Merge branch 'refactor/master/7012-rename-strings-to-interfaces-and-faces'

1 files changed, 119 insertions, 0 deletions

diff --git a/lib/puppet/interface/action.rb b/lib/puppet/interface/action.rb
new file mode 100644
index 000000000..e4a37a1f7
--- /dev/null
+++ b/lib/puppet/interface/action.rb
@@ -0,0 +1,119 @@
+# -*- coding: utf-8 -*-
+require 'puppet/interface'
+require 'puppet/interface/option'
+
+class Puppet::Interface::Action
+  def initialize(face, name, attrs = {})
+    raise "#{name.inspect} is an invalid action name" unless name.to_s =~ /^[a-z]\w*$/
+    @face    = face
+    @name    = name.to_sym
+    @options = {}
+    attrs.each do |k, v| send("#{k}=", v) end
+  end
+
+  attr_reader :name
+  def to_s() "#{@face}##{@name}" end
+
+
+  # Initially, this was defined to allow the @action.invoke pattern, which is
+  # a very natural way to invoke behaviour given our introspection
+  # capabilities.   Heck, our initial plan was to have the faces delegate to
+  # the action object for invocation and all.
+  #
+  # It turns out that we have a binding problem to solve: @face was bound to
+  # the parent class, not the subclass instance, and we don't pass the
+  # appropriate context or change the binding enough to make this work.
+  #
+  # We could hack around it, by either mandating that you pass the context in
+  # to invoke, or try to get the binding right, but that has probably got
+  # subtleties that we don't instantly think of – especially around threads.
+  #
+  # So, we are pulling this method for now, and will return it to life when we
+  # have the time to resolve the problem.  For now, you should replace...
+  #
+  #     @action = @face.get_action(name)
+  #     @action.invoke(arg1, arg2, arg3)
+  #
+  # ...with...
+  #
+  #     @action = @face.get_action(name)
+  #     @face.send(@action.name, arg1, arg2, arg3)
+  #
+  # I understand that is somewhat cumbersome, but it functions as desired.
+  # --daniel 2011-03-31
+  #
+  # PS: This code is left present, but commented, to support this chunk of
+  # documentation, for the benefit of the reader.
+  #
+  # def invoke(*args, &block)
+  #   @face.send(name, *args, &block)
+  # end
+
+  def when_invoked=(block)
+    # We need to build an instance method as a wrapper, using normal code, to
+    # be able to expose argument defaulting between the caller and definer in
+    # the Ruby API.  An extra method is, sadly, required for Ruby 1.8 to work.
+    #
+    # In future this also gives us a place to hook in additional behaviour
+    # such as calling out to the action instance to validate and coerce
+    # parameters, which avoids any exciting context switching and all.
+    #
+    # Hopefully we can improve this when we finally shuffle off the last of
+    # Ruby 1.8 support, but that looks to be a few "enterprise" release eras
+    # away, so we are pretty stuck with this for now.
+    #
+    # Patches to make this work more nicely with Ruby 1.9 using runtime
+    # version checking and all are welcome, but they can't actually help if
+    # the results are not totally hidden away in here.
+    #
+    # Incidentally, we though about vendoring evil-ruby and actually adjusting
+    # the internal C structure implementation details under the hood to make
+    # this stuff work, because it would have been cleaner.  Which gives you an
+    # idea how motivated we were to make this cleaner.  Sorry. --daniel 2011-03-31
+
+    internal_name = "#{@name} implementation, required on Ruby 1.8".to_sym
+    file = __FILE__ + "+eval"
+    line = __LINE__ + 1
+    wrapper = "def #{@name}(*args, &block)
+                 args << {} unless args.last.is_a? Hash
+                 args << block if block_given?
+                 self.__send__(#{internal_name.inspect}, *args)
+               end"
+
+    if @face.is_a?(Class)
+      @face.class_eval do eval wrapper, nil, file, line end
+      @face.define_method(internal_name, &block)
+    else
+      @face.instance_eval do eval wrapper, nil, file, line end
+      @face.meta_def(internal_name, &block)
+    end
+  end
+
+  def add_option(option)
+    option.aliases.each do |name|
+      if conflict = get_option(name) then
+        raise ArgumentError, "Option #{option} conflicts with existing option #{conflict}"
+      elsif conflict = @face.get_option(name) then
+        raise ArgumentError, "Option #{option} conflicts with existing option #{conflict} on #{@face}"
+      end
+    end
+
+    option.aliases.each do |name|
+      @options[name] = option
+    end
+
+    option
+  end
+
+  def option?(name)
+    @options.include? name.to_sym
+  end
+
+  def options
+    (@options.keys + @face.options).sort
+  end
+
+  def get_option(name)
+    @options[name.to_sym] || @face.get_option(name)
+  end
+end