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                 // Initialize $x0 and $y0 to prevent IDEs from getting confused.
  70                 $x0 = $y0 = 0;
  71                 foreach ( $diff->edits as $edit ) {
  72                         if ( $edit->type == 'copy' ) {
  73                                 if ( is_array( $block ) ) {
  74                                         if ( count( $edit->orig ) <= $nlead + $ntrail ) {
  75                                                 $block[] = $edit;
  76                                         } else {
  77                                                 if ( $ntrail ) {
  78                                                         $context = array_slice( $edit->orig, 0, $ntrail );
  79                                                         $block[] = new DiffOpCopy( $context );
  80                                                 }
  81                                                 $this->block( $x0, $ntrail + $xi - $x0,
  82                                                         $y0, $ntrail + $yi - $y0,
  83                                                         $block );
  84                                                 $block = false;
  85                                         }
  86                                 }
  87                                 $context = $edit->orig;
  88                         } else {
  89                                 if ( !is_array( $block ) ) {
  90                                         $context = array_slice( $context, count( $context ) - $nlead );
  91                                         $x0 = $xi - count( $context );
  92                                         $y0 = $yi - count( $context );
  93                                         $block = array();
  94                                         if ( $context ) {
  95                                                 $block[] = new DiffOpCopy( $context );
  96                                         }
  97                                 }
  98                                 $block[] = $edit;
  99                         }
 100
 101                         if ( $edit->orig ) {
 102                                 $xi += count( $edit->orig );
 103                         }
 104                         if ( $edit->closing ) {
 105                                 $yi += count( $edit->closing );
 106                         }
 107                 }
 108
 109                 if ( is_array( $block ) ) {
 110                         $this->block( $x0, $xi - $x0,
 111                                 $y0, $yi - $y0,
 112                                 $block );
 113                 }
 114
 115                 $end = $this->endDiff();
 116                 wfProfileOut( __METHOD__ );
 117
 118                 return $end;
 119         }
 120
 121         /**
 122          * @param int $xbeg
 123          * @param int $xlen
 124          * @param int $ybeg
 125          * @param int $ylen
 126          * @param $edits
 127          * @throws MWException
 128          */
 129         protected function block( $xbeg, $xlen, $ybeg, $ylen, &$edits ) {
 130                 wfProfileIn( __METHOD__ );
 131                 $this->startBlock( $this->blockHeader( $xbeg, $xlen, $ybeg, $ylen ) );
 132                 foreach ( $edits as $edit ) {
 133                         if ( $edit->type == 'copy' ) {
 134                                 $this->context( $edit->orig );
 135                         } elseif ( $edit->type == 'add' ) {
 136                                 $this->added( $edit->closing );
 137                         } elseif ( $edit->type == 'delete' ) {
 138                                 $this->deleted( $edit->orig );
 139                         } elseif ( $edit->type == 'change' ) {
 140                                 $this->changed( $edit->orig, $edit->closing );
 141                         } else {
 142                                 throw new MWException( "Unknown edit type: {$edit->type}" );
 143                         }
 144                 }
 145                 $this->endBlock();
 146                 wfProfileOut( __METHOD__ );
 147         }
 148
 149         protected function startDiff() {
 150                 ob_start();
 151         }
 152
 153         /**
 154          * @return string
 155          */
 156         protected function endDiff() {
 157                 $val = ob_get_contents();
 158                 ob_end_clean();
 159
 160                 return $val;
 161         }
 162
 163         /**
 164          * @param $xbeg
 165          * @param $xlen
 166          * @param $ybeg
 167          * @param $ylen
 168          * @return string
 169          */
 170         protected function blockHeader( $xbeg, $xlen, $ybeg, $ylen ) {
 171                 if ( $xlen > 1 ) {
 172                         $xbeg .= ',' . ( $xbeg + $xlen - 1 );
 173                 }
 174                 if ( $ylen > 1 ) {
 175                         $ybeg .= ',' . ( $ybeg + $ylen - 1 );
 176                 }
 177
 178                 return $xbeg . ( $xlen ? ( $ylen ? 'c' : 'd' ) : 'a' ) . $ybeg;
 179         }
 180
 181         protected function startBlock( $header ) {
 182                 echo $header . "\n";
 183         }
 184
 185         protected function endBlock() {
 186         }
 187
 188         /**
 189          * @param $lines
 190          * @param $prefix string
 191          */
 192         protected function lines( $lines, $prefix = ' ' ) {
 193                 foreach ( $lines as $line ) {
 194                         echo "$prefix $line\n";
 195                 }
 196         }
 197
 198         /**
 199          * @param $lines
 200          */
 201         protected function context( $lines ) {
 202                 $this->lines( $lines );
 203         }
 204
 205         /**
 206          * @param $lines
 207          */
 208         protected function added( $lines ) {
 209                 $this->lines( $lines, '>' );
 210         }
 211
 212         /**
 213          * @param $lines
 214          */
 215         protected function deleted( $lines ) {
 216                 $this->lines( $lines, '<' );
 217         }
 218
 219         /**
 220          * @param $orig
 221          * @param $closing
 222          */
 223         protected function changed( $orig, $closing ) {
 224                 $this->deleted( $orig );
 225                 echo "---\n";
 226                 $this->added( $closing );
 227         }
 228 }