Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php |
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| 34 | class Container implements \ArrayAccess |
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| 35 | { |
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| 36 | private $values = array(); |
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| 37 | private $factories; |
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| 38 | private $protected; |
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| 39 | private $frozen = array(); |
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| 40 | private $raw = array(); |
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| 41 | private $keys = array(); |
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| 42 | |||
| 43 | /** |
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| 44 | * Instantiate the container. |
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| 45 | * |
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| 46 | * Objects and parameters can be passed as argument to the constructor. |
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| 47 | * |
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| 48 | * @param array $values The parameters or objects. |
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| 49 | */ |
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| 50 | public function __construct(array $values = array()) |
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| 51 | { |
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| 52 | $this->factories = new \SplObjectStorage(); |
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| 53 | $this->protected = new \SplObjectStorage(); |
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| 54 | |||
| 55 | foreach ($values as $key => $value) { |
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| 56 | $this->offsetSet($key, $value); |
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| 57 | } |
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| 58 | } |
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| 59 | |||
| 60 | /** |
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| 61 | * Sets a parameter or an object. |
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| 62 | * |
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| 63 | * Objects must be defined as Closures. |
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| 64 | * |
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| 65 | * Allowing any PHP callable leads to difficult to debug problems |
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| 66 | * as function names (strings) are callable (creating a function with |
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| 67 | * the same name as an existing parameter would break your container). |
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| 68 | * |
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| 69 | * @param string $id The unique identifier for the parameter or object |
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| 70 | * @param mixed $value The value of the parameter or a closure to define an object |
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| 71 | * |
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| 72 | * @throws \RuntimeException Prevent override of a frozen service |
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| 73 | */ |
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| 74 | public function offsetSet($id, $value) |
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| 75 | { |
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| 76 | if (isset($this->frozen[$id])) { |
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| 77 | throw new \RuntimeException(sprintf('Cannot override frozen service "%s".', $id)); |
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| 78 | } |
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| 79 | |||
| 80 | $this->values[$id] = $value; |
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| 81 | $this->keys[$id] = true; |
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| 82 | } |
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| 83 | |||
| 84 | /** |
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| 85 | * Gets a parameter or an object. |
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| 86 | * |
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| 87 | * @param string $id The unique identifier for the parameter or object |
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| 88 | * |
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| 89 | * @return mixed The value of the parameter or an object |
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| 90 | * |
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| 91 | * @throws \InvalidArgumentException if the identifier is not defined |
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| 92 | */ |
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| 93 | public function offsetGet($id) |
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| 94 | { |
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| 95 | if (!isset($this->keys[$id])) { |
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| 96 | throw new \InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id)); |
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| 97 | } |
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| 98 | |||
| 99 | if ( |
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| 100 | isset($this->raw[$id]) |
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| 101 | || !is_object($this->values[$id]) |
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| 102 | || isset($this->protected[$this->values[$id]]) |
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| 103 | || !method_exists($this->values[$id], '__invoke') |
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| 104 | ) { |
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| 105 | return $this->values[$id]; |
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| 106 | } |
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| 107 | |||
| 108 | if (isset($this->factories[$this->values[$id]])) { |
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| 109 | return $this->values[$id]($this); |
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| 110 | } |
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| 111 | |||
| 112 | $raw = $this->values[$id]; |
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| 113 | $val = $this->values[$id] = $raw($this); |
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| 114 | $this->raw[$id] = $raw; |
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| 115 | |||
| 116 | $this->frozen[$id] = true; |
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| 117 | |||
| 118 | return $val; |
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| 119 | } |
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| 120 | |||
| 121 | /** |
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| 122 | * Checks if a parameter or an object is set. |
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| 123 | * |
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| 124 | * @param string $id The unique identifier for the parameter or object |
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| 125 | * |
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| 126 | * @return bool |
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| 127 | */ |
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| 128 | public function offsetExists($id) |
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| 129 | { |
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| 130 | return isset($this->keys[$id]); |
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| 131 | } |
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| 132 | |||
| 133 | /** |
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| 134 | * Unsets a parameter or an object. |
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| 135 | * |
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| 136 | * @param string $id The unique identifier for the parameter or object |
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| 137 | */ |
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| 138 | public function offsetUnset($id) |
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| 139 | { |
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| 140 | if (isset($this->keys[$id])) { |
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| 141 | if (is_object($this->values[$id])) { |
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| 142 | unset($this->factories[$this->values[$id]], $this->protected[$this->values[$id]]); |
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| 143 | } |
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| 144 | |||
| 145 | unset($this->values[$id], $this->frozen[$id], $this->raw[$id], $this->keys[$id]); |
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| 146 | } |
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| 147 | } |
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| 148 | |||
| 149 | /** |
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| 150 | * Marks a callable as being a factory service. |
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| 151 | * |
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| 152 | * @param callable $callable A service definition to be used as a factory |
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| 153 | * |
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| 154 | * @return callable The passed callable |
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| 155 | * |
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| 156 | * @throws \InvalidArgumentException Service definition has to be a closure of an invokable object |
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| 157 | */ |
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| 158 | public function factory($callable) |
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| 159 | { |
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| 160 | if (!method_exists($callable, '__invoke')) { |
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| 161 | throw new \InvalidArgumentException('Service definition is not a Closure or invokable object.'); |
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| 162 | } |
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| 163 | |||
| 164 | $this->factories->attach($callable); |
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| 165 | |||
| 166 | return $callable; |
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| 167 | } |
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| 168 | |||
| 169 | /** |
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| 170 | * Protects a callable from being interpreted as a service. |
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| 171 | * |
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| 172 | * This is useful when you want to store a callable as a parameter. |
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| 173 | * |
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| 174 | * @param callable $callable A callable to protect from being evaluated |
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| 175 | * |
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| 176 | * @return callable The passed callable |
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| 177 | * |
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| 178 | * @throws \InvalidArgumentException Service definition has to be a closure of an invokable object |
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| 179 | */ |
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| 180 | public function protect($callable) |
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| 181 | { |
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| 182 | if (!method_exists($callable, '__invoke')) { |
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| 183 | throw new \InvalidArgumentException('Callable is not a Closure or invokable object.'); |
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| 184 | } |
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| 185 | |||
| 186 | $this->protected->attach($callable); |
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| 187 | |||
| 188 | return $callable; |
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| 189 | } |
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| 190 | |||
| 191 | /** |
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| 192 | * Gets a parameter or the closure defining an object. |
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| 193 | * |
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| 194 | * @param string $id The unique identifier for the parameter or object |
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| 195 | * |
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| 196 | * @return mixed The value of the parameter or the closure defining an object |
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| 197 | * |
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| 198 | * @throws \InvalidArgumentException if the identifier is not defined |
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| 199 | */ |
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| 200 | public function raw($id) |
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| 201 | { |
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| 202 | if (!isset($this->keys[$id])) { |
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| 203 | throw new \InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id)); |
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| 204 | } |
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| 205 | |||
| 206 | if (isset($this->raw[$id])) { |
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| 207 | return $this->raw[$id]; |
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| 208 | } |
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| 209 | |||
| 210 | return $this->values[$id]; |
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| 211 | } |
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| 212 | |||
| 213 | /** |
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| 214 | * Extends an object definition. |
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| 215 | * |
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| 216 | * Useful when you want to extend an existing object definition, |
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| 217 | * without necessarily loading that object. |
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| 218 | * |
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| 219 | * @param string $id The unique identifier for the object |
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| 220 | * @param callable $callable A service definition to extend the original |
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| 221 | * |
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| 222 | * @return callable The wrapped callable |
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| 223 | * |
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| 224 | * @throws \InvalidArgumentException if the identifier is not defined or not a service definition |
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| 225 | */ |
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| 226 | public function extend($id, $callable) |
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| 227 | { |
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| 228 | if (!isset($this->keys[$id])) { |
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| 229 | throw new \InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id)); |
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| 230 | } |
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| 231 | |||
| 232 | if (!is_object($this->values[$id]) || !method_exists($this->values[$id], '__invoke')) { |
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| 233 | throw new \InvalidArgumentException(sprintf('Identifier "%s" does not contain an object definition.', $id)); |
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| 234 | } |
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| 235 | |||
| 236 | if (!is_object($callable) || !method_exists($callable, '__invoke')) { |
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| 237 | throw new \InvalidArgumentException('Extension service definition is not a Closure or invokable object.'); |
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| 238 | } |
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| 239 | |||
| 240 | $factory = $this->values[$id]; |
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| 241 | |||
| 242 | $extended = function ($c) use ($callable, $factory) { |
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| 243 | return $callable($factory($c), $c); |
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| 244 | }; |
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| 245 | |||
| 246 | if (isset($this->factories[$factory])) { |
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| 247 | $this->factories->detach($factory); |
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| 248 | $this->factories->attach($extended); |
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| 249 | } |
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| 250 | |||
| 251 | return $this[$id] = $extended; |
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| 252 | } |
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| 253 | |||
| 254 | /** |
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| 255 | * Returns all defined value names. |
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| 256 | * |
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| 257 | * @return array An array of value names |
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| 258 | */ |
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| 259 | public function keys() |
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| 260 | { |
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| 261 | return array_keys($this->values); |
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| 262 | } |
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| 263 | |||
| 264 | /** |
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| 265 | * Registers a service provider. |
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| 266 | * |
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| 267 | * @param ServiceProviderInterface $provider A ServiceProviderInterface instance |
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| 268 | * @param array $values An array of values that customizes the provider |
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| 269 | * |
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| 270 | * @return static |
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| 271 | */ |
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| 272 | public function register(ServiceProviderInterface $provider, array $values = array()) |
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| 273 | { |
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| 274 | $provider->register($this); |
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| 275 | |||
| 276 | foreach ($values as $key => $value) { |
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| 277 | $this[$key] = $value; |
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| 278 | } |
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| 279 | |||
| 280 | return $this; |
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| 281 | } |
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| 282 | } |
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| 283 |