Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Component\Diff;
Chris@0: 
Chris@0: use Drupal\Component\Diff\Engine\DiffEngine;
Chris@0: 
Chris@0: /**
Chris@0:  * Class representing a 'diff' between two sequences of strings.
Chris@0:  * @todo document
Chris@0:  * @subpackage DifferenceEngine
Chris@0:  *
Chris@0:  * Copied from https://www.drupal.org/project/diff which was based PHP diff
Chris@0:  * engine for phpwiki. (Taken from phpwiki-1.3.3) The original code in phpwiki
Chris@0:  * was copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org> and
Chris@0:  * licensed under GPL.
Chris@0:  */
Chris@0: class Diff {
Chris@0: 
Chris@0:   /**
Chris@0:    * The list of differences as an array of diff operations.
Chris@0:    *
Chris@0:    * @var \Drupal\Component\Diff\Engine\DiffOp[]
Chris@0:    */
Chris@0:   protected $edits;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructor.
Chris@0:    * Computes diff between sequences of strings.
Chris@0:    *
Chris@0:    * @param array $from_lines
Chris@0:    *   An array of strings.
Chris@0:    *   (Typically these are lines from a file.)
Chris@0:    * @param array $to_lines
Chris@0:    *   An array of strings.
Chris@0:    */
Chris@0:   public function __construct($from_lines, $to_lines) {
Chris@0:     $eng = new DiffEngine();
Chris@0:     $this->edits = $eng->diff($from_lines, $to_lines);
Chris@0:     //$this->_check($from_lines, $to_lines);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Compute reversed Diff.
Chris@0:    *
Chris@0:    * SYNOPSIS:
Chris@0:    *
Chris@0:    *  $diff = new Diff($lines1, $lines2);
Chris@0:    *  $rev = $diff->reverse();
Chris@0:    * @return object
Chris@0:    *   A Diff object representing the inverse of the original diff.
Chris@0:    */
Chris@0:   public function reverse() {
Chris@0:     $rev = $this;
Chris@0:     $rev->edits = [];
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       $rev->edits[] = $edit->reverse();
Chris@0:     }
Chris@0:     return $rev;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Check for empty diff.
Chris@0:    *
Chris@0:    * @return bool True iff two sequences were identical.
Chris@0:    */
Chris@0:   public function isEmpty() {
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       if ($edit->type != 'copy') {
Chris@0:         return FALSE;
Chris@0:       }
Chris@0:     }
Chris@0:     return TRUE;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Compute the length of the Longest Common Subsequence (LCS).
Chris@0:    *
Chris@0:    * This is mostly for diagnostic purposed.
Chris@0:    *
Chris@0:    * @return int The length of the LCS.
Chris@0:    */
Chris@0:   public function lcs() {
Chris@0:     $lcs = 0;
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       if ($edit->type == 'copy') {
Chris@0:         $lcs += sizeof($edit->orig);
Chris@0:       }
Chris@0:     }
Chris@0:     return $lcs;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the original set of lines.
Chris@0:    *
Chris@0:    * This reconstructs the $from_lines parameter passed to the
Chris@0:    * constructor.
Chris@0:    *
Chris@0:    * @return array The original sequence of strings.
Chris@0:    */
Chris@0:   public function orig() {
Chris@0:     $lines = [];
Chris@0: 
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       if ($edit->orig) {
Chris@0:         array_splice($lines, sizeof($lines), 0, $edit->orig);
Chris@0:       }
Chris@0:     }
Chris@0:     return $lines;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the closing set of lines.
Chris@0:    *
Chris@0:    * This reconstructs the $to_lines parameter passed to the
Chris@0:    * constructor.
Chris@0:    *
Chris@0:    * @return array The sequence of strings.
Chris@0:    */
Chris@0:   public function closing() {
Chris@0:     $lines = [];
Chris@0: 
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       if ($edit->closing) {
Chris@0:         array_splice($lines, sizeof($lines), 0, $edit->closing);
Chris@0:       }
Chris@0:     }
Chris@0:     return $lines;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Check a Diff for validity.
Chris@0:    *
Chris@0:    * This is here only for debugging purposes.
Chris@0:    */
Chris@0:   public function check($from_lines, $to_lines) {
Chris@0:     if (serialize($from_lines) != serialize($this->orig())) {
Chris@0:       trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
Chris@0:     }
Chris@0:     if (serialize($to_lines) != serialize($this->closing())) {
Chris@0:       trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
Chris@0:     }
Chris@0: 
Chris@0:     $rev = $this->reverse();
Chris@0:     if (serialize($to_lines) != serialize($rev->orig())) {
Chris@0:       trigger_error("Reversed original doesn't match", E_USER_ERROR);
Chris@0:     }
Chris@0:     if (serialize($from_lines) != serialize($rev->closing())) {
Chris@0:       trigger_error("Reversed closing doesn't match", E_USER_ERROR);
Chris@0:     }
Chris@0: 
Chris@0:     $prevtype = 'none';
Chris@0:     foreach ($this->edits as $edit) {
Chris@0:       if ( $prevtype == $edit->type ) {
Chris@0:         trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
Chris@0:       }
Chris@0:       $prevtype = $edit->type;
Chris@0:     }
Chris@0: 
Chris@0:     $lcs = $this->lcs();
Chris@0:     trigger_error('Diff okay: LCS = ' . $lcs, E_USER_NOTICE);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the list of differences as an array of diff operations.
Chris@0:    *
Chris@0:    * @return \Drupal\Component\Diff\Engine\DiffOp[]
Chris@0:    *   The list of differences as an array of diff operations.
Chris@0:    */
Chris@0:   public function getEdits() {
Chris@0:     return $this->edits;
Chris@0:   }
Chris@0: 
Chris@0: }