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 |