Hook class

lib/vagrant/action/hook.rb

@@ -0,0 +1,53 @@
+module Vagrant
+  module Action
+    # This class manages hooks into existing {Builder} stacks, and lets you
+    # add and remove middleware classes. This is the primary method by which
+    # plugins can hook into built-in middleware stacks.
+    class Hook
+      # This is a hash of the middleware to prepend to a certain
+      # other middleware.
+      #
+      # @return [Hash<Class, Array<Class>>]
+      attr_reader :before_hooks
+
+      # This is a hash of the middleware to append to a certain other
+      # middleware.
+      #
+      # @return [Hash<Class, Array<Class>>]
+      attr_reader :after_hooks
+
+      # This is a list of the hooks to just prepend to the beginning
+      #
+      # @return [Array<Class>]
+      attr_reader :prepend_hooks
+
+      # This is a list of the hooks to just append to the end
+      #
+      # @return [Array<Class>]
+      attr_reader :append_hooks
+
+      def initialize
+        @before_hooks  = Hash.new { |h, k| h[k] = [] }
+        @after_hooks   = Hash.new { |h, k| h[k] = [] }
+        @prepend_hooks = []
+        @append_hooks  = []
+      end
+
+      def before(existing, new)
+        @before_hooks[existing] << new
+      end
+
+      def after(existing, new)
+        @after_hooks[existing] << new
+      end
+
+      def append(new)
+        @append_hooks << new
+      end
+
+      def prepend(new)
+        @prepend_hooks << new
+      end
+    end
+  end
+end

test/unit/vagrant/action/hook_test.rb

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+require File.expand_path("../../../base", __FILE__)
+
+require "vagrant/action/hook"
+
+describe Vagrant::Action::Hook do
+  describe "defaults" do
+    its("after_hooks")   { should be_empty }
+    its("before_hooks")  { should be_empty }
+    its("append_hooks")  { should be_empty }
+    its("prepend_hooks") { should be_empty }
+  end
+
+  describe "before hooks" do
+    let(:existing) { "foo" }
+
+    it "should append them" do
+      subject.before(existing, 1)
+      subject.before(existing, 2)
+
+      subject.before_hooks[existing].should == [1, 2]
+    end
+  end
+
+  describe "after hooks" do
+    let(:existing) { "foo" }
+
+    it "should append them" do
+      subject.after(existing, 1)
+      subject.after(existing, 2)
+
+      subject.after_hooks[existing].should == [1, 2]
+    end
+  end
+
+  describe "append" do
+    it "should make a list" do
+      subject.append(1)
+      subject.append(2)
+
+      subject.append_hooks.should == [1, 2]
+    end
+  end
+
+  describe "prepend" do
+    it "should make a list" do
+      subject.prepend(1)
+      subject.prepend(2)
+
+      subject.prepend_hooks.should == [1, 2]
+    end
+  end
+end