#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
This file is part of the web2py Web Framework
Copyrighted by Massimo Di Pierro <mdipierro@cs.depaul.edu>
License: LGPLv3 (http://www.gnu.org/licenses/lgpl.html)
Functions required to execute app components
============================================
FOR INTERNAL USE ONLY
"""
import os
import stat
import thread
from fileutils import read_file
cfs = {} # for speed-up
cfs_lock = thread.allocate_lock() # and thread safety
def getcfs(key, filename, filter=None):
"""
Caches the *filtered* file `filename` with `key` until the file is
modified.
:param key: the cache key
:param filename: the file to cache
:param filter: is the function used for filtering. Normally `filename` is a
.py file and `filter` is a function that bytecode compiles the file.
In this way the bytecode compiled file is cached. (Default = None)
This is used on Google App Engine since pyc files cannot be saved.
"""
t = os.stat(filename)[stat.ST_MTIME]
cfs_lock.acquire()
item = cfs.get(key, None)
cfs_lock.release()
if item and item[0] == t:
return item[1]
if not filter:
data = read_file(filename)
else:
data = filter()
cfs_lock.acquire()
cfs[key] = (t, data)
cfs_lock.release()
return data