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 CHM 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 CHM, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 14 | class CHM |
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| 15 | { |
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| 16 | /** |
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| 17 | * The reader that provides the data. |
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| 18 | * |
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| 19 | * @var \CHMLib\Reader\Reader |
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| 20 | */ |
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| 21 | protected $reader; |
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| 22 | |||
| 23 | /** |
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| 24 | * The CHM initial header. |
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| 25 | * |
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| 26 | * @var \CHMLib\Header\ITSF |
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| 27 | */ |
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| 28 | protected $itsf; |
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| 29 | |||
| 30 | /** |
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| 31 | * The directory listing header. |
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| 32 | * |
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| 33 | * @var \CHMLib\Header\ITSP |
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| 34 | */ |
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| 35 | protected $itsp; |
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| 36 | |||
| 37 | /** |
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| 38 | * The entries found in this CHM. |
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| 39 | * |
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| 40 | * @var \CHMLib\Entry[] |
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| 41 | */ |
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| 42 | protected $entries; |
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| 43 | |||
| 44 | /** |
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| 45 | * The data sections. |
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| 46 | * |
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| 47 | * @var \CHMLib\Section\Section[] |
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| 48 | */ |
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| 49 | protected $sections; |
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| 50 | |||
| 51 | /** |
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| 52 | * The TOC. |
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| 53 | * |
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| 54 | * @var \CHMLib\TOCIndex\Tree|null|false |
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| 55 | */ |
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| 56 | protected $toc; |
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| 57 | |||
| 58 | /** |
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| 59 | * The index. |
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| 60 | * |
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| 61 | * @var \CHMLib\TOCIndex\Tree|null|false |
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| 62 | */ |
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| 63 | protected $index; |
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| 64 | |||
| 65 | /** |
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| 66 | * Initializes the instance. |
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| 67 | * |
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| 68 | * @param \CHMLib\Reader\Reader $reader The reader that provides the data. |
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| 69 | * |
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| 70 | * @throws \Exception Throws an Exception in case of errors. |
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| 71 | */ |
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| 72 | 4 | public function __construct(Reader $reader) |
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| 73 | { |
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| 74 | 4 | $this->reader = $reader; |
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| 75 | 4 | $reader->setPosition(0); |
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| 76 | 4 | $this->itsf = new Header\ITSF($reader); |
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| 77 | 4 | if ($this->itsf->getSectionOffset() >= 0 && $this->itsf->getSectionLength() >= 16 /* === 24*/) { |
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| 78 | 4 | $reader->setPosition($this->itsf->getSectionOffset()); |
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| 79 | 4 | /* Unknown (510) */ $reader->readUInt32(); |
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| 80 | 4 | /* Unknown (0) */ $reader->readUInt32(); |
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| 81 | 4 | $totalLength = $reader->readUInt64(); |
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| 82 | 4 | if ($totalLength !== $reader->getLength()) { |
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| 83 | throw new Exception("Invalid CHM size: expected length $totalLength, current length {$reader->getLength()}"); |
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| 84 | } |
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| 85 | 4 | } |
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| 86 | 4 | $reader->setPosition($this->itsf->getDirectoryOffset()); |
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| 87 | 4 | $this->itsp = new Header\ITSP($reader); |
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| 88 | |||
| 89 | 4 | $expectedDirectoryLength = $this->itsf->getDirectoryLength(); |
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| 90 | 4 | $calculatedDirectoryLength = $this->itsp->getHeaderLength() + $this->itsp->getNumberOfDirectoryChunks() * $this->itsp->getDirectoryChunkSize(); |
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| 91 | 4 | if ($expectedDirectoryLength !== $calculatedDirectoryLength) { |
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| 92 | throw new Exception("Unexpected directory list size (expected: $expectedDirectoryLength, calculated: $calculatedDirectoryLength)"); |
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| 93 | } |
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| 94 | |||
| 95 | 4 | $this->sections = array(); |
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| 96 | 4 | $this->sections[0] = new Section\UncompressedSection($this); |
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| 97 | |||
| 98 | 4 | $this->entries = $this->retrieveEntryList(); |
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| 99 | |||
| 100 | 4 | $this->retrieveSectionList(); |
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| 101 | |||
| 102 | 4 | $this->toc = null; |
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| 103 | 4 | $this->index = null; |
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| 104 | 4 | } |
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| 105 | |||
| 106 | /** |
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| 107 | * Destruct the instance. |
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| 108 | */ |
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| 109 | public function __destruct() |
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| 113 | |||
| 114 | /** |
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| 115 | * Create a new CHM instance reading a file. |
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| 116 | * |
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| 117 | * @param string $filename |
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| 118 | * |
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| 119 | * @return static |
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| 120 | */ |
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| 121 | 4 | public static function fromFile($filename) |
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| 127 | |||
| 128 | /** |
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| 129 | * Get the reader that provides the data. |
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| 130 | * |
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| 131 | * @return \CHMLib\Reader\Reader |
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| 132 | */ |
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| 133 | 486 | public function getReader() |
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| 137 | |||
| 138 | /** |
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| 139 | * Get the CHM initial header. |
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| 140 | * |
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| 141 | * @return \CHMLib\Header\ITSF |
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| 142 | */ |
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| 143 | 4 | public function getITSF() |
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| 147 | |||
| 148 | /** |
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| 149 | * Get the directory listing header. |
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| 150 | * |
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| 151 | * @return \CHMLib\Header\ITSP |
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| 152 | */ |
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| 153 | public function getITSP() |
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| 157 | |||
| 158 | /** |
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| 159 | * Get an entry given its full path. |
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| 160 | * |
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| 161 | * @param string $path The full path (case sensitive) of the entry to look for. |
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| 162 | * |
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| 163 | * @return \CHMLib\Entry|null |
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| 164 | */ |
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| 165 | 491 | public function getEntryByPath($path) |
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| 169 | |||
| 170 | /** |
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| 171 | * Get the entries contained in this CHM. |
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| 172 | * |
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| 173 | * @param int|null $type One or more Entry::TYPE_... values (defaults to Entry::TYPE_FILE | Entry::TYPE_DIRECTORY if null). |
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| 174 | */ |
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| 175 | 3 | public function getEntries($type = null) |
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| 176 | { |
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| 177 | 3 | if ($type === null) { |
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| 178 | $type = Entry::TYPE_FILE | Entry::TYPE_DIRECTORY; |
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| 179 | } |
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| 180 | 3 | $result = array(); |
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| 181 | 3 | foreach ($this->entries as $entry) { |
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| 182 | 3 | if (($entry->getType() & $type) !== 0) { |
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| 183 | 3 | $result[] = $entry; |
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| 184 | 3 | } |
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| 185 | 3 | } |
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| 186 | |||
| 187 | 3 | return $result; |
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| 188 | } |
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| 189 | |||
| 190 | /** |
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| 191 | * Return a section given its index. |
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| 192 | * |
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| 193 | * @param int $i |
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| 194 | * |
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| 195 | * @return \CHMLib\Section\Section|null |
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| 196 | */ |
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| 197 | 491 | public function getSectionByIndex($i) |
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| 201 | |||
| 202 | /** |
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| 203 | * Retrieve the list of the entries contained in this CHM. |
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| 204 | * |
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| 205 | * @throws \Exception Throws an Exception in case of errors. |
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| 206 | * |
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| 207 | * @return \CHMLib\Entry[] |
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| 208 | */ |
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| 209 | 4 | protected function retrieveEntryList() |
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| 241 | |||
| 242 | /** |
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| 243 | * Retrieve the list of the data sections contained in this CHM. |
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| 244 | * |
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| 245 | * @throws \Exception Throws an Exception in case of errors. |
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| 246 | */ |
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| 247 | 4 | protected function retrieveSectionList() |
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| 284 | |||
| 285 | /** |
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| 286 | * Get the TOC of this CHM file (if available). |
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| 287 | * |
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| 288 | * @return \CHMLib\TOCIndex\Tree|null |
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| 289 | */ |
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| 290 | 1 | View Code Duplication | public function getTOC() |
| 305 | |||
| 306 | /** |
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| 307 | * Get the index of this CHM file (if available). |
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| 308 | * |
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| 309 | * @return \CHMLib\TOCIndex\Tree|null |
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| 310 | */ |
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| 311 | View Code Duplication | public function getIndex() |
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| 326 | } |
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| 327 |
This check marks calls to methods that do not seem to exist on an object.
This is most likely the result of a method being renamed without all references to it being renamed likewise.