[GH-6] Setting things up for making sure a single cache root exists

lib/vagrant-cachier/action/ensure_single_cache_root.rb

@@ -0,0 +1,16 @@
+module VagrantPlugins
+  module Cachier
+    class Action
+      class EnsureSingleCacheRoot
+        def initialize(app, env)
+          @app = app
+        end
+
+        def call(env)
+          raise 'Do our work'
+          @app.call(env)
+        end
+      end
+    end
+  end
+end

lib/vagrant-cachier/plugin.rb

@@ -46,6 +46,21 @@ module VagrantPlugins
         Cap::Arch::PacmanCacheDir
       end
 
+      # TODO: This should be generic, we don't want to hard code every single
+      #       possible provider action class that Vagrant might have
+      ensure_single_cache_root = lambda do |hook|
+        require_relative 'action/ensure_single_cache_root'
+        hook.after VagrantPlugins::ProviderVirtualBox::Action::Boot, Action::EnsureSingleCacheRoot
+
+        if defined?(Vagrant::LXC)
+          # TODO: Require just the boot action file once its "require dependencies" are sorted out
+          require 'vagrant-lxc/action'
+          hook.after Vagrant::LXC::Action::Boot, Action::EnsureSingleCacheRoot
+        end
+      end
+      action_hook 'ensure-single-cache-root-exists-on-up',     :machine_action_up,     &ensure_single_cache_root
+      action_hook 'ensure-single-cache-root-exists-on-reload', :machine_action_reload, &ensure_single_cache_root
+
       clean_action_hook = lambda do |hook|
         require_relative 'action/clean'
         hook.before Vagrant::Action::Builtin::GracefulHalt, VagrantPlugins::Cachier::Action::Clean