wp-includes/Text/Diff/Engine/shell.php

   1 <?php
   2 /**
   3  * Class used internally by Diff to actually compute the diffs.
   4  *
   5  * This class uses the Unix `diff` program via shell_exec to compute the
   6  * differences between the two input arrays.
   7  *
   8  * Copyright 2007-2010 The Horde Project (http://www.horde.org/)
   9  *
  10  * See the enclosed file COPYING for license information (LGPL). If you did
  11  * not receive this file, see http://opensource.org/licenses/lgpl-license.php.
  12  *
  13  * @author  Milian Wolff <mail@milianw.de>
  14  * @package Text_Diff
  15  * @since   0.3.0
  16  */
  17 class Text_Diff_Engine_shell {
  18
  19     /**
  20      * Path to the diff executable
  21      *
  22      * @var string
  23      */
  24     var $_diffCommand = 'diff';
  25
  26     /**
  27      * Returns the array of differences.
  28      *
  29      * @param array $from_lines lines of text from old file
  30      * @param array $to_lines   lines of text from new file
  31      *
  32      * @return array all changes made (array with Text_Diff_Op_* objects)
  33      */
  34     function diff($from_lines, $to_lines)
  35     {
  36         array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
  37         array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
  38
  39         $temp_dir = Text_Diff::_getTempDir();
  40
  41         // Execute gnu diff or similar to get a standard diff file.
  42         $from_file = tempnam($temp_dir, 'Text_Diff');
  43         $to_file = tempnam($temp_dir, 'Text_Diff');
  44         $fp = fopen($from_file, 'w');
  45         fwrite($fp, implode("\n", $from_lines));
  46         fclose($fp);
  47         $fp = fopen($to_file, 'w');
  48         fwrite($fp, implode("\n", $to_lines));
  49         fclose($fp);
  50         $diff = shell_exec($this->_diffCommand . ' ' . $from_file . ' ' . $to_file);
  51         unlink($from_file);
  52         unlink($to_file);
  53
  54         if (is_null($diff)) {
  55             // No changes were made
  56             return array(new Text_Diff_Op_copy($from_lines));
  57         }
  58
  59         $from_line_no = 1;
  60         $to_line_no = 1;
  61         $edits = array();
  62
  63         // Get changed lines by parsing something like:
  64         // 0a1,2
  65         // 1,2c4,6
  66         // 1,5d6
  67         preg_match_all('#^(\d+)(?:,(\d+))?([adc])(\d+)(?:,(\d+))?$#m', $diff,
  68             $matches, PREG_SET_ORDER);
  69
  70         foreach ($matches as $match) {
  71             if (!isset($match[5])) {
  72                 // This paren is not set every time (see regex).
  73                 $match[5] = false;
  74             }
  75
  76             if ($match[3] == 'a') {
  77                 $from_line_no--;
  78             }
  79
  80             if ($match[3] == 'd') {
  81                 $to_line_no--;
  82             }
  83
  84             if ($from_line_no < $match[1] || $to_line_no < $match[4]) {
  85                 // copied lines
  86                 assert('$match[1] - $from_line_no == $match[4] - $to_line_no');
  87                 array_push($edits,
  88                     new Text_Diff_Op_copy(
  89                         $this->_getLines($from_lines, $from_line_no, $match[1] - 1),
  90                         $this->_getLines($to_lines, $to_line_no, $match[4] - 1)));
  91             }
  92
  93             switch ($match[3]) {
  94             case 'd':
  95                 // deleted lines
  96                 array_push($edits,
  97                     new Text_Diff_Op_delete(
  98                         $this->_getLines($from_lines, $from_line_no, $match[2])));
  99                 $to_line_no++;
 100                 break;
 101
 102             case 'c':
 103                 // changed lines
 104                 array_push($edits,
 105                     new Text_Diff_Op_change(
 106                         $this->_getLines($from_lines, $from_line_no, $match[2]),
 107                         $this->_getLines($to_lines, $to_line_no, $match[5])));
 108                 break;
 109
 110             case 'a':
 111                 // added lines
 112                 array_push($edits,
 113                     new Text_Diff_Op_add(
 114                         $this->_getLines($to_lines, $to_line_no, $match[5])));
 115                 $from_line_no++;
 116                 break;
 117             }
 118         }
 119
 120         if (!empty($from_lines)) {
 121             // Some lines might still be pending. Add them as copied
 122             array_push($edits,
 123                 new Text_Diff_Op_copy(
 124                     $this->_getLines($from_lines, $from_line_no,
 125                                      $from_line_no + count($from_lines) - 1),
 126                     $this->_getLines($to_lines, $to_line_no,
 127                                      $to_line_no + count($to_lines) - 1)));
 128         }
 129
 130         return $edits;
 131     }
 132
 133     /**
 134      * Get lines from either the old or new text
 135      *
 136      * @access private
 137      *
 138      * @param array &$text_lines Either $from_lines or $to_lines
 139      * @param int   &$line_no    Current line number
 140      * @param int   $end         Optional end line, when we want to chop more
 141      *                           than one line.
 142      *
 143      * @return array The chopped lines
 144      */
 145     function _getLines(&$text_lines, &$line_no, $end = false)
 146     {
 147         if (!empty($end)) {
 148             $lines = array();
 149             // We can shift even more
 150             while ($line_no <= $end) {
 151                 array_push($lines, array_shift($text_lines));
 152                 $line_no++;
 153             }
 154         } else {
 155             $lines = array(array_shift($text_lines));
 156             $line_no++;
 157         }
 158
 159         return $lines;
 160     }
 161
 162 }