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# -*- encoding: utf-8 -*-
# Copyright 2012 Martin Zimmermann <>. All rights reserved.
# License: BSD Style, 2 clauses -- see LICENSE.
# This provide some basic functionality of Acrylamid: caching and re-validating.
import os
import io
import zlib
import types
import pickle
import shutil
import tempfile
from os.path import join, exists, getmtime, getsize, dirname, basename
from acrylamid import log, defaults
from acrylamid.errors import AcrylamidException
from acrylamid.compat import PY2K, iteritems, iterkeys
from acrylamid.utils import (
classproperty, cached_property, Struct, hash, HashableList, find, execfile,
lchop, force_unicode as u
if PY2K:
import cPickle as pickle
__all__ = ['Memory', 'cache', 'Environment', 'Configuration']
class Memory(dict):
"""A callable dictionary object described at
def __call__(self, key, value=None):
if value is None:
return self.get(key)
rv = self.get(key)
self[key] = value
return rv != value
class cache(object):
"""A cache that stores all intermediates of an entry zlib-compressed on
file system. Inspired from ``werkzeug.contrib.cache``, but heavily modified
to fit our needs.
Terminology: A cache object is a pickled dictionary into a single file. An
intermediate (object) is a key/value pair that we store into a cache object.
An intermediate is the content of an entry that is the same for a chain of
filters used in different views.
:class:`cache` is designed as global singleton and should not be constructed.
.. attribute:: cache_dir
Location where all cache objects are being stored, defaults to `.cache/`.
The :class:`cache` does no longer maintain used/unused intermediates and cache
objects due performance reasons (and an edge case described in #67)."""
_fs_transaction_suffix = '.__ac_cache'
cache_dir = '.cache/'
mode = 0o600
memoize = Memory()
def init(self, cache_dir=None):
"""Initialize cache object by creating the cache_dir if non-existent,
read all available cache objects and restore memoized key/values.
:param cache_dir: the directory where cache files are stored.
:param mode: the file mode wanted for the cache files, default 0600
if cache_dir:
self.cache_dir = cache_dir
if not exists(self.cache_dir):
os.mkdir(self.cache_dir, 0o700)
except OSError:
raise AcrylamidException("could not create directory '%s'" % self.cache_dir)
# load memorized items
with, 'info'), 'rb') as fp:
except (IOError, pickle.PickleError):
self.emptyrun = True
self.emptyrun = False
def shutdown(self):
"""Write memoized key-value pairs to disk."""
with, 'info'), 'wb') as fp:
pickle.dump(self.memoize, fp, pickle.HIGHEST_PROTOCOL)
except (IOError, pickle.PickleError) as e:
log.warn('%s: %s' % (e.__class__.__name__, e))
def remove(self, path):
"""Remove a cache object completely from disk and `objects`."""
os.remove(join(self.cache_dir, path))
except OSError as e:
log.debug('OSError: %s' % e)
def clear(self, directory=None):
"""Wipe current cache objects and reset all stored informations.
:param directory: directory to clean (defaults to `.cache/`"""
if directory is not None:
self.cache_dir = directory
self.memoize = Memory()
shutil.rmtree(self.cache_dir, ignore_errors=True)
def get(self, path, key, default=None):
"""Restore value from obj[key] if mtime has not changed or return
:param path: path of this cache object
:param key: key of this value
:param default: default return value
with, path), 'rb') as fp:
return zlib.decompress(pickle.load(fp)[key]).decode('utf-8')
except KeyError:
except (IOError, pickle.PickleError, zlib.error):
self.remove(join(self.cache_dir, path))
return default
def set(self, path, key, value):
"""Save a key, value pair into a blob using pickle and moderate zlib
compression (level 6). We simply save a dictionary containing all
different intermediates (from every view) of an entry.
:param path: path of this cache object
:param key: dictionary key where we store the value
:param value: a string we compress with zlib and afterwards save
path = join(self.cache_dir, path)
if exists(path):
with, 'rb') as fp:
rv = pickle.load(fp)
except (pickle.PickleError, IOError):
rv = {}
with, 'wb') as fp:
rv[key] = zlib.compress(value.encode('utf-8'), 6)
pickle.dump(rv, fp, pickle.HIGHEST_PROTOCOL)
except (IOError, pickle.PickleError) as e:
log.warn('%s: %s' % (e.__class__.__name__, e))
fd, tmp = tempfile.mkstemp(suffix=self._fs_transaction_suffix,
with, 'wb') as fp:
pickle.dump({key: zlib.compress(value.encode('utf-8'), 6)}, fp,
os.rename(tmp, path)
os.chmod(path, self.mode)
except (IOError, OSError, pickle.PickleError, zlib.error) as e:
log.warn('%s: %s' % (e.__class__.__name__, e))
return value
def getmtime(self, path, default=0.0):
"""Get last modification timestamp from cache object but store it over
the whole compilation process so we have the same value for different
:param path: valid cache object
:param default: default value if an :class:`OSError` occurs
return getmtime(join(self.cache_dir, path))
except OSError:
return default
def size(self):
"""return size of all cacheobjects in bytes"""
res = getsize(join(self.cache_dir, 'info'))
except OSError:
res = 0
for (path, dirs, files) in os.walk(self.cache_dir):
for file in files:
filename = os.path.join(path, file)
res += getsize(filename)
return res
def load(path):
"""Load default configuration, prepare namespace and update configuration
with ``'s uppercase values and normalizes ambiguous values.
conf = Configuration(defaults.conf)
ns = dict([(k.upper(), v) for k, v in iteritems(defaults.conf)])
os.chdir(dirname(find(basename(path), u(dirname(path) or os.getcwd()))))
if PY2K:
execfile(path, ns)
exec(compile(open(path).read(), path, 'exec'), ns)
conf.update(dict([(k.lower(), ns[k]) for k in ns if k.upper() == k]))
# append trailing slash to *_dir and place certain values into an array
return defaults.normalize(conf)
class Environment(Struct):
"""Use *only* for the environment container. This class hides un-hashable
keys from :class:`Struct` hash function.
.. attribute:: modified
Return whether the Environment has changed between two runs. This
attribute must only be accessed after all modifications to the environment!
blacklist = set(['engine', 'translationsfor', 'options', 'archives', 'webassets'])
def new(self, env):
return Environment({'author':, 'url': env.url,
'options': env.options, 'globals': Struct()})
def keys(self):
return sorted(list(set(super(Environment, self).keys()) - self.blacklist))
def values(self):
for key in self.keys():
yield self[key]
def modified(self):
return hash(self) != cache.memoize(self.__class__.__name__)
class Configuration(Environment):
"""Similar to :class:`Environment` but allows hashing of a literarily
defined dictionary (that's the"""
blacklist = set(['if', 'hooks'])
def fetch(self, ns):
return Configuration((lchop(k, ns), v)
for k, v in iteritems(self) if k.startswith(ns))
def values(self):
for key in self.keys():
if isinstance(self[key], types.FunctionType):
if isinstance(self[key], list):
yield HashableList(self[key])
elif isinstance(self[key], dict):
yield Configuration(self[key])
elif isinstance(self[key], type(None)):
yield -1
yield self[key]
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