Prevent memory corruption when finalizing HIDAPI

hid.pyx

@@ -1,5 +1,6 @@
 import sys
-import atexit
+import weakref
+
 from chid cimport *
 from libc.stddef cimport wchar_t, size_t
 
@@ -65,21 +66,23 @@ def enumerate(int vendor_id=0, int product_id=0):
     hid_free_enumeration(info)
     return res
 
-def hidapi_exit():
-    """Callback for when the script exits.
-
-    This prevents memory leaks in the hidapi C library.
-    Note that the counterpart, hid_init(), is not called explicitly. It will
-    be called internally when first needed.
-    """
-    hid_exit()
-
 cdef class device:
     """Device class.
 
     A device instance can be used to read from and write to a HID device.
     """
+
     cdef hid_device *_c_hid
+    cdef object __weakref__ # enable weak-reference support
+
+    def __cinit__(self):
+        """Initialize the device instance.
+
+        Sets up `self.close()` to be automatically called once the strong count
+        goes to zero.  This is necessary to prevent issues later in the
+        execution, when finalizing the HIDAPI library itself.
+        """
+        weakref.finalize(self, self.close)
 
     def open(self, int vendor_id=0, int product_id=0, unicode serial_number=None):
         """Open the connection.
@@ -382,5 +385,6 @@ cdef class device:
         return U(<wchar_t*>hid_error(self._c_hid))
 
 
-# Set a callback to close the HID library as the script exits
-atexit.register(hidapi_exit)
+# Finalize the HIDAPI library *only* once there are no more references to this
+# module, and it is being garbage collected.
+weakref.finalize(sys.modules[__name__], hid_exit)