includes/diff/DiffFormatter.php

   1 <?php
   2 /**
   3  * Base for diff rendering classes. Portions taken from phpwiki-1.3.3.
   4  *
   5  * Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
   6  * You may copy this code freely under the conditions of the GPL.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup DifferenceEngine
  25  */
  26
  27 /**
  28  * Base class for diff formatters
  29  *
  30  * This class formats the diff in classic diff format.
  31  * It is intended that this class be customized via inheritance,
  32  * to obtain fancier outputs.
  33  * @todo document
  34  * @ingroup DifferenceEngine
  35  */
  36 abstract class DiffFormatter {
  37         /** @var int Number of leading context "lines" to preserve.
  38          *
  39          * This should be left at zero for this class, but subclasses
  40          * may want to set this to other values.
  41          */
  42         protected $leadingContextLines = 0;
  43
  44         /** @var int Number of trailing context "lines" to preserve.
  45          *
  46          * This should be left at zero for this class, but subclasses
  47          * may want to set this to other values.
  48          */
  49         protected $trailingContextLines = 0;
  50
  51         /**
  52          * Format a diff.
  53          *
  54          * @param $diff Diff A Diff object.
  55          * @return string The formatted output.
  56          */
  57         public function format( $diff ) {
  58                 wfProfileIn( __METHOD__ );
  59
  60                 $xi = $yi = 1;
  61                 $block = false;
  62                 $context = array();
  63
  64                 $nlead = $this->leadingContextLines;
  65                 $ntrail = $this->trailingContextLines;
  66
  67                 $this->startDiff();
  68
  69                 foreach ( $diff->edits as $edit ) {
  70                         if ( $edit->type == 'copy' ) {
  71                                 if ( is_array( $block ) ) {
  72                                         if ( count( $edit->orig ) <= $nlead + $ntrail ) {
  73                                                 $block[] = $edit;
  74                                         } else {
  75                                                 if ( $ntrail ) {
  76                                                         $context = array_slice( $edit->orig, 0, $ntrail );
  77                                                         $block[] = new DiffOp_Copy( $context );
  78                                                 }
  79                                                 $this->block( $x0, $ntrail + $xi - $x0,
  80                                                         $y0, $ntrail + $yi - $y0,
  81                                                         $block );
  82                                                 $block = false;
  83                                         }
  84                                 }
  85                                 $context = $edit->orig;
  86                         } else {
  87                                 if ( !is_array( $block ) ) {
  88                                         $context = array_slice( $context, count( $context ) - $nlead );
  89                                         $x0 = $xi - count( $context );
  90                                         $y0 = $yi - count( $context );
  91                                         $block = array();
  92                                         if ( $context ) {
  93                                                 $block[] = new DiffOp_Copy( $context );
  94                                         }
  95                                 }
  96                                 $block[] = $edit;
  97                         }
  98
  99                         if ( $edit->orig ) {
 100                                 $xi += count( $edit->orig );
 101                         }
 102                         if ( $edit->closing ) {
 103                                 $yi += count( $edit->closing );
 104                         }
 105                 }
 106
 107                 if ( is_array( $block ) ) {
 108                         $this->block( $x0, $xi - $x0,
 109                                 $y0, $yi - $y0,
 110                                 $block );
 111                 }
 112
 113                 $end = $this->endDiff();
 114                 wfProfileOut( __METHOD__ );
 115
 116                 return $end;
 117         }
 118
 119         /**
 120          * @param $xbeg
 121          * @param $xlen
 122          * @param $ybeg
 123          * @param $ylen
 124          * @param $edits
 125          */
 126         protected function block( $xbeg, $xlen, $ybeg, $ylen, &$edits ) {
 127                 wfProfileIn( __METHOD__ );
 128                 $this->startBlock( $this->blockHeader( $xbeg, $xlen, $ybeg, $ylen ) );
 129                 foreach ( $edits as $edit ) {
 130                         if ( $edit->type == 'copy' ) {
 131                                 $this->context( $edit->orig );
 132                         } elseif ( $edit->type == 'add' ) {
 133                                 $this->added( $edit->closing );
 134                         } elseif ( $edit->type == 'delete' ) {
 135                                 $this->deleted( $edit->orig );
 136                         } elseif ( $edit->type == 'change' ) {
 137                                 $this->changed( $edit->orig, $edit->closing );
 138                         } else {
 139                                 throw new MWException( "Unknown edit type: {$edit->type}" );
 140                         }
 141                 }
 142                 $this->endBlock();
 143                 wfProfileOut( __METHOD__ );
 144         }
 145
 146         protected function startDiff() {
 147                 ob_start();
 148         }
 149
 150         /**
 151          * @return string
 152          */
 153         protected function endDiff() {
 154                 $val = ob_get_contents();
 155                 ob_end_clean();
 156
 157                 return $val;
 158         }
 159
 160         /**
 161          * @param $xbeg
 162          * @param $xlen
 163          * @param $ybeg
 164          * @param $ylen
 165          * @return string
 166          */
 167         protected function blockHeader( $xbeg, $xlen, $ybeg, $ylen ) {
 168                 if ( $xlen > 1 ) {
 169                         $xbeg .= ',' . ( $xbeg + $xlen - 1 );
 170                 }
 171                 if ( $ylen > 1 ) {
 172                         $ybeg .= ',' . ( $ybeg + $ylen - 1 );
 173                 }
 174
 175                 return $xbeg . ( $xlen ? ( $ylen ? 'c' : 'd' ) : 'a' ) . $ybeg;
 176         }
 177
 178         protected function startBlock( $header ) {
 179                 echo $header . "\n";
 180         }
 181
 182         protected function endBlock() {
 183         }
 184
 185         /**
 186          * @param $lines
 187          * @param $prefix string
 188          */
 189         protected function lines( $lines, $prefix = ' ' ) {
 190                 foreach ( $lines as $line ) {
 191                         echo "$prefix $line\n";
 192                 }
 193         }
 194
 195         /**
 196          * @param $lines
 197          */
 198         protected function context( $lines ) {
 199                 $this->lines( $lines );
 200         }
 201
 202         /**
 203          * @param $lines
 204          */
 205         protected function added( $lines ) {
 206                 $this->lines( $lines, '>' );
 207         }
 208
 209         /**
 210          * @param $lines
 211          */
 212         protected function deleted( $lines ) {
 213                 $this->lines( $lines, '<' );
 214         }
 215
 216         /**
 217          * @param $orig
 218          * @param $closing
 219          */
 220         protected function changed( $orig, $closing ) {
 221                 $this->deleted( $orig );
 222                 echo "---\n";
 223                 $this->added( $closing );
 224         }
 225 }