| 1 | <?php |
| 2 | /* |
| 3 | +--------------------------------------------------------------------+ |
| 4 | | CiviCRM version 5 | |
| 5 | +--------------------------------------------------------------------+ |
| 6 | | Copyright CiviCRM LLC (c) 2004-2019 | |
| 7 | +--------------------------------------------------------------------+ |
| 8 | | This file is a part of CiviCRM. | |
| 9 | | | |
| 10 | | CiviCRM is free software; you can copy, modify, and distribute it | |
| 11 | | under the terms of the GNU Affero General Public License | |
| 12 | | Version 3, 19 November 2007 and the CiviCRM Licensing Exception. | |
| 13 | | | |
| 14 | | CiviCRM is distributed in the hope that it will be useful, but | |
| 15 | | WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 16 | | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
| 17 | | See the GNU Affero General Public License for more details. | |
| 18 | | | |
| 19 | | You should have received a copy of the GNU Affero General Public | |
| 20 | | License and the CiviCRM Licensing Exception along | |
| 21 | | with this program; if not, contact CiviCRM LLC | |
| 22 | | at info[AT]civicrm[DOT]org. If you have questions about the | |
| 23 | | GNU Affero General Public License or the licensing of CiviCRM, | |
| 24 | | see the CiviCRM license FAQ at http://civicrm.org/licensing | |
| 25 | +--------------------------------------------------------------------+ |
| 26 | */ |
| 27 | |
| 28 | namespace Civi\Core\Event; |
| 29 | |
| 30 | /** |
| 31 | * Class GenericHookEvent |
| 32 | * @package Civi\API\Event |
| 33 | * |
| 34 | * The GenericHookEvent is used to expose all traditional hooks to the |
| 35 | * Symfony EventDispatcher. |
| 36 | * |
| 37 | * The traditional notation for a hook is based on a function signature: |
| 38 | * |
| 39 | * function hook_civicrm_foo($bar, &$whiz, &$bang); |
| 40 | * |
| 41 | * The notation for Symfony Events is based on a class with properties |
| 42 | * and methods. This requires some kind of mapping. `GenericHookEvent` |
| 43 | * maps each parameter to a field (using magic methods): |
| 44 | * |
| 45 | * @code |
| 46 | * // Creating an event object. |
| 47 | * $event = GenericHookEvent::create(array( |
| 48 | * 'bar' => 'abc', |
| 49 | * 'whiz' => &$whiz, |
| 50 | * 'bang' => &$bang, |
| 51 | * ); |
| 52 | * |
| 53 | * // Accessing event properties. |
| 54 | * echo $event->bar; |
| 55 | * $event->whiz['array_field'] = 123; |
| 56 | * $event->bang->objProperty = 'abcd'; |
| 57 | * |
| 58 | * // Dispatching an event. |
| 59 | * Civi::service('dispatcher')->dispatch('hook_civicrm_foo', $event); |
| 60 | * @endCode |
| 61 | * |
| 62 | * Design Discussion: |
| 63 | * |
| 64 | * 1. Implementing new event classes for every hook would produce a |
| 65 | * large amount of boilerplate. Symfony Events have an interesting solution to |
| 66 | * that problem: use `GenericEvent` instead of custom event classes. |
| 67 | * `GenericHookEvent` is conceptually similar to `GenericEvent`, but it adds |
| 68 | * support for (a) altering properties and (b) mapping properties to hook notation |
| 69 | * (an ordered parameter list). |
| 70 | * |
| 71 | * 2. A handful of hooks define a return-value. The return-value is treated |
| 72 | * as an array, and all the returned values are merged into one big array. |
| 73 | * You can add and retrieve return-values using these methods: |
| 74 | * |
| 75 | * @code |
| 76 | * $event->addReturnValues(array(...)); |
| 77 | * foreach ($event->getReturnValues() as $retVal) { ... } |
| 78 | * @endCode |
| 79 | */ |
| 80 | class GenericHookEvent extends \Symfony\Component\EventDispatcher\Event { |
| 81 | |
| 82 | /** |
| 83 | * @var array |
| 84 | * Ex: array(0 => &$contactID, 1 => &$contentPlacement). |
| 85 | */ |
| 86 | protected $hookValues; |
| 87 | |
| 88 | /** |
| 89 | * @var array |
| 90 | * Ex: array(0 => 'contactID', 1 => 'contentPlacement'). |
| 91 | */ |
| 92 | protected $hookFields; |
| 93 | |
| 94 | /** |
| 95 | * @var array |
| 96 | * Ex: array('contactID' => 0, 'contentPlacement' => 1). |
| 97 | */ |
| 98 | protected $hookFieldsFlip; |
| 99 | |
| 100 | /** |
| 101 | * Some legacy hooks expect listener-functions to return a value. |
| 102 | * OOP listeners may set the $returnValue. |
| 103 | * |
| 104 | * This field is not recommended for use in new hooks. The return-value |
| 105 | * convention is not portable across different implementations of the hook |
| 106 | * system. Instead, it's more portable to provide an alterable, named field. |
| 107 | * |
| 108 | * @var mixed |
| 109 | * @deprecated |
| 110 | */ |
| 111 | private $returnValues = []; |
| 112 | |
| 113 | /** |
| 114 | * List of field names that are prohibited due to conflicts |
| 115 | * in the class-hierarchy. |
| 116 | * |
| 117 | * @var array |
| 118 | */ |
| 119 | private static $BLACKLIST = [ |
| 120 | 'name', |
| 121 | 'dispatcher', |
| 122 | 'propagationStopped', |
| 123 | 'hookBlacklist', |
| 124 | 'hookValues', |
| 125 | 'hookFields', |
| 126 | 'hookFieldsFlip', |
| 127 | ]; |
| 128 | |
| 129 | /** |
| 130 | * Create a GenericHookEvent using key-value pairs. |
| 131 | * |
| 132 | * @param array $params |
| 133 | * Ex: array('contactID' => &$contactID, 'contentPlacement' => &$contentPlacement). |
| 134 | * @return \Civi\Core\Event\GenericHookEvent |
| 135 | */ |
| 136 | public static function create($params) { |
| 137 | $e = new static(); |
| 138 | $e->hookValues = array_values($params); |
| 139 | $e->hookFields = array_keys($params); |
| 140 | $e->hookFieldsFlip = array_flip($e->hookFields); |
| 141 | self::assertValidHookFields($e->hookFields); |
| 142 | return $e; |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Create a GenericHookEvent using ordered parameters. |
| 147 | * |
| 148 | * @param array $hookFields |
| 149 | * Ex: array(0 => 'contactID', 1 => 'contentPlacement'). |
| 150 | * @param array $hookValues |
| 151 | * Ex: array(0 => &$contactID, 1 => &$contentPlacement). |
| 152 | * @return \Civi\Core\Event\GenericHookEvent |
| 153 | */ |
| 154 | public static function createOrdered($hookFields, $hookValues) { |
| 155 | $e = new static(); |
| 156 | if (count($hookValues) > count($hookFields)) { |
| 157 | $hookValues = array_slice($hookValues, 0, count($hookFields)); |
| 158 | } |
| 159 | $e->hookValues = $hookValues; |
| 160 | $e->hookFields = $hookFields; |
| 161 | $e->hookFieldsFlip = array_flip($e->hookFields); |
| 162 | self::assertValidHookFields($e->hookFields); |
| 163 | return $e; |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * @param array $fields |
| 168 | * List of field names. |
| 169 | */ |
| 170 | private static function assertValidHookFields($fields) { |
| 171 | $bad = array_intersect($fields, self::$BLACKLIST); |
| 172 | if ($bad) { |
| 173 | throw new \RuntimeException("Hook relies on conflicted field names: " |
| 174 | . implode(', ', $bad)); |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * @return array |
| 180 | * Ex: array(0 => &$contactID, 1 => &$contentPlacement). |
| 181 | */ |
| 182 | public function getHookValues() { |
| 183 | return $this->hookValues; |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * @return mixed |
| 188 | * @deprecated |
| 189 | */ |
| 190 | public function getReturnValues() { |
| 191 | return empty($this->returnValues) ? TRUE : $this->returnValues; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * @param mixed $fResult |
| 196 | * @return GenericHookEvent |
| 197 | * @deprecated |
| 198 | */ |
| 199 | public function addReturnValues($fResult) { |
| 200 | if (!empty($fResult) && is_array($fResult)) { |
| 201 | $this->returnValues = array_merge($this->returnValues, $fResult); |
| 202 | } |
| 203 | return $this; |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * @inheritDoc |
| 208 | */ |
| 209 | public function &__get($name) { |
| 210 | if (isset($this->hookFieldsFlip[$name])) { |
| 211 | return $this->hookValues[$this->hookFieldsFlip[$name]]; |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * @inheritDoc |
| 217 | */ |
| 218 | public function __set($name, $value) { |
| 219 | if (isset($this->hookFieldsFlip[$name])) { |
| 220 | $this->hookValues[$this->hookFieldsFlip[$name]] = $value; |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | /** |
| 225 | * @inheritDoc |
| 226 | */ |
| 227 | public function __isset($name) { |
| 228 | return isset($this->hookFieldsFlip[$name]) |
| 229 | && isset($this->hookValues[$this->hookFieldsFlip[$name]]); |
| 230 | } |
| 231 | |
| 232 | /** |
| 233 | * @inheritDoc |
| 234 | */ |
| 235 | public function __unset($name) { |
| 236 | if (isset($this->hookFieldsFlip[$name])) { |
| 237 | // Unset while preserving order. |
| 238 | $this->hookValues[$this->hookFieldsFlip[$name]] = NULL; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | /** |
| 243 | * Determine whether the hook supports the given field. |
| 244 | * |
| 245 | * The field may or may not be empty. Use isset() or empty() to |
| 246 | * check that. |
| 247 | * |
| 248 | * @param string $name |
| 249 | * @return bool |
| 250 | */ |
| 251 | public function hasField($name) { |
| 252 | return isset($this->hookFieldsFlip[$name]); |
| 253 | } |
| 254 | |
| 255 | } |