/xhp/fastpath.hpp
C++ Header | 46 lines | 3 code | 2 blank | 41 comment | 0 complexity | b67ab70bc3c99da6433ab2b66ac5145a MD5 | raw file
Possible License(s): MIT, MPL-2.0-no-copyleft-exception
- /*
- +----------------------------------------------------------------------+
- | XHP |
- +----------------------------------------------------------------------+
- | Copyright (c) 2009 - 2010 Facebook, Inc. (http://www.facebook.com) |
- +----------------------------------------------------------------------+
- | This source file is subject to version 3.01 of the PHP license, |
- | that is bundled with this package in the file LICENSE.PHP, and is |
- | available through the world-wide-web at the following url: |
- | http://www.php.net/license/3_01.txt |
- | If you did not receive a copy of the PHP license and are unable to |
- | obtain it through the world-wide-web, please send a note to |
- | license@php.net so we can mail you a copy immediately. |
- +----------------------------------------------------------------------+
- */
- #pragma once
- #include "xhp_preprocess.hpp"
- /**
- * Provides a fast way to scan over a buffer and figure out whether or not it
- * contains code that XHP needs to rewrite. This is valuable because the full
- * XHP parser is a lot more expensive to run. Since we assume (for now) that
- * most files won't contain XHP this fast fail greatly speeds up overal parse
- * times.
- *
- * The nature of this function is that it still may return false positives since
- * it only runs a simple lexical analysis on the source text. Particularly,
- * ternary operators returning numbers or constants with no spaces in between
- * tokens can fool it. i.e. `$foo = true ? 1:2` or `$foo = true ? foo:bar`.
- * That's not to say you should change your coding conventions because of this,
- * since it has no side effect other than slightly-slower parsing. Instead you
- * should install APC or something.
- *
- * Note that at this point the `len` parameter is just a formality and `yy` MUST
- * be NULL terminated. re2c doesn't provide any dependable means to scan a
- * buffer with no sentinal value. So for instance, if you want to use this on an
- * mmap'd file you must read it into memory first.
- *
- * Furthermore, it seems the primary maintainer of re2c doesn't want to
- * implement this, so we have to work around it for now.
- *
- * See: re2c-Support Requests-2407218 --
- * http://sourceforge.net/tracker/?func=detail&atid=616201&aid=2407218&group_id=96864
- */
- bool xhp_fastpath(const char* yy, const size_t len, const xhp_flags_t &flags);