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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 XhprofData 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 XhprofData, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 32 | class XhprofData { |
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| 33 | |||
| 34 | /** |
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| 35 | * @var array $config |
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| 36 | */ |
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| 37 | protected $config; |
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| 38 | |||
| 39 | /** |
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| 40 | * Hierarchical profiling data returned by xhprof. |
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| 41 | * @var array $hieraData |
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| 42 | */ |
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| 43 | protected $hieraData; |
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| 44 | |||
| 45 | /** |
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| 46 | * Per-function inclusive data. |
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| 47 | * @var array $inclusive |
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| 48 | */ |
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| 49 | protected $inclusive; |
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| 50 | |||
| 51 | /** |
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| 52 | * Per-function inclusive and exclusive data. |
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| 53 | * @var array $complete |
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| 54 | */ |
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| 55 | protected $complete; |
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| 56 | |||
| 57 | /** |
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| 58 | * Configuration data can contain: |
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| 59 | * - include: Array of function names to include in profiling. |
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| 60 | * - sort: Key to sort per-function reports on. |
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| 61 | * |
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| 62 | * @param array $data Xhprof profiling data, as returned by xhprof_disable() |
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| 63 | * @param array $config |
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| 64 | */ |
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| 65 | public function __construct( array $data, array $config = [] ) { |
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| 73 | |||
| 74 | /** |
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| 75 | * Get raw data collected by xhprof. |
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| 76 | * |
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| 77 | * Each key in the returned array is an edge label for the call graph in |
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| 78 | * the form "caller==>callee". There is once special case edge labled |
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| 79 | * simply "main()" which represents the global scope entry point of the |
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| 80 | * application. |
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| 81 | * |
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| 82 | * XHProf will collect different data depending on the flags that are used: |
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| 83 | * - ct: Number of matching events seen. |
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| 84 | * - wt: Inclusive elapsed wall time for this event in microseconds. |
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| 85 | * - cpu: Inclusive elapsed cpu time for this event in microseconds. |
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| 86 | * (XHPROF_FLAGS_CPU) |
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| 87 | * - mu: Delta of memory usage from start to end of callee in bytes. |
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| 88 | * (XHPROF_FLAGS_MEMORY) |
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| 89 | * - pmu: Delta of peak memory usage from start to end of callee in |
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| 90 | * bytes. (XHPROF_FLAGS_MEMORY) |
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| 91 | * - alloc: Delta of amount memory requested from malloc() by the callee, |
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| 92 | * in bytes. (XHPROF_FLAGS_MALLOC) |
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| 93 | * - free: Delta of amount of memory passed to free() by the callee, in |
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| 94 | * bytes. (XHPROF_FLAGS_MALLOC) |
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| 95 | * |
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| 96 | * @return array |
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| 97 | * @see getInclusiveMetrics() |
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| 98 | * @see getCompleteMetrics() |
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| 99 | */ |
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| 100 | public function getRawData() { |
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| 103 | |||
| 104 | /** |
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| 105 | * Convert an xhprof data key into an array of ['parent', 'child'] |
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| 106 | * function names. |
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| 107 | * |
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| 108 | * The resulting array is left padded with nulls, so a key |
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| 109 | * with no parent (eg 'main()') will return [null, 'function']. |
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| 110 | * |
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| 111 | * @return array |
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| 112 | */ |
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| 113 | public static function splitKey( $key ) { |
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| 116 | |||
| 117 | /** |
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| 118 | * Remove data for functions that are not included in the 'include' |
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| 119 | * configuration array. |
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| 120 | * |
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| 121 | * @param array $data Raw xhprof data |
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| 122 | * @return array |
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| 123 | */ |
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| 124 | protected function pruneData( $data ) { |
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| 141 | |||
| 142 | /** |
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| 143 | * Get the inclusive metrics for each function call. Inclusive metrics |
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| 144 | * for given function include the metrics for all functions that were |
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| 145 | * called from that function during the measurement period. |
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| 146 | * |
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| 147 | * See getRawData() for a description of the metric that are returned for |
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| 148 | * each funcition call. The values for the wt, cpu, mu and pmu metrics are |
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| 149 | * arrays with these values: |
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| 150 | * - total: Cumulative value |
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| 151 | * - min: Minimum value |
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| 152 | * - mean: Mean (average) value |
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| 153 | * - max: Maximum value |
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| 154 | * - variance: Variance (spread) of the values |
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| 155 | * |
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| 156 | * @return array |
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| 157 | * @see getRawData() |
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| 158 | * @see getCompleteMetrics() |
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| 159 | */ |
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| 160 | public function getInclusiveMetrics() { |
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| 234 | |||
| 235 | /** |
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| 236 | * Get the inclusive and exclusive metrics for each function call. |
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| 237 | * |
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| 238 | * In addition to the normal data contained in the inclusive metrics, the |
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| 239 | * metrics have an additional 'exclusive' measurement which is the total |
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| 240 | * minus the totals of all child function calls. |
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| 241 | * |
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| 242 | * @return array |
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| 243 | * @see getRawData() |
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| 244 | * @see getInclusiveMetrics() |
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| 245 | */ |
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| 246 | public function getCompleteMetrics() { |
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| 295 | |||
| 296 | /** |
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| 297 | * Get a list of all callers of a given function. |
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| 298 | * |
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| 299 | * @param string $function Function name |
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| 300 | * @return array |
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| 301 | * @see getEdges() |
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| 302 | */ |
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| 303 | View Code Duplication | public function getCallers( $function ) { |
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| 311 | |||
| 312 | /** |
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| 313 | * Get a list of all callees from a given function. |
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| 314 | * |
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| 315 | * @param string $function Function name |
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| 316 | * @return array |
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| 317 | * @see getEdges() |
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| 318 | */ |
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| 319 | View Code Duplication | public function getCallees( $function ) { |
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| 327 | |||
| 328 | /** |
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| 329 | * Find the critical path for the given metric. |
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| 330 | * |
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| 331 | * @param string $metric Metric to find critical path for |
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| 332 | * @return array |
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| 333 | */ |
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| 334 | public function getCriticalPath( $metric = 'wt' ) { |
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| 360 | |||
| 361 | /** |
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| 362 | * Make a closure to use as a sort function. The resulting function will |
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| 363 | * sort by descending numeric values (largest value first). |
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| 364 | * |
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| 365 | * @param string $key Data key to sort on |
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| 366 | * @param string $sub Sub key to sort array values on |
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| 367 | * @return Closure |
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| 368 | */ |
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| 369 | public static function makeSortFunction( $key, $sub ) { |
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| 384 | } |
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| 385 |
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Let’s assume that you have a directory layout like this:
. |-- OtherDir | |-- Bar.php | `-- Foo.php `-- SomeDir `-- Foo.phpand let’s assume the following content of
Bar.php:If both files
OtherDir/Foo.phpandSomeDir/Foo.phpare loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.phpHowever, as
OtherDir/Foo.phpdoes not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: