1 files changed, 62 insertions, 0 deletions
diff --git a/actionview/lib/action_view/template/handlers.rb b/actionview/lib/action_view/template/handlers.rb
new file mode 100644
index 0000000000..9e61ea4225
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers.rb
@@ -0,0 +1,62 @@
+module ActionView #:nodoc:
+  # = Action View Template Handlers
+  class Template
+    module Handlers #:nodoc:
+      autoload :ERB, 'action_view/template/handlers/erb'
+      autoload :Builder, 'action_view/template/handlers/builder'
+      autoload :Raw, 'action_view/template/handlers/raw'
+
+      def self.extended(base)
+        base.register_default_template_handler :erb, ERB.new
+        base.register_template_handler :builder, Builder.new
+        base.register_template_handler :raw, Raw.new
+        base.register_template_handler :ruby, :source.to_proc
+      end
+
+      @@template_handlers = {}
+      @@default_template_handlers = nil
+
+      def self.extensions
+        @@template_extensions ||= @@template_handlers.keys
+      end
+
+      # Register an object that knows how to handle template files with the given
+      # extensions. This can be used to implement new template types.
+      # The handler must respond to +:call+, which will be passed the template
+      # and should return the rendered template as a String.
+      def register_template_handler(*extensions, handler)
+        raise(ArgumentError, "Extension is required") if extensions.empty?
+        extensions.each do |extension|
+          @@template_handlers[extension.to_sym] = handler
+        end
+        @@template_extensions = nil
+      end
+
+      # Opposite to register_template_handler.
+      def unregister_template_handler(*extensions)
+        extensions.each do |extension|
+          handler = @@template_handlers.delete extension.to_sym
+          @@default_template_handlers = nil if @@default_template_handlers == handler
+        end
+        @@template_extensions = nil
+      end
+
+      def template_handler_extensions
+        @@template_handlers.keys.map(&:to_s).sort
+      end
+
+      def registered_template_handler(extension)
+        extension && @@template_handlers[extension.to_sym]
+      end
+
+      def register_default_template_handler(extension, klass)
+        register_template_handler(extension, klass)
+        @@default_template_handlers = klass
+      end
+
+      def handler_for_extension(extension)
+        registered_template_handler(extension) || @@default_template_handlers
+      end
+    end
+  end
+end