copy Lib/atexit.py from python2

Lib/atexit.py

@@ -0,0 +1,65 @@
+"""
+atexit.py - allow programmer to define multiple exit functions to be executed
+upon normal program termination.
+
+One public function, register, is defined.
+"""
+
+__all__ = ["register"]
+
+import sys
+
+_exithandlers = []
+def _run_exitfuncs():
+    """run any registered exit functions
+
+    _exithandlers is traversed in reverse order so functions are executed
+    last in, first out.
+    """
+
+    exc_info = None
+    while _exithandlers:
+        func, targs, kargs = _exithandlers.pop()
+        try:
+            func(*targs, **kargs)
+        except SystemExit:
+            exc_info = sys.exc_info()
+        except:
+            import traceback
+            print >> sys.stderr, "Error in atexit._run_exitfuncs:"
+            traceback.print_exc()
+            exc_info = sys.exc_info()
+
+    if exc_info is not None:
+        raise exc_info[0], exc_info[1], exc_info[2]
+
+
+def register(func, *targs, **kargs):
+    """register a function to be executed upon normal program termination
+
+    func - function to be called at exit
+    targs - optional arguments to pass to func
+    kargs - optional keyword arguments to pass to func
+
+    func is returned to facilitate usage as a decorator.
+    """
+    _exithandlers.append((func, targs, kargs))
+    return func
+
+if hasattr(sys, "exitfunc"):
+    # Assume it's another registered exit function - append it to our list
+    register(sys.exitfunc)
+sys.exitfunc = _run_exitfuncs
+
+if __name__ == "__main__":
+    def x1():
+        print("running x1")
+    def x2(n):
+        print("running x2(%r)" % (n,))
+    def x3(n, kwd=None):
+        print("running x3(%r, kwd=%r)" % (n, kwd))
+
+    register(x1)
+    register(x2, 12)
+    register(x3, 5, "bar")
+    register(x3, "no kwd args")