Initial Chef repository

cookbooks/poise/files/halite_gem/poise/utils/resource_provider_mixin.rb

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+#
+# Copyright 2015, Noah Kantrowitz
+#
+# 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.
+#
+
+
+module Poise
+  module Utils
+    # A mixin to dispatch other mixins with resource and provider
+    # implementations. The module this is included in must have Resource and
+    # Provider sub-modules.
+    #
+    # @since 2.0.0
+    # @example
+    #   module MyHelper
+    #     include Poise::Utils::ResourceProviderMixin
+    #     module Resource
+    #       # ...
+    #     end
+    #
+    #     module Provider
+    #       # ...
+    #     end
+    #   end
+    module ResourceProviderMixin
+      def self.included(klass)
+        # Warning here be dragons.
+        # Create a new anonymous module, klass will be the module that
+        # actually included ResourceProviderMixin. We want to keep a reference
+        # to that locked down so that we can close over it and use it in the
+        # "real" .included defined below to find the original relative consts.
+        mod = Module.new do
+          # Use define_method instead of def so we can close over klass and mod.
+          define_method(:included) do |inner_klass|
+            # Has to be explicit because super inside define_method.
+            super(inner_klass)
+            # Cargo this .included to things which include us.
+            inner_klass.extend(mod)
+            # Dispatch to submodules, inner_klass is the most recent includer.
+            if inner_klass < Chef::Resource
+              # Use klass::Resource to look up relative to the original module.
+              inner_klass.class_exec { include klass::Resource }
+            elsif inner_klass < Chef::Provider
+              # As above, klass::Provider.
+              inner_klass.class_exec { include klass::Provider }
+            end
+          end
+        end
+        # Add our .included to the original includer.
+        klass.extend(mod)
+      end
+    end
+  end
+end