Merge "Add hook for cleaning up data that depends on purged recentchanges rows"
[lhc/web/wiklou.git] / includes / diff / DairikiDiff.php
index e5e082f..d76af31 100644 (file)
@@ -67,7 +67,7 @@ abstract class DiffOp {
 
        /**
         * @param int $i
-        * @return string|null
+        * @return string[]|string|null
         */
        public function getClosing( $i = null ) {
                if ( $i === null ) {
@@ -191,244 +191,6 @@ class DiffOpChange extends DiffOp {
        }
 }
 
-/**
- * Class used internally by Diff to actually compute the diffs.
- *
- * The algorithm used here is mostly lifted from the perl module
- * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
- *     http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
- *
- * More ideas are taken from:
- *     http://www.ics.uci.edu/~eppstein/161/960229.html
- *
- * Some ideas (and a bit of code) are from analyze.c, from GNU
- * diffutils-2.7, which can be found at:
- *     ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
- *
- * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
- * are my own.
- *
- * Line length limits for robustness added by Tim Starling, 2005-08-31
- * Alternative implementation added by Guy Van den Broeck, 2008-07-30
- *
- * @author Geoffrey T. Dairiki, Tim Starling, Guy Van den Broeck
- * @private
- * @ingroup DifferenceEngine
- */
-class DiffEngine {
-       const MAX_XREF_LENGTH = 10000;
-
-       protected $xchanged, $ychanged;
-
-       protected $xv = [], $yv = [];
-       protected $xind = [], $yind = [];
-
-       protected $seq = [], $in_seq = [];
-
-       protected $lcs = 0;
-
-       /**
-        * @param string[] $from_lines
-        * @param string[] $to_lines
-        *
-        * @return DiffOp[]
-        */
-       public function diff( $from_lines, $to_lines ) {
-
-               // Diff and store locally
-               $this->diffLocal( $from_lines, $to_lines );
-
-               // Merge edits when possible
-               $this->shiftBoundaries( $from_lines, $this->xchanged, $this->ychanged );
-               $this->shiftBoundaries( $to_lines, $this->ychanged, $this->xchanged );
-
-               // Compute the edit operations.
-               $n_from = count( $from_lines );
-               $n_to = count( $to_lines );
-
-               $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] );
-
-                       // Skip matching "snake".
-                       $copy = [];
-                       while ( $xi < $n_from && $yi < $n_to
-                               && !$this->xchanged[$xi] && !$this->ychanged[$yi]
-                       ) {
-                               $copy[] = $from_lines[$xi++];
-                               ++$yi;
-                       }
-                       if ( $copy ) {
-                               $edits[] = new DiffOpCopy( $copy );
-                       }
-
-                       // Find deletes & adds.
-                       $delete = [];
-                       while ( $xi < $n_from && $this->xchanged[$xi] ) {
-                               $delete[] = $from_lines[$xi++];
-                       }
-
-                       $add = [];
-                       while ( $yi < $n_to && $this->ychanged[$yi] ) {
-                               $add[] = $to_lines[$yi++];
-                       }
-
-                       if ( $delete && $add ) {
-                               $edits[] = new DiffOpChange( $delete, $add );
-                       } elseif ( $delete ) {
-                               $edits[] = new DiffOpDelete( $delete );
-                       } elseif ( $add ) {
-                               $edits[] = new DiffOpAdd( $add );
-                       }
-               }
-
-               return $edits;
-       }
-
-       /**
-        * @param string[] $from_lines
-        * @param string[] $to_lines
-        */
-       private function diffLocal( $from_lines, $to_lines ) {
-               $wikidiff3 = new WikiDiff3();
-               $wikidiff3->diff( $from_lines, $to_lines );
-               $this->xchanged = $wikidiff3->removed;
-               $this->ychanged = $wikidiff3->added;
-       }
-
-       /**
-        * Adjust inserts/deletes of identical lines to join changes
-        * as much as possible.
-        *
-        * We do something when a run of changed lines include a
-        * line at one end and has an excluded, identical line at the other.
-        * We are free to choose which identical line is included.
-        * `compareseq' usually chooses the one at the beginning,
-        * but usually it is cleaner to consider the following identical line
-        * to be the "change".
-        *
-        * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
-        */
-       private function shiftBoundaries( $lines, &$changed, $other_changed ) {
-               $i = 0;
-               $j = 0;
-
-               assert( count( $lines ) == count( $changed ) );
-               $len = count( $lines );
-               $other_len = count( $other_changed );
-
-               while ( 1 ) {
-                       /*
-                        * Scan forwards to find beginning of another run of changes.
-                        * Also keep track of the corresponding point in the other file.
-                        *
-                        * Throughout this code, $i and $j are adjusted together so that
-                        * the first $i elements of $changed and the first $j elements
-                        * of $other_changed both contain the same number of zeros
-                        * (unchanged lines).
-                        * Furthermore, $j is always kept so that $j == $other_len or
-                        * $other_changed[$j] == false.
-                        */
-                       while ( $j < $other_len && $other_changed[$j] ) {
-                               $j++;
-                       }
-
-                       while ( $i < $len && !$changed[$i] ) {
-                               assert( $j < $other_len && ! $other_changed[$j] );
-                               $i++;
-                               $j++;
-                               while ( $j < $other_len && $other_changed[$j] ) {
-                                       $j++;
-                               }
-                       }
-
-                       if ( $i == $len ) {
-                               break;
-                       }
-
-                       $start = $i;
-
-                       // Find the end of this run of changes.
-                       while ( ++$i < $len && $changed[$i] ) {
-                               continue;
-                       }
-
-                       do {
-                               /*
-                                * Record the length of this run of changes, so that
-                                * we can later determine whether the run has grown.
-                                */
-                               $runlength = $i - $start;
-
-                               /*
-                                * Move the changed region back, so long as the
-                                * previous unchanged line matches the last changed one.
-                                * This merges with previous changed regions.
-                                */
-                               while ( $start > 0 && $lines[$start - 1] == $lines[$i - 1] ) {
-                                       $changed[--$start] = 1;
-                                       $changed[--$i] = false;
-                                       while ( $start > 0 && $changed[$start - 1] ) {
-                                               $start--;
-                                       }
-                                       assert( $j > 0 );
-                                       while ( $other_changed[--$j] ) {
-                                               continue;
-                                       }
-                                       assert( $j >= 0 && !$other_changed[$j] );
-                               }
-
-                               /*
-                                * Set CORRESPONDING to the end of the changed run, at the last
-                                * point where it corresponds to a changed run in the other file.
-                                * CORRESPONDING == LEN means no such point has been found.
-                                */
-                               $corresponding = $j < $other_len ? $i : $len;
-
-                               /*
-                                * Move the changed region forward, so long as the
-                                * first changed line matches the following unchanged one.
-                                * This merges with following changed regions.
-                                * Do this second, so that if there are no merges,
-                                * the changed region is moved forward as far as possible.
-                                */
-                               while ( $i < $len && $lines[$start] == $lines[$i] ) {
-                                       $changed[$start++] = false;
-                                       $changed[$i++] = 1;
-                                       while ( $i < $len && $changed[$i] ) {
-                                               $i++;
-                                       }
-
-                                       assert( $j < $other_len && ! $other_changed[$j] );
-                                       $j++;
-                                       if ( $j < $other_len && $other_changed[$j] ) {
-                                               $corresponding = $i;
-                                               while ( $j < $other_len && $other_changed[$j] ) {
-                                                       $j++;
-                                               }
-                                       }
-                               }
-                       } while ( $runlength != $i - $start );
-
-                       /*
-                        * If possible, move the fully-merged run of changes
-                        * back to a corresponding run in the other file.
-                        */
-                       while ( $corresponding < $i ) {
-                               $changed[--$start] = 1;
-                               $changed[--$i] = 0;
-                               assert( $j > 0 );
-                               while ( $other_changed[--$j] ) {
-                                       continue;
-                               }
-                               assert( $j >= 0 && !$other_changed[$j] );
-                       }
-               }
-       }
-}
-
 /**
  * Class representing a 'diff' between two sequences of strings.
  * @todo document
@@ -443,15 +205,22 @@ class Diff {
        public $edits;
 
        /**
-        * Constructor.
+        * @var int If this diff complexity is exceeded, a ComplexityException is thrown
+        *          0 means no limit.
+        */
+       protected $bailoutComplexity = 0;
+
+       /**
         * Computes diff between sequences of strings.
         *
         * @param string[] $from_lines An array of strings.
         *   Typically these are lines from a file.
         * @param string[] $to_lines An array of strings.
+        * @throws \MediaWiki\Diff\ComplexityException
         */
        public function __construct( $from_lines, $to_lines ) {
                $eng = new DiffEngine;
+               $eng->setBailoutComplexity( $this->bailoutComplexity );
                $this->edits = $eng->diff( $from_lines, $to_lines );
        }
 
@@ -559,236 +328,7 @@ class Diff {
 }
 
 /**
- * @todo document, bad name.
- * @private
- * @ingroup DifferenceEngine
- */
-class MappedDiff extends Diff {
-       /**
-        * Constructor.
-        *
-        * Computes diff between sequences of strings.
-        *
-        * This can be used to compute things like
-        * case-insensitve diffs, or diffs which ignore
-        * changes in white-space.
-        *
-        * @param string[] $from_lines An array of strings.
-        *   Typically these are lines from a file.
-        * @param string[] $to_lines An array of strings.
-        * @param string[] $mapped_from_lines This array should
-        *   have the same size number of elements as $from_lines.
-        *   The elements in $mapped_from_lines and
-        *   $mapped_to_lines are what is actually compared
-        *   when computing the diff.
-        * @param string[] $mapped_to_lines This array should
-        *   have the same number of elements as $to_lines.
-        */
-       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 ) );
-
-               parent::__construct( $mapped_from_lines, $mapped_to_lines );
-
-               $xi = $yi = 0;
-               $editCount = count( $this->edits );
-               for ( $i = 0; $i < $editCount; $i++ ) {
-                       $orig = &$this->edits[$i]->orig;
-                       if ( is_array( $orig ) ) {
-                               $orig = array_slice( $from_lines, $xi, count( $orig ) );
-                               $xi += count( $orig );
-                       }
-
-                       $closing = &$this->edits[$i]->closing;
-                       if ( is_array( $closing ) ) {
-                               $closing = array_slice( $to_lines, $yi, count( $closing ) );
-                               $yi += count( $closing );
-                       }
-               }
-       }
-}
-
-/**
- * Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
+ * @deprecated Alias for WordAccumulator, to be soon removed
  */
-
-/**
- * @todo document
- * @private
- * @ingroup DifferenceEngine
- */
-class HWLDFWordAccumulator {
-       public $insClass = ' class="diffchange diffchange-inline"';
-       public $delClass = ' class="diffchange diffchange-inline"';
-
-       private $lines = [];
-       private $line = '';
-       private $group = '';
-       private $tag = '';
-
-       /**
-        * @param string $new_tag
-        */
-       private function flushGroup( $new_tag ) {
-               if ( $this->group !== '' ) {
-                       if ( $this->tag == 'ins' ) {
-                               $this->line .= "<ins{$this->insClass}>" .
-                                       htmlspecialchars( $this->group ) . '</ins>';
-                       } elseif ( $this->tag == 'del' ) {
-                               $this->line .= "<del{$this->delClass}>" .
-                                       htmlspecialchars( $this->group ) . '</del>';
-                       } else {
-                               $this->line .= htmlspecialchars( $this->group );
-                       }
-               }
-               $this->group = '';
-               $this->tag = $new_tag;
-       }
-
-       /**
-        * @param string $new_tag
-        */
-       private function flushLine( $new_tag ) {
-               $this->flushGroup( $new_tag );
-               if ( $this->line != '' ) {
-                       array_push( $this->lines, $this->line );
-               } else {
-                       # make empty lines visible by inserting an NBSP
-                       array_push( $this->lines, '&#160;' );
-               }
-               $this->line = '';
-       }
-
-       /**
-        * @param string[] $words
-        * @param string $tag
-        */
-       public function addWords( $words, $tag = '' ) {
-               if ( $tag != $this->tag ) {
-                       $this->flushGroup( $tag );
-               }
-
-               foreach ( $words as $word ) {
-                       // new-line should only come as first char of word.
-                       if ( $word == '' ) {
-                               continue;
-                       }
-                       if ( $word[0] == "\n" ) {
-                               $this->flushLine( $tag );
-                               $word = substr( $word, 1 );
-                       }
-                       assert( !strstr( $word, "\n" ) );
-                       $this->group .= $word;
-               }
-       }
-
-       /**
-        * @return string[]
-        */
-       public function getLines() {
-               $this->flushLine( '~done' );
-
-               return $this->lines;
-       }
-}
-
-/**
- * @todo document
- * @private
- * @ingroup DifferenceEngine
- */
-class WordLevelDiff extends MappedDiff {
-       const MAX_LINE_LENGTH = 10000;
-
-       /**
-        * @param string[] $orig_lines
-        * @param string[] $closing_lines
-        */
-       public function __construct( $orig_lines, $closing_lines ) {
-
-               list( $orig_words, $orig_stripped ) = $this->split( $orig_lines );
-               list( $closing_words, $closing_stripped ) = $this->split( $closing_lines );
-
-               parent::__construct( $orig_words, $closing_words,
-                       $orig_stripped, $closing_stripped );
-       }
-
-       /**
-        * @param string[] $lines
-        *
-        * @return array[]
-        */
-       private function split( $lines ) {
-
-               $words = [];
-               $stripped = [];
-               $first = true;
-               foreach ( $lines as $line ) {
-                       # If the line is too long, just pretend the entire line is one big word
-                       # This prevents resource exhaustion problems
-                       if ( $first ) {
-                               $first = false;
-                       } else {
-                               $words[] = "\n";
-                               $stripped[] = "\n";
-                       }
-                       if ( strlen( $line ) > self::MAX_LINE_LENGTH ) {
-                               $words[] = $line;
-                               $stripped[] = $line;
-                       } else {
-                               $m = [];
-                               if ( preg_match_all( '/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
-                                       $line, $m )
-                               ) {
-                                       foreach ( $m[0] as $word ) {
-                                               $words[] = $word;
-                                       }
-                                       foreach ( $m[1] as $stripped_word ) {
-                                               $stripped[] = $stripped_word;
-                                       }
-                               }
-                       }
-               }
-
-               return [ $words, $stripped ];
-       }
-
-       /**
-        * @return string[]
-        */
-       public function orig() {
-               $orig = new HWLDFWordAccumulator;
-
-               foreach ( $this->edits as $edit ) {
-                       if ( $edit->type == 'copy' ) {
-                               $orig->addWords( $edit->orig );
-                       } elseif ( $edit->orig ) {
-                               $orig->addWords( $edit->orig, 'del' );
-                       }
-               }
-               $lines = $orig->getLines();
-
-               return $lines;
-       }
-
-       /**
-        * @return string[]
-        */
-       public function closing() {
-               $closing = new HWLDFWordAccumulator;
-
-               foreach ( $this->edits as $edit ) {
-                       if ( $edit->type == 'copy' ) {
-                               $closing->addWords( $edit->closing );
-                       } elseif ( $edit->closing ) {
-                               $closing->addWords( $edit->closing, 'ins' );
-                       }
-               }
-               $lines = $closing->getLines();
-
-               return $lines;
-       }
-
+class HWLDFWordAccumulator extends MediaWiki\Diff\WordAccumulator {
 }