Merge "Make wikidiff3 the only diff engine"
[lhc/web/wiklou.git] / includes / diff / DairikiDiff.php
index bc57c93..e5e082f 100644 (file)
@@ -249,8 +249,8 @@ class DiffEngine {
                $edits = [];
                $xi = $yi = 0;
                while ( $xi < $n_from || $yi < $n_to ) {
-                       assert( '$yi < $n_to || $this->xchanged[$xi]' );
-                       assert( '$xi < $n_from || $this->ychanged[$yi]' );
+                       assert( $yi < $n_to || $this->xchanged[$xi] );
+                       assert( $xi < $n_from || $this->ychanged[$yi] );
 
                        // Skip matching "snake".
                        $copy = [];
@@ -292,290 +292,10 @@ class DiffEngine {
         * @param string[] $to_lines
         */
        private function diffLocal( $from_lines, $to_lines ) {
-               global $wgExternalDiffEngine;
-
-               if ( $wgExternalDiffEngine == 'wikidiff3' ) {
-                       // wikidiff3
-                       $wikidiff3 = new WikiDiff3();
-                       $wikidiff3->diff( $from_lines, $to_lines );
-                       $this->xchanged = $wikidiff3->removed;
-                       $this->ychanged = $wikidiff3->added;
-                       unset( $wikidiff3 );
-               } else {
-                       // old diff
-                       $n_from = count( $from_lines );
-                       $n_to = count( $to_lines );
-                       $this->xchanged = $this->ychanged = [];
-                       $this->xv = $this->yv = [];
-                       $this->xind = $this->yind = [];
-                       $this->seq = [];
-                       $this->in_seq = [];
-                       $this->lcs = 0;
-
-                       // Skip leading common lines.
-                       for ( $skip = 0; $skip < $n_from && $skip < $n_to; $skip++ ) {
-                               if ( $from_lines[$skip] !== $to_lines[$skip] ) {
-                                       break;
-                               }
-                               $this->xchanged[$skip] = $this->ychanged[$skip] = false;
-                       }
-                       // Skip trailing common lines.
-                       $xi = $n_from;
-                       $yi = $n_to;
-                       for ( $endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++ ) {
-                               if ( $from_lines[$xi] !== $to_lines[$yi] ) {
-                                       break;
-                               }
-                               $this->xchanged[$xi] = $this->ychanged[$yi] = false;
-                       }
-
-                       // Ignore lines which do not exist in both files.
-                       for ( $xi = $skip; $xi < $n_from - $endskip; $xi++ ) {
-                               $xhash[$this->lineHash( $from_lines[$xi] )] = 1;
-                       }
-
-                       for ( $yi = $skip; $yi < $n_to - $endskip; $yi++ ) {
-                               $line = $to_lines[$yi];
-                               $this->ychanged[$yi] = empty( $xhash[$this->lineHash( $line )] );
-                               if ( $this->ychanged[$yi] ) {
-                                       continue;
-                               }
-                               $yhash[$this->lineHash( $line )] = 1;
-                               $this->yv[] = $line;
-                               $this->yind[] = $yi;
-                       }
-                       for ( $xi = $skip; $xi < $n_from - $endskip; $xi++ ) {
-                               $line = $from_lines[$xi];
-                               $this->xchanged[$xi] = empty( $yhash[$this->lineHash( $line )] );
-                               if ( $this->xchanged[$xi] ) {
-                                       continue;
-                               }
-                               $this->xv[] = $line;
-                               $this->xind[] = $xi;
-                       }
-
-                       // Find the LCS.
-                       $this->compareSeq( 0, count( $this->xv ), 0, count( $this->yv ) );
-               }
-       }
-
-       /**
-        * Returns the whole line if it's small enough, or the MD5 hash otherwise
-        *
-        * @param string $line
-        *
-        * @return string
-        */
-       private function lineHash( $line ) {
-               if ( strlen( $line ) > self::MAX_XREF_LENGTH ) {
-                       return md5( $line );
-               } else {
-                       return $line;
-               }
-       }
-
-       /**
-        * Divide the Largest Common Subsequence (LCS) of the sequences
-        * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
-        * sized segments.
-        *
-        * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an
-        * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
-        * sub sequences.  The first sub-sequence is contained in [X0, X1),
-        * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
-        * that (X0, Y0) == (XOFF, YOFF) and
-        * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
-        *
-        * This function assumes that the first lines of the specified portions
-        * of the two files do not match, and likewise that the last lines do not
-        * match.  The caller must trim matching lines from the beginning and end
-        * of the portions it is going to specify.
-        *
-        * @param int $xoff
-        * @param int $xlim
-        * @param int $yoff
-        * @param int $ylim
-        * @param int $nchunks
-        *
-        * @return array List of two elements, integer and array[].
-        */
-       private function diag( $xoff, $xlim, $yoff, $ylim, $nchunks ) {
-               $flip = false;
-
-               if ( $xlim - $xoff > $ylim - $yoff ) {
-                       // Things seems faster (I'm not sure I understand why)
-                       // when the shortest sequence in X.
-                       $flip = true;
-                       list( $xoff, $xlim, $yoff, $ylim ) = [ $yoff, $ylim, $xoff, $xlim ];
-               }
-
-               if ( $flip ) {
-                       for ( $i = $ylim - 1; $i >= $yoff; $i-- ) {
-                               $ymatches[$this->xv[$i]][] = $i;
-                       }
-               } else {
-                       for ( $i = $ylim - 1; $i >= $yoff; $i-- ) {
-                               $ymatches[$this->yv[$i]][] = $i;
-                       }
-               }
-
-               $this->lcs = 0;
-               $this->seq[0] = $yoff - 1;
-               $this->in_seq = [];
-               $ymids[0] = [];
-
-               $numer = $xlim - $xoff + $nchunks - 1;
-               $x = $xoff;
-               for ( $chunk = 0; $chunk < $nchunks; $chunk++ ) {
-                       if ( $chunk > 0 ) {
-                               for ( $i = 0; $i <= $this->lcs; $i++ ) {
-                                       $ymids[$i][$chunk - 1] = $this->seq[$i];
-                               }
-                       }
-
-                       $x1 = $xoff + (int)( ( $numer + ( $xlim - $xoff ) * $chunk ) / $nchunks );
-                       // @codingStandardsIgnoreStart Ignore Squiz.WhiteSpace.SemicolonSpacing.Incorrect
-                       for ( ; $x < $x1; $x++ ) {
-                               // @codingStandardsIgnoreEnd
-                               $line = $flip ? $this->yv[$x] : $this->xv[$x];
-                               if ( empty( $ymatches[$line] ) ) {
-                                       continue;
-                               }
-
-                               $k = 0;
-                               $matches = $ymatches[$line];
-                               reset( $matches );
-                               while ( list( , $y ) = each( $matches ) ) {
-                                       if ( empty( $this->in_seq[$y] ) ) {
-                                               $k = $this->lcsPos( $y );
-                                               assert( '$k > 0' );
-                                               $ymids[$k] = $ymids[$k - 1];
-                                               break;
-                                       }
-                               }
-
-                               while ( list( , $y ) = each( $matches ) ) {
-                                       if ( $y > $this->seq[$k - 1] ) {
-                                               assert( '$y < $this->seq[$k]' );
-                                               // Optimization: this is a common case:
-                                               // next match is just replacing previous match.
-                                               $this->in_seq[$this->seq[$k]] = false;
-                                               $this->seq[$k] = $y;
-                                               $this->in_seq[$y] = 1;
-                                       } elseif ( empty( $this->in_seq[$y] ) ) {
-                                               $k = $this->lcsPos( $y );
-                                               assert( '$k > 0' );
-                                               $ymids[$k] = $ymids[$k - 1];
-                                       }
-                               }
-                       }
-               }
-
-               $seps[] = $flip ? [ $yoff, $xoff ] : [ $xoff, $yoff ];
-               $ymid = $ymids[$this->lcs];
-               for ( $n = 0; $n < $nchunks - 1; $n++ ) {
-                       $x1 = $xoff + (int)( ( $numer + ( $xlim - $xoff ) * $n ) / $nchunks );
-                       $y1 = $ymid[$n] + 1;
-                       $seps[] = $flip ? [ $y1, $x1 ] : [ $x1, $y1 ];
-               }
-               $seps[] = $flip ? [ $ylim, $xlim ] : [ $xlim, $ylim ];
-
-               return [ $this->lcs, $seps ];
-       }
-
-       /**
-        * @param int $ypos
-        *
-        * @return int
-        */
-       private function lcsPos( $ypos ) {
-               $end = $this->lcs;
-               if ( $end == 0 || $ypos > $this->seq[$end] ) {
-                       $this->seq[++$this->lcs] = $ypos;
-                       $this->in_seq[$ypos] = 1;
-
-                       return $this->lcs;
-               }
-
-               $beg = 1;
-               while ( $beg < $end ) {
-                       $mid = (int)( ( $beg + $end ) / 2 );
-                       if ( $ypos > $this->seq[$mid] ) {
-                               $beg = $mid + 1;
-                       } else {
-                               $end = $mid;
-                       }
-               }
-
-               assert( '$ypos != $this->seq[$end]' );
-
-               $this->in_seq[$this->seq[$end]] = false;
-               $this->seq[$end] = $ypos;
-               $this->in_seq[$ypos] = 1;
-
-               return $end;
-       }
-
-       /**
-        * Find LCS of two sequences.
-        *
-        * The results are recorded in the vectors $this->{x,y}changed[], by
-        * storing a 1 in the element for each line that is an insertion
-        * or deletion (ie. is not in the LCS).
-        *
-        * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
-        *
-        * Note that XLIM, YLIM are exclusive bounds.
-        * All line numbers are origin-0 and discarded lines are not counted.
-        *
-        * @param int $xoff
-        * @param int $xlim
-        * @param int $yoff
-        * @param int $ylim
-        */
-       private function compareSeq( $xoff, $xlim, $yoff, $ylim ) {
-               // Slide down the bottom initial diagonal.
-               while ( $xoff < $xlim && $yoff < $ylim && $this->xv[$xoff] == $this->yv[$yoff] ) {
-                       ++$xoff;
-                       ++$yoff;
-               }
-
-               // Slide up the top initial diagonal.
-               while ( $xlim > $xoff && $ylim > $yoff
-                       && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]
-               ) {
-                       --$xlim;
-                       --$ylim;
-               }
-
-               if ( $xoff == $xlim || $yoff == $ylim ) {
-                       $lcs = 0;
-               } else {
-                       // This is ad hoc but seems to work well.
-                       // $nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
-                       // $nchunks = max(2,min(8,(int)$nchunks));
-                       $nchunks = min( 7, $xlim - $xoff, $ylim - $yoff ) + 1;
-                       list( $lcs, $seps ) = $this->diag( $xoff, $xlim, $yoff, $ylim, $nchunks );
-               }
-
-               if ( $lcs == 0 ) {
-                       // X and Y sequences have no common subsequence:
-                       // mark all changed.
-                       while ( $yoff < $ylim ) {
-                               $this->ychanged[$this->yind[$yoff++]] = 1;
-                       }
-                       while ( $xoff < $xlim ) {
-                               $this->xchanged[$this->xind[$xoff++]] = 1;
-                       }
-               } else {
-                       // Use the partitions to split this problem into subproblems.
-                       reset( $seps );
-                       $pt1 = $seps[0];
-                       while ( $pt2 = next( $seps ) ) {
-                               $this->compareSeq( $pt1[0], $pt2[0], $pt1[1], $pt2[1] );
-                               $pt1 = $pt2;
-                       }
-               }
+               $wikidiff3 = new WikiDiff3();
+               $wikidiff3->diff( $from_lines, $to_lines );
+               $this->xchanged = $wikidiff3->removed;
+               $this->ychanged = $wikidiff3->added;
        }
 
        /**
@@ -595,7 +315,7 @@ class DiffEngine {
                $i = 0;
                $j = 0;
 
-               assert( 'count($lines) == count($changed)' );
+               assert( count( $lines ) == count( $changed ) );
                $len = count( $lines );
                $other_len = count( $other_changed );
 
@@ -616,7 +336,7 @@ class DiffEngine {
                        }
 
                        while ( $i < $len && !$changed[$i] ) {
-                               assert( '$j < $other_len && ! $other_changed[$j]' );
+                               assert( $j < $other_len && ! $other_changed[$j] );
                                $i++;
                                $j++;
                                while ( $j < $other_len && $other_changed[$j] ) {
@@ -653,11 +373,11 @@ class DiffEngine {
                                        while ( $start > 0 && $changed[$start - 1] ) {
                                                $start--;
                                        }
-                                       assert( '$j > 0' );
+                                       assert( $j > 0 );
                                        while ( $other_changed[--$j] ) {
                                                continue;
                                        }
-                                       assert( '$j >= 0 && !$other_changed[$j]' );
+                                       assert( $j >= 0 && !$other_changed[$j] );
                                }
 
                                /*
@@ -681,7 +401,7 @@ class DiffEngine {
                                                $i++;
                                        }
 
-                                       assert( '$j < $other_len && ! $other_changed[$j]' );
+                                       assert( $j < $other_len && ! $other_changed[$j] );
                                        $j++;
                                        if ( $j < $other_len && $other_changed[$j] ) {
                                                $corresponding = $i;
@@ -699,11 +419,11 @@ class DiffEngine {
                        while ( $corresponding < $i ) {
                                $changed[--$start] = 1;
                                $changed[--$i] = 0;
-                               assert( '$j > 0' );
+                               assert( $j > 0 );
                                while ( $other_changed[--$j] ) {
                                        continue;
                                }
-                               assert( '$j >= 0 && !$other_changed[$j]' );
+                               assert( $j >= 0 && !$other_changed[$j] );
                        }
                }
        }
@@ -867,8 +587,8 @@ class MappedDiff extends Diff {
        public function __construct( $from_lines, $to_lines,
                $mapped_from_lines, $mapped_to_lines ) {
 
-               assert( 'count( $from_lines ) == count( $mapped_from_lines )' );
-               assert( 'count( $to_lines ) == count( $mapped_to_lines )' );
+               assert( count( $from_lines ) == count( $mapped_from_lines ) );
+               assert( count( $to_lines ) == count( $mapped_to_lines ) );
 
                parent::__construct( $mapped_from_lines, $mapped_to_lines );
 
@@ -959,7 +679,7 @@ class HWLDFWordAccumulator {
                                $this->flushLine( $tag );
                                $word = substr( $word, 1 );
                        }
-                       assert( '!strstr( $word, "\n" )' );
+                       assert( !strstr( $word, "\n" ) );
                        $this->group .= $word;
                }
        }