mirror of https://github.com/python/cpython
101 lines
3.1 KiB
Python
101 lines
3.1 KiB
Python
import contextlib
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import functools
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import sys
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import threading
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import unittest
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from test.support.import_helper import import_fresh_module
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OS_ENV_LOCK = threading.Lock()
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TZPATH_LOCK = threading.Lock()
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TZPATH_TEST_LOCK = threading.Lock()
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def call_once(f):
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"""Decorator that ensures a function is only ever called once."""
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lock = threading.Lock()
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cached = functools.lru_cache(None)(f)
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@functools.wraps(f)
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def inner():
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with lock:
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return cached()
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return inner
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@call_once
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def get_modules():
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"""Retrieve two copies of zoneinfo: pure Python and C accelerated.
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Because this function manipulates the import system in a way that might
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be fragile or do unexpected things if it is run many times, it uses a
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`call_once` decorator to ensure that this is only ever called exactly
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one time — in other words, when using this function you will only ever
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get one copy of each module rather than a fresh import each time.
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"""
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import zoneinfo as c_module
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py_module = import_fresh_module("zoneinfo", blocked=["_zoneinfo"])
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return py_module, c_module
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@contextlib.contextmanager
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def set_zoneinfo_module(module):
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"""Make sure sys.modules["zoneinfo"] refers to `module`.
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This is necessary because `pickle` will refuse to serialize
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an type calling itself `zoneinfo.ZoneInfo` unless `zoneinfo.ZoneInfo`
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refers to the same object.
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"""
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NOT_PRESENT = object()
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old_zoneinfo = sys.modules.get("zoneinfo", NOT_PRESENT)
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sys.modules["zoneinfo"] = module
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yield
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if old_zoneinfo is not NOT_PRESENT:
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sys.modules["zoneinfo"] = old_zoneinfo
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else: # pragma: nocover
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sys.modules.pop("zoneinfo")
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class ZoneInfoTestBase(unittest.TestCase):
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@classmethod
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def setUpClass(cls):
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cls.klass = cls.module.ZoneInfo
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super().setUpClass()
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@contextlib.contextmanager
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def tzpath_context(self, tzpath, block_tzdata=True, lock=TZPATH_LOCK):
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def pop_tzdata_modules():
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tzdata_modules = {}
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for modname in list(sys.modules):
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if modname.split(".", 1)[0] != "tzdata": # pragma: nocover
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continue
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tzdata_modules[modname] = sys.modules.pop(modname)
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return tzdata_modules
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with lock:
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if block_tzdata:
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# In order to fully exclude tzdata from the path, we need to
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# clear the sys.modules cache of all its contents — setting the
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# root package to None is not enough to block direct access of
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# already-imported submodules (though it will prevent new
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# imports of submodules).
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tzdata_modules = pop_tzdata_modules()
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sys.modules["tzdata"] = None
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old_path = self.module.TZPATH
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try:
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self.module.reset_tzpath(tzpath)
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yield
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finally:
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if block_tzdata:
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sys.modules.pop("tzdata")
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for modname, module in tzdata_modules.items():
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sys.modules[modname] = module
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self.module.reset_tzpath(old_path)
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