/usr/lib/python2.7/dist-packages/pytools/persistent_dict.py is in python-pytools 2017.6-1.
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from __future__ import division, with_statement, absolute_import
__copyright__ = """
Copyright (C) 2011,2014 Andreas Kloeckner
Copyright (C) 2017 Matt Wala
"""
__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 collections
import six
import sys
import os
import shutil
import errno
__doc__ = """
Persistent Hashing
==================
This module contains functionality that allows hashing with keys that remain
valid across interpreter invocations, unlike Python's built-in hashes.
.. autoexception:: NoSuchEntryError
.. autoexception:: ReadOnlyEntryError
.. autoclass:: KeyBuilder
.. autoclass:: PersistentDict
.. autoclass:: WriteOncePersistentDict
"""
try:
import hashlib
new_hash = hashlib.sha256
except ImportError:
# for Python << 2.5
import sha
new_hash = sha.new
def _make_dir_recursively(dir):
try:
os.makedirs(dir)
except OSError as e:
from errno import EEXIST
if e.errno != EEXIST:
raise
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, lock_file):
self.lock_file = lock_file
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, delete_on_error):
from os.path import isdir
self.existed = isdir(path)
self.path = path
self.delete_on_error = delete_on_error
cleanup_m.register(self)
def reset(self):
try:
shutil.rmtree(self.path)
except OSError as e:
if e.errno != errno.ENOENT:
raise
def mkdir(self):
from os import mkdir
try:
mkdir(self.path)
except OSError as e:
if e.errno != errno.EEXIST:
raise
def clean_up(self):
pass
def error_clean_up(self):
if self.delete_on_error:
self.reset()
# }}}
# {{{ key generation
class KeyBuilder(object):
def rec(self, key_hash, key):
digest = None
try:
digest = key._pytools_persistent_hash_digest
except AttributeError:
pass
if digest is None:
try:
method = key.update_persistent_hash
except AttributeError:
pass
else:
inner_key_hash = new_hash()
method(inner_key_hash, self)
digest = inner_key_hash.digest()
if digest is None:
try:
method = getattr(self, "update_for_"+type(key).__name__)
except AttributeError:
pass
else:
inner_key_hash = new_hash()
method(inner_key_hash, key)
digest = inner_key_hash.digest()
if digest is None:
raise TypeError("unsupported type for persistent hash keying: %s"
% type(key))
if not isinstance(key, type):
try:
key._pytools_persistent_hash_digest = digest
except Exception:
pass
key_hash.update(digest)
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'))
# }}}
# }}}
# {{{ lru cache
class _LinkedList(object):
"""The list operates on nodes of the form [value, leftptr, rightpr]. To create a
node of this form you can use `LinkedList.new_node().`
Supports inserting at the left and deleting from an arbitrary location.
"""
def __init__(self):
self.count = 0
self.head = None
self.end = None
@staticmethod
def new_node(element):
return [element, None, None]
def __len__(self):
return self.count
def appendleft_node(self, node):
self.count += 1
if self.head is None:
self.head = self.end = node
return
self.head[1] = node
node[2] = self.head
self.head = node
def pop_node(self):
end = self.end
self.remove_node(end)
return end
def remove_node(self, node):
self.count -= 1
if self.head is self.end:
assert node is self.head
self.head = self.end = None
return
left = node[1]
right = node[2]
if left is None:
self.head = right
else:
left[2] = right
if right is None:
self.end = left
else:
right[1] = left
node[1] = node[2] = None
class _LRUCache(collections.MutableMapping):
"""A mapping that keeps at most *maxsize* items with an LRU replacement policy.
"""
def __init__(self, maxsize):
self.lru_order = _LinkedList()
self.maxsize = maxsize
self.cache = {}
def __delitem__(self, item):
node = self.cache[item]
self.lru_order.remove_node(node)
del self.cache[item]
def __getitem__(self, item):
node = self.cache[item]
self.lru_order.remove_node(node)
self.lru_order.appendleft_node(node)
# A linked list node contains a tuple of the form (item, value).
return node[0][1]
def __contains__(self, item):
return item in self.cache
def __iter__(self):
return iter(self.cache)
def __len__(self):
return len(self.cache)
def clear(self):
self.cache.clear()
self.lru_order = _LinkedList()
def __setitem__(self, item, value):
if self.maxsize < 1:
return
try:
node = self.cache[item]
self.lru_order.remove_node(node)
except KeyError:
if len(self.lru_order) >= self.maxsize:
# Make room for new elements.
end_node = self.lru_order.pop_node()
del self.cache[end_node[0][0]]
node = self.lru_order.new_node((item, value))
self.cache[item] = node
self.lru_order.appendleft_node(node)
assert len(self.cache) == len(self.lru_order), \
(len(self.cache), len(self.lru_order))
assert len(self.lru_order) <= self.maxsize
return node[0]
# }}}
# {{{ top-level
class NoSuchEntryError(KeyError):
pass
class ReadOnlyEntryError(KeyError):
pass
class _PersistentDictBase(object):
def __init__(self, identifier, key_builder=None, container_dir=None):
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 store_if_not_present(self, key, value):
self.store(key, value, _skip_if_present=True)
def store(self, key, value, _skip_if_present=False):
raise NotImplementedError()
def fetch(self, key):
raise NotImplementedError()
def _read(self, path):
from six.moves.cPickle import load
with open(path, "rb") as inf:
return load(inf)
def _write(self, path, value):
from six.moves.cPickle import dump, HIGHEST_PROTOCOL
with open(path, "wb") as outf:
dump(value, outf, protocol=HIGHEST_PROTOCOL)
def _item_dir(self, hexdigest_key):
from os.path import join
return join(self.container_dir, hexdigest_key)
def _key_file(self, hexdigest_key):
from os.path import join
return join(self._item_dir(hexdigest_key), "key")
def _contents_file(self, hexdigest_key):
from os.path import join
return join(self._item_dir(hexdigest_key), "contents")
def _lock_file(self, hexdigest_key):
from os.path import join
return join(self.container_dir, str(hexdigest_key) + ".lock")
def _make_container_dir(self):
_make_dir_recursively(self.container_dir)
def _collision_check(self, key, stored_key):
if stored_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
stored_key == key
raise NoSuchEntryError(key)
def __getitem__(self, key):
return self.fetch(key)
def __setitem__(self, key, value):
self.store(key, value)
def __delitem__(self, key):
raise NotImplementedError()
def clear(self):
try:
shutil.rmtree(self.container_dir)
except OSError as e:
if e.errno != errno.ENOENT:
raise
self._make_container_dir()
class WriteOncePersistentDict(_PersistentDictBase):
def __init__(self, identifier, key_builder=None, container_dir=None,
in_mem_cache_size=256):
"""
:arg identifier: a file-name-compatible string identifying this
dictionary
:arg key_builder: a subclass of :class:`KeyBuilder`
:arg in_mem_cache_size: retain an in-memory cache of up to
*in_mem_cache_size* items
.. automethod:: __getitem__
.. automethod:: __setitem__
.. automethod:: clear
.. automethod:: store_if_not_present
"""
_PersistentDictBase.__init__(self, identifier, key_builder, container_dir)
self._cache = _LRUCache(in_mem_cache_size)
def _spin_until_removed(self, lock_file):
from os.path import exists
attempts = 0
while exists(lock_file):
from time import sleep
sleep(1)
attempts += 1
if attempts > 10:
from warnings import warn
warn("waiting until unlocked--delete '%s' if necessary"
% lock_file)
if attempts > 3 * 60:
raise RuntimeError("waited more than three minutes "
"on the lock file '%s'"
"--something is wrong" % lock_file)
def store(self, key, value, _skip_if_present=False):
hexdigest_key = self.key_builder(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self._lock_file(hexdigest_key))
item_dir_m = ItemDirManager(
cleanup_m, self._item_dir(hexdigest_key),
delete_on_error=False)
if item_dir_m.existed:
if _skip_if_present:
return
raise ReadOnlyEntryError(key)
item_dir_m.mkdir()
key_path = self._key_file(hexdigest_key)
value_path = self._contents_file(hexdigest_key)
self._write(value_path, value)
self._write(key_path, key)
logger.debug("%s: disk cache store [key=%s]" % (
self.identifier, hexdigest_key))
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def fetch(self, key):
hexdigest_key = self.key_builder(key)
# {{{ in memory cache
try:
stored_key, stored_value = self._cache[hexdigest_key]
except KeyError:
pass
else:
logger.debug("%s: in mem cache hit [key=%s]" % (
self.identifier, hexdigest_key))
self._collision_check(key, stored_key)
return stored_value
# }}}
# {{{ check path exists and is unlocked
item_dir = self._item_dir(hexdigest_key)
from os.path import isdir
if not isdir(item_dir):
logger.debug("%s: disk cache miss [key=%s]" % (
self.identifier, hexdigest_key))
raise NoSuchEntryError(key)
lock_file = self._lock_file(hexdigest_key)
self._spin_until_removed(lock_file)
# }}}
key_file = self._key_file(hexdigest_key)
contents_file = self._contents_file(hexdigest_key)
# Note: Unlike PersistentDict, this doesn't autodelete invalid entires,
# because that would lead to a race condition.
# {{{ load key file and do equality check
try:
read_key = self._read(key_file)
except:
from warnings import warn
warn("pytools.persistent_dict.WriteOncePersistentDict(%s) "
"encountered an invalid "
"key file for key %s. Remove the directory "
"'%s' if necessary."
% (self.identifier, hexdigest_key, item_dir))
raise NoSuchEntryError(key)
self._collision_check(key, read_key)
# }}}
logger.debug("%s: disk cache hit [key=%s]" % (
self.identifier, hexdigest_key))
# {{{ load contents
try:
read_contents = self._read(contents_file)
except:
warn("pytools.persistent_dict.WriteOncePersistentDict(%s) "
"encountered an invalid "
"key file for key %s. Remove the directory "
"'%s' if necessary."
% (self.identifier, hexdigest_key, item_dir))
raise NoSuchEntryError(key)
# }}}
self._cache[hexdigest_key] = (key, read_contents)
return read_contents
def clear(self):
_PersistentDictBase.clear(self)
self._cache.clear()
class PersistentDict(_PersistentDictBase):
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`
.. automethod:: __getitem__
.. automethod:: __setitem__
.. automethod:: __delitem__
.. automethod:: clear
.. automethod:: store_if_not_present
"""
_PersistentDictBase.__init__(self, identifier, key_builder, container_dir)
def store(self, key, value, _skip_if_present=False):
hexdigest_key = self.key_builder(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self._lock_file(hexdigest_key))
item_dir_m = ItemDirManager(
cleanup_m, self._item_dir(hexdigest_key),
delete_on_error=True)
if item_dir_m.existed:
if _skip_if_present:
return
item_dir_m.reset()
item_dir_m.mkdir()
key_path = self._key_file(hexdigest_key)
value_path = self._contents_file(hexdigest_key)
self._write(value_path, value)
self._write(key_path, key)
logger.debug("%s: cache store [key=%s]" % (
self.identifier, hexdigest_key))
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def fetch(self, key):
hexdigest_key = self.key_builder(key)
item_dir = self._item_dir(hexdigest_key)
from os.path import isdir
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._lock_file(hexdigest_key))
item_dir_m = ItemDirManager(
cleanup_m, item_dir, delete_on_error=False)
key_path = self._key_file(hexdigest_key)
value_path = self._contents_file(hexdigest_key)
# {{{ load key
try:
read_key = self._read(key_path)
except:
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)
self._collision_check(key, read_key)
# }}}
logger.debug("%s: cache hit [key=%s]" % (
self.identifier, hexdigest_key))
# {{{ load value
try:
read_contents = self._read(value_path)
except:
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)
item_dir = self._item_dir(hexdigest_key)
from os.path import isdir
if not isdir(item_dir):
raise NoSuchEntryError(key)
cleanup_m = CleanupManager()
try:
try:
LockManager(cleanup_m, self._lock_file(hexdigest_key))
item_dir_m = ItemDirManager(
cleanup_m, item_dir, delete_on_error=False)
key_file = self._key_file(hexdigest_key)
# {{{ load key
try:
read_key = self._read(key_file)
except:
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)
self._collision_check(key, read_key)
# }}}
item_dir_m.reset()
except:
cleanup_m.error_clean_up()
raise
finally:
cleanup_m.clean_up()
def __delitem__(self, key):
self.remove(key)
# }}}
# vim: foldmethod=marker
|