2 files changed, 52 insertions, 0 deletions
diff --git a/ext/psych/lib/psych/handler.rb b/ext/psych/lib/psych/handler.rb
index d3b99636c4..c55afe745f 100644
--- a/ext/psych/lib/psych/handler.rb
+++ b/ext/psych/lib/psych/handler.rb
@@ -25,6 +25,19 @@ module Psych
     # Default dumping options
     OPTIONS = DumperOptions.new
 
+    # Events that a Handler should respond to.
+    EVENTS = [ :alias,
+               :empty,
+               :end_document,
+               :end_mapping,
+               :end_sequence,
+               :end_stream,
+               :scalar,
+               :start_document,
+               :start_mapping,
+               :start_sequence,
+               :start_stream ]
+
     ###
     # Called with +encoding+ when the YAML stream starts.  This method is
     # called once per stream.  A stream may contain multiple documents.
diff --git a/ext/psych/lib/psych/handlers/recorder.rb b/ext/psych/lib/psych/handlers/recorder.rb
new file mode 100644
index 0000000000..4eae62e5f9
--- /dev/null
+++ b/ext/psych/lib/psych/handlers/recorder.rb
@@ -0,0 +1,39 @@
+require 'psych/handler'
+
+module Psych
+  module Handlers
+    ###
+    # This handler will capture an event and record the event.  Recorder events
+    # are available vial Psych::Handlers::Recorder#events.
+    #
+    # For example:
+    #
+    #   recorder = Psych::Handlers::Recorder.new
+    #   parser = Psych::Parser.new recorder
+    #   parser.parse '--- foo'
+    #
+    #   recorder.events # => [list of events]
+    #
+    #   # Replay the events
+    #
+    #   emitter = Psych::Emitter.new $stdout
+    #   recorder.events.each do |m, args|
+    #     emitter.send m, *args
+    #   end
+
+    class Recorder < Psych::Handler
+      attr_reader :events
+
+      def initialize
+        @events = []
+        super
+      end
+
+      EVENTS.each do |event|
+        define_method event do |*args|
+          @events << [event, args]
+        end
+      end
+    end
+  end
+end