Fixes responseWriter.Size()

- "written" boolean is not longer needed
- size is reseted
- addition instead of assignation

response_writer.go

@@ -12,6 +12,10 @@ import (
 	"net/http"
 )
 
+const (
+	NoWritten = -1
+)
+
 type (
 	ResponseWriter interface {
 		http.ResponseWriter
@@ -29,28 +33,27 @@ type (
 		http.ResponseWriter
 		status int
 		size   int
-		written bool
 	}
 )
 
 func (w *responseWriter) reset(writer http.ResponseWriter) {
 	w.ResponseWriter = writer
 	w.status = 200
-	w.written = false
+	w.size = NoWritten
 }
 
 func (w *responseWriter) WriteHeader(code int) {
 	if code > 0 {
 		w.status = code
-		if w.written {
+		if w.Written() {
 			log.Println("[GIN] WARNING. Headers were already written!")
 		}
 	}
 }
 
 func (w *responseWriter) WriteHeaderNow() {
-	if !w.written {
-		w.written = true
+	if !w.Written() {
+		w.size = 0
 		w.ResponseWriter.WriteHeader(w.status)
 	}
 }
@@ -58,7 +61,7 @@ func (w *responseWriter) WriteHeaderNow() {
 func (w *responseWriter) Write(data []byte) (n int, err error) {
 	w.WriteHeaderNow()
 	n, err = w.ResponseWriter.Write(data)
-	w.size = n
+	w.size += n
 	return
 }
 
@@ -71,7 +74,7 @@ func (w *responseWriter) Size() int {
 }
 
 func (w *responseWriter) Written() bool {
-	return w.written
+	return w.size != NoWritten
 }
 
 // Implements the http.Hijacker interface