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- from ctypes import c_void_p
-
-
- class CPointerBase:
- """
- Base class for objects that have a pointer access property
- that controls access to the underlying C pointer.
- """
- _ptr = None # Initially the pointer is NULL.
- ptr_type = c_void_p
- destructor = None
- null_ptr_exception_class = AttributeError
-
- @property
- def ptr(self):
- # Raise an exception if the pointer isn't valid so that NULL pointers
- # aren't passed to routines -- that's very bad.
- if self._ptr:
- return self._ptr
- raise self.null_ptr_exception_class('NULL %s pointer encountered.' % self.__class__.__name__)
-
- @ptr.setter
- def ptr(self, ptr):
- # Only allow the pointer to be set with pointers of the compatible
- # type or None (NULL).
- if not (ptr is None or isinstance(ptr, self.ptr_type)):
- raise TypeError('Incompatible pointer type: %s.' % type(ptr))
- self._ptr = ptr
-
- def __del__(self):
- """
- Free the memory used by the C++ object.
- """
- if self.destructor and self._ptr:
- try:
- self.destructor(self.ptr)
- except (AttributeError, ImportError, TypeError):
- pass # Some part might already have been garbage collected
|
