1 files changed, 83 insertions, 0 deletions
diff --git a/lib/chef/resource/action_class.rb b/lib/chef/resource/action_class.rb
new file mode 100644
index 0000000000..12211418e9
--- /dev/null
+++ b/lib/chef/resource/action_class.rb
@@ -0,0 +1,83 @@
+#
+# Author:: John Keiser (<jkeiser@chef.io)
+# Copyright:: Copyright (c) 2015 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# 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.
+#
+
+require 'chef/exceptions'
+
+class Chef
+  class Resource
+    module ActionClass
+      #
+      # If load_current_value! is defined on the resource, use that.
+      #
+      def load_current_resource
+        if new_resource.respond_to?(:load_current_value!)
+          # dup the resource and then reset desired-state properties.
+          current_resource = new_resource.dup
+
+          # We clear desired state in the copy, because it is supposed to be actual state.
+          # We keep identity properties and non-desired-state, which are assumed to be
+          # "control" values like `recurse: true`
+          current_resource.class.properties.each do |name,property|
+            if property.desired_state? && !property.identity? && !property.name_property?
+              property.reset(current_resource)
+            end
+          end
+
+          # Call the actual load_current_value! method. If it raises
+          # CurrentValueDoesNotExist, set current_resource to `nil`.
+          begin
+            # If the user specifies load_current_value do |desired_resource|, we
+            # pass in the desired resource as well as the current one.
+            if current_resource.method(:load_current_value!).arity > 0
+              current_resource.load_current_value!(new_resource)
+            else
+              current_resource.load_current_value!
+            end
+          rescue Chef::Exceptions::CurrentValueDoesNotExist
+            current_resource = nil
+          end
+        end
+
+        @current_resource = current_resource
+      end
+
+      def self.included(other)
+        other.extend(ClassMethods)
+        other.use_inline_resources
+        other.include_resource_dsl true
+      end
+
+      module ClassMethods
+        #
+        # The Chef::Resource class this ActionClass was declared against.
+        #
+        # @return [Class] The Chef::Resource class this ActionClass was declared against.
+        #
+        attr_accessor :resource_class
+
+        def to_s
+          "#{resource_class} action provider"
+        end
+
+        def inspect
+          to_s
+        end
+      end
+    end
+  end
+end