* @param bool &$success
681	*
682	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
683	*/
684	private function _get( $key, &$success = null ) {
685	if ( WP_APCU_LOCAL_CACHE && array_key_exists( $key, $this->local_cache )
686	) {
687	$success = true;
688	$var = $this->local_cache[ $key ];
689	} else {
690	$var = apcu_fetch( $key, $success );
691	if ( $success && WP_APCU_LOCAL_CACHE ) {
692	$this->local_cache[ $key ] = $var;
693	}
694	}
695
696	if ( is_object( $var ) ) {
697	$var = clone $var;
698	}
699
700	return $var;
701	}
702
703	/**
704	* Retrieves the non persistent cache contents, if it exists
705	*
706	* @param string $key What the contents in the cache are called
707	* @param bool &$success
708	*
709	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
710	*/
711	private function _get_np( $key, &$success = null ) {
712	if ( array_key_exists( $key, $this->non_persistent_cache ) ) {
713	$success = true;
714
715	return $this->non_persistent_cache[ $key ];
716	}
717
718	$success = false;
719
720	return false;
721	}
722
723	/**
724	* Get the cache version of a given key
725	*
726	* @param string $key
727	*
728	* @return int cache version
729	*/
730	private function _get_cache_version( $key ) {
731	if ( $this->apcu_available ) {
732	$version = (int) apcu_fetch( $key );
733	} elseif ( array_key_exists( $key, $this->non_persistent_cache ) ) {
734	$version = (int) $this->non_persistent_cache[ $key ];
735	} else {
736	$version = 0;
737	}
738
739	return $version;
740	}
741
742	/**
743	* Build cache version key
744	*
745	* @param string $type Type of key, for site or group
746	* @param mixed $value the group or site id
747	*
748	* @return string The key
749	*/
750	private function _get_cache_version_key( $type, $value ) {
751	return WP_APCU_KEY_SALT . ':' . $this->abspath . ':' . $type . ':' . $value;
752	}
753
754	/**
755	* Get the groups cache version
756	*
757	* @param string $group The group to get version for
758	*
759	* @return int The group cache version
760	*/
761	private function _get_group_cache_version( $group ) {
762	if ( ! isset( $this->group_versions[ $group ] ) ) {
763	$this->group_versions[ $group ] = $this->_get_cache_version(
764	$this->_get_cache_version_key(
765	'GroupVersion',
766	$group
767	)
768	);
769	}
770
771	return $this->group_versions[ $group ];
772	}
773
774	/**
775	* Retrieve multiple values from cache.
776	*
777	* Gets multiple values from cache, including across multiple groups
778	*
779	* Usage: array( 'group0' => array( 'key0', 'key1', 'key2', ), 'group1' => array( 'key0' ) )
780	*
781	* @param array $groups Array of groups and keys to retrieve
782	*
783	* @return array\|bool Array of cached values as
784	* array( 'group0' => array( 'key0' => 'value0', 'key1' => 'value1', 'key2' => 'value2', ) )
785	* Non-existent keys are not returned.
786	*/
787	public function get_multi( $groups ) {
788	if ( empty( $groups ) \|\| ! is_array( $groups ) ) {
789	return false;
790	}
791
792	$vars = [];
793	$success = false;
794
795	foreach ( $groups as $group => $keys ) {
796	$vars[ $group ] = [];
797
798	foreach ( $keys as $key ) {
799	$var = $this->get( $key, $group, false, $success );
800
801	if ( $success ) {
802	$vars[ $group ][ $key ] = $var;
803	}
804	}
805	}
806
807	return $vars;
808	}
809
810	/**
811	* Get the sites cache version
812	*
813	* @param int $site The site to get version for
814	*
815	* @return int The site cache version
816	*/
817	private function _get_site_cache_version( $site ) {
818	if ( ! isset( $this->site_versions[ $site ] ) ) {
819	$this->site_versions[ $site ] = $this->_get_cache_version(
820	$this->_get_cache_version_key(
821	'SiteVersion',
822	$site
823	)
824	);
825	}
826
827	return $this->site_versions[ $site ];
828	}
829
830	/**
831	* Increment numeric cache item's value
832	*
833	* @param int\|string $key The cache key to increment
834	* @param int $offset The amount by which to increment the item's value. Default is 1.
835	* @param string $group The group the key is in.
836	*
837	* @return false\|int False on failure, the item's new value on success.
838	*/
839	public function incr( $key, $offset = 1, $group = 'default' ) {
840	$key = $this->_key( $key, $group );
841
842	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
843	return $this->_incr_np( $key, $offset );
844	}
845
846	return $this->_incr( $key, $offset );
847	}
848
849	/**
850	* Increment numeric APCu cache item's value
851	*
852	* @param string $key The cache key to increment
853	* @param int $offset The amount by which to increment the item's value. Default is 1.
854	*
855	* @return false\|int False on failure, the item's new value on success.
856	*/
857	private function _incr( $key, $offset ) {
858	$this->_get( $key, $success );
859	if ( ! $success ) {
860	return false;
861	}
862
863	$value = apcu_inc( $key, max( (int) $offset, 0 ) );
864	if ( $value !== false && WP_APCU_LOCAL_CACHE ) {
865	$this->local_cache[ $key ] = $value;
866	}
867
868	return $value;
869	}
870
871	/**
872	* Increment numeric non persistent cache item's value
873	*
874	* @param string $key The cache key to increment
875	* @param int $offset The amount by which to increment the item's value. Default is 1.
876	*
877	* @return false\|int False on failure, the item's new value on success.
878	*/
879	private function _incr_np( $key, $offset ) {
880	if ( ! $this->_exists_np( $key ) ) {
881	return false;
882	}
883
884	$offset = max( (int) $offset, 0 );
885	$var = $this->_get_np( $key );
886	$var = is_numeric( $var ) ? $var : 0;
887	$var += $offset;
888
889	return $this->_set_np( $key, $var );
890	}
891
892	/**
893	* Checks if the given group is a non persistent group
894	*
895	* @param string $group The group to be checked
896	*
897	* @return bool True if the group is a non persistent group else false
898	*/
899	private function _is_non_persistent_group( $group ) {
900	return isset( $this->non_persistent_groups[ $group ] );
901	}
902
903	/**
904	* Works out a cache key based on a given key and group
905	*
906	* @param int\|string $key The key
907	* @param string $group The group
908	*
909	* @return string Returns the calculated cache key
910	*/
911	private function _key( $key, $group ) {
912	if ( empty( $group ) ) {
913	$group = 'default';
914	}
915
916	$prefix = 0;
917
918	if ( ! isset( $this->global_groups[ $group ] ) ) {
919	$prefix = $this->blog_prefix;
920	}
921
922	$group_version = $this->_get_group_cache_version( $group );
923	$site_version = $this->_get_site_cache_version( $prefix );
924
925	return WP_APCU_KEY_SALT . ':' . $this->abspath . ':' . $prefix . ':' . $group . ':' . $key . ':v' . $site_version . '.' . $group_version;
926	}
927
928	/**
929	* Replace the contents in the cache, if contents already exist
930	*
931	* @param int\|string $key What to call the contents in the cache
932	* @param mixed $var The contents to store in the cache
933	* @param string $group Where to group the cache contents
934	* @param int $ttl When to expire the cache contents
935	*
936	* @return bool False if not exists, true if contents were replaced
937	*/
938	public function replace( $key, $var, $group = 'default', $ttl = 0 ) {
939	$key = $this->_key( $key, $group );
940
941	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
942	return $this->_replace_np( $key, $var );
943	}
944
945	return $this->_replace( $key, $var, $ttl );
946	}
947
948	/**
949	* Replace the contents in the APCu cache, if contents already exist
950	*
951	* @param string $key What to call the contents in the cache
952	* @param mixed $var The contents to store in the cache
953	* @param int $ttl When to expire the cache contents
954	*
955	* @return bool False if not exists, true if contents were replaced
956	*/
957	private function _replace( $key, $var, $ttl ) {
958	$this->_get( $key, $success );
959	if ( $success ) {
960	return false;
961	}
962
963	return $this->_set( $key, $var, $ttl );
964	}
965
966	/**
967	* Replace the contents in the non persistent cache, if contents already exist
968	*
969	* @param string $key What to call the contents in the cache
970	* @param mixed $var The contents to store in the cache
971	*
972	* @return bool False if not exists, true if contents were replaced
973	*/
974	private function _replace_np( $key, $var ) {
975	if ( ! $this->_exists_np( $key ) ) {
976	return false;
977	}
978
979	return $this->_set_np( $key, $var );
980	}
981
982	/**
983	* Sets the data contents into the cache
984	*
985	* @param int\|string $key What to call the contents in the cache
986	* @param mixed $var The contents to store in the cache
987	* @param string $group Where to group the cache contents
988	* @param int $ttl When the cache data should be expired
989	*
990	* @return bool True if cache set successfully else false
991	*/
992	public function set( $key, $var, $group = 'default', $ttl = 0 ) {
993	$key = $this->_key( $key, $group );
994
995	if ( ! $this->apcu_available \|\| $this->_is_non_persistent_group( $group ) ) {
996	return $this->_set_np( $key, $var );
997	}
998
999	return $this->_set( $key, $var, $ttl );
1000	}
1001
1002	/**
1003	* Sets the data contents into the APCu cache
1004	*
1005	* @param string $key What to call the contents in the cache
1006	* @param mixed $var The contents to store in the cache
1007	* @param int $ttl When the cache data should be expired
1008	*
1009	* @return bool True if cache set successfully else false
1010	*/
1011	private function _set( $key, $var, $ttl ) {
1012	if ( is_object( $var ) ) {
1013	$var = clone $var;
1014	}
1015
1016	if ( apcu_store( $key, $var, max( (int) $ttl, 0 ) ) ) {
1017	if ( WP_APCU_LOCAL_CACHE ) {
1018	$this->local_cache[ $key ] = $var;
1019	}
1020
1021	return true;
1022	}
1023
1024	return false;
1025	}
1026
1027	/**
1028	* Sets the data contents into the non persistent cache
1029	*
1030	* @param string $key What to call the contents in the cache
1031	* @param mixed $var The contents to store in the cache
1032	*
1033	* @return bool True if cache set successfully else false
1034	*/
1035	private function _set_np( $key, $var ) {
1036	if ( is_object( $var ) ) {
1037	$var = clone $var;
1038	}
1039
1040	return $this->non_persistent_cache[ $key ] = $var;
1041	}
1042
1043	/**
1044	* Set the cache version for a given key
1045	*
1046	* @param string $key
1047	* @param int $version
1048	*
1049	* @return mixed
1050	*/
1051	private function _set_cache_version( $key, $version ) {
1052	if ( $this->apcu_available ) {
1053	return apcu_store( $key, $version );
1054	}
1055
1056	return $this->non_persistent_cache[ $key ] = $version;
1057	}
1058
1059	/**
1060	* Set the version for a groups cache
1061	*
1062	* @param string $group
1063	* @param int $version
1064	*/
1065	private function _set_group_cache_version( $group, $version ) {
1066	$this->_set_cache_version( $this->_get_cache_version_key( 'GroupVersion', $group ), $version );
1067	}
1068
1069	/**
1070	* Set the version for a sites cache
1071	*
1072	* @param int $site
1073	* @param int $version
1074	*/
1075	private function _set_site_cache_version( $site, $version ) {
1076	$this->_set_cache_version( $this->_get_cache_version_key( 'SiteVersion', $site ), $version );
1077	}
1078
1079	/**
1080	* Switch the internal blog id.
1081	*
1082	* This changes the blog id used to create keys in blog specific groups.
1083	*
1084	* @param int $blog_id Blog ID
1085	*/
1086	public function switch_to_blog( $blog_id ) {
1087	$this->blog_prefix = $this->multi_site ? $blog_id : 1;
1088	}
1089
1090	/**
1091	* @return string
1092	*/
1093	public function getAbspath() {
1094	return $this->abspath;
1095	}
1096
1097	/**
1098	* @return bool
1099	*/
1100	public function getApcuAvailable() {
1101	return $this->apcu_available;
1102	}
1103
1104	/**
1105	* @return int
1106	*/
1107	public function getBlogPrefix() {
1108	return $this->blog_prefix;
1109	}
1110
1111	/**
1112	* @return int
1113	*/
1114	public function getCacheHits() {
1115	return $this->cache_hits;
1116	}
1117
1118	/**
1119	* @return int
1120	*/
1121	public function getCacheMisses() {
1122	return $this->cache_misses;
1123	}
1124
1125	/**
1126	* @return array
1127	*/
1128	public function getGlobalGroups() {
1129	return $this->global_groups;
1130	}
1131
1132	/**
1133	* @return array
1134	*/
1135	public function getGroupVersions() {
1136	return $this->group_versions;
1137	}
1138
1139	/**
1140	* @return bool
1141	*/
1142	public function getMultiSite() {
1143	return $this->multi_site;
1144	}
1145
1146	/**
1147	* @return array
1148	*/
1149	public function getNonPersistentCache() {
1150	return $this->non_persistent_cache;
1151	}
1152
1153	/**
1154	* @return array
1155	*/
1156	public function getNonPersistentGroups() {
1157	return $this->non_persistent_groups;
1158	}
1159
1160	/**
1161	* @return array
1162	*/
1163	public function getSiteVersions() {
1164	return $this->site_versions;
1165	}
1166	}