1 files changed, 36 insertions, 4 deletions
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 7b2655b2d8..3d27ff2b24 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -1,4 +1,5 @@
 require 'active_support/core_ext/module/attribute_accessors'
+require 'action_dispatch/http/filter_redirect'
 require 'monitor'
 
 module ActionDispatch # :nodoc:
@@ -90,7 +91,10 @@ module ActionDispatch # :nodoc:
       end
 
       def each(&block)
-        @buf.each(&block)
+        @response.sending!
+        x = @buf.each(&block)
+        @response.sent!
+        x
       end
 
       def close
@@ -117,6 +121,8 @@ module ActionDispatch # :nodoc:
       @blank        = false
       @cv           = new_cond
       @committed    = false
+      @sending      = false
+      @sent         = false
       @content_type = nil
       @charset      = nil
 
@@ -137,17 +143,37 @@ module ActionDispatch # :nodoc:
       end
     end
 
+    def await_sent
+      synchronize { @cv.wait_until { @sent } }
+    end
+
     def commit!
       synchronize do
+        before_committed
         @committed = true
         @cv.broadcast
       end
     end
 
-    def committed?
-      @committed
+    def sending!
+      synchronize do
+        before_sending
+        @sending = true
+        @cv.broadcast
+      end
     end
 
+    def sent!
+      synchronize do
+        @sent = true
+        @cv.broadcast
+      end
+    end
+
+    def sending?;   synchronize { @sending };   end
+    def committed?; synchronize { @committed }; end
+    def sent?;      synchronize { @sent };      end
+
     # Sets the HTTP status code.
     def status=(status)
       @status = Rack::Utils.status_code(status)
@@ -272,6 +298,12 @@ module ActionDispatch # :nodoc:
 
   private
 
+    def before_committed
+    end
+
+    def before_sending
+    end
+
     def merge_default_headers(original, default)
       return original unless default.respond_to?(:merge)
 
@@ -312,7 +344,7 @@ module ActionDispatch # :nodoc:
         header.delete CONTENT_TYPE
         [status, header, []]
       else
-        [status, header, self]
+        [status, header, Rack::BodyProxy.new(self){}]
       end
     end
   end