/usr/lib/python3/dist-packages/pytools/persistent_dict.py is in python3-pytools 2016.2.6-1.
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from __future__ import division, with_statement
from __future__ import absolute_import
import six
__copyright__ = "Copyright (C) 2011,2014 Andreas Kloeckner"
__license__ = """
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
import logging
logger = logging.getLogger(__name__)
import sys
import os
import errno
try:
import hashlib
new_hash = hashlib.sha256
except ImportError:
# for Python << 2.5
import sha
new_hash = sha.new
def _erase_dir(dir):
from os import listdir, unlink, rmdir
from os.path import join, isdir
for name in listdir(dir):
sub_name = join(dir, name)
if isdir(sub_name):
_erase_dir(sub_name)
else:
unlink(sub_name)
rmdir(dir)
def update_checksum(checksum, obj):
if isinstance(obj, six.text_type):
checksum.update(obj.encode("utf8"))
else:
checksum.update(obj)
# {{{ cleanup managers
class CleanupBase(object):
pass
class CleanupManager(CleanupBase):
def __init__(self):
self.cleanups = []
def register(self, c):
self.cleanups.insert(0, c)
def clean_up(self):
for c in self.cleanups:
c.clean_up()
def error_clean_up(self):
for c in self.cleanups:
c.error_clean_up()
class LockManager(CleanupBase):
def __init__(self, cleanup_m, container_dir):
if container_dir is not None:
self.lock_file = os.path.join(container_dir, "lock")
attempts = 0
while True:
try:
self.fd = os.open(self.lock_file,
os.O_CREAT | os.O_WRONLY | os.O_EXCL)
break
except OSError:
pass
from time import sleep
sleep(1)
attempts += 1
if attempts > 10:
from warnings import warn
warn("could not obtain lock--delete '%s' if necessary"
% self.lock_file)
if attempts > 3 * 60:
raise RuntimeError("waited more than three minutes "
"on the lock file '%s'"
"--something is wrong" % self.lock_file)
cleanup_m.register(self)
def clean_up(self):
import os
os.close(self.fd)
os.unlink(self.lock_file)
def error_clean_up(self):
pass
class ItemDirManager(CleanupBase):
def __init__(self, cleanup_m, path):
from os import mkdir
import errno
self.path = path
try:
mkdir(self.path)
except OSError as e:
if e.errno != errno.EEXIST:
raise
self.existed = True
else:
cleanup_m.register(self)
self.existed = False
def sub(self, n):
from os.path import join
return join(self.path, n)
def reset(self):
try:
_erase_dir(self.path)
except OSError as e:
if e.errno != errno.ENOENT:
raise
try:
os.mkdir(self.path)
except OSError as e:
if e.errno != errno.EEXIST:
raise
def clean_up(self):
pass
def error_clean_up(self):
_erase_dir(self.path)
# }}}
# {{{ key generation
class KeyBuilder(object):
def rec(self, key_hash, key):
try:
method = key.update_persistent_hash
except AttributeError:
pass
else:
method(key_hash, self)
return
try:
method = getattr(self, "update_for_"+type(key).__name__)
except AttributeError:
pass
else:
method(key_hash, key)
return
raise TypeError("unsupported type for persistent hash keying: %s"
% type(key))
def __call__(self, key):
key_hash = new_hash()
self.rec(key_hash, key)
return key_hash.hexdigest()
# {{{ updaters
def update_for_int(self, key_hash, key):
key_hash.update(str(key).encode("utf8"))
update_for_long = update_for_int
update_for_bool = update_for_int
def update_for_float(self, key_hash, key):
key_hash.update(repr(key).encode("utf8"))
if sys.version_info >= (3,):
def update_for_str(self, key_hash, key):
key_hash.update(key.encode('utf8'))
def update_for_bytes(self, key_hash, key):
key_hash.update(key)
else:
def update_for_str(self, key_hash, key):
key_hash.update(key)
def update_for_unicode(self, key_hash, key):
key_hash.update(key.encode('utf8'))
def update_for_tuple(self, key_hash, key):
for obj_i in key:
self.rec(key_hash, obj_i)
def update_for_frozenset(self, key_hash, key):
for set_key in sorted(key):
self.rec(key_hash, set_key)
def update_for_NoneType(self, key_hash, key): # noqa
key_hash.update("<None>".encode('utf8'))
def update_for_dtype(self, key_hash, key):
key_hash.update(key.str.encode('utf8'))
# }}}
# }}}
# {{{ top-level
class NoSuchEntryError(KeyError):
pass
class PersistentDict(object):
def __init__(self, identifier, key_builder=None, container_dir=None):
"""
:arg identifier: a file-name-compatible string identifying this
dictionary
:arg key_builder: a subclass of :class:`KeyBuilder`
"""
self.identifier = identifier
if key_builder is None:
key_builder = KeyBuilder()
self.key_builder = key_builder
from os.path import join
if container_dir is None:
import appdirs
container_dir = join(
appdirs.user_cache_dir("pytools", "pytools"),
"pdict-v2-%s-py%s" % (
identifier,
".".join(str(i) for i in sys.version_info),))
self.container_dir = container_dir
self._make_container_dir()
def _make_container_dir(self):
# {{{ ensure container directory exists
try:
os.makedirs(self.container_dir)
except OSError as e:
from errno import EEXIST
if e.errno != EEXIST:
raise
# }}}
def store(self, key, value, info_files={}):
hexdigest_key = self.key_builder(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self.container_dir)
from os.path import join
item_dir_m = ItemDirManager(cleanup_m,
join(self.container_dir, hexdigest_key))
if item_dir_m.existed:
item_dir_m.reset()
for info_name, info_value in six.iteritems(info_files):
info_path = item_dir_m.sub("info_"+info_name)
with open(info_path, "wt") as outf:
outf.write(info_value)
from six.moves.cPickle import dump, HIGHEST_PROTOCOL
value_path = item_dir_m.sub("contents")
with open(value_path, "wb") as outf:
dump(value, outf, protocol=HIGHEST_PROTOCOL)
logger.debug("%s: cache store [key=%s]" % (
self.identifier, hexdigest_key))
# Write key last, so that if the reader below
key_path = item_dir_m.sub("key")
with open(key_path, "wb") as outf:
dump(key, outf, protocol=HIGHEST_PROTOCOL)
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def fetch(self, key):
hexdigest_key = self.key_builder(key)
from os.path import join, isdir
item_dir = join(self.container_dir, hexdigest_key)
if not isdir(item_dir):
logger.debug("%s: cache miss [key=%s]" % (
self.identifier, hexdigest_key))
raise NoSuchEntryError(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self.container_dir)
item_dir_m = ItemDirManager(cleanup_m, item_dir)
key_path = item_dir_m.sub("key")
value_path = item_dir_m.sub("contents")
from six.moves.cPickle import load
# {{{ load key file
exc = None
try:
with open(key_path, "rb") as inf:
read_key = load(inf)
except IOError as e:
exc = e
except EOFError as e:
exc = e
if exc is not None:
item_dir_m.reset()
from warnings import warn
warn("pytools.persistent_dict.PersistentDict(%s) "
"encountered an invalid "
"key file for key %s. Entry deleted."
% (self.identifier, hexdigest_key))
raise NoSuchEntryError(key)
# }}}
if read_key != key:
# Key collision, oh well.
from warnings import warn
warn("%s: key collision in cache at '%s' -- these are "
"sufficiently unlikely that they're often "
"indicative of a broken implementation "
"of equality comparison"
% (self.identifier, self.container_dir))
# This is here so we can debug the equality comparison
read_key == key
raise NoSuchEntryError(key)
logger.debug("%s: cache hit [key=%s]" % (
self.identifier, hexdigest_key))
# {{{ load value
exc = None
try:
with open(value_path, "rb") as inf:
read_contents = load(inf)
except IOError as e:
exc = e
except EOFError as e:
exc = e
if exc is not None:
item_dir_m.reset()
from warnings import warn
warn("pytools.persistent_dict.PersistentDict(%s) "
"encountered an invalid "
"key file for key %s. Entry deleted."
% (self.identifier, hexdigest_key))
raise NoSuchEntryError(key)
# }}}
return read_contents
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def remove(self, key):
hexdigest_key = self.key_builder(key)
from os.path import join, isdir
item_dir = join(self.container_dir, hexdigest_key)
if not isdir(item_dir):
raise NoSuchEntryError(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self.container_dir)
item_dir_m = ItemDirManager(cleanup_m, item_dir)
item_dir_m.reset()
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def __getitem__(self, key):
return self.fetch(key)
def __setitem__(self, key, value):
return self.store(key, value)
def __delitem__(self, key):
self.remove(key)
def clear(self):
try:
_erase_dir(self.container_dir)
except OSError as e:
if e.errno != errno.ENOENT:
raise
self._make_container_dir()
# }}}
# vim: foldmethod=marker
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