PhutilProseDifferenceEngine.php
a64328ab3d62stable

PhutilProseDifferenceEngine.php
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			<?php

			final class PhutilProseDifferenceEngine extends Phobject {

			public function getDiff($u, $v) {
			$diff = id(new PhutilProseDiff());

			$this->buildDiff($diff, $u, $v, 1);
			$diff->reorderParts();

			return $diff;
			}

			private function buildDiff(PhutilProseDiff $diff, $u, $v, $level) {
			if ($level == 4) {
			$diff->addPart('-', $u);
			$diff->addPart('+', $v);
			return;
			}

			$u_parts = $this->splitCorpus($u, $level);
			$v_parts = $this->splitCorpus($v, $level);

			$matrix = id(new PhutilEditDistanceMatrix())
			->setSequences($u_parts, $v_parts)
			->setComputeString(true);

			// For word-level and character-level changes, smooth the output string
			// to reduce the choppiness of the diff.
			if ($level > 1) {
			$matrix->setApplySmoothing(true);
			}

			$u_pos = 0;
			$v_pos = 0;

			$edits = $matrix->getEditString();
			$edits_length = strlen($edits);

			for ($ii = 0; $ii < $edits_length; $ii++) {
			$c = $edits[$ii];
			if ($c == 's') {
			$diff->addPart('=', $u_parts[$u_pos]);
			$u_pos++;
			$v_pos++;
			} else if ($c == 'd') {
			$diff->addPart('-', $u_parts[$u_pos]);
			$u_pos++;
			} else if ($c == 'i') {
			$diff->addPart('+', $v_parts[$v_pos]);
			$v_pos++;
			} else if ($c == 'x') {
			$this->buildDiff($diff, $u_parts[$u_pos], $v_parts[$v_pos], $level + 1);
			$u_pos++;
			$v_pos++;
			} else {
			throw new Exception(
			pht(
			'Unexpected character ("%s") in edit string.',
			$c));
			}
			}
			}

			private function splitCorpus($corpus, $level) {
			switch ($level) {
			case 1:
			// Level 1: Split into sentences.
			$expr = '/([\n,!;?\.]+)/';
			break;
			case 2:
			// Level 2: Split into words.
			$expr = '/(\s+)/';
			break;
			case 3:
			// Level 3: Split into characters.
			return phutil_utf8v_combined($corpus);
			}

			$pieces = preg_split($expr, $corpus, -1, PREG_SPLIT_DELIM_CAPTURE);
			return $this->stitchPieces($pieces);
			}

			private function stitchPieces(array $pieces) {
			$results = array();
			$count = count($pieces);
			for ($ii = 0; $ii < $count; $ii += 2) {
			$result = $pieces[$ii];
			if ($ii + 1 < $count) {
			$result .= $pieces[$ii + 1];
			}
			$results[] = $result;
			}

			// If the input ended with a delimiter, we can get an empty final piece.
			// Just discard it.
			if (last($results) == '') {
			array_pop($results);
			}

			return $results;
			}

			}

libphutil/src/utils/PhutilProseDifferenceEngine.phpa64328ab3d62stable

PhutilProseDifferenceEngine.phpView Options

libphutil/src/utils/PhutilProseDifferenceEngine.php
a64328ab3d62stable

PhutilProseDifferenceEngine.php
View Options