Add a new util for generating tempfiles

lib/vagrant/util.rb

@@ -9,6 +9,7 @@ module Vagrant
     autoload :SafeExec,                  'vagrant/util/safe_exec'
     autoload :StackedProcRunner,         'vagrant/util/stacked_proc_runner'
     autoload :TemplateRenderer,          'vagrant/util/template_renderer'
+    autoload :Tempfile,                  'vagrant/util/tempfile'
     autoload :Subprocess,                'vagrant/util/subprocess'
   end
 end

lib/vagrant/util/tempfile.rb

@@ -0,0 +1,58 @@
+require "tempfile"
+
+module Vagrant
+  module Util
+    class Tempfile
+      # Utility function for creating a temporary file that will persist for
+      # the duration of the block and then be removed after the block finishes.
+      #
+      # @example
+      #
+      #   Tempfile.create("arch-configure-networks") do |f|
+      #     f.write("network-1")
+      #     f.fsync
+      #     f.close
+      #     do_something_with_file(f.path)
+      #   end
+      #
+      # @example
+      #
+      #   Tempfile.create(["runner", "ps1"]) do |f|
+      #     # f will have a suffix of ".ps1"
+      #     # ...
+      #   end
+      #
+      # @param [String, Array] name the prefix of the tempfile to create
+      # @param [Hash] options a list of options
+      # @param [Proc] block the block to yield the file object to
+      #
+      # @yield [File]
+      def self.create(name, options = {})
+        raise "No block given!" if !block_given?
+
+        options = {
+          binmode: true
+        }.merge(options)
+
+        # The user can specify an array where the first parameter is the prefix
+        # and the last parameter is the file suffix. We want to prefix the
+        # "prefix" with `vagrant-`, and this does that
+        if name.is_a?(Array)
+          basename = ["vagrant-#{name[0]}", name[1]]
+        else
+          basename = "vagrant-#{name}"
+        end
+
+        Dir::Tmpname.create(basename) do |path|
+          begin
+            f = File.open(path, "w+")
+            f.binmode if options[:binmode]
+            yield f
+          ensure
+            File.unlink(f.path) if File.file?(f.path)
+          end
+        end
+      end
+    end
+  end
+end