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 $filePath The path to the file that will be parsed into a ContentItem |
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112 | * |
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113 | * @throws FileNotFoundException The given file path does not exist |
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114 | * @throws IOException The file was not a valid ContentItem. This would meam there was no front matter or |
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115 | * no body |
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116 | */ |
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117 | 120 | public function __construct($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 $needle |
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157 | * |
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158 | * @return bool |
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159 | */ |
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160 | final public function hasTwigDependency($namespace, $needle) |
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164 | |||
165 | /** |
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166 | * Read the file, and parse its contents. |
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167 | */ |
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168 | 120 | final public function refreshFileContent() |
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169 | { |
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170 | // This function can be called after the initial object was created and the file may have been deleted since the |
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171 | // creation of the object. |
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172 | 120 | View Code Duplication | if (!$this->fs->exists($this->filePath)) |
173 | { |
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174 | 2 | throw new FileNotFoundException(null, 0, null, $this->filePath); |
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175 | } |
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176 | |||
177 | // $fileStructure[1] is the YAML |
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178 | // $fileStructure[2] is the amount of new lines after the closing `---` and the beginning of content |
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179 | // $fileStructure[3] is the body of the document |
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180 | 119 | $fileStructure = array(); |
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181 | |||
182 | 119 | $rawFileContents = file_get_contents($this->filePath); |
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183 | 119 | preg_match('/---\R(.*?\R)?---(\s+)(.*)/s', $rawFileContents, $fileStructure); |
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184 | |||
185 | 119 | if (count($fileStructure) != 4) |
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186 | { |
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187 | 9 | throw new InvalidSyntaxException('Invalid FrontMatter file', 0, null, $this->getRelativeFilePath()); |
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188 | } |
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189 | |||
190 | 110 | if (empty(trim($fileStructure[3]))) |
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191 | { |
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192 | 1 | throw new InvalidSyntaxException('FrontMatter files must have a body to render', 0, null, $this->getRelativeFilePath()); |
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193 | } |
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194 | |||
195 | // 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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196 | 109 | $this->lineOffset = substr_count($fileStructure[1], "\n") + substr_count($fileStructure[2], "\n") + 1; |
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197 | 109 | $this->bodyContent = $fileStructure[3]; |
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198 | |||
199 | 109 | if (!empty(trim($fileStructure[1]))) |
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200 | { |
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201 | 92 | $this->frontMatter = Yaml::parse($fileStructure[1], Yaml::PARSE_DATETIME); |
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202 | |||
203 | 92 | if (!empty($this->frontMatter) && !is_array($this->frontMatter)) |
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204 | { |
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205 | 92 | throw new ParseException('The evaluated FrontMatter should be an array'); |
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206 | } |
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207 | } |
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208 | else |
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209 | { |
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210 | 20 | $this->frontMatter = array(); |
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211 | } |
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212 | |||
213 | 108 | $this->frontMatterEvaluated = false; |
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214 | 108 | $this->bodyContentEvaluated = false; |
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215 | 108 | $this->permalink = null; |
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216 | |||
217 | 108 | $this->findTwigDataDependencies('collections'); |
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218 | 108 | $this->findTwigDataDependencies('data'); |
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219 | 108 | } |
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220 | |||
221 | /** |
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222 | * Get all of the references to either DataItems or ContentItems inside of given string. |
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223 | * |
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224 | * @param string $filter 'collections' or 'data' |
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225 | */ |
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226 | 108 | private function findTwigDataDependencies($filter) |
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235 | |||
236 | // |
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237 | // Permalink and redirect functionality |
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238 | // |
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239 | |||
240 | 39 | final protected function buildPermalink() |
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241 | { |
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242 | 39 | if (!is_null($this->permalink)) |
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243 | { |
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244 | 8 | return; |
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245 | } |
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246 | |||
247 | 37 | if (!is_null($this->frontMatterParser) && $this->frontMatterParser->hasExpansion()) |
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248 | { |
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249 | throw new \Exception('The permalink for this item has not been set'); |
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250 | } |
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251 | |||
252 | 37 | $permalink = (is_array($this->frontMatter) && isset($this->frontMatter['permalink'])) ? |
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253 | 37 | $this->frontMatter['permalink'] : $this->getPathPermalink(); |
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254 | |||
255 | 37 | View Code Duplication | if (is_array($permalink)) |
256 | { |
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257 | 19 | $this->permalink = $permalink[0]; |
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258 | 19 | array_shift($permalink); |
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259 | 19 | $this->redirects = $permalink; |
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260 | } |
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261 | else |
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262 | { |
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263 | 24 | $this->permalink = $permalink; |
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264 | 24 | $this->redirects = array(); |
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265 | } |
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266 | 37 | } |
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267 | |||
268 | // |
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269 | // WritableFrontMatter Implementation |
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270 | // |
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271 | |||
272 | /** |
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273 | * {@inheritdoc} |
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274 | */ |
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275 | 7 | final public function evaluateFrontMatter($variables = null) |
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276 | { |
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277 | 7 | if (!is_null($variables)) |
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278 | { |
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279 | 7 | $this->frontMatter = array_merge($this->frontMatter, $variables); |
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280 | 7 | $this->evaluateYaml($this->frontMatter); |
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281 | } |
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282 | 7 | } |
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283 | |||
284 | /** |
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285 | * {@inheritdoc} |
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286 | */ |
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287 | 29 | final public function getFrontMatter($evaluateYaml = true) |
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288 | { |
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289 | 29 | if (is_null($this->frontMatter)) |
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290 | { |
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291 | $this->frontMatter = array(); |
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292 | } |
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293 | 29 | elseif (!$this->frontMatterEvaluated && $evaluateYaml) |
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294 | { |
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295 | 23 | $this->evaluateYaml($this->frontMatter); |
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296 | } |
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297 | |||
298 | 28 | return $this->frontMatter; |
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299 | } |
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300 | |||
301 | /** |
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302 | * {@inheritdoc} |
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303 | */ |
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304 | 2 | final public function hasExpandedFrontMatter() |
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308 | |||
309 | /** |
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310 | * {@inheritdoc. |
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311 | */ |
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312 | final public function appendFrontMatter(array $frontMatter) |
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313 | { |
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314 | foreach ($frontMatter as $key => $value) |
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315 | { |
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316 | $this->writableFrontMatter[$key] = $value; |
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317 | } |
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318 | } |
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319 | |||
320 | /** |
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321 | * {@inheritdoc. |
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322 | */ |
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323 | final public function deleteFrontMatter($key) |
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324 | { |
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325 | if (!isset($this->writableFrontMatter[$key])) |
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326 | { |
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327 | return; |
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328 | } |
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329 | |||
330 | unset($this->writableFrontMatter[$key]); |
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331 | } |
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332 | |||
333 | /** |
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334 | * {@inheritdoc. |
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335 | */ |
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336 | 2 | final public function setFrontMatter(array $frontMatter) |
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337 | { |
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338 | 2 | if (!is_array($frontMatter)) |
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339 | { |
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340 | throw new \InvalidArgumentException('An array is required for setting the writable FrontMatter'); |
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341 | } |
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342 | |||
343 | 2 | $this->writableFrontMatter = $frontMatter; |
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344 | 2 | } |
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345 | |||
346 | /** |
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347 | * Evaluate an array of data for FrontMatter variables. This function will modify the array in place. |
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348 | * |
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349 | * @param array $yaml An array of data containing FrontMatter variables |
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350 | * |
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351 | * @throws YamlVariableUndefinedException A FrontMatter variable used does not exist |
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352 | */ |
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353 | 30 | private function evaluateYaml(&$yaml) |
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354 | { |
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355 | try |
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356 | { |
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357 | 30 | $this->frontMatterParser = new Parser($yaml, array( |
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358 | 30 | 'filename' => $this->getFileName(), |
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359 | 30 | 'basename' => $this->getName(), |
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360 | )); |
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361 | 29 | $this->frontMatterEvaluated = true; |
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362 | } |
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363 | 1 | catch (\Exception $e) |
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364 | { |
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365 | 1 | throw FileAwareException::castException($e, $this->getRelativeFilePath()); |
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366 | } |
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367 | 29 | } |
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368 | |||
369 | // |
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370 | // ArrayAccess Implementation |
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371 | // |
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372 | |||
373 | /** |
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374 | * {@inheritdoc} |
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375 | */ |
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376 | public function offsetSet($offset, $value) |
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377 | { |
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378 | if (is_null($offset)) |
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379 | { |
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380 | throw new \InvalidArgumentException('$offset cannot be null'); |
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381 | } |
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382 | |||
383 | $this->writableFrontMatter[$offset] = $value; |
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384 | } |
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385 | |||
386 | /** |
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387 | * {@inheritdoc} |
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388 | */ |
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389 | 34 | public function offsetExists($offset) |
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390 | { |
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391 | 34 | if (isset($this->writableFrontMatter[$offset]) || isset($this->frontMatter[$offset])) |
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392 | { |
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393 | 33 | return true; |
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394 | } |
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395 | |||
396 | 14 | $fxnCall = 'get' . ucfirst($offset); |
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397 | |||
398 | 14 | return method_exists($this, $fxnCall) && in_array($fxnCall, static::$whiteListFunctions); |
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399 | } |
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400 | |||
401 | /** |
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402 | * {@inheritdoc} |
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403 | */ |
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404 | public function offsetUnset($offset) |
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408 | |||
409 | /** |
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410 | * {@inheritdoc} |
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411 | */ |
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412 | 51 | public function offsetGet($offset) |
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413 | { |
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414 | 51 | $fxnCall = 'get' . ucfirst($offset); |
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415 | |||
416 | 51 | if (in_array($fxnCall, self::$whiteListFunctions) && method_exists($this, $fxnCall)) |
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417 | { |
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418 | 6 | return call_user_func_array(array($this, $fxnCall), array()); |
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433 | } |
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434 |
Very long variable names usually make code harder to read. It is therefore recommended not to make variable names too verbose.