PhragmentPatchUtil.php
c038c643f498production

PhragmentPatchUtil.php
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			<?php

			final class PhragmentPatchUtil extends Phobject {

			const EMPTY_HASH = '0000000000000000000000000000000000000000';

			/**
			* Calculate the DiffMatchPatch patch between two Phabricator files.
			*
			* @phutil-external-symbol class diff_match_patch
			*/
			public static function calculatePatch(
			PhabricatorFile $old = null,
			PhabricatorFile $new = null) {

			$root = dirname(phutil_get_library_root('phabricator'));
			require_once $root.'/externals/diff_match_patch/diff_match_patch.php';

			$old_hash = self::EMPTY_HASH;
			$new_hash = self::EMPTY_HASH;

			if ($old !== null) {
			$old_hash = $old->getContentHash();
			}
			if ($new !== null) {
			$new_hash = $new->getContentHash();
			}

			$old_content = '';
			$new_content = '';

			if ($old_hash === $new_hash) {
			return null;
			}

			if ($old_hash !== self::EMPTY_HASH) {
			$old_content = $old->loadFileData();
			} else {
			$old_content = '';
			}

			if ($new_hash !== self::EMPTY_HASH) {
			$new_content = $new->loadFileData();
			} else {
			$new_content = '';
			}

			$dmp = new diff_match_patch();
			$dmp_patches = $dmp->patch_make($old_content, $new_content);
			return $dmp->patch_toText($dmp_patches);
			}

			}