PyObjC 和 method_exchangeImplementations：崩溃。正确用法？

Question

我正在使用 PyObjC。 PyObjC 不提供 method_exchangeImplementations 接口，因此我尝试通过 ctypes 使用该函数。我试图从某些窗口控制器类覆盖 windowShouldClose: 。

我的代码：

import objc
BrowserWindowController = objc.lookUpClass("BrowserWindowController")

class BrowserWindowController(objc.Category(BrowserWindowController)):
    def myWindowShouldClose_(self, sender):
        print "myWindowShouldClose", self, sender
        return self.myWindowShouldClose_(sender)

from ctypes import *
capi = pythonapi

# id objc_getClass(const char *name)
capi.objc_getClass.restype = c_void_p
capi.objc_getClass.argtypes = [c_char_p]

# SEL sel_registerName(const char *str)
capi.sel_registerName.restype = c_void_p
capi.sel_registerName.argtypes = [c_char_p]

def capi_get_selector(name):
    return c_void_p(capi.sel_registerName(name))

# Method class_getInstanceMethod(Class aClass, SEL aSelector)
# Will also search superclass for implementations.
capi.class_getInstanceMethod.restype = c_void_p
capi.class_getInstanceMethod.argtypes = [c_void_p, c_void_p]

# void method_exchangeImplementations(Method m1, Method m2)
capi.method_exchangeImplementations.restype = None
capi.method_exchangeImplementations.argtypes = [c_void_p, c_void_p]

def hook_into_close():
    clazz = capi.objc_getClass("BrowserWindowController")
    origClose = capi.class_getInstanceMethod(clazz, capi_get_selector("windowShouldClose:"))
    newClose = capi.class_getInstanceMethod(clazz, capi_get_selector("myWindowShouldClose:"))
    capi.method_exchangeImplementations(origClose, newClose)

这会崩溃。 [NSWindow _close] 中有一些奇怪的回溯。

代码基本正确吗？

问题是什么？

Answer 1

啊，当我在 def myWindowShouldClose_ 前面添加 @objc.signature(BrowserWindowController.windowWillClose_.signature) 时，它不再崩溃了。

所以这只是错误/不匹配的签名。