Differential D19452 Diff 46533 src/applications/differential/engine/DifferentialChangesetEngine.php

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Standalone View

src/applications/differential/engine/DifferentialChangesetEngine.php

This file was added.

				<?php

				final class DifferentialChangesetEngine extends Phobject {

				public function rebuildChangesets(array $changesets) {
				assert_instances_of($changesets, 'DifferentialChangeset');

				foreach ($changesets as $changeset) {
				$this->detectGeneratedCode($changeset);
				}

				$this->detectCopiedCode($changesets);
				}


				/* -( Generated Code )----------------------------------------------------- */


				private function detectGeneratedCode(DifferentialChangeset $changeset) {
				$is_generated_trusted = $this->isTrustedGeneratedCode($changeset);
				if ($is_generated_trusted) {
				$changeset->setTrustedChangesetAttribute(
				DifferentialChangeset::ATTRIBUTE_GENERATED,
				$is_generated_trusted);
				}

				$is_generated_untrusted = $this->isUntrustedGeneratedCode($changeset);
				if ($is_generated_untrusted) {
				$changeset->setUntrustedChangesetAttribute(
				DifferentialChangeset::ATTRIBUTE_GENERATED,
				$is_generated_untrusted);
				}
				}

				private function isTrustedGeneratedCode(DifferentialChangeset $changeset) {

				$filename = $changeset->getFilename();

				$paths = PhabricatorEnv::getEnvConfig('differential.generated-paths');
				foreach ($paths as $regexp) {
				if (preg_match($regexp, $filename)) {
				return true;
				}
				}

				return false;
				}

				private function isUntrustedGeneratedCode(DifferentialChangeset $changeset) {

				if ($changeset->getHunks()) {
				$new_data = $changeset->makeNewFile();
				if (strpos($new_data, '@'.'generated') !== false) {
				return true;
				}
				}

				return false;
				}


				/* -( Copied Code )-------------------------------------------------------- */


				private function detectCopiedCode(array $changesets) {
				$min_width = 30;
				$min_lines = 3;

				$map = array();
				$files = array();
				$types = array();
				foreach ($changesets as $changeset) {
				$file = $changeset->getFilename();
				foreach ($changeset->getHunks() as $hunk) {
				$lines = $hunk->getStructuredOldFile();
				foreach ($lines as $line => $info) {
				$type = $info['type'];
				if ($type == '\\') {
				continue;
				}
				$types[$file][$line] = $type;

				$text = $info['text'];
				$text = trim($text);
				$files[$file][$line] = $text;

				if (strlen($text) >= $min_width) {
				$map[$text][] = array($file, $line);
				}
				}
				}
				}

				foreach ($changesets as $changeset) {
				$copies = array();
				foreach ($changeset->getHunks() as $hunk) {
				$added = $hunk->getStructuredNewFile();
				$atype = array();

				foreach ($added as $line => $info) {
				$atype[$line] = $info['type'];
				$added[$line] = trim($info['text']);
				}

				$skip_lines = 0;
				foreach ($added as $line => $code) {
				if ($skip_lines) {
				// We're skipping lines that we already processed because we
				// extended a block above them downward to include them.
				$skip_lines--;
				continue;
				}

				if ($atype[$line] !== '+') {
				// This line hasn't been changed in the new file, so don't try
				// to figure out where it came from.
				continue;
				}

				if (empty($map[$code])) {
				// This line was too short to trigger copy/move detection.
				continue;
				}

				if (count($map[$code]) > 16) {
				// If there are a large number of identical lines in this diff,
				// don't try to figure out where this block came from: the analysis
				// is O(N^2), since we need to compare every line against every
				// other line. Even if we arrive at a result, it is unlikely to be
				// meaningful. See T5041.
				continue;
				}

				$best_length = 0;

				// Explore all candidates.
				foreach ($map[$code] as $val) {
				list($file, $orig_line) = $val;
				$length = 1;

				// Search backward and forward to find all of the adjacent lines
				// which match.
				foreach (array(-1, 1) as $direction) {
				$offset = $direction;
				while (true) {
				if (isset($copies[$line + $offset])) {
				// If we run into a block above us which we've already
				// attributed to a move or copy from elsewhere, stop
				// looking.
				break;
				}

				if (!isset($added[$line + $offset])) {
				// If we've run off the beginning or end of the new file,
				// stop looking.
				break;
				}

				if (!isset($files[$file][$orig_line + $offset])) {
				// If we've run off the beginning or end of the original
				// file, we also stop looking.
				break;
				}

				$old = $files[$file][$orig_line + $offset];
				$new = $added[$line + $offset];
				if ($old !== $new) {
				// If the old line doesn't match the new line, stop
				// looking.
				break;
				}

				$length++;
				$offset += $direction;
				}
				}

				if ($length < $best_length) {
				// If we already know of a better source (more matching lines)
				// for this move/copy, stick with that one. We prefer long
				// copies/moves which match a lot of context over short ones.
				continue;
				}

				if ($length == $best_length) {
				if (idx($types[$file], $orig_line) != '-') {
				// If we already know of an equally good source (same number
				// of matching lines) and this isn't a move, stick with the
				// other one. We prefer moves over copies.
				continue;
				}
				}

				$best_length = $length;
				// ($offset - 1) contains number of forward matching lines.
				$best_offset = $offset - 1;
				$best_file = $file;
				$best_line = $orig_line;
				}

				$file = ($best_file == $changeset->getFilename() ? '' : $best_file);
				for ($i = $best_length; $i--; ) {
				$type = idx($types[$best_file], $best_line + $best_offset - $i);
				$copies[$line + $best_offset - $i] = ($best_length < $min_lines
				? array() // Ignore short blocks.
				: array($file, $best_line + $best_offset - $i, $type));
				}

				$skip_lines = $best_offset;
				}
				}

				$copies = array_filter($copies);
				if ($copies) {
				$metadata = $changeset->getMetadata();
				$metadata['copy:lines'] = $copies;
				$changeset->setMetadata($metadata);
				}
				}

				}

				}