Reworked handling of options/context and resolved double-decoration

lib/draper/base.rb

@@ -2,7 +2,7 @@ module Draper
   class Base
     require 'active_support/core_ext/class/attribute'
     class_attribute :denied, :allowed, :model_class
-    attr_accessor :context, :model
+    attr_accessor :model, :options
 
     DEFAULT_DENIED = Object.new.methods << :method_missing
     FORCED_PROXY = [:to_param, :id]
@@ -23,7 +23,7 @@ module Draper
       input.inspect # forces evaluation of a lazy query from AR
       self.class.model_class = input.class if model_class.nil?
       @model = input
-      self.context = options.fetch(:context, {})
+      self.options = options
     end
 
     # Proxies to the class specified by `decorates` to automatically
@@ -119,7 +119,10 @@ module Draper
     # @param [Object] instance(s) to wrap
     # @param [Hash] options (optional)
     def self.decorate(input, options = {})
-      if input.respond_to?(:each)
+      if input.instance_of?(self)
+        input.options = options unless options.empty?
+        return input
+      elsif input.respond_to?(:each)
         Draper::DecoratedEnumerableProxy.new(input, self, options)
       elsif options[:infer]
         input.decorator(options)
@@ -214,6 +217,14 @@ module Draper
       super || model_class.respond_to?(method)
     end
 
+    def context
+      options.fetch(:context, {})      
+    end
+    
+    def context=(input)
+      options[:context] = input
+    end
+
   private
     def allow?(method)
       (!allowed? || allowed.include?(method) || FORCED_PROXY.include?(method)) && !denied.include?(method)

spec/draper/base_spec.rb

@@ -224,6 +224,25 @@ describe Draper::Base do
         let(:source) { Product.new }
 
         it { should be_instance_of(Draper::Base) }
+        
+        context "when the input is already decorated" do
+          it "does not perform double-decoration" do
+            decorated = ProductDecorator.decorate(source)
+            ProductDecorator.decorate(decorated).object_id.should == decorated.object_id
+          end
+        
+          it "overwrites options with provided options" do
+            first_run = ProductDecorator.decorate(source, :context => {:role => :user})
+            second_run = ProductDecorator.decorate(first_run, :context => {:role => :admin})
+            second_run.context[:role].should == :admin
+          end
+          
+          it "leaves existing options if none are supplied" do
+            first_run = ProductDecorator.decorate(source, :context => {:role => :user})
+            second_run = ProductDecorator.decorate(first_run)
+            second_run.context[:role].should == :user
+          end
+        end
       end
     end
 
@@ -247,6 +266,14 @@ describe Draper::Base do
       end
     end
     
+    context "with options" do
+      let(:options) {{ :more => "settings" }}
+      
+      subject { Draper::Base.decorate(source, options ) }
+      
+      its(:options) { should eq(options) }
+    end
+
     context "does not infer collections by default" do
       subject { Draper::Base.decorate(source).to_ary }