only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffEngine.php @@ -0,0 +1,456 @@ + 2, and some optimizations) + * are my own. + * + * Line length limits for robustness added by Tim Starling, 2005-08-31 + * + * @author Geoffrey T. Dairiki, Tim Starling + * @private + * @subpackage DifferenceEngine + */ +class DiffEngine { + + const USE_ASSERTS = FALSE; + + const MAX_XREF_LENGTH = 10000; + + public function diff($from_lines, $to_lines) { + + $n_from = sizeof($from_lines); + $n_to = sizeof($to_lines); + + $this->xchanged = $this->ychanged = array(); + $this->xv = $this->yv = array(); + $this->xind = $this->yind = array(); + unset($this->seq); + unset($this->in_seq); + unset($this->lcs); + + // 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->_line_hash($from_lines[$xi])] = 1; + } + + for ($yi = $skip; $yi < $n_to - $endskip; $yi++) { + $line = $to_lines[$yi]; + if ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) { + continue; + } + $yhash[$this->_line_hash($line)] = 1; + $this->yv[] = $line; + $this->yind[] = $yi; + } + for ($xi = $skip; $xi < $n_from - $endskip; $xi++) { + $line = $from_lines[$xi]; + if ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) { + continue; + } + $this->xv[] = $line; + $this->xind[] = $xi; + } + + // Find the LCS. + $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv)); + + // Merge edits when possible + $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged); + $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged); + + // Compute the edit operations. + $edits = array(); + $xi = $yi = 0; + while ($xi < $n_from || $yi < $n_to) { + $this::USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]); + $this::USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]); + + // Skip matching "snake". + $copy = array(); + 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. + $delete = array(); + while ($xi < $n_from && $this->xchanged[$xi]) { + $delete[] = $from_lines[$xi++]; + } + $add = array(); + while ($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 $edits; + } + + /** + * Returns the whole line if it's small enough, or the MD5 hash otherwise. + */ + protected function _line_hash($line) { + if (Unicode::strlen($line) > $this::MAX_XREF_LENGTH) { + return md5($line); + } + else { + return $line; + } + } + + + /** + * Divide the Largest Common Subsequence (LCS) of the sequences + * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally + * sized segments. + * + * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an + * array of NCHUNKS+1 (X, Y) indexes giving the diving points between + * sub sequences. The first sub-sequence is contained in [X0, X1), + * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note + * that (X0, Y0) == (XOFF, YOFF) and + * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM). + * + * This function assumes that the first lines of the specified portions + * of the two files do not match, and likewise that the last lines do not + * match. The caller must trim matching lines from the beginning and end + * of the portions it is going to specify. + */ + protected function _diag($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, $ylim) = array($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 = array(); + $ymids[0] = array(); + + $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); + for ( ; $x < $x1; $x++) { + $line = $flip ? $this->yv[$x] : $this->xv[$x]; + if (empty($ymatches[$line])) { + continue; + } + $matches = $ymatches[$line]; + reset($matches); + while (list ($junk, $y) = each($matches)) { + if (empty($this->in_seq[$y])) { + $k = $this->_lcs_pos($y); + $this::USE_ASSERTS && assert($k > 0); + $ymids[$k] = $ymids[$k-1]; + break; + } + } + while (list ($junk, $y) = each($matches)) { + if ($y > $this->seq[$k-1]) { + $this::USE_ASSERTS && assert($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 = $this->_lcs_pos($y); + $this::USE_ASSERTS && assert($k > 0); + $ymids[$k] = $ymids[$k-1]; + } + } + } + } + + $seps[] = $flip ? array($yoff, $xoff) : array($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[] = $flip ? array($y1, $x1) : array($x1, $y1); + } + $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim); + + return array($this->lcs, $seps); + } + + protected function _lcs_pos($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; + } + } + + $this::USE_ASSERTS && assert($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 $this->{x,y}changed[], by + * storing a 1 in the element for each line that is an insertion + * or deletion (ie. is not in the LCS). + * + * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1. + * + * Note that XLIM, YLIM are exclusive bounds. + * All line numbers are origin-0 and discarded lines are not counted. + */ + protected function _compareseq($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 = $pt2; + } + } + } + + /** + * Adjust inserts/deletes of identical lines to join changes + * as much as possible. + * + * We do something when a run of changed lines include a + * line at one end and has an excluded, identical line at the other. + * We are free to choose which identical line is included. + * `compareseq' usually chooses the one at the beginning, + * but usually it is cleaner to consider the following identical line + * to be the "change". + * + * This is extracted verbatim from analyze.c (GNU diffutils-2.7). + */ + protected function _shift_boundaries($lines, &$changed, $other_changed) { + $i = 0; + $j = 0; + + $this::USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)'); + $len = sizeof($lines); + $other_len = sizeof($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]) { + $this::USE_ASSERTS && assert('$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--; + } + $this::USE_ASSERTS && assert('$j > 0'); + while ($other_changed[--$j]) { + continue; + } + $this::USE_ASSERTS && assert('$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++; + } + $this::USE_ASSERTS && assert('$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; + $this::USE_ASSERTS && assert('$j > 0'); + while ($other_changed[--$j]) { + continue; + } + $this::USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]'); + } + } + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffOp.php @@ -0,0 +1,26 @@ +orig ? sizeof($this->orig) : 0; + } + + public function nclosing() { + return $this->closing ? sizeof($this->closing) : 0; + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffOpAdd.php @@ -0,0 +1,21 @@ +closing = $lines; + $this->orig = FALSE; + } + + public function reverse() { + return new DiffOpDelete($this->closing); + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffOpChange.php @@ -0,0 +1,21 @@ +orig = $orig; + $this->closing = $closing; + } + + public function reverse() { + return new DiffOpChange($this->closing, $this->orig); + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffOpCopy.php @@ -0,0 +1,24 @@ +orig = $orig; + $this->closing = $closing; + } + + public function reverse() { + return new DiffOpCopy($this->closing, $this->orig); + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/DiffOpDelete.php @@ -0,0 +1,21 @@ +orig = $lines; + $this->closing = FALSE; + } + + public function reverse() { + return new DiffOpAdd($this->orig); + } +} only in patch2: unchanged: --- /dev/null +++ b/core/lib/Drupal/Component/Diff/Engine/HWLDFWordAccumulator.php @@ -0,0 +1,80 @@ +group !== '') { + if ($this->tag == 'mark') { + $this->line .= '' . String::checkPlain($this->group) . ''; + } + else { + $this->line .= String::checkPlain($this->group); + } + } + $this->group = ''; + $this->tag = $new_tag; + } + + protected function _flushLine($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, $this::NBSP); + } + $this->line = ''; + } + + public function addWords($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); + $word = Unicode::substr($word, 1); + } + assert(!strstr($word, "\n")); + $this->group .= $word; + } + } + + public function getLines() { + $this->_flushLine('~done'); + return $this->lines; + } +}