Inline object creation.

Allows the creation of related objects during a workflow.
For example, this patch implements importing keypairs during
the launch instance workflow and allocating floating IP
addresses during the floating IP associate workflow.

This required several significant changes:

  * SelfHandlingForm should no long return a redirect.
    Instead, it should return either the object it
    created/acted on, or else a boolean such as True.

  * The ModalFormView now differentiates between GET
    and POST.

  * Due to the previous two items, SelfHandlingForm
    was mostly gutted (no more maybe_handle, etc.).

  * Modals now operate via a "stack" where only the
    top modal is visible at any given time and closing
    one causes the next one to become visible.

In the process of these large changes there was a large
amount of general code cleanup, especially in the javascript
code and the existing SelfHandlingForm subclasses/ModalFormView
subclasses. Many small bugs were fixed along with the cleanup.

Implements blueprint inline-object-creation.

Fixes bug 994677.
Fixes bug 1025977.
Fixes bug 1027342.
Fixes bug 1025919.

Change-Id: I1808b34cbf6f813eaedf767a6364e815c0c5e969

horizon/forms/fields.py

@@ -0,0 +1,61 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 Nebula, Inc.
+#
+#    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.
+
+from django.core import urlresolvers
+from django.forms import fields, widgets
+
+
+class DynamicSelectWidget(widgets.Select):
+    """
+    A subclass of the ``Select`` widget which renders extra attributes for use
+    in callbacks to handle dynamic changes to the available choices.
+    """
+    _data_add_url_attr = "data-add-item-url"
+
+    def render(self, *args, **kwargs):
+        add_item_url = self.get_add_item_url()
+        if add_item_url is not None:
+            self.attrs.update({self._data_add_url_attr: add_item_url})
+        return super(DynamicSelectWidget, self).render(*args, **kwargs)
+
+    def get_add_item_url(self):
+        if callable(self.add_item_link):
+            return self.add_item_link()
+        try:
+            return urlresolvers.reverse(self.add_item_link)
+        except urlresolvers.NoReverseMatch:
+            return self.add_item_link
+
+
+class DynamicChoiceField(fields.ChoiceField):
+    """
+    A subclass of ``ChoiceField`` with additional properties that make
+    dynamically updating its elements easier.
+
+    Notably, the field declaration takes an extra argument, ``add_item_link``
+    which may be a string or callable defining the URL that should be used
+    for the "add" link associated with the field.
+    """
+    widget = DynamicSelectWidget
+
+    def __init__(self, add_item_link=None, *args, **kwargs):
+        super(DynamicChoiceField, self).__init__(*args, **kwargs)
+        self.widget.add_item_link = add_item_link
+
+
+class DynamicTypedChoiceField(DynamicChoiceField, fields.TypedChoiceField):
+    """ Simple mix of ``DynamicChoiceField`` and ``TypedChoiceField``. """
+    pass