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:
Complex classes like IRI often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use IRI, and based on these observations, apply Extract Interface, too.
1 | <?php |
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19 | class IRI |
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20 | { |
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21 | /** |
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22 | * The scheme |
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23 | * |
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24 | * @var string|null |
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25 | */ |
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26 | private $scheme = null; |
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27 | |||
28 | /** |
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29 | * The user information |
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30 | * |
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31 | * @var string|null |
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32 | */ |
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33 | private $userinfo = null; |
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34 | |||
35 | /** |
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36 | * The host |
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37 | * |
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38 | * @var string|null |
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39 | */ |
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40 | private $host = null; |
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41 | |||
42 | /** |
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43 | * The port |
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44 | * |
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45 | * @var string|null |
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46 | */ |
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47 | private $port = null; |
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48 | |||
49 | /** |
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50 | * The path |
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51 | * |
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52 | * @var string |
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53 | */ |
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54 | private $path = ''; |
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55 | |||
56 | /** |
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57 | * The query component |
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58 | * |
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59 | * @var string|null |
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60 | */ |
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61 | private $query = null; |
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62 | |||
63 | /** |
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64 | * The fragment identifier |
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65 | * |
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66 | * @var string|null |
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67 | */ |
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68 | private $fragment = null; |
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69 | |||
70 | |||
71 | /** |
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72 | * Constructor |
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73 | * |
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74 | * @param null|string|IRI $iri The IRI. |
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75 | * |
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76 | * @throws \InvalidArgumentException If an invalid IRI is passed. |
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77 | * |
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78 | * @api |
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79 | */ |
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80 | 802 | public function __construct($iri = null) |
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101 | |||
102 | /** |
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103 | * Get the scheme |
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104 | * |
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105 | * @return string|null Returns the scheme or null if not set. |
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106 | */ |
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107 | 12 | public function getScheme() |
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111 | |||
112 | /** |
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113 | * Get the authority |
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114 | * |
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115 | * @return string|null Returns the authority or null if not set. |
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116 | */ |
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117 | 724 | public function getAuthority() |
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134 | |||
135 | /** |
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136 | * Get the user information |
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137 | * |
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138 | * @return string|null Returns the user information or null if not set. |
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139 | */ |
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140 | 12 | public function getUserInfo() |
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144 | |||
145 | /** |
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146 | * Get the host |
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147 | * |
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148 | * @return string|null Returns the host or null if not set. |
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149 | */ |
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150 | 12 | public function getHost() |
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154 | |||
155 | /** |
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156 | * Get the port |
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157 | * |
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158 | * @return string|null Returns the port or null if not set. |
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159 | */ |
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160 | 12 | public function getPort() |
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164 | |||
165 | /** |
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166 | * Get the path |
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167 | * |
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168 | * @return string Returns the path which might be empty. |
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169 | */ |
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170 | 12 | public function getPath() |
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174 | |||
175 | /** |
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176 | * Get the query component |
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177 | * |
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178 | * @return string|null Returns the query component or null if not set. |
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179 | */ |
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180 | 12 | public function getQuery() |
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184 | |||
185 | /** |
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186 | * Get the fragment identifier |
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187 | * |
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188 | * @return string|null Returns the fragment identifier or null if not set. |
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189 | */ |
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190 | 12 | public function getFragment() |
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194 | |||
195 | /** |
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196 | * Find out whether the IRI is absolute |
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197 | * |
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198 | * @return bool Returns true if the IRI is absolute, false otherwise. |
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199 | * |
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200 | * @api |
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201 | */ |
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202 | 78 | public function isAbsolute() |
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206 | |||
207 | /** |
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208 | * Get as absolute IRI, i.e., without fragment identifier |
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209 | * |
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210 | * @return IRI The absolute IRI, i.e., without fragment identifier |
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211 | * |
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212 | * @throws \UnexpectedValueException If the IRI is a relative IRI. |
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213 | * |
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214 | * @link http://tools.ietf.org/html/rfc3987#section-2.2 RFC3987 absolute-IRI |
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215 | * |
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216 | * @api |
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217 | */ |
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218 | 2 | public function getAbsoluteIri() |
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229 | |||
230 | /** |
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231 | * Check whether the passed IRI is equal |
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232 | * |
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233 | * @param IRI|string $iri IRI to compare to this instance. |
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234 | * |
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235 | * @return bool Returns true if the two IRIs are equal, false otherwise. |
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236 | * |
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237 | * @api |
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238 | */ |
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239 | 12 | public function equals($iri) |
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244 | |||
245 | /** |
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246 | * Resolve a (relative) IRI reference against this IRI |
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247 | * |
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248 | * @param IRI|string $reference The (relative) IRI reference that should |
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249 | * be resolved against this IRI. |
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250 | * |
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251 | * @return IRI The resolved IRI. |
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252 | * |
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253 | * @throws \InvalidArgumentException If an invalid IRI is passed. |
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254 | * |
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255 | * @link http://tools.ietf.org/html/rfc3986#section-5.2 |
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256 | * |
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257 | * @api |
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258 | */ |
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259 | 654 | public function resolve($reference) |
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339 | |||
340 | /** |
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341 | * Transform this IRI to a IRI reference relative to the passed base IRI |
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342 | * |
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343 | * @param IRI|string $base The (relative) IRI reference that should be |
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344 | * be used as base IRI. |
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345 | * @param bool Defines whether schema-relative IRIs such |
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346 | * as `//example.com` should be created (`true`) |
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347 | * or not (`false`). |
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348 | * |
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349 | * @return IRI The IRI reference relative to the passed base IRI. |
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350 | * |
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351 | * @throws \InvalidArgumentException If an invalid IRI is passed. |
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352 | * |
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353 | * @api |
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354 | */ |
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355 | 57 | public function relativeTo($base, $schemaRelative = false) |
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427 | |||
428 | /** |
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429 | * Convert an IRI to a relative IRI reference using this IRI as base |
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430 | * |
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431 | * This method provides a more convenient interface than the |
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432 | * {@link IRI::relativeTo()} method if the base IRI stays the same while |
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433 | * the IRIs to convert to relative IRI references change. |
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434 | * |
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435 | * @param string|IRI $iri The IRI to convert to a relative reference |
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436 | * @param bool Defines whether schema-relative IRIs such |
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437 | * as `//example.com` should be created (`true`) |
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438 | * or not (`false`). |
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439 | * |
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440 | * @throws \InvalidArgumentException If an invalid IRI is passed. |
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441 | * |
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442 | * @see \ML\IRI\IRI::relativeTo() |
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443 | * |
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444 | * @return IRI The relative IRI reference |
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445 | */ |
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446 | 57 | public function baseFor($iri, $schemaRelative = false) |
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454 | |||
455 | /** |
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456 | * Get a string representation of this IRI object |
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457 | * |
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458 | * @return string A string representation of this IRI instance. |
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459 | * |
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460 | * @api |
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461 | */ |
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462 | 724 | public function __toString() |
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486 | |||
487 | /** |
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488 | * Parse an IRI into it's components |
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489 | * |
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490 | * This is done according to |
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491 | * {@link http://tools.ietf.org/html/rfc3986#section-3.1 RFC3986}. |
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492 | * |
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493 | * @param string $iri The IRI to parse. |
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494 | */ |
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495 | 801 | protected function parse($iri) |
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554 | |||
555 | /** |
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556 | * Remove dot-segments |
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557 | * |
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558 | * This method removes the special "." and ".." complete path segments |
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559 | * from an IRI. |
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560 | * |
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561 | * @param string $input The IRI from which dot segments should be removed. |
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562 | * |
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563 | * @return string The IRI with all dot-segments removed. |
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564 | * |
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565 | * @link http://tools.ietf.org/html/rfc3986#section-5.2.4 |
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566 | */ |
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567 | 606 | private static function removeDotSegments($input) |
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604 | } |
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605 |
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVar
assignment in line 1 and the$higher
assignment in line 2 are dead. The first because$myVar
is never used and the second because$higher
is always overwritten for every possible time line.