ctypes - 有没有办法确保我所有的 ctypes 都有 argtypes？

Question

我知道我应该指定 argtypes对于我的 C/C++ 函数，因为我的某些调用会导致堆栈损坏。

    myCfunc.argtypes = [ct.c_void_p, ct.POINTER(ct.c_void_p)]
    myCfunc.errcheck = my_error_check

事实上，我想确认我没有忘记为大约 100 个函数调用中的任何一个指定函数原型(prototype)( argtypes/ errcheck )......

现在我只是通过我的 Python 文件 grep 并在视觉上与包含原型(prototype)定义的文件进行比较。

有没有更好的方法来验证我是否定义了 argtypes/ errcheck我所有的电话？

Answer 1

@eryksun 提到的命名空间让我将 dll 包装在一个只公开显式注释函数的类中。只要 dll 没有函数名称“annotate”或“_error_check”(我没有)，以下方法似乎对我有用:

import ctypes as ct

class MyWinDll:
    def __init__(self, dll_filename):
        self._dll = ct.WinDLL(dll_filename)
        # Specify function prototypes using the annotate function
        self.annotate(self._dll.myCfunc, [ct.POINTER(ct.c_void_p)], self._error_check)
        self.annotate(self._dll.myCfunc2, [ct.c_void_p], self._error_check)
        ...

    def annotate(self, function, argtypes, errcheck):
        # note that "annotate" may not be used as a function name in the dll...
        function.argtypes = argtypes
        function.errcheck = errcheck
        setattr(self, function.__name__, function)

    def _error_check(self, result, func, arguments):
        if result != 0:
            raise Exception

if __name__ == '__main__':
    dll = MyWinDll('myWinDll.dll')
    handle = ct.c_void_p(None)
    # Now call the dll functions using the wrapper object
    dll.myCfunc(ct.byref(handle))
    dll.myCfunc2(handle)

更新: @eryksun 的评论让我尝试通过让用户控制 WinDLL 来改进代码构造函数并尝试减少重复代码:

import ctypes as ct

DEFAULT = object()

def annotate(dll_object, function_name, argtypes, restype=DEFAULT, errcheck=DEFAULT):
    function = getattr(dll_object._dll, function_name)
    function.argtypes = argtypes
    # restype and errcheck is optional in the function_prototypes list
    if restype is DEFAULT:
        restype = dll_object.default_restype
    function.restype = restype
    if errcheck is DEFAULT:
        errcheck = dll_object.default_errcheck
    function.errcheck = errcheck
    setattr(dll_object, function_name, function)


class MyDll:
    def __init__(self, ct_dll, **function_prototypes):
        self._dll = ct_dll
        for name, prototype in function_prototypes.items():
            annotate(self, name, *prototype)


class OneDll(MyDll):
    def __init__(self, ct_dll):
        # set default values for function_prototypes
        self.default_restype = ct.c_int
        self.default_errcheck = self._error_check
        function_prototypes = {
            'myCfunc': [[ct.POINTER(ct.c_void_p)]],
            'myCfunc2': [[ct.c_void_p]],
            # ...
            'myCgetErrTxt': [[ct.c_int, ct.c_char_p, ct.c_size_t], DEFAULT, None]
        }
        super().__init__(ct_dll, **function_prototypes)

    # My error check function actually calls the dll, so I keep it here...
    def _error_check(self, result, func, arguments):
        msg = ct.create_string_buffer(255)
        if result != 0:
            raise Exception(self.myCgetErrTxt(result, msg, ct.sizeof(msg)))


if __name__ == '__main__':
    ct_dll = ct.WinDLL('myWinDll.dll')
    dll = OneDll(ct_dll)
    handle = ct.c_void_p(None)
    dll.myCfunc(ct.byref(handle))
    dll.myCfunc2(handle)

(不知道要不要删掉原来的代码，留着供引用。)