sqlite-object-cache / includes / class-sqlite-object-cache.php

class-sqlite-object-cache.php in SQLite Object Cache 1.6.0, at includes/class-sqlite-object-cache.php

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1	<?php
2	/**
3	* Main plugin class file.
4	*
5	* @package WordPress Plugin Template/Includes
6	*/
7
8	if ( ! defined( 'ABSPATH' ) ) {
9	exit;
10	}
11
12	/**
13	* Main plugin class.
14	*
15	* Only make one instance of this, please.
16	*/
17	class SQLite_Object_Cache {
18	const CLEAN_EVENT_HOOK = 'sqlite_object_cache_clean';
19
20	/**
21	* Local instance of SQLite_Object_Cache_Admin_API
22	*
23	* @var SQLite_Object_Cache_Admin_API\|null
24	*/
25	public $admin;
26
27	/**
28	* Settings class object
29	*
30	* @var object
31	* @access public
32	* @since 1.0.0
33	*/
34	public $settings;
35
36	/**
37	* The version number.
38	*
39	* @var string
40	* @access public
41	* @since 1.0.0
42	*/
43	public $_version;
44
45	/**
46	* The token.
47	*
48	* @var string
49	* @access public
50	* @since 1.0.0
51	*/
52	public $_token;
53
54	/**
55	* The main plugin file.
56	*
57	* @var string
58	* @access public
59	* @since 1.0.0
60	*/
61	public $file;
62
63	/**
64	* The main plugin directory.
65	*
66	* @var string
67	* @access public
68	* @since 1.0.0
69	*/
70	public $dir;
71
72	/**
73	* The plugin assets directory.
74	*
75	* @var string
76	* @access public
77	* @since 1.0.0
78	*/
79	public $assets_dir;
80
81	/**
82	* The plugin assets URL.
83	*
84	* @var string
85	* @access public
86	* @since 1.0.0
87	*/
88	public $assets_url;
89
90	/**
91	* Suffix for JavaScripts.
92	*
93	* @var string
94	* @access public
95	* @since 1.0.0
96	*/
97	public $script_suffix;
98
99	/**
100	* Path for the drop-in when it is working.
101	* @var string
102	*/
103	public $dropinfiledest;
104
105	/**
106	* Path for the drop-in in the plugin tree.
107	* @var string
108	*/
109	public $dropinfilesource;
110
111	/**
112	* Minimum required sqlite version.
113	*
114	* @var string
115	*/
116	public $minimum_sqlite_version = '3.7.0';
117
118	/**
119	* Constructor function.
120	*
121	* @param string $file File constructor.
122	* @param string $version Plugin version.
123	*/
124	public function __construct( $file = '', $version = '1.6.0' ) {
125	$this->_version = $version;
126	$this->_token = 'sqlite_object_cache';
127
128	// Load plugin environment variables.
129	$this->file = $file;
130	$this->dir =
131	trailingslashit( dirname( trailingslashit( WP_PLUGIN_DIR ) . plugin_basename( $this->file ) ) );
132	$this->assets_dir = trailingslashit( $this->dir . 'assets' );
133	$this->dropinfilesource = $this->assets_dir . 'drop-in/object-cache.php';
134	$this->dropinfiledest = trailingslashit( WP_CONTENT_DIR ) . 'object-cache.php';
135
136	$this->assets_url = esc_url( trailingslashit( plugins_url( '/assets/', $this->file ) ) );
137
138	$this->script_suffix = defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ? '' : '.min';
139
140	register_activation_hook( $this->file, array( $this, 'on_activation' ) );
141	register_deactivation_hook( $this->file, array( $this, 'on_deactivation' ) );
142
143	if ( is_admin() ) {
144	// Load API for generic admin functions.
145	$this->admin = new SQLite_Object_Cache_Admin_API();
146	// Suppress backups
147	new SQLite_Backup_Exclusion();
148
149	add_action( 'admin_notices', function () {
150	$purged = get_site_transient( 'sqlite-object-cache-flush-on-update' );
151	if ( $purged ) {
152	delete_site_transient( 'sqlite-object-cache-flush-on-update' );
153	$message = esc_html( __( 'A software installation or upgrade operation flushed the SQLite Object Cache.', 'sqlite-object-cache' ) )
154	?>
155	<div class="notice notice-info sqlite-object-cache is-dismissible">
156	<p><?php echo $message ?></p>
157	</div>
158	<?php
159	}
160	} );
161	}
162
163	add_action( 'admin_init', array( $this, 'maybe_update_dropin' ) );
164
165	/* Ensure nothing is cached after software upgrades. */
166	add_action( 'upgrader_process_complete', function () {
167	add_action( 'shutdown', function () {
168	wp_cache_flush();
169	set_site_transient( 'sqlite-object-cache-flush-on-update', true, HOUR_IN_SECONDS );
170	}, 999 );
171	wp_cache_flush();
172	}, 0 );
173
174
175	/* handle cron cache cleanup */
176	add_action( self::CLEAN_EVENT_HOOK, array( $this, 'clean_job' ), 10, 0 );
177	if ( ! wp_next_scheduled( self::CLEAN_EVENT_HOOK ) ) {
178	wp_schedule_event( time() + HOUR_IN_SECONDS, 'hourly', self::CLEAN_EVENT_HOOK );
179	}
180	/* Handle probabilistic non-cron cleanup, one request in 2000. */
181	if ( 1 === rand( 1, 2000 ) ) {
182	add_action( 'shutdown', function () {
183	$this->clean_job( 1.25 );
184	}, 999, 0 );
185	}
186	}
187
188	/**
189	* WP_Cron task to clean cache entries.
190	*
191	* @param float $grace_factor Default 1.0
192	*
193	* @return void
194	*/
195	public function clean_job( $grace_factor = 1.0 ) {
196	$option = get_option( $this->_token . '_settings', array() );
197	$target_size = empty ( $option['target_size'] ) ? 16 : $option['target_size'];
198	$target_size = ( 1024 1024 );
199	$threshold_size = (int) ( $target_size * $grace_factor );
200
201	global $wp_object_cache;
202	if ( ! method_exists( $wp_object_cache, 'sqlite_get_size' ) ) {
203	return;
204	}
205	/* Clean up old statistics. Do this even when the cache is not over size. */
206	$retention = empty ( $option['retainmeasurements'] ) ? 24 : $option['retainmeasurements'];
207	$wp_object_cache->sqlite_reset_statistics( $retention * HOUR_IN_SECONDS );
208
209	$current_size = $wp_object_cache->sqlite_get_size();
210	/* Skip this if the current size is small enough. */
211	if ( $current_size <= $threshold_size ) {
212	return;
213	}
214
215	/* Remove expired items (transients mostly). */
216	if ( $wp_object_cache->sqlite_remove_expired() ) {
217	/* If anything was removed, get the size again. */
218	$current_size = $wp_object_cache->sqlite_get_size();
219	}
220
221	/* Skip this if the size is small enough, after removing expired items. */
222	if ( $current_size <= $threshold_size ) {
223	return;
224	}
225
226	/* Delete the least-recently-updated items to get to the target size. */
227	$wp_object_cache->sqlite_delete_old( $target_size, $current_size );
228	}
229
230	/**
231	* Plugin activation hook
232	*
233	* @return void
234	*/
235	public function on_activation() {
236
237	$this->sync_apcu_global_to_option( true );
238	if ( true === $this->has_sqlite() ) {
239	add_action( 'shutdown', array( $this, 'update_dropin' ) );
240	add_action( 'shutdown', array( $this, 'delete_all_transients_from_db' ) );
241	}
242	}
243
244	/**
245	* Determine whether we can use SQLite3.
246	*
247	* @return bool\|string true, or an error message.
248	*/
249	public function has_sqlite() {
250	if ( ! class_exists( 'SQLite3' ) \|\| ! extension_loaded( 'sqlite3' ) ) {
251	return __( 'You cannot use the SQLite Object Cache plugin. Your server does not have php\'s SQLite3 extension installed.', 'sqlite-object-cache' );
252	}
253
254	$sqlite_version = $this->sqlite_get_version();
255	if ( version_compare( $sqlite_version, $this->minimum_sqlite_version ) < 0 ) {
256	return sprintf(
257	/* translators: 1 actual SQLite version. 2 required SQLite version) */
258	__( 'You cannot use the SQLite Object Cache plugin. Your server only offers SQLite3 version %1$s, but at least %2$s is required.', 'sqlite-object-cache' ),
259	$sqlite_version, $this->minimum_sqlite_version );
260	}
261
262	return true;
263	}
264
265	/**
266	* Get the version number for the SQLite extension.
267	*
268	* @return string\|false SQLite's version number.
269	*/
270	public function sqlite_get_version() {
271
272	if ( class_exists( 'SQLite3' ) ) {
273	$version = SQLite3::version();
274
275	return $version['versionString'];
276	}
277
278	return false;
279	}
280
281	/**
282	* Test if we can write in the WP_CONTENT_DIR and modify the `object-cache.php` drop-in
283	*
284	* @return true\|WP_Error
285	* @author Till Krüss
286	*
287	*/
288	public function test_filesystem_writing() {
289	global $wp_filesystem;
290
291	if ( ! $this->initialize_filesystem( '', true ) ) {
292	return new WP_Error( 'fs', __( 'Could not initialize filesystem.', 'sqlite-object-cache' ) );
293	}
294
295	$testfiledest = WP_CONTENT_DIR . '/sqlite-write-test.tmp';
296
297	if ( ! $wp_filesystem->exists( $this->dropinfilesource ) ) {
298	return new WP_Error( 'exists', __( 'Object cache drop-in file doesn’t exist.', 'sqlite-object-cache' ) );
299	}
300
301	if ( $wp_filesystem->exists( $testfiledest ) && ! $wp_filesystem->delete( $testfiledest ) ) {
302	return new WP_Error( 'delete', __( 'Test file exists, but couldn’t be deleted.', 'sqlite-object-cache' ) );
303	}
304
305	if ( ! $wp_filesystem->is_writable( WP_CONTENT_DIR ) ) {
306	return new WP_Error( 'copy', __( 'Content directory is not writable.', 'sqlite-object-cache' ) );
307	}
308
309	if ( ! $wp_filesystem->copy( $this->dropinfilesource, $testfiledest, true, FS_CHMOD_FILE ) ) {
310	return new WP_Error( 'copy', __( 'Failed to copy test file.', 'sqlite-object-cache' ) );
311	}
312
313	if ( ! $wp_filesystem->exists( $testfiledest ) ) {
314	return new WP_Error( 'exists', __( 'Copied test file doesn’t exist.', 'sqlite-object-cache' ) );
315	}
316
317	$meta = get_file_data( $testfiledest, array( 'Version' => 'Version' ) );
318
319	if ( $meta['Version'] !== $this->_version ) {
320	return new WP_Error( 'version', __( 'Couldn’t verify test file contents.', 'sqlite-object-cache' ) );
321	}
322
323	if ( ! $wp_filesystem->delete( $testfiledest ) ) {
324	return new WP_Error( 'delete', __( 'Copied test file couldn’t be deleted.', 'sqlite-object-cache' ) );
325	}
326
327	return true;
328	}
329
330	/**
331	* Initializes the WP filesystem API to be ready for use
332	*
333	* @param string $url The URL to post the form to.
334	* @param bool $silent Whether to ask the user for credentials if necessary or not.
335	*
336	* @return bool
337	* @author Till Krüss
338	*
339	*/
340	public function initialize_filesystem( $url, $silent = false ) {
341	require_once ABSPATH . 'wp-admin/includes/file.php';
342	if ( $silent ) {
343	ob_start();
344	}
345
346	$credentials = request_filesystem_credentials( $url );
347
348	if ( false === $credentials ) {
349	if ( $silent ) {
350	ob_end_clean();
351	}
352
353	return false;
354	}
355
356	if ( ! WP_Filesystem( $credentials ) ) {
357	request_filesystem_credentials( $url );
358
359	if ( $silent ) {
360	ob_end_clean();
361	}
362
363	return false;
364	}
365
366	return true;
367	}
368
369	/**
370	* Calls the drop-in update method if necessary
371	*
372	* @return void
373	* @author Till Krüss
374	*/
375	public function maybe_update_dropin() {
376	if ( defined( 'WP_SQLITE_OBJECT_CACHE_DISABLE_DROPIN_AUTOUPDATE' ) && WP_SQLITE_OBJECT_CACHE_DISABLE_DROPIN_AUTOUPDATE ) {
377	return;
378	}
379
380	$has = $this->has_sqlite();
381	if ( ( true === $has ) && $this->object_cache_dropin_needs_updating() ) {
382	add_action( 'shutdown', array( $this, 'update_dropin' ) );
383	}
384	}
385
386	/**
387	* Checks if the `object-cache.php` drop-in is outdated
388	* @return bool
389	* @author Till Krüss
390	*
391	*/
392	public function object_cache_dropin_needs_updating() {
393	global $wp_object_cache;
394	if ( ! method_exists( $wp_object_cache, 'dropin_get_version' ) ) {
395	return true;
396	}
397	return version_compare( $wp_object_cache->dropin_get_version(), $this->_version, '<' );
398	}
399
400	/**
401	* Updates the `object-cache.php` drop-in
402	*
403	* @return void
404	* @author Till Krüss
405	*/
406	public function update_dropin() {
407	global $wp_filesystem;
408	$has = $this->has_sqlite();
409	if ( true === $has && $this->initialize_filesystem( '', true ) ) {
410
411	$this->delete_sqlite_files();
412	$result = $wp_filesystem->copy( $this->dropinfilesource, $this->dropinfiledest, true, FS_CHMOD_FILE );
413	/**
414	* Fires on cache enable event
415	*
416	* @param bool $result Whether the filesystem event (copy of the `object-cache.php` file) was successful.
417	*
418	* @since 0.1.0
419	*/
420	do_action( 'sqlite_object_cache_update_dropin', $result );
421	}
422	}
423
424	/**
425	* Validates the `object-cache.php` drop-in
426	*
427	* @return bool
428	* @author Till Krüss
429	*/
430	public function validate_object_cache_dropin() {
431	global $wp_object_cache;
432
433	if ( ! method_exists( $wp_object_cache, 'dropin_get_version' ) ) {
434	return false;
435	}
436
437	$dropin = get_plugin_data( $this->dropinfiledest );
438	$plugin = get_plugin_data( $this->dropinfilesource );
439
440	/**
441	* Filters the drop-in validation state
442	*
443	* @param bool $state The validation state of the drop-in.
444	* @param string $dropin The `PluginURI` of the drop-in.
445	* @param string $plugin The `PluginURI` of the plugin.
446	*
447	* @since 2.0.16
448	*/
449	return apply_filters(
450	'sqlite_object_cache_validate_dropin',
451	$dropin['PluginURI'] === $plugin['PluginURI'],
452	$dropin['PluginURI'],
453	$plugin['PluginURI']
454	);
455	}
456
457	/**
458	* Plugin deactivation hook
459	*
460	* @param string $plugin Plugin basename.
461	*
462	* @return void
463	* @author Till Krüss
464	*/
465	public function on_deactivation( $plugin ) {
466
467	wp_cache_flush();
468
469	wp_unschedule_hook( self::CLEAN_EVENT_HOOK );
470	$this->delete_sqlite_files();
471	$this->delete_dropin();
472	$this->delete_all_transients_from_db();
473	}
474
475	private function delete_sqlite_files() {
476	global $wp_filesystem;
477	global $wp_object_cache;
478
479	if ( method_exists( $wp_object_cache, 'sqlite_files' ) ) {
480	if ( $this->initialize_filesystem( '', true ) ) {
481	foreach ( $wp_object_cache->sqlite_files() as $file ) {
482	$wp_filesystem->delete( $file );
483	}
484	}
485	}
486	}
487
488	private function delete_dropin() {
489	global $wp_filesystem;
490	ob_start();
491
492	if ( $this->validate_object_cache_dropin() && $this->initialize_filesystem( '', true ) ) {
493	$wp_filesystem->delete( $this->dropinfiledest );
494	}
495
496	ob_end_clean();
497	}
498
499	/**
500	* Deletes all transients from the database.
501	*
502	* It is necessary to do this when deactivating a persistent object cache
503	* because the transients are kept there, and the ones in the database are
504	* possibly stale.
505	*
506	* This hammers performance. But deactivating a persistent object cache is
507	* not a common operation.
508	*
509	* @global wpdb $wpdb WordPress database abstraction object.
510	*/
511	public function delete_all_transients_from_db() {
512	global $wpdb;
513	if ( ! is_multisite() ) {
514	$this->clear_blog_transients();
515	// Single site stores site transients in the options table.
516	$this->clear_blog_transients( '_site_transient_' );
517	} else {
518	foreach ( get_sites( array( 'number' => 0, 'fields' => 'ids', 'no_found_rows' => true, 'orderby' => false ) ) as $site_id ) {
519	try {
520	switch_to_blog( $site_id );
521	$this->clear_blog_transients();
522	} catch ( Exception $ex ) {
523	/* Avoid crashes on transient clearing */
524	error_log( 'SQLite Object Cache problem clearing transients. Blog ' . $site_id . ':' . $ex->getMessage() );
525	} finally {
526	restore_current_blog();
527	}
528	}
529	// Multisite stores site transients in the sitemeta table.
530	$wpdb->query(
531	$wpdb->prepare(
532	"DELETE FROM {$wpdb->sitemeta} WHERE a.meta_key LIKE %s",
533	$wpdb->esc_like( '_site_transient_' ) . '%'
534	)
535	);
536	}
537	}
538
539	/**
540	* DELETE transients from the current blog's options table.
541	*
542	* @param string $tag _site_transient_ or _transient_, the default.
543	*
544	* @return void
545	*/
546	private function clear_blog_transients( $tag = '_transient_') {
547	global $wpdb;
548	$wpdb->query(
549	$wpdb->prepare(
550	"DELETE FROM {$wpdb->options} WHERE option_name LIKE %s",
551	$wpdb->esc_like( $tag ) . '%'
552	)
553	);
554	}
555
556	/**
557	* @return bool True if APCu support is activated for this plugin.
558	*/
559	public function apcu_is_activated() {
560	return defined( 'WP_SQLITE_OBJECT_CACHE_APCU' ) && WP_SQLITE_OBJECT_CACHE_APCU
561	&& $this->apcu_extension_is_enabled();
562	}
563
564	/**
565	* @return bool True if the APCu extension is loaded and enabled.
566	*/
567	public function apcu_extension_is_enabled() {
568	return function_exists( 'apcu_enabled' ) && apcu_enabled();
569	}
570
571	/**
572	* Make sure WP_SQLITE_OBJECT_CACHE_APCU and $option['use_apcu'] match.
573	*
574	* @param bool $unconditional true if we should always change the option to match WP_SQLITE_OBJECT_CACHE_APCU.
575	*
576	* @return string 'on' or 'off': the current activation state of epcu.
577	*/
578	public function sync_apcu_global_to_option( $unconditional = true ) {
579	global $wp_object_cache;
580	$option = get_option( $this->_token . '_settings', array() );
581	$option_dirty = false;
582	$updated_flag = array_key_exists( 'use_apcu_updated', $option );
583	$use_apcu = array_key_exists( 'use_apcu', $option ) && 'on' === $option['use_apcu'] ? 'on' : 'off';
584	if ( $updated_flag ) {
585	unset ( $option['use_apcu_updated'] );
586	$option_dirty = true;
587	}
588	$target_use_apcu = $this->apcu_is_activated() ? 'on' : 'off';
589	if ( ! $unconditional && $updated_flag ) {
590	$target_use_apcu = $use_apcu;
591	}
592	if ( $target_use_apcu !== $use_apcu ) {
593	$option['use_apcu'] = $target_use_apcu;
594	$option_dirty = true;
595	}
596	if ( $option_dirty ) {
597	if ( method_exists( $wp_object_cache, 'apcu-clear_cache' ) ) {
598	$wp_object_cache->apcu_clear_cache();
599	}
600	update_option( $this->_token . '_settings', $option, true );
601	}
602
603	return $target_use_apcu;
604	}
605
606	}
607