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# -*- Mode: Python -*-
# GObject-Introspection - a framework for introspecting GObject libraries
# Copyright (C) 2008-2010 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 errno
import cPickle
import glob
import hashlib
import os
import shutil
import sys
import tempfile
import giscanner
_CACHE_VERSION_FILENAME = '.cache-version'
def _get_versionhash():
toplevel = os.path.dirname(giscanner.__file__)
# Use pyc instead of py to avoid extra IO
sources = glob.glob(os.path.join(toplevel, '*.pyc'))
sources.append(sys.argv[0])
# Using mtimes is a bit (5x) faster than hashing the file contents
mtimes = (str(os.stat(source).st_mtime) for source in sources)
return hashlib.sha1(''.join(mtimes)).hexdigest()
def _get_cachedir():
if 'GI_SCANNER_DISABLE_CACHE' in os.environ:
return None
homedir = os.environ.get('HOME')
if homedir is None:
return None
if not os.path.exists(homedir):
return None
cachedir = os.path.join(homedir, '.cache')
if not os.path.exists(cachedir):
try:
os.mkdir(cachedir, 0755)
except OSError:
return None
scannerdir = os.path.join(cachedir, 'g-ir-scanner')
if not os.path.exists(scannerdir):
try:
os.mkdir(scannerdir, 0755)
except OSError:
return None
# 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 as e:
if e.errno != errno.EPERM:
raise
self._directory = None
self._check_cache_version()
def _check_cache_version(self):
if self._directory is None:
return
current_hash = _get_versionhash()
version = os.path.join(self._directory, _CACHE_VERSION_FILENAME)
try:
cache_hash = open(version).read()
except IOError as e:
# File does not exist
if e.errno == errno.ENOENT:
cache_hash = 0
else:
raise
if current_hash == cache_hash:
return
self._clean()
try:
fp = open(version, 'w')
except IOError as e:
# Permission denied
if e.errno == errno.EACCES:
return
else:
raise
fp.write(current_hash)
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 _remove_filename(self, filename):
try:
os.unlink(filename)
except IOError as e:
# Permission denied
if e.errno == errno.EACCES:
return
else:
raise
except OSError as e:
# File does not exist
if e.errno == errno.ENOENT:
return
else:
raise
def _clean(self):
for filename in os.listdir(self._directory):
if filename == _CACHE_VERSION_FILENAME:
continue
self._remove_filename(os.path.join(self._directory, filename))
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
tmp_fd, tmp_filename = tempfile.mkstemp(prefix='g-ir-scanner-cache-')
try:
cPickle.dump(data, os.fdopen(tmp_fd, 'w'))
except IOError as e:
# No space left on device
if e.errno == errno.ENOSPC:
self._remove_filename(tmp_filename)
return
else:
raise
try:
shutil.move(tmp_filename, store_filename)
except IOError as e:
# Permission denied
if e.errno == errno.EACCES:
self._remove_filename(tmp_filename)
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 as 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 (AttributeError, EOFError, ValueError, cPickle.BadPickleGet):
# Broken cache entry, remove it
self._remove_filename(store_filename)
data = None
return data
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