Added insert, swap, and delete helpers to Vagrant::Action::Builder

lib/vagrant/action/builder.rb

@@ -45,6 +45,52 @@ module Vagrant
         end
       end
 
+      # Inserts a middleware at the given index or directly before the
+      # given middleware object.
+      def insert(index, middleware, *args, &block)
+        index = self.index(index) unless index.is_a?(Integer)
+        stack.insert(index, [middleware, args, block])
+      end
+
+      alias_method :insert_before, :insert
+
+      # Inserts a middleware after the given index or middleware object.
+      def insert_after(index, middleware, *args, &block)
+        index = self.index(index) unless index.is_a?(Integer)
+        raise "no such middleware to insert after: #{index.inspect}" unless index
+        insert(index + 1, middleware, *args, &block)
+      end
+
+      # Swaps out the given middlware object or index with the new
+      # middleware.
+      def swap(index, middleware, *args, &block)
+        if index.is_a?(Integer)
+          delete(index)
+          insert(index, middleware, *args, &block)
+        else
+          insert_before(index, middleware, *args, &block)
+          delete(index)
+        end
+      end
+
+      # Deletes the given middleware object or index
+      def delete(index)
+        index = self.index(index) unless index.is_a?(Integer)
+        stack.delete_at(index)
+      end
+
+      # Returns the numeric index for the given middleware object.
+      #
+      # @param [Object] object The item to find the index for
+      # @return [Integer]
+      def index(object)
+        stack.each_with_index do |item, i|
+          return i if item[0] == object
+        end
+
+        nil
+      end
+
       # Converts the builder stack to a runnable action sequence.
       #
       # @param [Vagrant::Action::Environment] env The action environment

test/vagrant/action/builder_test.rb

@@ -46,6 +46,86 @@ class ActionBuilderTest < Test::Unit::TestCase
       end
     end
 
+    context "inserting" do
+      setup do
+        @instance.use "1"
+        @instance.use "2"
+      end
+
+      should "insert at the proper numeric index" do
+        @instance.insert(1, "3")
+        assert_equal "3", @instance.stack[1].first
+      end
+
+      should "insert next to the proper object if given" do
+        @instance.insert("2", "3")
+        assert_equal "3", @instance.stack[1].first
+      end
+
+      should "be able to call insert_before as well" do
+        @instance.insert_before("1", "0")
+        assert_equal "0", @instance.stack.first.first
+      end
+
+      should "be able to insert_after" do
+        @instance.insert_after("1", "0")
+        assert_equal "0", @instance.stack[1].first
+      end
+
+      should "be able to insert_after using numeric index" do
+        @instance.insert_after(1, "0")
+        assert_equal "0", @instance.stack[2].first
+      end
+
+      should "raise an exception if invalid index" do
+        assert_raises(RuntimeError) {
+          @instance.insert_after("15", "0")
+        }
+      end
+    end
+
+    context "swapping" do
+      setup do
+        @instance.use "1"
+        @instance.use "2"
+      end
+
+      should "be able to swap using the object" do
+        @instance.swap "1", "3"
+        assert_equal "3", @instance.stack.first.first
+      end
+
+      should "be able to swap using the index" do
+        @instance.swap 0, "3"
+        assert_equal "3", @instance.stack.first.first
+      end
+    end
+
+    context "deleting" do
+      setup do
+        @instance.use "1"
+      end
+
+      should "delete the proper object" do
+        @instance.delete("1")
+        assert @instance.stack.empty?
+      end
+
+      should "delete by index if given" do
+        @instance.delete(0)
+        assert @instance.stack.empty?
+      end
+    end
+
+    context "getting an index of an object" do
+      should "return the proper index if it exists" do
+        @instance.use 1
+        @instance.use 2
+        @instance.use 3
+        assert_equal 1, @instance.index(2)
+      end
+    end
+
     context "converting to an app" do
       should "preprend error halt to the chain" do
         result = mock("result")