import ctypes
from . import NamedEvent
class WindowsNamedEvent(NamedEvent):
"""
Named events using the native Windows APIs
"""
__SYNCHRONIZE = 0x00100000
__EVENT_MODIFY_STATE = 2
__WAIT_FAILED = 0xFFFFFFFF
__ERROR_FILE_NOT_FOUND = 2
__INFINITE = 0xffffffff
@staticmethod
def __raise_last_error():
err_no = ctypes.GetLastError()
raise WindowsError(err_no, ctypes.FormatError(err_no))
def exists(name: str) -> bool:
event = ctypes.windll.kernel32.OpenEventW(WindowsNamedEvent.__SYNCHRONIZE | WindowsNamedEvent.__EVENT_MODIFY_STATE, False, name)
if event == 0:
if ctypes.GetLastError() == WindowsNamedEvent.__ERROR_FILE_NOT_FOUND:
return False
else:
WindowsNamedEvent.__raise_last_error()
else:
result = ctypes.windll.kernel32.CloseHandle(event)
if result == 0:
WindowsNamedEvent.__raise_last_error()
return True
def __init__(self, name: str):
event = ctypes.windll.kernel32.CreateEventW(ctypes.c_void_p(), True, False, name)
if event == 0:
WindowsNamedEvent.__raise_last_error()
self.__event = event
self.__name = name
def signal(self):
result = ctypes.windll.kernel32.SetEvent(self.__event)
if result == 0:
WindowsNamedEvent.__raise_last_error()
result = ctypes.windll.kernel32.ResetEvent(self.__event)
if result == 0:
WindowsNamedEvent.__raise_last_error()
def wait(self):
result = ctypes.windll.kernel32.WaitForSingleObject(self.__event, WindowsNamedEvent.__INFINITE)
if result == WindowsNamedEvent.__WAIT_FAILED:
WindowsNamedEvent.__raise_last_error()
def name(self) -> str:
return self.__name
def close(self):
result = ctypes.windll.kernel32.CloseHandle(self.__event)
if result == 0:
WindowsNamedEvent.__raise_last_error()
