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b90e57be TO |
1 | <?php |
2 | ||
3 | namespace Civi\Core\Event; | |
4 | ||
5 | /** | |
6 | * The `EventScanner` is a utility for scanning a class to see if it has any event-listeners. It may check | |
7 | * for common interfaces and conventions. Example: | |
8 | * | |
9 | * ``` | |
10 | * $map = EventScanner::findListeners($someObject); | |
11 | * $dispatcher->addListenerMap($someObject, $map); | |
12 | * ``` | |
13 | */ | |
14 | class EventScanner { | |
15 | ||
16 | /** | |
17 | * In-memory cache of the listener-maps found on various classes. | |
18 | * | |
19 | * This cache is a little unusual -- it is geared toward improving unit-tests. Bear in mind: | |
20 | * | |
21 | * - The `EventScanner` is fundamentally scanning class-structure. | |
22 | * - Within a given PHP process, the class-structure cannot change. Therefore, the cached view in `static::$listenerMaps` cannot be stale. | |
23 | * - There are three kinds of PHP processes: | |
24 | * 1. System-flushes -- During this operation, we rebuild the `Container`. This may do some scanning, and the results will be recorded in `Container`. | |
25 | * 2. Ordinary page-loads -- We use the `Container` cache. It shouldn't need any more scans. | |
26 | * 3. Headless unit-tests -- For these, we must frequently tear-down and rebuild a fresh `Container`, often with varying decisions about | |
27 | * which extensions/services/classes to activate. The container-cache does not operate. | |
28 | * | |
29 | * Here's how `$listenerMaps` plays out in each: | |
30 | * | |
31 | * 1. The `$listenerMaps` is not needed or used. | |
32 | * 2. The `$listenerMaps` (and `EventScanner` generally) is not needed or used. | |
33 | * 3. The `$listenerMaps` is used frequently, preventing redundant scanning. | |
34 | * | |
35 | * A more common approach would be to use `Civi::$statics` or `Civi::cache()`. These would be inappropriate because we want the data to be | |
36 | * preserved across multiple test-runs -- and because the underlying data (PHP class-structure) does not change within a unit-test. | |
37 | * | |
38 | * @var array | |
39 | * Ex: ['api_v3_SyntaxConformanceTest' => [...listener-names...]] | |
40 | */ | |
41 | private static $listenerMaps = []; | |
42 | ||
43 | /** | |
44 | * Scan an object or class for event listeners. | |
45 | * | |
46 | * Note: This requires scanning. Consequently, it should not be run in bulk on a regular (runtime) basis. Instead, store | |
47 | * the listener-maps in a cache (e.g. `Container`). | |
48 | * | |
49 | * @param string|object $target | |
50 | * The object/class which will receive the notifications. | |
51 | * Use a string (class-name) if the listeners are static methods. | |
52 | * Use an object-instance if the listeners are regular methods. | |
53 | * @param string|null $self | |
54 | * If the target $class is focused on a specific entity/form/etc, use the `$self` parameter to specify it. | |
55 | * This will activate support for `self_{$event}` methods. | |
42f0bf16 | 56 | * Ex: if '$self' is 'Contact', then 'function self_hook_civicrm_pre()' maps to 'on_hook_civicrm_pre::Contact'. |
b90e57be TO |
57 | * @return array |
58 | * List of events/listeners. Format is compatible with 'getSubscribedEvents()'. | |
59 | * Ex: ['some.event' => [['firstFunc'], ['secondFunc']] | |
60 | */ | |
60a1dbc1 | 61 | public static function findListeners($target, $self = NULL): array { |
b90e57be TO |
62 | $class = is_object($target) ? get_class($target) : $target; |
63 | $key = "$class::" . ($self ?: ''); | |
64 | if (isset(self::$listenerMaps[$key])) { | |
65 | return self::$listenerMaps[$key]; | |
66 | } | |
67 | ||
68 | $listenerMap = []; | |
ee44263e | 69 | // These 2 interfaces do the same thing; one is meant for unit tests and the other for runtime code |
d5f5cc4c | 70 | if (is_subclass_of($class, '\Civi\Core\HookInterface')) { |
b90e57be TO |
71 | $listenerMap = static::mergeListenerMap($listenerMap, static::findFunctionListeners($class, $self)); |
72 | } | |
73 | if (is_subclass_of($class, '\Symfony\Component\EventDispatcher\EventSubscriberInterface')) { | |
74 | $listenerMap = static::mergeListenerMap($listenerMap, static::normalizeListenerMap($class::getSubscribedEvents())); | |
75 | } | |
76 | ||
77 | if (CIVICRM_UF === 'UnitTests') { | |
78 | self::$listenerMaps[$key] = $listenerMap; | |
79 | } | |
80 | return $listenerMap; | |
81 | } | |
82 | ||
83 | /** | |
84 | * @param string $class | |
85 | * @param string|null $self | |
86 | * If the target $class is focused on a specific entity/form/etc, use the `$self` parameter to specify it. | |
87 | * This will activate support for `self_{$event}` methods. | |
88 | * Ex: if '$self' is 'Contact', then 'function self_hook_civicrm_pre()' maps to 'hook_civicrm_pre::Contact'. | |
60a1dbc1 | 89 | * @return array |
b90e57be | 90 | */ |
60a1dbc1 | 91 | protected static function findFunctionListeners(string $class, $self = NULL): array { |
b90e57be TO |
92 | $listenerMap = []; |
93 | ||
94 | /** | |
95 | * @param string $underscore | |
96 | * Ex: 'civi_foo_bar', 'hook_civicrm_foo' | |
97 | * @return string | |
98 | * Ex: 'civi.foo.bar', 'hook_civicrm_foo' | |
99 | */ | |
100 | $toEventName = function ($underscore) { | |
101 | if (substr($underscore, 0, 5) === 'hook_') { | |
102 | return $underscore; | |
103 | } | |
104 | else { | |
105 | return str_replace('_', '.', $underscore); | |
106 | } | |
107 | }; | |
108 | ||
109 | $addListener = function ($event, $func, $priority = 0) use (&$listenerMap) { | |
110 | $listenerMap[$event][] = [$func, $priority]; | |
111 | }; | |
112 | ||
113 | foreach (get_class_methods($class) as $func) { | |
114 | if (preg_match('/^(hook_|on_|self_)/', $func, $m)) { | |
115 | switch ($m[1]) { | |
116 | case 'hook_': | |
117 | $addListener('&' . $func, $func); | |
118 | break; | |
119 | ||
120 | case 'on_': | |
121 | $addListener($toEventName(substr($func, 3)), $func); | |
122 | break; | |
123 | ||
124 | case 'self_': | |
125 | if ($self === NULL) { | |
126 | throw new \RuntimeException("Cannot add self_*() listeners for $class"); | |
127 | } | |
128 | $addListener($toEventName(substr($func, 5)) . '::' . $self, $func); | |
129 | break; | |
130 | } | |
131 | } | |
132 | } | |
133 | ||
134 | return $listenerMap; | |
135 | } | |
136 | ||
137 | /** | |
138 | * Convert the listeners to a standard flavor. | |
139 | * | |
60a1dbc1 | 140 | * @param iterable $listenerMap |
b90e57be TO |
141 | * List of events/listeners. Listeners may be given in singular or plural form. |
142 | * Ex: ['some.event' => 'oneListener'] | |
143 | * Ex: ['some.event' => ['oneListener', 100]] | |
144 | * Ex: ['some.event' => [['firstListener', 100], ['secondListener']]] | |
145 | * @return array | |
146 | * List of events/listeners. All listeners are described in plural form. | |
147 | * Ex: ['some.event' => [['firstListener', 100], ['secondListener']]] | |
148 | */ | |
60a1dbc1 | 149 | protected static function normalizeListenerMap(iterable $listenerMap): array { |
b90e57be TO |
150 | $r = []; |
151 | foreach ($listenerMap as $eventName => $params) { | |
152 | $r[$eventName] = []; | |
153 | if (\is_string($params)) { | |
154 | $r[$eventName][] = [$params]; | |
155 | } | |
156 | elseif (\is_string($params[0])) { | |
157 | $r[$eventName][] = $params; | |
158 | } | |
159 | else { | |
160 | $r[$eventName] = array_merge($r[$eventName], $params); | |
161 | } | |
162 | } | |
163 | return $r; | |
164 | } | |
165 | ||
60a1dbc1 | 166 | protected static function mergeListenerMap(array $left, array $right): array { |
b90e57be TO |
167 | if ($left === []) { |
168 | return $right; | |
169 | } | |
170 | foreach ($right as $eventName => $listeners) { | |
171 | $left[$eventName] = array_merge($left[$eventName] ?? [], $listeners); | |
172 | } | |
173 | return $left; | |
174 | } | |
175 | ||
176 | } |