1 files changed, 134 insertions, 0 deletions
diff --git a/lib/chef/experimental/resource2.rb b/lib/chef/experimental/resource2.rb
new file mode 100644
index 0000000000..2c91f79097
--- /dev/null
+++ b/lib/chef/experimental/resource2.rb
@@ -0,0 +1,134 @@
+class Chef
+  module Experimental
+    class Resource2 < Chef::Resource
+      def current_resource
+        return @current_resource if instance_variable_defined?(:@current_resource)
+        provider = provider_for_action(self.class.default_action)
+        provider.load_current_resource
+        @current_resource = provider.current_resource
+      end
+
+      def self.property_type(type=NOT_PASSED,**options,&block)
+        # Combine the type with "is"
+        if type != NOT_PASSED
+          if options[:is]
+            options[:is] = ([ type ] + [ options[:is] ]).flatten(1)
+          else
+            options[:is] = type
+          end
+        end
+
+        ReadProperty.new(**options)
+      end
+
+      def self.load(&block)
+        new_action_provider_class.load_block = block
+      end
+
+      def self.new_action_provider_class
+        return @action_provider_class if @action_provider_class
+
+        unless self == Resource2
+          base_provider = superclass.action_provider_class
+        end
+
+        base_provider ||= ActionProviderClass
+
+        resource_class = self
+        action_provider_class = Class.new(base_provider) do
+          use_inline_resources
+          include_resource_dsl true
+        end
+        action_provider_class.resource_class = self
+        @action_provider_class = action_provider_class
+      end
+
+      class ActionProviderClass < Chef::Provider
+        def initialize(*args)
+          super
+          remove_instance_variable(:@current_resource)
+        end
+
+        def load_current_resource
+          # Copy over all non-desired-state
+          self.current_resource = self.class.resource_class.new(new_resource.name, run_context)
+          current_resource.instance_eval { @current_resource = nil }
+          self.class.resource_class.state_properties.each do |property|
+            if property.is_set?(new_resource)
+              property.set(current_resource, property.get(new_resource))
+            end
+          end
+          begin
+            current_resource.instance_eval(&self.class.load_block)
+          rescue ResourceDoesNotExistError
+            self.current_resource = nil
+          end
+        end
+
+        def converge(*properties, &converge_block)
+          properties = new_resource.state_properties if properties.empty?
+          modified = properties.map do |property|
+            property = new_resource.properties[property] if !property.is_a?(Property)
+            new_value = property.get(new_resource)
+            if current_resource.nil?
+              "  set #{property.name} to #{new_value}"
+            elsif property.is_set?(new_resource)
+              current_value = property.get(current_resource)
+              if new_value != current_value
+                "  set #{property.name} to #{new_value} (was #{current_value})"
+              end
+            end
+          end.compact
+
+          if !modified.empty?
+            if current_resource.nil?
+              converge_by([ "create #{current_resource}", **modified ], &converge_block)
+            else
+              converge_by([ "update #{current_resource}", **modified ], &converge_block)
+            end
+          end
+        end
+
+        def resource_does_not_exist!
+          raise ResourceDoesNotExistError, new_resource
+        end
+
+        def self.resource_class
+          @resource_class
+        end
+        def self.resource_class=(value)
+          raise "Cannot set resource_class on #{self} to two different resources! (Setting to #{value}, was #{resource_class})" if resource_class && resource_class != value
+          @resource_class = value
+        end
+
+        def self.load_block
+          return @load_block if @load_block
+          return superclass.load_block if superclass.respond_to?(:load_block)
+        end
+        def self.load_block=(value)
+          @load_block = value
+        end
+
+        def self.to_s
+          "#{resource_class} action provider"
+        end
+        def self.inspect
+          to_s
+        end
+      end
+
+      class ReadProperty < Property
+        def get(resource)
+          if !is_set?(resource) && desired_state? && resource.current_resource
+            super(resource.current_resource)
+          else
+            super(resource)
+          end
+        end
+      end
+    end
+  end
+
+  class ResourceDoesNotExistError < StandardError
+  end
+end