52 lines
1.9 KiB
Python
52 lines
1.9 KiB
Python
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"""同一本地数据库的 Windows named mutex。"""
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from __future__ import annotations
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import ctypes
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from ctypes import wintypes
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import hashlib
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import os
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from pathlib import Path
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from cmbuyer_client.core.errors import SingleInstanceError
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class NamedMutex:
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_ALREADY_EXISTS = 183
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def __init__(self, database_path: Path) -> None:
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if os.name != "nt":
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raise SingleInstanceError("named_mutex_requires_windows")
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canonical = str(database_path.expanduser().resolve()).casefold().encode("utf-8")
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# Global namespace 覆盖同一 Windows 用户的多个交互 session；默认 DACL 不向其他用户泄露句柄。
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name = "Global\\cmbuyer-" + hashlib.sha256(canonical).hexdigest()
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kernel32 = ctypes.WinDLL("kernel32", use_last_error=True)
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kernel32.CreateMutexW.argtypes = (wintypes.LPVOID, wintypes.BOOL, wintypes.LPCWSTR)
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kernel32.CreateMutexW.restype = wintypes.HANDLE
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kernel32.ReleaseMutex.argtypes = (wintypes.HANDLE,)
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kernel32.ReleaseMutex.restype = wintypes.BOOL
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kernel32.CloseHandle.argtypes = (wintypes.HANDLE,)
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kernel32.CloseHandle.restype = wintypes.BOOL
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ctypes.set_last_error(0)
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handle = kernel32.CreateMutexW(None, True, name)
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if not handle:
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raise SingleInstanceError("named_mutex_failed")
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if ctypes.get_last_error() == self._ALREADY_EXISTS:
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kernel32.CloseHandle(handle)
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raise SingleInstanceError("instance_already_running")
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self._kernel32 = kernel32
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self._handle = handle
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def close(self) -> None:
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handle = getattr(self, "_handle", None)
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if handle:
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self._kernel32.ReleaseMutex(handle)
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self._kernel32.CloseHandle(handle)
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self._handle = None
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def __enter__(self) -> "NamedMutex":
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return self
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def __exit__(self, exc_type: object, exc: object, traceback: object) -> None:
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self.close()
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