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  * $Horde: framework/Text_Diff/Diff/Engine/shell.php,v 1.8 2008/01/04 10:07:50 jan Exp $
   9  *
  10  * Copyright 2007-2008 The Horde Project (http://www.horde.org/)
  11  *
  12  * See the enclosed file COPYING for license information (LGPL). If you did
  13  * not receive this file, see http://opensource.org/licenses/lgpl-license.php.
  14  *
  15  * @author  Milian Wolff <mail@milianw.de>
  16  * @package Text_Diff
  17  * @since   0.3.0
  18  */
  19 class Text_Diff_Engine_shell {
  20
  21     /**
  22      * Path to the diff executable
  23      *
  24      * @var string
  25      */
  26     var $_diffCommand = 'diff';
  27
  28     /**
  29      * Returns the array of differences.
  30      *
  31      * @param array $from_lines lines of text from old file
  32      * @param array $to_lines   lines of text from new file
  33      *
  34      * @return array all changes made (array with Text_Diff_Op_* objects)
  35      */
  36     function diff($from_lines, $to_lines)
  37     {
  38         array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
  39         array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
  40
  41         $temp_dir = Text_Diff::_getTempDir();
  42
  43         // Execute gnu diff or similar to get a standard diff file.
  44         $from_file = tempnam($temp_dir, 'Text_Diff');
  45         $to_file = tempnam($temp_dir, 'Text_Diff');
  46         $fp = fopen($from_file, 'w');
  47         fwrite($fp, implode("\n", $from_lines));
  48         fclose($fp);
  49         $fp = fopen($to_file, 'w');
  50         fwrite($fp, implode("\n", $to_lines));
  51         fclose($fp);
  52         $diff = shell_exec($this->_diffCommand . ' ' . $from_file . ' ' . $to_file);
  53         unlink($from_file);
  54         unlink($to_file);
  55
  56         if (is_null($diff)) {
  57             // No changes were made
  58             return array(new Text_Diff_Op_copy($from_lines));
  59         }
  60
  61         $from_line_no = 1;
  62         $to_line_no = 1;
  63         $edits = array();
  64
  65         // Get changed lines by parsing something like:
  66         // 0a1,2
  67         // 1,2c4,6
  68         // 1,5d6
  69         preg_match_all('#^(\d+)(?:,(\d+))?([adc])(\d+)(?:,(\d+))?$#m', $diff,
  70             $matches, PREG_SET_ORDER);
  71
  72         foreach ($matches as $match) {
  73             if (!isset($match[5])) {
  74                 // This paren is not set every time (see regex).
  75                 $match[5] = false;
  76             }
  77
  78             if ($match[3] == 'a') {
  79                 $from_line_no--;
  80             }
  81
  82             if ($match[3] == 'd') {
  83                 $to_line_no--;
  84             }
  85
  86             if ($from_line_no < $match[1] || $to_line_no < $match[4]) {
  87                 // copied lines
  88                 assert('$match[1] - $from_line_no == $match[4] - $to_line_no');
  89                 array_push($edits,
  90                     new Text_Diff_Op_copy(
  91                         $this->_getLines($from_lines, $from_line_no, $match[1] - 1),
  92                         $this->_getLines($to_lines, $to_line_no, $match[4] - 1)));
  93             }
  94
  95             switch ($match[3]) {
  96             case 'd':
  97                 // deleted lines
  98                 array_push($edits,
  99                     new Text_Diff_Op_delete(
 100                         $this->_getLines($from_lines, $from_line_no, $match[2])));
 101                 $to_line_no++;
 102                 break;
 103
 104             case 'c':
 105                 // changed lines
 106                 array_push($edits,
 107                     new Text_Diff_Op_change(
 108                         $this->_getLines($from_lines, $from_line_no, $match[2]),
 109                         $this->_getLines($to_lines, $to_line_no, $match[5])));
 110                 break;
 111
 112             case 'a':
 113                 // added lines
 114                 array_push($edits,
 115                     new Text_Diff_Op_add(
 116                         $this->_getLines($to_lines, $to_line_no, $match[5])));
 117                 $from_line_no++;
 118                 break;
 119             }
 120         }
 121
 122         if (!empty($from_lines)) {
 123             // Some lines might still be pending. Add them as copied
 124             array_push($edits,
 125                 new Text_Diff_Op_copy(
 126                     $this->_getLines($from_lines, $from_line_no,
 127                                      $from_line_no + count($from_lines) - 1),
 128                     $this->_getLines($to_lines, $to_line_no,
 129                                      $to_line_no + count($to_lines) - 1)));
 130         }
 131
 132         return $edits;
 133     }
 134
 135     /**
 136      * Get lines from either the old or new text
 137      *
 138      * @access private
 139      *
 140      * @param array &$text_lines Either $from_lines or $to_lines
 141      * @param int   &$line_no    Current line number
 142      * @param int   $end         Optional end line, when we want to chop more
 143      *                           than one line.
 144      *
 145      * @return array The chopped lines
 146      */
 147     function _getLines(&$text_lines, &$line_no, $end = false)
 148     {
 149         if (!empty($end)) {
 150             $lines = array();
 151             // We can shift even more
 152             while ($line_no <= $end) {
 153                 array_push($lines, array_shift($text_lines));
 154                 $line_no++;
 155             }
 156         } else {
 157             $lines = array(array_shift($text_lines));
 158             $line_no++;
 159         }
 160
 161         return $lines;
 162     }
 163
 164 }