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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 SectionProfiler 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 SectionProfiler, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 31 | class SectionProfiler { |
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| 32 | /** @var array Map of (mem,real,cpu) */ |
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| 33 | protected $start; |
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| 34 | /** @var array Map of (mem,real,cpu) */ |
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| 35 | protected $end; |
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| 36 | /** @var array List of resolved profile calls with start/end data */ |
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| 37 | protected $stack = []; |
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| 38 | /** @var array Queue of open profile calls with start data */ |
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| 39 | protected $workStack = []; |
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| 40 | |||
| 41 | /** @var array Map of (function name => aggregate data array) */ |
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| 42 | protected $collated = []; |
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| 43 | /** @var bool */ |
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| 44 | protected $collateDone = false; |
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| 45 | |||
| 46 | /** @var bool Whether to collect the full stack trace or just aggregates */ |
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| 47 | protected $collateOnly = true; |
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| 48 | /** @var array Cache of a standard broken collation entry */ |
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| 49 | protected $errorEntry; |
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| 50 | |||
| 51 | /** |
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| 52 | * @param array $params |
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| 53 | */ |
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| 54 | public function __construct( array $params = [] ) { |
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| 58 | |||
| 59 | /** |
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| 60 | * @param string $section |
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| 61 | * @return SectionProfileCallback |
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| 62 | */ |
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| 63 | public function scopedProfileIn( $section ) { |
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| 68 | |||
| 69 | /** |
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| 70 | * @param ScopedCallback $section |
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| 71 | */ |
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| 72 | public function scopedProfileOut( ScopedCallback &$section ) { |
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| 75 | |||
| 76 | /** |
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| 77 | * Get the aggregated inclusive profiling data for each method |
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| 78 | * |
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| 79 | * The percent time for each time is based on the current "total" time |
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| 80 | * used is based on all methods so far. This method can therefore be |
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| 81 | * called several times in between several profiling calls without the |
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| 82 | * delays in usage of the profiler skewing the results. A "-total" entry |
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| 83 | * is always included in the results. |
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| 84 | * |
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| 85 | * @return array List of method entries arrays, each having: |
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| 86 | * - name : method name |
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| 87 | * - calls : the number of invoking calls |
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| 88 | * - real : real time elapsed (ms) |
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| 89 | * - %real : percent real time |
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| 90 | * - cpu : real time elapsed (ms) |
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| 91 | * - %cpu : percent real time |
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| 92 | * - memory : memory used (bytes) |
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| 93 | * - %memory : percent memory used |
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| 94 | * - min_real : min real time in a call (ms) |
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| 95 | * - max_real : max real time in a call (ms) |
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| 96 | */ |
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| 97 | public function getFunctionStats() { |
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| 135 | |||
| 136 | /** |
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| 137 | * Clear all of the profiling data for another run |
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| 138 | */ |
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| 139 | public function reset() { |
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| 147 | |||
| 148 | /** |
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| 149 | * @return array Initial collation entry |
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| 150 | */ |
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| 151 | protected function getZeroEntry() { |
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| 161 | |||
| 162 | /** |
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| 163 | * @return array Initial collation entry for errors |
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| 164 | */ |
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| 165 | protected function getErrorEntry() { |
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| 170 | |||
| 171 | /** |
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| 172 | * Update the collation entry for a given method name |
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| 173 | * |
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| 174 | * @param string $name |
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| 175 | * @param float $elapsedCpu |
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| 176 | * @param float $elapsedReal |
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| 177 | * @param int $memChange |
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| 178 | */ |
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| 179 | protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) { |
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| 192 | |||
| 193 | /** |
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| 194 | * This method should not be called outside SectionProfiler |
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| 195 | * |
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| 196 | * @param string $functionname |
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| 197 | */ |
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| 198 | public function profileInInternal( $functionname ) { |
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| 220 | |||
| 221 | /** |
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| 222 | * This method should not be called outside SectionProfiler |
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| 223 | * |
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| 224 | * @param string $functionname |
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| 225 | */ |
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| 226 | public function profileOutInternal( $functionname ) { |
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| 272 | |||
| 273 | /** |
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| 274 | * Returns a tree of function calls with their real times |
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| 275 | * @return string |
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| 276 | * @throws Exception |
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| 277 | */ |
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| 278 | public function getCallTreeReport() { |
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| 286 | |||
| 287 | /** |
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| 288 | * Recursive function the format the current profiling array into a tree |
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| 289 | * |
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| 290 | * @param array $stack Profiling array |
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| 291 | * @return array |
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| 292 | */ |
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| 293 | protected function remapCallTree( array $stack ) { |
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| 327 | |||
| 328 | /** |
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| 329 | * Callback to get a formatted line for the call tree |
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| 330 | * @param array $entry |
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| 331 | * @return string |
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| 332 | */ |
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| 333 | protected function getCallTreeLine( $entry ) { |
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| 343 | |||
| 344 | /** |
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| 345 | * Populate collated data |
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| 346 | */ |
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| 347 | protected function collateData() { |
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| 417 | |||
| 418 | /** |
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| 419 | * Dummy calls to calculate profiling overhead |
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| 420 | * |
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| 421 | * @param int $profileCount |
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| 422 | */ |
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| 423 | protected function calculateOverhead( $profileCount ) { |
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| 431 | |||
| 432 | /** |
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| 433 | * Counts the number of profiled function calls sitting under |
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| 434 | * the given point in the call graph. Not the most efficient algo. |
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| 435 | * |
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| 436 | * @param array $stack |
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| 437 | * @param int $start |
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| 438 | * @return int |
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| 439 | */ |
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| 440 | protected function calltreeCount( $stack, $start ) { |
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| 448 | |||
| 449 | /** |
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| 450 | * Get the initial time of the request, based on getrusage() |
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| 451 | * |
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| 452 | * @param string|bool $metric Metric to use, with the following possibilities: |
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| 453 | * - user: User CPU time (without system calls) |
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| 454 | * - cpu: Total CPU time (user and system calls) |
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| 455 | * - wall (or any other string): elapsed time |
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| 456 | * - false (default): will fall back to default metric |
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| 457 | * @return float |
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| 458 | */ |
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| 459 | protected function getTime( $metric = 'wall' ) { |
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| 476 | |||
| 477 | /** |
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| 478 | * Add an entry in the debug log file |
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| 479 | * |
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| 480 | * @param string $s String to output |
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| 481 | */ |
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| 482 | protected function debug( $s ) { |
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| 487 | |||
| 488 | /** |
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| 489 | * Add an entry in the debug log group |
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| 490 | * |
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| 491 | * @param string $group Group to send the message to |
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| 492 | * @param string $s String to output |
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| 493 | */ |
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| 494 | protected function debugGroup( $group, $s ) { |
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| 499 | } |
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| 500 | |||
| 526 |
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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: