62 lines
2 KiB
Python
62 lines
2 KiB
Python
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from ctypes import pointer, windll
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from ctypes.wintypes import BOOL, DWORD, HANDLE
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from typing import List, Optional
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from prompt_toolkit.win32_types import SECURITY_ATTRIBUTES
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__all__ = ["wait_for_handles", "create_win32_event"]
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WAIT_TIMEOUT = 0x00000102
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INFINITE = -1
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def wait_for_handles(
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handles: List[HANDLE], timeout: int = INFINITE
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) -> Optional[HANDLE]:
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"""
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Waits for multiple handles. (Similar to 'select') Returns the handle which is ready.
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Returns `None` on timeout.
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http://msdn.microsoft.com/en-us/library/windows/desktop/ms687025(v=vs.85).aspx
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Note that handles should be a list of `HANDLE` objects, not integers. See
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this comment in the patch by @quark-zju for the reason why:
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''' Make sure HANDLE on Windows has a correct size
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Previously, the type of various HANDLEs are native Python integer
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types. The ctypes library will treat them as 4-byte integer when used
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in function arguments. On 64-bit Windows, HANDLE is 8-byte and usually
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a small integer. Depending on whether the extra 4 bytes are zero-ed out
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or not, things can happen to work, or break. '''
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This function returns either `None` or one of the given `HANDLE` objects.
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(The return value can be tested with the `is` operator.)
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"""
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arrtype = HANDLE * len(handles)
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handle_array = arrtype(*handles)
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ret = windll.kernel32.WaitForMultipleObjects(
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len(handle_array), handle_array, BOOL(False), DWORD(timeout)
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)
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if ret == WAIT_TIMEOUT:
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return None
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else:
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return handles[ret]
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def create_win32_event() -> HANDLE:
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"""
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Creates a Win32 unnamed Event .
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http://msdn.microsoft.com/en-us/library/windows/desktop/ms682396(v=vs.85).aspx
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"""
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return HANDLE(
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windll.kernel32.CreateEventA(
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pointer(SECURITY_ATTRIBUTES()),
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BOOL(True), # Manual reset event.
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BOOL(False), # Initial state.
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None, # Unnamed event object.
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)
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)
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