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如何处理Python中的PyCapsule类型

python-c-api pyside winapi python

5

David · 技术社区 · 10 年前

我试图从

QtGui.QWidget.effectiveWinId()

到

win32gui.SetWindowLong()

valideWinId()正在返回:

<capsule object NULL at 0x027C9BF0>
<class 'PyCapsule'>

SetWindowLong()需要一个PyHANDLE(doc表示它“应该”也接受一个整数)

TypeError: The object is not a PyHANDLE object

所以我的问题是如何从PyCapsule对象中获取值,或者检查它是否为NULL?PyCapsule似乎都是C代码的内部API。

我还发现了这个bug,它做的事情与我想要的Python的2.X PyCObject相似,而Python 3.X中不存在这个bug: http://srinikom.github.io/pyside-bz-archive/show_bug.cgi?id=523#c18

1 回复 | 直到 10 年前

1

8

David 10 年前

好吧,我设法弄明白了:

# ...
capsule = self.effectiveWinId()
ctypes.pythonapi.PyCapsule_GetPointer.restype = ctypes.c_void_p
ctypes.pythonapi.PyCapsule_GetPointer.argtypes = [ctypes.py_object, ctypes.c_char_p]
handle = ctypes.pythonapi.PyCapsule_GetPointer(capsule, None)
win32gui.SetWindowLong(handle, win32con.GWL_WNDPROC, self.new_window_procedure)
# ...

下面是一个python类,用于处理重写win32窗口过程:

import win32con
import win32gui
import win32api
import ctypes
import pywintypes

def convert_capsule_to_int(capsule):
    ctypes.pythonapi.PyCapsule_GetPointer.restype = ctypes.c_void_p
    ctypes.pythonapi.PyCapsule_GetPointer.argtypes = [ctypes.py_object, ctypes.c_char_p]
    return ctypes.pythonapi.PyCapsule_GetPointer(capsule, None)

class WindowProcedure(object):
    self.handle_WM_DESTROY = False
    def __init__(self, handle):
        if isinstance(handle, int) or isinstance(handle, type(pywintypes.HANDLE())):
            self.handle = handle
        else:
            self.handle = convert_capsule_to_int(handle)
        self.old_proc = win32gui.GetWindowLong(self.handle, win32con.GWL_WNDPROC)
        if not self.old_proc:
            raise RuntimeError("Failed to set/get window procedure!") 
        if not win32gui.SetWindowLong(self.handle, win32con.GWL_WNDPROC, self.new_window_procedure):
            raise RuntimeError("Failed to set/get window procedure!")

    def handle_old_procedure(self, hwnd, msg, wparam, lparam):
        # For some reason the executable would hang after a QtGui.QWidget exit
        # so I'm forcing it here if self.handle_WM_DESTROY is true
        if msg == win32con.WM_DESTROY and self.handle_WM_DESTROY:
            win32gui.DestroyWindow(hwnd)
            return 0
        return win32gui.CallWindowProc(self.old_proc, hwnd, msg, wparam, lparam)