Merge branch 'machine-abstraction'

This branch brings in the "machine abstraction" code. This is a major
milestone in the development of Vagrant as it abstracts all of the
VirtualBox-specific code out into a plugin. There is zero VirtualBox
specific code in the core ("lib/") directory at this point. Read on for
important points.

== Gotchas

White it is technically possible now to write plugins for other
providers, there is still major work to be done to make this feasible.
The plugin interface itself is pretty much done, but there are some
issues:

* ":virtualbox" is the hardcoded provider to be used at the moment.

* There is no way to configure a provider. For example,
  `config.vm.customize` would never work for anything other than
  VirtualBox, so there needs to be a way to have provider-specific
  configuration. This will come soon.

* Shared folders and networking need to be rearchitected to be friendly
  for multiple providers, since it is unrealistic that a provider such as
  EC2 could provide the same level of networking, for example.

* There is no way easy way (like `vagrant package --base`) to create
  boxes for providers other than VirtualBox. This will be addressed in a
  whole new feature of Vagrant probably in a future release after
  provider stuff has shipped.

== Writing a Provider

To write a provider, you create a Vagrant plugin that defines a
"provider". See the "plugins/providers/virtualbox/plugin.rb" for more
details. Providers themselves have an exremely simple API. The burden
for writing providers mostly rests on the fact that you must define
complex middleware sequences.

Lots more work to come in the future, but this is a BIG MILESTONE!

lib/vagrant.rb

@@ -66,7 +66,6 @@ module Vagrant
   autoload :BoxCollection, 'vagrant/box_collection'
   autoload :CLI,           'vagrant/cli'
   autoload :Command,       'vagrant/command'
-  autoload :Communication, 'vagrant/communication'
   autoload :Config,        'vagrant/config'
   autoload :DataStore,     'vagrant/data_store'
   autoload :Downloaders,   'vagrant/downloaders'
@@ -76,27 +75,23 @@ module Vagrant
   autoload :Errors,        'vagrant/errors'
   autoload :Guest,         'vagrant/guest'
   autoload :Hosts,         'vagrant/hosts'
+  autoload :Machine,       'vagrant/machine'
   autoload :Plugin,        'vagrant/plugin'
-  autoload :SSH,           'vagrant/ssh'
   autoload :TestHelpers,   'vagrant/test_helpers'
   autoload :UI,            'vagrant/ui'
   autoload :Util,          'vagrant/util'
-  autoload :VM,            'vagrant/vm'
 
   # These are the various plugin versions and their components in
   # a lazy loaded Hash-like structure.
-  c = PLUGIN_COMPONENTS = Registry.new
-  c.register(:"1")                 { Plugin::V1::Plugin }
-  c.register([:"1", :command])     { Plugin::V1::Command }
-  c.register([:"1", :config])      { Plugin::V1::Config }
-  c.register([:"1", :guest])       { Plugin::V1::Guest }
-  c.register([:"1", :host])        { Plugin::V1::Host }
-  c.register([:"1", :provisioner]) { Plugin::V1::Provisioner }
-
-  # Returns a `Vagrant::Registry` object that contains all the built-in
-  # middleware stacks.
-  def self.actions
-    @actions ||= Vagrant::Action::Builtin.new
+  PLUGIN_COMPONENTS = Registry.new.tap do |c|
+    c.register(:"1")                  { Plugin::V1::Plugin }
+    c.register([:"1", :command])      { Plugin::V1::Command }
+    c.register([:"1", :communicator]) { Plugin::V1::Communicator }
+    c.register([:"1", :config])       { Plugin::V1::Config }
+    c.register([:"1", :guest])        { Plugin::V1::Guest }
+    c.register([:"1", :host])         { Plugin::V1::Host }
+    c.register([:"1", :provider])     { Plugin::V1::Provider }
+    c.register([:"1", :provisioner])  { Plugin::V1::Provisioner }
   end
 
   # The source root is the path to the root directory of

lib/vagrant/action.rb

@@ -2,60 +2,35 @@
 
 module Vagrant
   module Action
-    autoload :Builtin,     'vagrant/action/builtin'
     autoload :Environment, 'vagrant/action/environment'
     autoload :Runner,      'vagrant/action/runner'
     autoload :Warden,      'vagrant/action/warden'
 
-    module Box
-      autoload :Add,       'vagrant/action/box/add'
-      autoload :Download,  'vagrant/action/box/download'
-      autoload :Verify,    'vagrant/action/box/verify'
-    end
-
-    module Env
-      autoload :Set, 'vagrant/action/env/set'
+    # Builtin contains middleware classes that are shipped with Vagrant-core
+    # and are thus available to all plugins as a "standard library" of sorts.
+    module Builtin
+      autoload :BoxAdd,  "vagrant/action/builtin/box_add"
+      autoload :Call,    "vagrant/action/builtin/call"
+      autoload :Confirm, "vagrant/action/builtin/confirm"
+      autoload :EnvSet,  "vagrant/action/builtin/env_set"
+      autoload :SSHExec, "vagrant/action/builtin/ssh_exec"
+      autoload :SSHRun,  "vagrant/action/builtin/ssh_run"
     end
 
     module General
-      autoload :CheckVirtualbox, 'vagrant/action/general/check_virtualbox'
       autoload :Package,  'vagrant/action/general/package'
       autoload :Validate, 'vagrant/action/general/validate'
     end
 
-    module VM
-      autoload :Boot,                'vagrant/action/vm/boot'
-      autoload :CheckAccessible,     'vagrant/action/vm/check_accessible'
-      autoload :CheckBox,            'vagrant/action/vm/check_box'
-      autoload :CheckGuestAdditions, 'vagrant/action/vm/check_guest_additions'
-      autoload :CheckPortCollisions, 'vagrant/action/vm/check_port_collisions'
-      autoload :CleanMachineFolder,  'vagrant/action/vm/clean_machine_folder'
-      autoload :ClearForwardedPorts, 'vagrant/action/vm/clear_forwarded_ports'
-      autoload :ClearNetworkInterfaces, 'vagrant/action/vm/clear_network_interfaces'
-      autoload :ClearSharedFolders,  'vagrant/action/vm/clear_shared_folders'
-      autoload :Customize,           'vagrant/action/vm/customize'
-      autoload :DefaultName,         'vagrant/action/vm/default_name'
-      autoload :Destroy,             'vagrant/action/vm/destroy'
-      autoload :DestroyUnusedNetworkInterfaces, 'vagrant/action/vm/destroy_unused_network_interfaces'
-      autoload :DiscardState,        'vagrant/action/vm/discard_state'
-      autoload :Export,              'vagrant/action/vm/export'
-      autoload :ForwardPorts,        'vagrant/action/vm/forward_ports'
-      autoload :Halt,                'vagrant/action/vm/halt'
-      autoload :HostName,            'vagrant/action/vm/host_name'
-      autoload :Import,              'vagrant/action/vm/import'
-      autoload :MatchMACAddress,     'vagrant/action/vm/match_mac_address'
-      autoload :Network,             'vagrant/action/vm/network'
-      autoload :NFS,                 'vagrant/action/vm/nfs'
-      autoload :Package,             'vagrant/action/vm/package'
-      autoload :PackageVagrantfile,  'vagrant/action/vm/package_vagrantfile'
-      autoload :Provision,           'vagrant/action/vm/provision'
-      autoload :ProvisionerCleanup,  'vagrant/action/vm/provisioner_cleanup'
-      autoload :PruneNFSExports,     'vagrant/action/vm/prune_nfs_exports'
-      autoload :Resume,              'vagrant/action/vm/resume'
-      autoload :SaneDefaults,        'vagrant/action/vm/sane_defaults'
-      autoload :ShareFolders,        'vagrant/action/vm/share_folders'
-      autoload :SetupPackageFiles,   'vagrant/action/vm/setup_package_files'
-      autoload :Suspend,             'vagrant/action/vm/suspend'
+    # This is the action that will add a box from a URL. This middleware
+    # sequence is built-in to Vagrant. Plugins can hook into this like any
+    # other middleware sequence. This is particularly useful for provider
+    # plugins, which can hook in to do things like verification of boxes
+    # that are downloaded.
+    def self.action_box_add
+      Builder.new.tap do |b|
+        b.use Builtin::BoxAdd
+      end
     end
   end
 end

lib/vagrant/action/builder.rb

@@ -9,18 +9,21 @@ module Action
     #
     # Building an action sequence is very easy:
     #
-    #     app = Vagrant::Action::Builder.new do
-    #       use MiddlewareA
-    #       use MiddlewareB
+    #     app = Vagrant::Action::Builder.new.tap do |b|
+    #       b.use MiddlewareA
+    #       b.use MiddlewareB
     #     end
     #
     #     Vagrant::Action.run(app)
     #
     class Builder
-      # Initializes the builder. An optional block can be passed which
-      # will be evaluated in the context of the instance.
-      def initialize(&block)
-        instance_eval(&block) if block_given?
+      # This is a shortcut for a middleware sequence with only one item
+      # in it. For a description of the arguments and the documentation, please
+      # see {#use} instead.
+      #
+      # @return [Builder]
+      def self.build(middleware, *args, &block)
+        new.use(middleware, *args, &block)
       end
 
       # Returns a mergeable version of the builder. If `use` is called with
@@ -38,11 +41,6 @@ def flatten
       #
       # @param [Class] middleware The middleware class
       def use(middleware, *args, &block)
-        # Prepend with a environment setter if args are given
-        if !args.empty? && args.first.is_a?(Hash) && middleware != Env::Set
-          self.use(Env::Set, args.shift, &block)
-        end
-
         if middleware.kind_of?(Builder)
           # Merge in the other builder's stack into our own
           self.stack.concat(middleware.stack)