Reducing object allocations by reusing the Array object from the parent middleware

lib/rack/chunked.rb

@@ -99,7 +99,7 @@ def chunkable_version?(ver)
     # but does not have content-length or transfer-encoding headers,
     # modify the response to use chunked transfer-encoding.
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
 
       if chunkable_version?(env[SERVER_PROTOCOL]) &&
          !STATUS_WITH_NO_ENTITY_BODY.key?(status.to_i) &&
@@ -108,13 +108,13 @@ def call(env)
 
         headers[TRANSFER_ENCODING] = 'chunked'
         if headers['trailer']
-          body = TrailerBody.new(body)
+          response[2] = TrailerBody.new(body)
         else
-          body = Body.new(body)
+          response[2] = Body.new(body)
         end
       end
 
-      [status, headers, body]
+      response
     end
   end
 end

lib/rack/common_logger.rb

@@ -40,9 +40,10 @@ def initialize(app, logger = nil)
     # cause the request not to be logged.
     def call(env)
       began_at = Utils.clock_time
-      status, headers, body = @app.call(env)
-      body = BodyProxy.new(body) { log(env, status, headers, began_at) }
-      [status, headers, body]
+      status, headers, body = response = @app.call(env)
+
+      response[2] = BodyProxy.new(body) { log(env, status, headers, began_at) }
+      response
     end
 
     private

lib/rack/conditional_get.rb

@@ -28,17 +28,17 @@ def initialize(app)
     def call(env)
       case env[REQUEST_METHOD]
       when "GET", "HEAD"
-        status, headers, body = @app.call(env)
+        status, headers, body = response = @app.call(env)
+
         if status == 200 && fresh?(env, headers)
-          status = 304
+          response[0] = 304
           headers.delete(CONTENT_TYPE)
           headers.delete(CONTENT_LENGTH)
-          original_body = body
-          body = Rack::BodyProxy.new([]) do
-            original_body.close if original_body.respond_to?(:close)
+          response[2] = Rack::BodyProxy.new([]) do
+            body.close if body.respond_to?(:close)
           end
         end
-        [status, headers, body]
+        response
       else
         @app.call(env)
       end

lib/rack/content_length.rb

@@ -17,18 +17,18 @@ def initialize(app)
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
 
       if !STATUS_WITH_NO_ENTITY_BODY.key?(status.to_i) &&
          !headers[CONTENT_LENGTH] &&
          !headers[TRANSFER_ENCODING] &&
          body.respond_to?(:to_ary)
 
-        body = body.to_ary
+        response[2] = body = body.to_ary
         headers[CONTENT_LENGTH] = body.sum(&:bytesize).to_s
       end
 
-      [status, headers, body]
+      response
     end
   end
 end

lib/rack/content_type.rb

@@ -21,13 +21,13 @@ def initialize(app, content_type = "text/html")
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, _ = response = @app.call(env)
 
       unless STATUS_WITH_NO_ENTITY_BODY.key?(status.to_i)
         headers[CONTENT_TYPE] ||= @content_type
       end
 
-      [status, headers, body]
+      response
     end
   end
 end

lib/rack/deflater.rb

@@ -44,10 +44,10 @@ def initialize(app, options = {})
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
 
       unless should_deflate?(env, status, headers, body)
-        return [status, headers, body]
+        return response
       end
 
       request = Request.new(env)
@@ -67,9 +67,10 @@ def call(env)
         headers.delete(CONTENT_LENGTH)
         mtime = headers["last-modified"]
         mtime = Time.httpdate(mtime).to_i if mtime
-        [status, headers, GzipStream.new(body, mtime, @sync)]
+        response[2] = GzipStream.new(body, mtime, @sync)
+        response
       when "identity"
-        [status, headers, body]
+        response
       else # when nil
         # Only possible encoding values here are 'gzip', 'identity', and nil
         message = "An acceptable encoding for the requested resource #{request.fullpath} could not be found."

lib/rack/etag.rb

@@ -26,7 +26,7 @@ def initialize(app, no_cache_control = nil, cache_control = DEFAULT_CACHE_CONTRO
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
 
       if etag_status?(status) && body.respond_to?(:to_ary) && !skip_caching?(headers)
         body = body.to_ary
@@ -42,7 +42,7 @@ def call(env)
         end
       end
 
-      [status, headers, body]
+      response
     end
 
     private

lib/rack/head.rb

@@ -12,17 +12,15 @@ def initialize(app)
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      _, _, body = response = @app.call(env)
 
       if env[REQUEST_METHOD] == HEAD
-        [
-          status, headers, Rack::BodyProxy.new([]) do
-            body.close if body.respond_to? :close
-          end
-        ]
-      else
-        [status, headers, body]
+        response[2] = Rack::BodyProxy.new([]) do
+          body.close if body.respond_to? :close
+        end
       end
+
+      response
     end
   end
 end

lib/rack/runtime.rb

@@ -21,15 +21,15 @@ def initialize(app, name = nil)
 
     def call(env)
       start_time = Utils.clock_time
-      status, headers, body = @app.call(env)
+      _, headers, _ = response = @app.call(env)
 
       request_time = Utils.clock_time - start_time
 
       unless headers.key?(@header_name)
         headers[@header_name] = FORMAT_STRING % request_time
       end
 
-      [status, headers, body]
+      response
     end
   end
 end

lib/rack/sendfile.rb

@@ -111,7 +111,7 @@ def initialize(app, variation = nil, mappings = [])
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
 
       if body.respond_to?(:to_path)
         case type = variation(env)
@@ -122,7 +122,7 @@ def call(env)
             # '?' must be percent-encoded because it is not query string but a part of path
             headers[type.downcase] = ::Rack::Utils.escape_path(url).gsub('?', '%3F')
             obody = body
-            body = Rack::BodyProxy.new([]) do
+            response[2] = Rack::BodyProxy.new([]) do
               obody.close if obody.respond_to?(:close)
             end
           else
@@ -133,15 +133,15 @@ def call(env)
           headers[CONTENT_LENGTH] = '0'
           headers[type.downcase] = path
           obody = body
-          body = Rack::BodyProxy.new([]) do
+          response[2] = Rack::BodyProxy.new([]) do
             obody.close if obody.respond_to?(:close)
           end
         when '', nil
         else
           env[RACK_ERRORS].puts "Unknown x-sendfile variation: '#{type}'.\n"
         end
       end
-      [status, headers, body]
+      response
     end
 
     private

lib/rack/show_status.rb

@@ -22,7 +22,7 @@ def initialize(app)
     end
 
     def call(env)
-      status, headers, body = @app.call(env)
+      status, headers, body = response = @app.call(env)
       empty = headers[CONTENT_LENGTH].to_i <= 0
 
       # client or server error, or explicit message
@@ -40,15 +40,15 @@ def call(env)
         html = @template.result(binding)
         size = html.bytesize
 
-        original_body = body
-        body = Rack::BodyProxy.new([html]) do
-          original_body.close if original_body.respond_to?(:close)
+        response[2] = Rack::BodyProxy.new([html]) do
+          body.close if body.respond_to?(:close)
         end
 
-        [status, headers.merge(CONTENT_TYPE => "text/html", CONTENT_LENGTH => size.to_s), body]
-      else
-        [status, headers, body]
+        headers[CONTENT_TYPE] = "text/html"
+        headers[CONTENT_LENGTH] = size.to_s
       end
+
+      response
     end
 
     def h(obj)                  # :nodoc:

lib/rack/tempfile_reaper.rb

@@ -17,17 +17,17 @@ def call(env)
       env[RACK_TEMPFILES] ||= []
 
       begin
-        status, headers, body = @app.call(env)
+        _, _, body = response = @app.call(env)
       rescue Exception
         env[RACK_TEMPFILES]&.each(&:close!)
         raise
       end
 
-      body_proxy = BodyProxy.new(body) do
+      response[2] = BodyProxy.new(body) do
         env[RACK_TEMPFILES]&.each(&:close!)
       end
 
-      [status, headers, body_proxy]
+      response
     end
   end
 end