kopia lustrzana https://github.com/inkstitch/inkstitch
90 wiersze
2.5 KiB
Python
90 wiersze
2.5 KiB
Python
# Authors: see git history
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#
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# Copyright (c) 2010 Authors
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# Licensed under the GNU GPL version 3.0 or later. See the file LICENSE for details.
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import atexit
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import hashlib
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import os
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import pickle
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import sqlite3
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import diskcache # type: ignore[import-untyped]
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from lib.utils.settings import global_settings
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from .paths import get_user_dir
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from functools import lru_cache
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# simplify use of lru_cache decorator
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def cache(*args, **kwargs):
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return lru_cache(maxsize=None)(*args, **kwargs)
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__stitch_plan_cache = None
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def get_stitch_plan_cache():
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global __stitch_plan_cache
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if __stitch_plan_cache is None:
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cache_dir = get_user_dir('cache')
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stitch_plan_dir = os.path.join(cache_dir, 'stitch_plan')
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size_limit = global_settings['cache_size'] * 1024 * 1024
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try:
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__stitch_plan_cache = diskcache.Cache(stitch_plan_dir, size=size_limit)
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except (sqlite3.DatabaseError, sqlite3.OperationalError):
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# reset cache database file if it couldn't parse correctly
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cache_file = os.path.join(stitch_plan_dir, 'cache.db')
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if os.path.exists(cache_file):
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os.remove(cache_file)
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__stitch_plan_cache = diskcache.Cache(stitch_plan_dir, size=size_limit)
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__stitch_plan_cache.size_limit = size_limit
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# reset cache if warnings appear within the files
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warnings = __stitch_plan_cache.check()
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if warnings:
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__stitch_plan_cache.clear()
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atexit.register(__stitch_plan_cache.close)
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return __stitch_plan_cache
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def is_cache_disabled():
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return not global_settings['cache_size']
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class CacheKeyGenerator(object):
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"""Generate cache keys given arbitrary data.
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Given arbitrary data, generate short cache key that is extremely likely
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to be unique.
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Use example:
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>>> generator = CacheKeyGenerator()
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>>> generator.update(b'12345')
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>>> generator.update([1, 2, 3, {4, 5, 6}])
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>>> generator.get_cache_key()
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"""
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def __init__(self):
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# SHA1 is chosen for speed. We don't need cryptography-grade hashing
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# for this use case.
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self._hasher = hashlib.sha1()
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def update(self, data):
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"""Provide data to be hashed into a cache key.
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Arguments:
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data -- a bytes object or any object that can be pickled
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"""
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if not isinstance(data, bytes):
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data = pickle.dumps(data)
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self._hasher.update(data)
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def get_cache_key(self):
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return self._hasher.hexdigest()
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