404-solution / includes / diagnostics / AjaxFrequentCheckpointWriter.php

AjaxFrequentCheckpointWriter.php in 404 Solution trunk, at includes/diagnostics/AjaxFrequentCheckpointWriter.php

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1	<?php
2
3	if (!defined('ABSPATH')) {
4	exit;
5	}
6
7	/**
8	* Writes lightweight checkpoint records and caches their resolved request path.
9	*
10	* The cache lets callbacks executing inside wpdb reuse the path resolved by
11	* the pre-query probe. Re-entering wp_upload_dir() or WordPress filters from a
12	* query callback can issue nested SQL and recursively dispatch the callback
13	* being measured.
14	*/
15	final class ABJ_404_Solution_AjaxFrequentCheckpointWriter {
16
17	/** @var string */
18	private static $resolvedRequestId = '';
19
20	/** @var string */
21	private static $resolvedDirectory = '';
22
23	/** @var int */
24	private static $checkpointSequence = 0;
25
26	public static function rememberResolvedDirectory(string $requestId, string $directory): void {
27	if ($requestId === '') {
28	return;
29	}
30	self::$resolvedRequestId = $requestId;
31	self::$resolvedDirectory = $directory;
32	}
33
34	public static function resolvedDirectoryForRequest(string $requestId): string {
35	return $requestId !== '' && $requestId === self::$resolvedRequestId
36	? self::$resolvedDirectory
37	: '';
38	}
39
40	/**
41	* Whether directory resolution already ran for this request.
42	*
43	* Kept separate from resolvedDirectoryForRequest() because an empty
44	* directory is a valid cached failure. Re-running WordPress filters after
45	* that failure can recurse into the same database boundary being traced.
46	*/
47	public static function hasResolvedDirectoryForRequest(string $requestId): bool {
48	return $requestId !== '' && $requestId === self::$resolvedRequestId;
49	}
50
51	public static function resetForTests(): void {
52	self::$resolvedRequestId = '';
53	self::$resolvedDirectory = '';
54	self::$checkpointSequence = 0;
55	}
56
57	/**
58	* @param array<string, mixed> $fields
59	*/
60	public static function append(
61	string $requestId,
62	string $event,
63	array $fields,
64	string $directory,
65	bool $directoryWasResolved,
66	string $checkpointId = ''
67	): void {
68	if ($checkpointId === '') {
69	$checkpointId = self::checkpointId();
70	ABJ_404_Solution_CheckpointIntentStore::append(
71	ABJ_404_Solution_CheckpointRecordFactory::intent(array(
72	'request_id' => $requestId,
73	'event' => $event,
74	'checkpoint_id' => $checkpointId,
75	'hrtime_ns' => function_exists('hrtime') ? (int)hrtime(true) : null,
76	'pid' => ABJ_404_Solution_PhpRuntimeCapabilityAdapter::processId(),
77	))
78	);
79	}
80	if ($directory === '') {
81	return;
82	}
83	if (!$directoryWasResolved
84	&& (!class_exists('ABJ_404_Solution_FileSystemService')
85	\|\| !ABJ_404_Solution_FileSystemService::createDirectoryWithErrorMessages($directory))) {
86	return;
87	}
88	ABJ_404_Solution_CheckpointJournalWriter::append($directory, array_merge(
89	$fields,
90	ABJ_404_Solution_CheckpointRecordFactory::frequent(array(
91	'ts' => self::nowFloat(),
92	'hrtime_ns' => function_exists('hrtime') ? (int)hrtime(true) : null,
93	'request_id' => $requestId,
94	'event' => $event,
95	'checkpoint_id' => $checkpointId,
96	'pid' => ABJ_404_Solution_PhpRuntimeCapabilityAdapter::processId(),
97	))
98	));
99	}
100
101	private static function checkpointId(): string {
102	self::$checkpointSequence++;
103	$startedNs = function_exists('hrtime') ? (int)hrtime(true) : 0;
104	return self::alphabeticHex(
105	ABJ_404_Solution_PhpRuntimeCapabilityAdapter::processNumericToken()
106	) . '-'
107	. self::alphabeticHex($startedNs) . '-f'
108	. self::alphabeticHex(self::$checkpointSequence);
109	}
110
111	private static function alphabeticHex(int $value): string {
112	return strtr(dechex($value), '0123456789abcdef', 'ghijklmnopqrstuv');
113	}
114
115	private static function nowFloat(): ?float {
116	if (function_exists('abj_clock')) {
117	return abj_clock()->nowFloat();
118	}
119	if (class_exists('ABJ_404_Solution_SystemClock')) {
120	return (new ABJ_404_Solution_SystemClock())->nowFloat();
121	}
122	return null;
123	}
124	}
125