use the body proxy to freeze headers

avoid freezing the headers until the web server has actually read data
from the body proxy.  Once the webserver has read data, then we should
throw an error if someone tries to set a header

3 files changed, 41 insertions, 8 deletions

diff --git a/actionpack/lib/action_controller/metal/live.rb b/actionpack/lib/action_controller/metal/live.rb
index fe63cf2b98..41b997a755 100644
--- a/actionpack/lib/action_controller/metal/live.rb
+++ b/actionpack/lib/action_controller/metal/live.rb
@@ -125,9 +125,11 @@ module ActionController
       end
 
       def each
+        @response.sending!
         while str = @buf.pop
           yield str
         end
+        @response.sent!
       end
 
       def close
@@ -179,12 +181,16 @@ module ActionController
 
       private
 
-      def finalize_response
+      def before_committed
         super
         jar = request.cookie_jar
         # The response can be committed multiple times
         jar.write self unless committed?
-        jar.commit!
+      end
+
+      def before_sending
+        super
+        request.cookie_jar.commit!
         headers.freeze
       end
 
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index 009f83861d..e9166d8747 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -595,7 +595,7 @@ module ActionController
         @controller.process(name)
 
         if cookies = @request.env['action_dispatch.cookies']
-          unless cookies.committed?
+          unless @response.committed?
             cookies.write(@response)
           end
         end
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index b5454f519f..3d27ff2b24 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -91,7 +91,10 @@ module ActionDispatch # :nodoc:
       end
 
       def each(&block)
-        @buf.each(&block)
+        @response.sending!
+        x = @buf.each(&block)
+        @response.sent!
+        x
       end
 
       def close
@@ -118,6 +121,8 @@ module ActionDispatch # :nodoc:
       @blank        = false
       @cv           = new_cond
       @committed    = false
+      @sending      = false
+      @sent         = false
       @content_type = nil
       @charset      = nil
 
@@ -138,18 +143,37 @@ module ActionDispatch # :nodoc:
       end
     end
 
+    def await_sent
+      synchronize { @cv.wait_until { @sent } }
+    end
+
     def commit!
       synchronize do
-        finalize_response
+        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)
@@ -274,7 +298,10 @@ module ActionDispatch # :nodoc:
 
   private
 
-    def finalize_response
+    def before_committed
+    end
+
+    def before_sending
     end
 
     def merge_default_headers(original, default)