From 99dc6df38adf0a80ab43e8871c3994e0da5417ca Mon Sep 17 00:00:00 2001 From: Guy Sartorelli Date: Wed, 11 Jan 2023 10:45:26 +1300 Subject: [PATCH] API Replace thirdparty difflib with maintained lib --- composer.json | 1 + src/View/Parsers/Diff.php | 404 +++++++----- tests/php/View/Parsers/DiffTest.php | 158 ++++- thirdparty/difflib/difflib.php | 911 ---------------------------- 4 files changed, 382 insertions(+), 1092 deletions(-) delete mode 100644 thirdparty/difflib/difflib.php diff --git a/composer.json b/composer.json index 67fb3246e..4f505bbdc 100644 --- a/composer.json +++ b/composer.json @@ -33,6 +33,7 @@ "monolog/monolog": "^3.2.0", "nikic/php-parser": "^4.15.0", "psr/container": "^1.1 || ^2.0", + "sebastian/diff": "^4.0", "silverstripe/config": "^2", "silverstripe/assets": "^2", "silverstripe/vendor-plugin": "^2", diff --git a/src/View/Parsers/Diff.php b/src/View/Parsers/Diff.php index 3521fa43c..022d19fbc 100644 --- a/src/View/Parsers/Diff.php +++ b/src/View/Parsers/Diff.php @@ -2,32 +2,258 @@ namespace SilverStripe\View\Parsers; -use InvalidArgumentException; +use Masterminds\HTML5\Elements; +use SebastianBergmann\Diff\Differ; use SilverStripe\Core\Convert; use SilverStripe\Core\Injector\Injector; -require_once 'difflib/difflib.php'; - /** - * Class representing a 'diff' between two sequences of strings. + * Class representing a 'diff' between two sequences of HTML strings. */ -class Diff extends \Diff +class Diff { - public static $html_cleaner_class = null; + private const OLD_VAL = 'old'; + private const NEW_VAL = 'new'; + + private static ?Differ $differ = null; + + public static ?string $html_cleaner_class = null; + + /** + * Get a diff between two sets of HTML content. The result is an HTML fragment which can be added directly + * into the DOM. elements are used to indicate new content, and elements are used to indicate + * removed content. + * + * @param bool $escape If true, the HTML in $from and $to will be escaped after the diff operation is performed. + */ + public static function compareHtml(string|array $from, string|array $to, bool $escape = false): string + { + // Get HTML chunks even if we're going to escape it later + // The diff algorithm sees "some" as a single piece rather than "" and "some" being separate + $from = self::explodeToHtmlChunks($from); + $to = self::explodeToHtmlChunks($to); + + // Diff the chunks + $differ = self::getDiffer(); + $diff = $differ->diffToArray($from, $to); + + // If we aren't escaping the HTML, convert the first diff into clean HTML blocks and then run a new diff + // on the blocks to get an end result that doesn't have broken HTML + if (!$escape) { + $diifAsBlocks = self::convertDiffToHtmlBlocks($diff); + $diff = $differ->diffToArray($diifAsBlocks[self::OLD_VAL], $diifAsBlocks[self::NEW_VAL]); + } + + $diff = self::createFinalDiffBlocks($diff, $escape); + + // Take the diff and slap the appropriate and tags in place + $content = ''; + foreach ($diff as $edit) { + list($value, $type) = $edit; + if (is_array($value)) { + $value = implode(' ', $value); + } + if ($escape) { + $value = Convert::raw2xml($value); + } + + switch ($type) { + case Differ::OLD: + $content .= ' ' . $value . ' '; + break; + + case Differ::ADDED: + $content .= ' ' . $value . ' '; + break; + + case Differ::REMOVED: + $content .= ' ' . $value . ' '; + break; + } + } + + return self::cleanHTML($content); + } + + /** + * Takes a final diff and pulls the distinct tokens into related blocks + * i.e. we avoid having multiple separate additions/subtractions in a row + * + * Similar to SebastianBergmann\Diff\Output\AbstractChunkOutputBuilder::getCommonChunks but it's HTML aware. + */ + private static function createFinalDiffBlocks(array $diff, bool $escaped): array + { + $blocks = []; + $building = null; + $openTagsInBlock = 0; + + foreach ($diff as $edit) { + list($value, $type) = $edit; + $isClosingTag = !$escaped && str_starts_with($value, ' + * + * - Some text + * + Other text + * + * -

+ * + * We don't want to end up breaking up the HTML like this: + *

SomeOther text

 + * Instead we want to retain the valid HTML like this: + *

Some text

 + *

Other text

 + */ + private static function convertDiffToHtmlBlocks(array $diff): array + { + $openTagsInBlock[self::OLD_VAL] = $openTagsInBlock[self::NEW_VAL] = 0; + $htmlBlocks[self::OLD_VAL] = $htmlBlocks[self::NEW_VAL] = []; + + foreach ($diff as $edit) { + list($value, $type) = $edit; + switch ($type) { + case Differ::OLD: + if ($value === '') { + break; + } + self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::OLD_VAL, false, $value); + self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::NEW_VAL, false, $value); + break; + + case Differ::ADDED: + self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::NEW_VAL, true, $value); + break; + + case Differ::REMOVED: + self::addToHtmlBlocks($htmlBlocks, $openTagsInBlock, self::OLD_VAL, true, $value); + break; + } + } + return $htmlBlocks; + } + + /** + * Add an intermediate diff value to the appropriate HTML block + */ + private static function addToHtmlBlocks( + array &$htmlBlocks, + array &$openTagsInBlock, + string $oldOrNew, + bool $lookForTag, + string $value + ): void + { + $alreadyMidBlock = $openTagsInBlock[$oldOrNew] > 0; + $canAddTagsToBlock = $lookForTag || $alreadyMidBlock; + + if ($alreadyMidBlock) { + // If we haven't closed all tags in the block, this value is part of the previous HTML block + $htmlBlocks[$oldOrNew][count($htmlBlocks[$oldOrNew]) - 1] .= ' ' . $value; + } else { + // Otherwise it's part of a new block + $htmlBlocks[$oldOrNew][] = $value; + } + + if ($canAddTagsToBlock && self::isOpeningNonVoidTag($value)) { + // If we're mid block or explicitly looking for new tags, we should add any new non-void tags to the block + $openTagsInBlock[$oldOrNew]++; + } elseif ($alreadyMidBlock && str_starts_with($value, ']/', $value, $matches); + return isset($matches[1]) && Elements::isElement($matches[1]) && !Elements::isA($matches[1], Elements::VOID_TAG); + } + + /** + * Takes a long HTML string (or array of strings) and breaks it up into chunks of HTML + * e.g. '
Some Text
' becomes ['
', 'Some', 'Text', '
'] + * + * @param string|array $content If passed as an array, values will be concatenated with a comma. + */ + private static function explodeToHtmlChunks(string|array $content): array + { + if (is_array($content)) { + $content = array_filter($content, 'is_scalar'); + // Convert array to CSV + $content = implode(',', $content); + } + + $content = str_replace([' ', '<', '>'], [' ',' <', '> '], $content); + $candidateChunks = preg_split('/[\s]+/', $content); + $chunks = []; + $currentChunk = ''; + + foreach ($candidateChunks as $item) { + if ($item === '') { + continue; + } + // If we've started a chunk, keep going until we close the tag. + if ($currentChunk !== '') { + $currentChunk .= ' ' . $item; + if (!str_ends_with($item, '>')) { + continue; + } else { + $chunks[] = $currentChunk; + $currentChunk = ''; + continue; + } + } + + // If we open a tag, start a new chunk. + if (str_starts_with($item, '<') && !str_ends_with($item, '>')) { + $currentChunk = $item; + continue; + } + + // If we're not starting or continuing a tag chunk, just add this as its own chunk. + $chunks[] = $item; + } + + return $chunks; + } /** * Attempt to clean invalid HTML, which messes up diffs. * This cleans code if possible, using an instance of HTMLCleaner * - * NB: By default, only extremely simple tidying is performed, - * by passing through DomDocument::loadHTML and saveXML - * - * @param string $content HTML content - * @param HTMLCleaner $cleaner Optional instance of a HTMLCleaner class to + * @param ?HTMLCleaner $cleaner Optional instance of a HTMLCleaner class to * use, overriding self::$html_cleaner_class - * @return mixed|string */ - public static function cleanHTML($content, $cleaner = null) + private static function cleanHTML(string $content, ?HTMLCleaner $cleaner = null): string { if (!$cleaner) { if (self::$html_cleaner_class && class_exists(self::$html_cleaner_class)) { @@ -38,6 +264,7 @@ class Diff extends \Diff } } + /** @var HTMLCleaner $cleaner */ if ($cleaner) { $content = $cleaner->cleanHTML($content); } else { @@ -47,157 +274,16 @@ class Diff extends \Diff } // Remove empty and tags because browsers hate them - $content = preg_replace('/<(ins|del)[^>]*\/>/', '', $content ?? ''); + $content = preg_replace('/<(ins|del)[^>]*\/>/', '', $content); return $content; } - /** - * @param string $from - * @param string $to - * @param bool $escape - * @return string - */ - public static function compareHTML($from, $to, $escape = false) + private static function getDiffer(): Differ { - // First split up the content into words and tags - $set1 = self::getHTMLChunks($from); - $set2 = self::getHTMLChunks($to); - - // Diff that - $diff = new Diff($set1, $set2); - - $tagStack[1] = $tagStack[2] = 0; - $rechunked[1] = $rechunked[2] = []; - - // Go through everything, converting edited tags (and their content) into single chunks. Otherwise - // the generated HTML gets crusty - foreach ($diff->edits as $edit) { - $lookForTag = false; - $stuffFor = []; - switch ($edit->type) { - case 'copy': - $lookForTag = false; - $stuffFor[1] = $edit->orig; - $stuffFor[2] = $edit->orig; - break; - - case 'change': - $lookForTag = true; - $stuffFor[1] = $edit->orig; - $stuffFor[2] = $edit->final; - break; - - case 'add': - $lookForTag = true; - $stuffFor[1] = null; - $stuffFor[2] = $edit->final; - break; - - case 'delete': - $lookForTag = true; - $stuffFor[1] = $edit->orig; - $stuffFor[2] = null; - break; - } - - foreach ($stuffFor as $listName => $chunks) { - if ($chunks) { - foreach ($chunks as $item) { - // $tagStack > 0 indicates that we should be tag-building - if ($tagStack[$listName]) { - $rechunked[$listName][sizeof($rechunked[$listName])-1] .= ' ' . $item; - } else { - $rechunked[$listName][] = $item; - } - - if ($lookForTag - && !$tagStack[$listName] - && isset($item[0]) - && $item[0] == "<" - && substr($item ?? '', 0, 2) != "edits as $edit) { - $orig = ($escape) ? Convert::raw2xml($edit->orig) : $edit->orig; - $final = ($escape) ? Convert::raw2xml($edit->final) : $edit->final; - - switch ($edit->type) { - case 'copy': - $content .= " " . implode(" ", $orig) . " "; - break; - - case 'change': - $content .= " " . implode(" ", $final) . " "; - $content .= " " . implode(" ", $orig) . " "; - break; - - case 'add': - $content .= " " . implode(" ", $final) . " "; - break; - - case 'delete': - $content .= " " . implode(" ", $orig) . " "; - break; - } - } - - return self::cleanHTML($content); - } - - /** - * @param string|bool|array $content If passed as an array, values will be concatenated with a comma. - * @return array - */ - public static function getHTMLChunks($content) - { - if ($content && !is_string($content) && !is_array($content) && !is_numeric($content) && !is_bool($content)) { - throw new InvalidArgumentException('$content parameter needs to be a string or array'); - } - if (is_bool($content)) { - // Convert boolean to strings - $content = $content ? "true" : "false"; - } - if (is_array($content)) { - $content = array_filter($content ?? [], 'is_scalar'); - // Convert array to CSV - $content = implode(',', $content); - } - - $content = str_replace([" ", "<", ">"], [" "," <", "> "], $content ?? ''); - $candidateChunks = preg_split("/[\t\r\n ]+/", $content ?? ''); - $chunks = []; - for ($i = 0; $i < count($candidateChunks ?? []); $i++) { - $item = $candidateChunks[$i]; - if (isset($item[0]) && $item[0] == "<") { - $newChunk = $item; - while ($item[strlen($item)-1] != ">") { - if (++$i >= count($candidateChunks ?? [])) { - break; - } - $item = $candidateChunks[$i]; - $newChunk .= ' ' . $item; - } - $chunks[] = $newChunk; - } else { - $chunks[] = $item; - } - } - return $chunks; + return self::$differ; } } diff --git a/tests/php/View/Parsers/DiffTest.php b/tests/php/View/Parsers/DiffTest.php index 3eab9c66c..85ee8b21b 100644 --- a/tests/php/View/Parsers/DiffTest.php +++ b/tests/php/View/Parsers/DiffTest.php @@ -8,6 +8,118 @@ use SilverStripe\View\Parsers\Diff; class DiffTest extends SapphireTest { + /** + * Most if not all other tests strip out the whitespace from comparisons to avoid complexities with checking + * if the actual HTML content is correct, since whitespace in HTML isn't all that vital and the algorithm + * can add some extra spaces where they're not stricly necessary but don't affect anything. + * + * This test is here to ensure that spaces _are_ kept where they're actually needed (i.e. between text) + */ + public function testKeepsSpacesBetweenText() + { + $from = 'Some text more text'; + $to = 'Other text more text'; + $diff = Diff::compareHtml($from, $to); + $this->assertEquals('Some Other text more text', $diff, false); + + // Note that the end result here isn't perfect (there are new spaces where there weren't before)... + // If we make improvements later on that keep only the original spaces, that would be preferred. + // This test is more here to protect against any unexpected changes to the spacing, so that we can make an intentional + // decision as to whether those changes are desirable. + $diff = Diff::compareHtml($from, $to, true); + $this->assertEquals('<span> Some Other text </span> <span> more text </span>', $diff, true); + } + + public function provideCompareHtml(): array + { + return [ + [ + 'from' => '

Some text

', + 'to' => '

Other text

', + 'escape' => false, + 'expected' => '

SomeOther text

', + ], + [ + 'from' => '

Some text

', + 'to' => 'Other text', + 'escape' => false, + 'expected' => '

Some text

Other text', + ], + [ + 'from' => '

Some text

', + 'to' => '

Other text

', + 'escape' => false, + 'expected' => '

Some textOther text

', + ], + [ + 'from' => '

About

', + 'to' => '

About

', + 'escape' => false, + 'expected' => '

About

About

', + ], + [ + 'from' => '

About

A comprehensive Library

', + 'to' => '

About

A comprehensive

', + 'escape' => false, + 'expected' => '

About

A comprehensive Library

A comprehensive

', + ], + [ + 'from' => '

Some textmore stuff

', + 'to' => '

Some text

more stuff

', + 'escape' => false, + 'expected' => '

Sometextmorestuff

morestuff

', + ], + // Same examples as above, but with escaped HTML + [ + 'from' => '

Some text

', + 'to' => '

Other text

', + 'escape' => true, + 'expected' => '<p><span>SomeOther text</span></p>', + ], + [ + 'from' => '

Some text

', + 'to' => 'Other text', + 'escape' => true, + 'expected' => '<p><span>SomeOther text</span></p>', + ], + [ + 'from' => '

Some text

', + 'to' => '

Other text

', + 'escape' => true, + 'expected' => '<p><span>SomeOther text</span></p>', + ], + [ + 'from' => '

About

', + 'to' => '

About

', + 'escape' => true, + // Note: This sees the whole h2 tag as being changed because of the initial call to explodeToHtmlChunks. + // There is room to improve this in the future, but care would have to be taken not to aversely affect other scenarios. + 'expected' => '<h2 class="mb-3 h4"><h2 class="mb-3 h2">About</h2>', + ], + [ + 'from' => '

About

A comprehensive Library

', + 'to' => '

About

A comprehensive

', + 'escape' => true, + 'expected' => '<div class="BorderGrid-cell"><h2 class="mb-3 h4">About</h2><span class="etc"><p class="f4 my-3">A comprehensive Library</p></span></div>', + ], + [ + 'from' => '

Some textmore stuff

', + 'to' => '

Some text

more stuff

', + 'escape' => true, + 'expected' => '<p><span>Some text</span><span></p><p>more stuff</span></p>', + ], + ]; + } + + /** + * @dataProvider provideCompareHtml + */ + public function testCompareHTML(string|array $from, string|array $to, bool $escape, string $expected) + { + $diff = Diff::compareHtml($from, $to, $escape); + $this->assertEquals($this->removeWhiteSpace($expected), $this->removeWhiteSpace($diff)); + } + /** * @see https://groups.google.com/forum/#!topic/silverstripe-dev/yHcluCvuszo */ @@ -18,12 +130,12 @@ class DiffTest extends SapphireTest return; } - $from = " + $from = '
- - + + - + @@ -32,29 +144,24 @@ class DiffTest extends SapphireTest -
Row 1
Row 1
Row 2 Row 2
Row 3
"; + '; - $to = " + $to = '
- - + + - + -
Row 1
Row 1
Row 2 Row 2
"; + '; - $expected = "" . $to . "" . "" . $from . ""; - $compare = Diff::compareHTML($from, $to); + $expected = '' . $from . '' . '' . $to . ''; + $compare = Diff::compareHtml($from, $to); - // Very hard to debug this way, wouldn't need to do this if PHP had an *actual* DOM parsing lib, - // and not just the poor excuse that is DOMDocument - $compare = preg_replace('/[\s\t\n\r]*/', '', $compare ?? ''); - $expected = preg_replace('/[\s\t\n\r]*/', '', $expected ?? ''); - - $this->assertEquals($expected, $compare); + $this->assertEquals($this->removeWhiteSpace($expected), $this->removeWhiteSpace($compare)); } /** @@ -72,8 +179,10 @@ class DiffTest extends SapphireTest // We're cheating our test a little bit here, because depending on what HTML cleaner you have, you'll get // spaces added or not added around the tags. - $expected = "/^ *$sentenceOne<\/del> *$sentenceTwo *$sentenceOne<\/ins> *$/"; - $actual = Diff::compareHTML($from, $to); + $quotedOne = preg_quote($sentenceOne, '/'); + $quotedTwo = preg_quote($sentenceTwo, '/'); + $expected = '/^ *' . $quotedOne . '<\/del> *' . $quotedTwo . ' *' . $quotedOne . '<\/ins> *$/'; + $actual = Diff::compareHtml($from, $to); $this->assertMatchesRegularExpression($expected, $actual); } @@ -82,9 +191,14 @@ class DiffTest extends SapphireTest { $from = ['Lorem', ['array here please ignore'], 'ipsum dolor']; $to = 'Lorem,ipsum'; - $expected = "/^Lorem,ipsum *dolor<\/del> *$/"; - $actual = Diff::compareHTML($from, $to); + $expected = '/^Lorem,ipsum *dolor<\/del> *$/'; + $actual = Diff::compareHtml($from, $to); $this->assertMatchesRegularExpression($expected, $actual); } + + private function removeWhiteSpace(string $value): string + { + return preg_replace('/[\s]*/', '', $value); + } } diff --git a/thirdparty/difflib/difflib.php b/thirdparty/difflib/difflib.php deleted file mode 100644 index 319349ad5..000000000 --- a/thirdparty/difflib/difflib.php +++ /dev/null @@ -1,911 +0,0 @@ - - * - * This file is part of PhpWiki. - * - * PhpWiki is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * PhpWiki is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with PhpWiki; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - */ - -// difflib.php -// -// A PHP diff engine for phpwiki. - -abstract class DiffOp -{ - public $type; - public $orig; - public $final; - - abstract public function reverse(); - - public function norig() - { - return $this->orig ? sizeof($this->orig) : 0; - } - - public function nfinal() - { - return $this->final ? sizeof($this->final) : 0; - } -} - -class DiffOp_Copy extends DiffOp -{ - public $type = 'copy'; - - function __construct($orig, $final = false) - { - if (!is_array($final)) - $final = $orig; - $this->orig = $orig; - $this->final = $final; - } - - public function reverse() - { - return new DiffOp_Copy($this->final, $this->orig); - } -} - -class DiffOp_Delete extends DiffOp -{ - public $type = 'delete'; - - function __construct($lines) - { - $this->orig = $lines; - $this->final = false; - } - - public function reverse() - { - return new DiffOp_Add($this->orig); - } -} - -class DiffOp_Add extends DiffOp -{ - public $type = 'add'; - - function __construct($lines) - { - $this->final = $lines; - $this->orig = false; - } - - public function reverse() - { - return new DiffOp_Delete($this->final); - } -} - -class DiffOp_Change extends DiffOp -{ - public $type = 'change'; - - function __construct($orig, $final) - { - $this->orig = $orig; - $this->final = $final; - } - - public function reverse() - { - return new DiffOp_Change($this->final, $this->orig); - } -} - -/** - * 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 are (and a bit of code) are from 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 - * - * Finally, some ideas (subdivision by NCHUNKS > 2, and some optimizations) - * are my own. - * - * @author Geoffrey T. Dairiki - * @access private - */ -class DiffEngine -{ - public $xchanged; - public $ychanged; - public $xv; - public $yv; - public $xind; - public $yind; - public $lcs; - public $seq; - public $in_seq; - - public function diff($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++) - $xhash[$from_lines[$xi]] = 1; - for ($yi = $skip; $yi < $n_to - $endskip; $yi++) { - $line = $to_lines[$yi]; - if (($this->ychanged[$yi] = empty($xhash[$line]))) - continue; - $yhash[$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($yhash[$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 < $n_to) { - assert($yi < $n_to || $this->xchanged[$xi]); - 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) - $edits[] = new DiffOp_Copy($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) - $edits[] = new DiffOp_Change($delete, $add); - elseif ($delete) - $edits[] = new DiffOp_Delete($delete); - elseif ($add) - $edits[] = new DiffOp_Add($add); - } - return $edits; - } - - /* Divide the Largest Common Subsequence (LCS) of the sequences - * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally - * sized segments. - * - * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an - * array of NCHUNKS+1 (X, Y) indexes giving the diving points between - * sub sequences. The first sub-sequence is contained in [X0, X1), - * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note - * that (X0, Y0) == (XOFF, YOFF) and - * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM). - * - * This function assumes that the first lines of the specified portions - * of the two files do not match, and likewise that the last lines do not - * match. The caller must trim matching lines from the beginning and end - * of the portions it is going to specify. - */ - private function diag($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, $ylim) - = array($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); - $pointer = 0; - foreach ($matches as $y) { - $pointer++; - if (empty($this->in_seq[$y])) { - $k = $this->lcs_pos($y); - assert($k > 0); - $ymids[$k] = $ymids[$k - 1]; - break; - } - } - foreach (array_slice($matches ?? [], $pointer ?? 0) as $y) { - if ($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 = $this->lcs_pos($y); - 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, $seps); - } - - private function lcs_pos($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 = $mid; - } - - assert($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 $this->{x,y}changed[], by - * storing a 1 in the element for each line that is an insertion - * or deletion (ie. is not in the LCS). - * - * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1. - * - * Note that XLIM, YLIM are exclusive bounds. - * All line numbers are origin-0 and discarded lines are not counted. - */ - private function compareseq($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 = $pt2; - } - } - } - - /* Adjust inserts/deletes of identical lines to join changes - * as much as possible. - * - * We do something when a run of changed lines include a - * line at one end and has an excluded, identical line at the other. - * We are free to choose which identical line is included. - * `compareseq' usually chooses the one at the beginning, - * but usually it is cleaner to consider the following identical line - * to be the "change". - * - * This is extracted verbatim from analyze.c (GNU diffutils-2.7). - */ - private function shift_boundaries($lines, &$changed, $other_changed) - { - $i = 0; - $j = 0; - - assert(sizeof($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[$i]) { - assert($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. - */ -class Diff -{ - public $edits; - - /** - * Computes diff between sequences of strings. - * - * @param $from_lines array An array of strings. - * (Typically these are lines from a file.) - * @param $to_lines array An array of strings. - */ - function __construct($from_lines, $to_lines) - { - $eng = new DiffEngine(); - $this->edits = $eng->diff($from_lines, $to_lines); - } - - /** - * Check for empty diff. - * - * @return bool True iff two sequences were identical. - */ - public function isEmpty() - { - foreach ($this->edits as $edit) { - if ($edit->type != 'copy') - return false; - } - return true; - } - - /** - * Get the original set of lines. - * - * This reconstructs the $from_lines parameter passed to the - * constructor. - * - * @return array The original sequence of strings. - */ - public function orig() - { - $lines = array(); - - foreach ($this->edits as $edit) { - if ($edit->orig) - array_splice($lines, sizeof($lines ?? []), 0, $edit->orig); - } - return $lines; - } - - /** - * Get the final set of lines. - * - * This reconstructs the $to_lines parameter passed to the - * constructor. - * - * @return array The sequence of strings. - */ - public function finalize() - { - $lines = array(); - - foreach ($this->edits as $edit) { - if ($edit->final) - array_splice($lines, sizeof($lines ?? []), 0, $edit->final); - } - return $lines; - } -} - -/** - * FIXME: bad name. - */ -class MappedDiff - extends Diff -{ - /** - * 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 $from_lines array An array of strings. - * (Typically these are lines from a file.) - * - * @param $to_lines array An array of strings. - * - * @param $mapped_from_lines array 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 $mapped_to_lines array This array should - * have the same number of elements as $to_lines. - */ - function __construct($from_lines, $to_lines, - $mapped_from_lines, $mapped_to_lines) - { - - assert(sizeof($from_lines ?? []) == sizeof($mapped_from_lines ?? [])); - assert(sizeof($to_lines ?? []) == sizeof($mapped_to_lines ?? [])); - - parent::__construct($mapped_from_lines, $mapped_to_lines); - - $xi = $yi = 0; - // Optimizing loop invariants: - // http://phplens.com/lens/php-book/optimizing-debugging-php.php - for ($i = 0, $max = sizeof($this->edits); $i < $max; $i++) { - $orig = &$this->edits[$i]->orig; - if (is_array($orig)) { - $orig = array_slice($from_lines ?? [], $xi ?? 0, sizeof($orig ?? [])); - $xi += sizeof($orig ?? []); - } - - $final = &$this->edits[$i]->final; - if (is_array($final)) { - $final = array_slice($to_lines ?? [], $yi ?? 0, sizeof($final ?? [])); - $yi += sizeof($final ?? []); - } - } - } -} - -/** - * A class to format Diffs - * - * This class formats the diff in classic diff format. - * It is intended that this class be customized via inheritance, - * to obtain fancier outputs. - */ -class DiffFormatter -{ - /** - * Number of leading context "lines" to preserve. - * - * This should be left at zero for this class, but subclasses - * may want to set this to other values. - */ - public $leading_context_lines = 0; - - /** - * Number of trailing context "lines" to preserve. - * - * This should be left at zero for this class, but subclasses - * may want to set this to other values. - */ - public $trailing_context_lines = 0; - - /** - * Format a diff. - * - * @param $diff object A Diff object. - * @return string The formatted output. - */ - public function format($diff) - { - - $xi = $yi = 1; - $block = false; - $context = array(); - - $nlead = $this->leading_context_lines; - $ntrail = $this->trailing_context_lines; - - $this->start_diff(); - $x0 = 0; - $y0 = 0; - - foreach ($diff->edits as $edit) { - if ($edit->type == 'copy') { - if (is_array($block)) { - if (sizeof($edit->orig ?? []) <= $nlead + $ntrail) { - $block[] = $edit; - } else { - if ($ntrail) { - $context = array_slice($edit->orig ?? [], 0, $ntrail); - $block[] = new DiffOp_Copy($context); - } - $this->block($x0, $ntrail + $xi - $x0, - $y0, $ntrail + $yi - $y0, - $block); - $block = false; - } - } - $context = $edit->orig; - } else { - if (!is_array($block)) { - $context = array_slice($context ?? [], max(0, sizeof($context ?? []) - $nlead) ?? 0); - $x0 = $xi - sizeof($context ?? []); - $y0 = $yi - sizeof($context ?? []); - $block = array(); - if ($context) - $block[] = new DiffOp_Copy($context); - } - $block[] = $edit; - } - - if ($edit->orig) - $xi += sizeof($edit->orig ?? []); - if ($edit->final) - $yi += sizeof($edit->final ?? []); - } - - if (is_array($block)) - $this->block($x0, $xi - $x0, - $y0, $yi - $y0, - $block); - - return $this->end_diff(); - } - - private function block($xbeg, $xlen, $ybeg, $ylen, &$edits) - { - $this->start_block($this->block_header($xbeg, $xlen, $ybeg, $ylen)); - foreach ($edits as $edit) { - if ($edit->type == 'copy') - $this->context($edit->orig); - elseif ($edit->type == 'add') - $this->added($edit->final); - elseif ($edit->type == 'delete') - $this->deleted($edit->orig); - elseif ($edit->type == 'change') - $this->changed($edit->orig, $edit->final); - else - trigger_error("Unknown edit type", E_USER_ERROR); - } - $this->end_block(); - } - - protected function start_diff() - { - ob_start(); - } - - protected function end_diff() - { - $val = ob_get_contents(); - ob_end_clean(); - return $val; - } - - protected function block_header($xbeg, $xlen, $ybeg, $ylen) - { - if ($xlen > 1) - $xbeg .= "," . ($xbeg + $xlen - 1); - if ($ylen > 1) - $ybeg .= "," . ($ybeg + $ylen - 1); - - return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg; - } - - protected function start_block($header) - { - echo $header; - } - - protected function end_block() - { - } - - protected function lines($lines, $prefix = ' ') - { - foreach ($lines as $line) - echo "$prefix $line\n"; - } - - protected function context($lines) - { - $this->lines($lines); - } - - protected function added($lines) - { - $this->lines($lines, ">"); - } - - protected function deleted($lines) - { - $this->lines($lines, "<"); - } - - protected function changed($orig, $final) - { - $this->deleted($orig); - echo "---\n"; - $this->added($final); - } -} - -/** - * "Unified" diff formatter. - * - * This class formats the diff in classic "unified diff" format. - */ -class UnifiedDiffFormatter extends DiffFormatter -{ - function __construct($context_lines = 4) - { - $this->leading_context_lines = $context_lines; - $this->trailing_context_lines = $context_lines; - } - - protected function block_header($xbeg, $xlen, $ybeg, $ylen) - { - if ($xlen != 1) - $xbeg .= "," . $xlen; - if ($ylen != 1) - $ybeg .= "," . $ylen; - return "@@ -$xbeg +$ybeg @@\n"; - } - - protected function added($lines) - { - $this->lines($lines, "+"); - } - - protected function deleted($lines) - { - $this->lines($lines, "-"); - } - - protected function changed($orig, $final) - { - $this->deleted($orig); - $this->added($final); - } -} - -/** - * block conflict diff formatter. - * - * This class will format a diff identical to Diff3 (i.e. editpage - * conflicts), but when there are only two source files. To be used by - * future enhancements to reloading / upgrading pgsrc. - * - * Functional but not finished yet, need to eliminate redundant block - * suffixes (i.e. "=======" immediately followed by another prefix) - * see class LoadFileConflictPageEditor - */ -class BlockDiffFormatter extends DiffFormatter -{ - function __construct($context_lines = 4) - { - $this->leading_context_lines = $context_lines; - $this->trailing_context_lines = $context_lines; - } - - protected function lines($lines, $prefix = '') - { - if (!$prefix == '') - echo "$prefix\n"; - foreach ($lines as $line) - echo "$line\n"; - if (!$prefix == '') - echo "$prefix\n"; - } - - protected function added($lines) - { - $this->lines($lines, ">>>>>>>"); - } - - protected function deleted($lines) - { - $this->lines($lines, "<<<<<<<"); - } - - protected function block_header($xbeg, $xlen, $ybeg, $ylen) - { - return ""; - } - - protected function changed($orig, $final) - { - $this->deleted($orig); - $this->added($final); - } -}