404-solution / includes / view-build / ViewCacheInvalidator.php

ViewCacheInvalidator.php in 404 Solution trunk, at includes/view-build/ViewCacheInvalidator.php

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1	<?php
2
3	if (!defined('ABSPATH')) {
4	exit;
5	}
6
7	/**
8	* Cache invalidation orchestration for admin view queries. Coordinates
9	* status-count cache invalidation, view snapshot invalidation, and regex
10	* cache clearing when redirects mutate.
11	*/
12	class ABJ_404_Solution_ViewCacheInvalidator {
13
14	/** @var ABJ_404_Solution_DatabaseCore */
15	private $dbCore;
16
17	/** @var ABJ_404_Solution_RedirectsRepository */
18	private $redirectsRepo;
19
20	/** @var string */
21	private $viewDoneFreshnessOptionName;
22
23	/**
24	* @param ABJ_404_Solution_DatabaseCore $dbCore
25	* @param ABJ_404_Solution_RedirectsRepository $redirectsRepo
26	* @param string $viewDoneFreshnessOptionName
27	*/
28	public function __construct(
29	ABJ_404_Solution_DatabaseCore $dbCore,
30	ABJ_404_Solution_RedirectsRepository $redirectsRepo,
31	string $viewDoneFreshnessOptionName
32	) {
33	$this->dbCore = $dbCore;
34	$this->redirectsRepo = $redirectsRepo;
35	$this->viewDoneFreshnessOptionName = $viewDoneFreshnessOptionName;
36	}
37
38	/** @return void */
39	public function setSqlBigSelects(): void {
40	$ignoreErrorsOptions = array('log_errors' => false);
41	$this->dbCore->queryAndGetResults("set session max_join_size = 18446744073709551615",
42	$ignoreErrorsOptions);
43	$this->dbCore->queryAndGetResults("set session sql_big_selects = 1", $ignoreErrorsOptions);
44	}
45
46	/**
47	* Open/close the bulk-mutation window.
48	*
49	* @template T
50	* @param callable():T $work
51	* @return T
52	*/
53	public function runWithDeferredInvalidation(callable $work) {
54	$prior = ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress;
55	ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress = true;
56	try {
57	return $work();
58	} finally {
59	ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress = $prior;
60	}
61	}
62
63	/**
64	* Invalidate cached status counts.
65	* Call this when redirects are created, updated, or deleted.
66	*
67	* @return void
68	*/
69	public function invalidateStatusCountsCache(): void {
70	if (ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress) {
71	return;
72	}
73	self::markTransientStale(array(
74	'current' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_REDIRECT_STATUS,
75	'last_known' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_REDIRECT_STATUS_LAST_KNOWN,
76	'kind' => 'array',
77	));
78	self::markTransientStale(array(
79	'current' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_CAPTURED_STATUS,
80	'last_known' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_CAPTURED_STATUS_LAST_KNOWN,
81	'kind' => 'array',
82	));
83	self::markTransientStale(array(
84	'current' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_HIGH_IMPACT_CAPTURED,
85	'last_known' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_HIGH_IMPACT_CAPTURED_LAST_KNOWN,
86	'kind' => 'count',
87	));
88	$this->invalidateViewSnapshotCache();
89	}
90
91	/**
92	* Debounced, captured-scoped status-count invalidation for the
93	* high-frequency captured-insert path (report.md Finding 4).
94	*
95	* A captured 404 insert only changes the captured + high-impact counts; it
96	* never changes the redirect (manual/auto/regex) counts, so this leaves the
97	* REDIRECT status-count cache intact (the redirects tab stays warm through a
98	* capture burst). It also collapses a burst into at most one invalidation per
99	* cooldown window, so the SUM(CASE) captured-count aggregate is recomputed at
100	* most once per window instead of cold on every admin load.
101	*
102	* It does NOT clear the view snapshot: the admin table read is live off
103	* wp_abj404_redirects (Denorm Step 3b -- no snapshot result cache), so a new
104	* captured row appears on the next read regardless. The detect-only poll
105	* (Finding 3) reads the same live source, so staleness is still detected.
106	*
107	* Static + pure transient ops: holds no instance state, so the
108	* frontend-capture hot path can call it without a fully-wired invalidator.
109	*
110	* @return void
111	*/
112	public static function invalidateCapturedStatusCountsCacheDebounced(): void {
113	if (ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress) {
114	return;
115	}
116	if (!self::claimCapturedCountInvalidateCooldown()) {
117	return;
118	}
119	self::invalidateCapturedStatusCountsCache();
120	}
121
122	/**
123	* Single-flight claim on the captured-count invalidation cooldown.
124	* Returns true only for the caller that wins the race.
125	*
126	* A plain get_transient()/set_transient() pair is check-then-act: under
127	* a burst of near-simultaneous captured-URL inserts (bot-scanner flood
128	* traffic across parallel PHP-FPM workers -- the exact profile this
129	* debounce exists for), multiple requests can each read an empty
130	* cooldown before any of them writes it, so the "collapse a burst to
131	* one invalidation" guarantee silently fails under real concurrency.
132	* Same TOCTOU shape as Ajax_Php::consumeRateLimit(), fixed the same way:
133	* wp_cache_add() only succeeds in creating the key if it doesn't already
134	* exist, so concurrent callers on a persistent object cache serialize on
135	* that add. Sites without a persistent object cache keep the narrower
136	* pre-existing transient race rather than gain a DB dependency in this
137	* intentionally zero-dependency method (called from the frontend
138	* capture hot path without a wired invalidator instance).
139	*/
140	private static function claimCapturedCountInvalidateCooldown(): bool {
141	$key = ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_CAPTURED_COUNT_INVALIDATE_COOLDOWN;
142	$ttl = ABJ_404_Solution_ViewReadRuntimeState::CAPTURED_COUNT_INVALIDATE_COOLDOWN_SECONDS;
143	if (function_exists('wp_using_ext_object_cache') && wp_using_ext_object_cache()
144	&& function_exists('wp_cache_add')) {
145	return (bool)wp_cache_add($key, 1, 'abj404_view_cache_invalidate', $ttl);
146	}
147	if (get_transient($key)) {
148	return false;
149	}
150	set_transient($key, 1, $ttl);
151	return true;
152	}
153
154	/**
155	* Mark captured-scoped count caches stale without applying a debounce.
156	*/
157	public static function invalidateCapturedStatusCountsCache(): void {
158	if (ABJ_404_Solution_ViewReadRuntimeState::$bulkMutationInProgress) {
159	return;
160	}
161	self::markTransientStale(array(
162	'current' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_CAPTURED_STATUS,
163	'last_known' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_CAPTURED_STATUS_LAST_KNOWN,
164	'kind' => 'array',
165	));
166	self::markTransientStale(array(
167	'current' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_HIGH_IMPACT_CAPTURED,
168	'last_known' => ABJ_404_Solution_ViewReadRuntimeState::CACHE_KEY_HIGH_IMPACT_CAPTURED_LAST_KNOWN,
169	'kind' => 'count',
170	));
171	}
172
173	/**
174	* Preserve a trustworthy current value before expiring its fresh cache key.
175	*
176	* @param array{current:string,last_known:string,kind:'array'\|'count'} $cache
177	*/
178	private static function markTransientStale(array $cache): void {
179	$current = get_transient($cache['current']);
180	$isTrustworthy = ($cache['kind'] === 'array' && is_array($current))
181	\|\| ($cache['kind'] === 'count' && is_numeric($current));
182	if ($isTrustworthy) {
183	// allow-cache-empty: numeric zero is a trustworthy computed count and shaped all-zero status arrays still contain their named keys.
184	set_transient(
185	$cache['last_known'],
186	$cache['kind'] === 'count' ? intval($current) : $current,
187	ABJ_404_Solution_ViewReadRuntimeState::STATUS_LAST_KNOWN_CACHE_TTL
188	);
189	}
190	delete_transient($cache['current']);
191	}
192
193	/**
194	* Expire the view snapshot: mark the built-at freshness marker stale so the
195	* next admin read treats the derived view as out of date.
196	*
197	* Deliberately one delete_option() and nothing else. Through 4.2.x this
198	* also cleared a snapshot RESULT cache -- rows in {prefix}abj404_view_cache
199	* and per-key transients named abj404_view_* -- but denorm Step 3e-B
200	* (5f4fcfb4, shipped in 4.3.1) removed that subsystem: the admin table read
201	* is now live off the abj404_redirects denorm columns, and no code path has
202	* written either store since. The two DELETEs outlived their writers and
203	* ran on every redirect create, update and delete to remove rows nothing
204	* can create, so they were removed rather than bounded:
205	*
206	* - `DELETE FROM {wp_abj404_view_cache} WHERE 1=1` -- a table-wide
207	* destructive statement whose result set is permanently empty.
208	* - `option_name LIKE '_transient_abj404_view_%'` against wp_options --
209	* worse, because the pattern begins with `_`, LIKE's single-character
210	* wildcard, leaving the range optimizer no literal prefix to seek on.
211	* Every row of the site's largest, hottest shared table was read, on
212	* the redirect-mutation path, to delete none of them. (The plugin's
213	* other wp_options sweeps -- Uninstaller, PluginLogicLifecycle,
214	* DatabaseUpgradeDailyMaintenance -- all go through prepare() with
215	* esc_like(); this one never did.)
216	*
217	* Residue on sites that upgraded from a snapshot-cache version is inert:
218	* the view_cache rows are read by nothing and the table is dropped at
219	* uninstall, and the orphaned transients carry their `_transient_timeout_`
220	* companions, so WordPress's own expired-transient collection reaps them.
221	* Physically dropping the vestigial table is the separately-tracked
222	* one-way-door step (i463-C/D), alongside DropStagedViewTables.
223	*
224	* @return void
225	*/
226	public function invalidateViewSnapshotCache(): void {
227	if (function_exists('delete_option')) {
228	delete_option($this->viewDoneFreshnessOptionName);
229	}
230	}
231
232	/**
233	* @return void
234	*/
235	public function clearRegexRedirectsCache(): void {
236	$this->redirectsRepo->clearRegexRedirectsCache();
237	}
238
239	}
240