jenkins-bot has submitted this change and it was merged.
Change subject: Merge Wikidiff3 into DiffEngine
......................................................................
Merge Wikidiff3 into DiffEngine
Change-Id: Ib4d083a5200824e4d032de6921c375e455e77fb2
---
M autoload.php
M includes/diff/DairikiDiff.php
R includes/diff/DiffEngine.php
3 files changed, 199 insertions(+), 235 deletions(-)
Approvals:
MaxSem: Looks good to me, approved
Jforrester: Looks good to me, approved
jenkins-bot: Verified
diff --git a/autoload.php b/autoload.php
index 2f7a9ba..4875fcb 100644
--- a/autoload.php
+++ b/autoload.php
@@ -352,7 +352,7 @@
'DerivativeResourceLoaderContext' => __DIR__ .
'/includes/resourceloader/DerivativeResourceLoaderContext.php',
'DescribeFileOp' => __DIR__ . '/includes/filebackend/FileOp.php',
'Diff' => __DIR__ . '/includes/diff/DairikiDiff.php',
- 'DiffEngine' => __DIR__ . '/includes/diff/DairikiDiff.php',
+ 'DiffEngine' => __DIR__ . '/includes/diff/DiffEngine.php',
'DiffFormatter' => __DIR__ . '/includes/diff/DiffFormatter.php',
'DiffHistoryBlob' => __DIR__ . '/includes/HistoryBlob.php',
'DiffOp' => __DIR__ . '/includes/diff/DairikiDiff.php',
@@ -1087,7 +1087,7 @@
'RCFeedFormatter' => __DIR__ . '/includes/rcfeed/RCFeedFormatter.php',
'RSSFeed' => __DIR__ . '/includes/Feed.php',
'RandomPage' => __DIR__ . '/includes/specials/SpecialRandompage.php',
- 'RangeDifference' => __DIR__ . '/includes/diff/WikiDiff3.php',
+ 'RangeDifference' => __DIR__ . '/includes/diff/DiffEngine.php',
'RawAction' => __DIR__ . '/includes/actions/RawAction.php',
'RawMessage' => __DIR__ . '/includes/Message.php',
'ReadOnlyError' => __DIR__ . '/includes/exception/ReadOnlyError.php',
@@ -1505,7 +1505,6 @@
'WebRequestUpload' => __DIR__ . '/includes/WebRequestUpload.php',
'WebResponse' => __DIR__ . '/includes/WebResponse.php',
'WikiCategoryPage' => __DIR__ . '/includes/page/WikiCategoryPage.php',
- 'WikiDiff3' => __DIR__ . '/includes/diff/WikiDiff3.php',
'WikiExporter' => __DIR__ . '/includes/export/WikiExporter.php',
'WikiFilePage' => __DIR__ . '/includes/page/WikiFilePage.php',
'WikiImporter' => __DIR__ . '/includes/import/WikiImporter.php',
diff --git a/includes/diff/DairikiDiff.php b/includes/diff/DairikiDiff.php
index ec2689c..dbb32e6 100644
--- a/includes/diff/DairikiDiff.php
+++ b/includes/diff/DairikiDiff.php
@@ -192,235 +192,6 @@
}
/**
- * 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 {
- protected $xchanged, $ychanged;
-
- /**
- * @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
* @private
diff --git a/includes/diff/WikiDiff3.php b/includes/diff/DiffEngine.php
similarity index 75%
rename from includes/diff/WikiDiff3.php
rename to includes/diff/DiffEngine.php
index f35e30f..75e8791 100644
--- a/includes/diff/WikiDiff3.php
+++ b/includes/diff/DiffEngine.php
@@ -31,12 +31,16 @@
*
* This implementation supports an upper bound on the execution time.
*
+ * 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
+ *
* Complexity: O((M + N)D) worst case time, O(M + N + D^2) expected time, O(M
+ N) space
*
- * @author Guy Van den Broeck
+ * @author Guy Van den Broeck, Geoffrey T. Dairiki, Tim Starling
* @ingroup DifferenceEngine
*/
-class WikiDiff3 {
+class DiffEngine {
// Input variables
private $from;
@@ -62,7 +66,197 @@
$this->powLimit = $powLimit;
}
- public function diff( /*array*/ $from, /*array*/ $to ) {
+ /**
+ * @param string[] $from_lines
+ * @param string[] $to_lines
+ *
+ * @return DiffOp[]
+ */
+ public function diff( $from_lines, $to_lines ) {
+
+ // Diff and store locally
+ $this->diffInternal( $from_lines, $to_lines );
+
+ // Merge edits when possible
+ $this->shiftBoundaries( $from_lines, $this->removed,
$this->added );
+ $this->shiftBoundaries( $to_lines, $this->added, $this->removed
);
+
+ // 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 || $this->removed[$xi] );
+ assert( $xi < $n_from || $this->added[$yi] );
+
+ // Skip matching "snake".
+ $copy = [];
+ while ( $xi < $n_from && $yi < $n_to
+ && !$this->removed[$xi] &&
!$this->added[$yi]
+ ) {
+ $copy[] = $from_lines[$xi++];
+ ++$yi;
+ }
+ if ( $copy ) {
+ $edits[] = new DiffOpCopy( $copy );
+ }
+
+ // Find deletes & adds.
+ $delete = [];
+ while ( $xi < $n_from && $this->removed[$xi] ) {
+ $delete[] = $from_lines[$xi++];
+ }
+
+ $add = [];
+ while ( $yi < $n_to && $this->added[$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;
+ }
+
+ /**
+ * 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] );
+ }
+ }
+ }
+
+ protected function diffInternal( /*array*/ $from, /*array*/ $to ) {
// remember initial lengths
$m = count( $from );
$n = count( $to );
--
To view, visit https://gerrit.wikimedia.org/r/285548
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: merged
Gerrit-Change-Id: Ib4d083a5200824e4d032de6921c375e455e77fb2
Gerrit-PatchSet: 9
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: MaxSem <[email protected]>
Gerrit-Reviewer: Jforrester <[email protected]>
Gerrit-Reviewer: MaxSem <[email protected]>
Gerrit-Reviewer: jenkins-bot <>
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