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 FrontMatterDocument 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 FrontMatterDocument, and based on these observations, apply Extract Interface, too.
1 | <?php |
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20 | abstract class FrontMatterDocument extends PermalinkDocument implements |
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21 | \ArrayAccess, |
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22 | JailedDocumentInterface, |
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23 | WritableDocumentInterface |
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24 | { |
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25 | const TEMPLATE = "---\n%s\n---\n\n%s"; |
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26 | |||
27 | /** |
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28 | * The names of FrontMatter keys that are specially defined for all Documents |
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29 | * |
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30 | * @var array |
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31 | */ |
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32 | public static $specialFrontMatterKeys = array( |
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33 | 'filename', 'basename' |
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34 | ); |
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35 | |||
36 | protected static $whiteListFunctions = array( |
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37 | 'getPermalink', 'getRedirects', 'getTargetFile', 'getName', 'getFilePath', 'getRelativeFilePath', 'getContent', |
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38 | 'getExtension', 'getFrontMatter' |
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39 | ); |
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40 | |||
41 | /** |
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42 | * An array to keep track of collection or data dependencies used inside of a Twig template. |
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43 | * |
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44 | * $dataDependencies['collections'] = array() |
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45 | * $dataDependencies['data'] = array() |
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46 | * |
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47 | * @var array |
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48 | */ |
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49 | protected $dataDependencies; |
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50 | |||
51 | /** |
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52 | * FrontMatter values that can be injected or set after the file has been parsed. Values in this array will take |
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53 | * precedence over values in $frontMatter. |
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54 | * |
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55 | * @var array |
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56 | */ |
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57 | protected $writableFrontMatter; |
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58 | |||
59 | /** |
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60 | * A list of Front Matter values that should not be returned directly from the $frontMatter array. Values listed |
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61 | * here have dedicated functions that handle those Front Matter values and the respective functions should be called |
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62 | * instead. |
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63 | * |
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64 | * @var string[] |
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65 | */ |
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66 | protected $frontMatterBlacklist; |
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67 | |||
68 | /** |
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69 | * Set to true if the front matter has already been evaluated with variable interpolation. |
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70 | * |
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71 | * @var bool |
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72 | */ |
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73 | protected $frontMatterEvaluated; |
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74 | |||
75 | /** |
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76 | * @var Parser |
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77 | */ |
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78 | protected $frontMatterParser; |
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79 | |||
80 | /** |
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81 | * An array containing the Yaml of the file. |
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82 | * |
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83 | * @var array |
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84 | */ |
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85 | protected $frontMatter; |
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86 | |||
87 | /** |
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88 | * Set to true if the body has already been parsed as markdown or any other format. |
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89 | * |
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90 | * @var bool |
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91 | */ |
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92 | protected $bodyContentEvaluated; |
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93 | |||
94 | /** |
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95 | * Only the body of the file, i.e. the content. |
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96 | * |
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97 | * @var string |
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98 | */ |
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99 | protected $bodyContent; |
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100 | |||
101 | /** |
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102 | * The number of lines that Twig template errors should offset. |
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103 | * |
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104 | * @var int |
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105 | */ |
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106 | private $lineOffset; |
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107 | |||
108 | /** |
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109 | * ContentItem constructor. |
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110 | * |
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111 | * @param string $filePath The path to the file that will be parsed into a ContentItem |
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112 | * |
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113 | * @throws FileNotFoundException The given file path does not exist |
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114 | * @throws IOException The file was not a valid ContentItem. This would meam there was no front matter or |
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115 | * no body |
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116 | */ |
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117 | 137 | public function __construct($filePath) |
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124 | |||
125 | /** |
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126 | * Return the body of the Content Item. |
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127 | * |
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128 | * @return string |
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129 | */ |
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130 | abstract public function getContent(); |
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131 | |||
132 | /** |
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133 | * The number of lines that are taken up by FrontMatter and white space. |
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134 | * |
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135 | * @return int |
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136 | */ |
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137 | final public function getLineOffset() |
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141 | |||
142 | /** |
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143 | * Get the name of the item, which is just the filename without the extension. |
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144 | * |
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145 | * @return string |
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146 | */ |
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147 | 62 | final public function getName() |
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151 | |||
152 | /** |
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153 | * Check whether this object has a reference to a collection or data item. |
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154 | * |
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155 | * @param string $namespace 'collections' or 'data' |
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156 | * @param string $needle |
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157 | * |
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158 | * @return bool |
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159 | */ |
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160 | 17 | final public function hasTwigDependency($namespace, $needle) |
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166 | |||
167 | /** |
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168 | * Read the file, and parse its contents. |
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169 | */ |
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170 | 137 | final public function refreshFileContent() |
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171 | { |
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172 | // This function can be called after the initial object was created and the file may have been deleted since the |
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173 | // creation of the object. |
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174 | 137 | if (!$this->fs->exists($this->filePath)) |
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175 | { |
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176 | 2 | throw new FileNotFoundException(null, 0, null, $this->filePath); |
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177 | } |
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178 | |||
179 | // $fileStructure[1] is the YAML |
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180 | // $fileStructure[2] is the amount of new lines after the closing `---` and the beginning of content |
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181 | // $fileStructure[3] is the body of the document |
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182 | 136 | $fileStructure = array(); |
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183 | |||
184 | 136 | $rawFileContents = file_get_contents($this->filePath); |
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185 | 136 | preg_match('/---\R(.*?\R)?---(\s+)(.*)/s', $rawFileContents, $fileStructure); |
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186 | |||
187 | 136 | if (count($fileStructure) != 4) |
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188 | { |
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189 | 9 | throw new InvalidSyntaxException('Invalid FrontMatter file', 0, null, $this->getRelativeFilePath()); |
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190 | } |
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191 | |||
192 | 127 | if (empty(trim($fileStructure[3]))) |
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193 | { |
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194 | 1 | throw new InvalidSyntaxException('FrontMatter files must have a body to render', 0, null, $this->getRelativeFilePath()); |
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195 | } |
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196 | |||
197 | // The hard coded 1 is the offset used to count the new line used after the first `---` that is not caught in the regex |
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198 | 126 | $this->lineOffset = substr_count($fileStructure[1], "\n") + substr_count($fileStructure[2], "\n") + 1; |
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199 | 126 | $this->bodyContent = $fileStructure[3]; |
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200 | |||
201 | 126 | if (!empty(trim($fileStructure[1]))) |
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202 | { |
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203 | 92 | $this->frontMatter = Yaml::parse($fileStructure[1], Yaml::PARSE_DATETIME); |
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204 | |||
205 | 92 | if (!empty($this->frontMatter) && !is_array($this->frontMatter)) |
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206 | { |
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207 | 92 | throw new ParseException('The evaluated FrontMatter should be an array'); |
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208 | } |
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209 | } |
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210 | else |
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211 | { |
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212 | 37 | $this->frontMatter = array(); |
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213 | } |
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214 | |||
215 | 125 | $this->frontMatterEvaluated = false; |
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216 | 125 | $this->bodyContentEvaluated = false; |
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217 | 125 | $this->permalink = null; |
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218 | |||
219 | 125 | $this->findTwigDataDependencies('collections'); |
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220 | 125 | $this->findTwigDataDependencies('data'); |
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221 | 125 | } |
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222 | |||
223 | /** |
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224 | * Get all of the references to either DataItems or ContentItems inside of given string. |
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225 | * |
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226 | * @param string $filter 'collections' or 'data' |
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227 | */ |
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228 | 125 | private function findTwigDataDependencies($filter) |
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237 | |||
238 | // |
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239 | // Permalink and redirect functionality |
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240 | // |
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241 | |||
242 | 39 | final protected function buildPermalink() |
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243 | { |
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244 | 39 | if (!is_null($this->permalink)) |
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245 | { |
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246 | 8 | return; |
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247 | } |
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248 | |||
249 | 37 | if (!is_null($this->frontMatterParser) && $this->frontMatterParser->hasExpansion()) |
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250 | { |
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251 | throw new \Exception('The permalink for this item has not been set'); |
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252 | } |
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253 | |||
254 | 37 | $permalink = (is_array($this->frontMatter) && isset($this->frontMatter['permalink'])) ? |
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255 | 37 | $this->frontMatter['permalink'] : $this->getPathPermalink(); |
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256 | |||
257 | 37 | View Code Duplication | if (is_array($permalink)) |
258 | { |
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259 | 19 | $this->permalink = $permalink[0]; |
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260 | 19 | array_shift($permalink); |
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261 | 19 | $this->redirects = $permalink; |
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262 | } |
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263 | else |
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264 | { |
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265 | 24 | $this->permalink = $permalink; |
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266 | 24 | $this->redirects = array(); |
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267 | } |
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268 | 37 | } |
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269 | |||
270 | // |
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271 | // WritableFrontMatter Implementation |
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272 | // |
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273 | |||
274 | /** |
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275 | * {@inheritdoc} |
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276 | */ |
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277 | 7 | final public function evaluateFrontMatter($variables = null) |
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278 | { |
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279 | 7 | if (!is_null($variables)) |
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280 | { |
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281 | 7 | $this->frontMatter = array_merge($this->frontMatter, $variables); |
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282 | 7 | $this->evaluateYaml($this->frontMatter); |
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283 | } |
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284 | 7 | } |
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285 | |||
286 | /** |
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287 | * {@inheritdoc} |
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288 | */ |
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289 | 29 | final public function getFrontMatter($evaluateYaml = true) |
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290 | { |
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291 | 29 | if (is_null($this->frontMatter)) |
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292 | { |
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293 | $this->frontMatter = array(); |
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294 | } |
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295 | 29 | elseif (!$this->frontMatterEvaluated && $evaluateYaml) |
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296 | { |
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297 | 23 | $this->evaluateYaml($this->frontMatter); |
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298 | } |
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299 | |||
300 | 28 | return $this->frontMatter; |
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301 | } |
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302 | |||
303 | /** |
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304 | * {@inheritdoc} |
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305 | */ |
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306 | 2 | final public function hasExpandedFrontMatter() |
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310 | |||
311 | /** |
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312 | * {@inheritdoc. |
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313 | */ |
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314 | final public function appendFrontMatter(array $frontMatter) |
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315 | { |
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316 | foreach ($frontMatter as $key => $value) |
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317 | { |
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318 | $this->writableFrontMatter[$key] = $value; |
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319 | } |
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320 | } |
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321 | |||
322 | /** |
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323 | * {@inheritdoc. |
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324 | */ |
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325 | final public function deleteFrontMatter($key) |
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326 | { |
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327 | if (!isset($this->writableFrontMatter[$key])) |
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328 | { |
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329 | return; |
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330 | } |
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331 | |||
332 | unset($this->writableFrontMatter[$key]); |
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333 | } |
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334 | |||
335 | /** |
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336 | * {@inheritdoc. |
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337 | */ |
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338 | 2 | final public function setFrontMatter(array $frontMatter) |
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339 | { |
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340 | 2 | if (!is_array($frontMatter)) |
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341 | { |
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342 | throw new \InvalidArgumentException('An array is required for setting the writable FrontMatter'); |
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343 | } |
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344 | |||
345 | 2 | $this->writableFrontMatter = $frontMatter; |
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346 | 2 | } |
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347 | |||
348 | /** |
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349 | * Evaluate an array of data for FrontMatter variables. This function will modify the array in place. |
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350 | * |
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351 | * @param array $yaml An array of data containing FrontMatter variables |
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352 | * |
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353 | * @throws YamlVariableUndefinedException A FrontMatter variable used does not exist |
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354 | */ |
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355 | 30 | private function evaluateYaml(&$yaml) |
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356 | { |
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357 | try |
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358 | { |
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359 | 30 | $this->frontMatterParser = new Parser($yaml, array( |
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360 | 30 | 'filename' => $this->getFileName(), |
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361 | 30 | 'basename' => $this->getName(), |
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362 | )); |
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363 | 29 | $this->frontMatterEvaluated = true; |
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364 | } |
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365 | 1 | catch (\Exception $e) |
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366 | { |
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367 | 1 | throw FileAwareException::castException($e, $this->getRelativeFilePath()); |
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368 | } |
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369 | 29 | } |
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370 | |||
371 | // |
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372 | // ArrayAccess Implementation |
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373 | // |
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374 | |||
375 | /** |
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376 | * {@inheritdoc} |
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377 | */ |
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378 | public function offsetSet($offset, $value) |
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379 | { |
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380 | if (is_null($offset)) |
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381 | { |
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382 | throw new \InvalidArgumentException('$offset cannot be null'); |
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383 | } |
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384 | |||
385 | $this->writableFrontMatter[$offset] = $value; |
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386 | } |
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387 | |||
388 | /** |
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389 | * {@inheritdoc} |
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390 | */ |
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391 | 34 | public function offsetExists($offset) |
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392 | { |
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393 | 34 | if (isset($this->writableFrontMatter[$offset]) || isset($this->frontMatter[$offset])) |
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394 | { |
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395 | 33 | return true; |
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396 | } |
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397 | |||
398 | 14 | $fxnCall = 'get' . ucfirst($offset); |
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399 | |||
400 | 14 | return method_exists($this, $fxnCall) && in_array($fxnCall, static::$whiteListFunctions); |
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401 | } |
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402 | |||
403 | /** |
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404 | * {@inheritdoc} |
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405 | */ |
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406 | public function offsetUnset($offset) |
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410 | |||
411 | /** |
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412 | * {@inheritdoc} |
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413 | */ |
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414 | 51 | public function offsetGet($offset) |
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415 | { |
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416 | 51 | $fxnCall = 'get' . ucfirst($offset); |
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417 | |||
418 | 51 | if (in_array($fxnCall, self::$whiteListFunctions) && method_exists($this, $fxnCall)) |
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419 | { |
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420 | 6 | return call_user_func_array(array($this, $fxnCall), array()); |
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435 | } |
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436 |
Very long variable names usually make code harder to read. It is therefore recommended not to make variable names too verbose.