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# -*- Mode: Python -*-
# GObject-Introspection - a framework for introspecting GObject libraries
# Copyright (C) 2008 Johan Dahlin
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
#
import cPickle
import hashlib
import os
import errno
def _get_cachedir():
cachedir = os.path.join(os.environ['HOME'], '.cache')
if not os.path.exists(cachedir):
os.mkdir(cachedir, 0755)
scannerdir = os.path.join(cachedir, 'g-ir-scanner')
if not os.path.exists(scannerdir):
os.mkdir(scannerdir, 0755)
# If it exists and is a file, don't cache at all
elif not os.path.isdir(scannerdir):
return None
return scannerdir
class CacheStore(object):
def __init__(self):
try:
self._directory = _get_cachedir()
except OSError, e:
if e.errno != errno.EPERM:
raise
self._directory = None
def _get_filename(self, filename):
# If we couldn't create the directory we're probably
# on a read only home directory where we just disable
# the cache all together.
if self._directory is None:
return
hexdigest = hashlib.sha1(filename).hexdigest()
return os.path.join(self._directory, hexdigest)
def _cache_is_valid(self, store_filename, filename):
return (os.stat(store_filename).st_mtime >=
os.stat(filename).st_mtime)
def _purge_cache(self, filename):
try:
os.unlink(filename)
except IOError, e:
# Permission denied
if e.errno == errno.EACCES:
return
# File does not exist
elif e.errno == errno.ENOENT:
return
else:
raise
def store(self, filename, data):
store_filename = self._get_filename(filename)
if store_filename is None:
return
if (os.path.exists(store_filename) and
self._cache_is_valid(store_filename, filename)):
return None
fd = open(store_filename, 'w')
try:
cPickle.dump(data, fd)
except IOError, e:
# No space left on device
if e.errno == e.ENOSPC:
return
else:
raise
def load(self, filename):
store_filename = self._get_filename(filename)
if store_filename is None:
return
try:
fd = open(store_filename)
except IOError, e:
if e.errno == errno.ENOENT:
return None
else:
raise
if not self._cache_is_valid(store_filename, filename):
return None
try:
data = cPickle.load(fd)
except (EOFError, ValueError, cPickle.BadPickleGet):
# Broken cache entry, remove it
self._purge_cache(store_filename)
data = None
return data
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