Merge "Add a funcutils file for working with functions."

1 files changed, 76 insertions, 0 deletions

diff --git a/openstack/common/funcutils.py b/openstack/common/funcutils.py
new file mode 100644
index 0000000..b04d58f
--- /dev/null
+++ b/openstack/common/funcutils.py
@@ -0,0 +1,76 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack Foundation.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Utility methods for working with functions/decorators."""
+
+import inspect
+
+
+def get_wrapped_function(function):
+    """Get the method at the bottom of a stack of decorators."""
+
+    if not hasattr(function, 'func_closure') or not function.func_closure:
+        return function
+
+    def _get_wrapped_function(function):
+        if not hasattr(function, 'func_closure') or not function.func_closure:
+            return None
+
+        for closure in function.func_closure:
+            func = closure.cell_contents
+
+            deeper_func = _get_wrapped_function(func)
+            if deeper_func:
+                return deeper_func
+            elif hasattr(closure.cell_contents, '__call__'):
+                return closure.cell_contents
+
+    return _get_wrapped_function(function)
+
+
+def getcallargs(function, *args, **kwargs):
+    """This is a simplified inspect.getcallargs (2.7+).
+
+    It should be replaced when python >= 2.7 is standard.
+    """
+
+    keyed_args = {}
+    argnames, varargs, keywords, defaults = inspect.getargspec(function)
+
+    keyed_args.update(kwargs)
+
+    # NOTE(alaski) the implicit 'self' or 'cls' argument shows up in
+    # argnames but not in args or kwargs.  Uses 'in' rather than '==' because
+    # some tests use 'self2'.
+    if 'self' in argnames[0] or 'cls' == argnames[0]:
+        # The function may not actually be a method or have im_self.
+        # Typically seen when it's stubbed with mox.
+        if inspect.ismethod(function) and hasattr(function, 'im_self'):
+            keyed_args[argnames[0]] = function.im_self
+        else:
+            keyed_args[argnames[0]] = None
+
+    remaining_argnames = filter(lambda x: x not in keyed_args, argnames)
+    keyed_args.update(dict(zip(remaining_argnames, args)))
+
+    if defaults:
+        num_defaults = len(defaults)
+        for argname, value in zip(argnames[-num_defaults:], defaults):
+            if argname not in keyed_args:
+                keyed_args[argname] = value
+
+    return keyed_args