From a1d7c336635693106b495d0e0ba7d35a68d8f7e9 Mon Sep 17 00:00:00 2001
From: 2beaucoup <andre.ruediger@gmail.com>
Date: Wed, 10 Dec 2014 10:56:38 +0100
Subject: [PATCH] =htc simplify content negotiation

---
 .../scala/akka/http/marshalling/Marshal.scala | 37 ++++++++-----------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/akka-http/src/main/scala/akka/http/marshalling/Marshal.scala b/akka-http/src/main/scala/akka/http/marshalling/Marshal.scala
index d935230f54..980180f9c3 100644
--- a/akka-http/src/main/scala/akka/http/marshalling/Marshal.scala
+++ b/akka-http/src/main/scala/akka/http/marshalling/Marshal.scala
@@ -43,32 +43,27 @@ class Marshal[A](val value: A) {
     def qValueCS(charset: HttpCharset) = request.qValueForCharset(charset, charsetRanges)
 
     m(value).fast.map { marshallings ⇒
-      def weight(mt: MediaType, cs: HttpCharset): Float = math.min(qValueMT(mt), qValueCS(cs))
-      val defaultMarshallingWeight: MarshallingWeight =
-        new MarshallingWeight(0f, { () ⇒
-          val supportedContentTypes = marshallings collect {
-            case Marshalling.WithFixedCharset(mt, cs, _) ⇒ ContentType(mt, cs)
-            case Marshalling.WithOpenCharset(mt, _)      ⇒ ContentType(mt)
-          }
-          throw UnacceptableResponseContentTypeException(supportedContentTypes.toSet)
-        })
+      val defaultMarshallingWeight = new MarshallingWeight(0f, { () ⇒
+        val supportedContentTypes = marshallings collect {
+          case Marshalling.WithFixedCharset(mt, cs, _) ⇒ ContentType(mt, cs)
+          case Marshalling.WithOpenCharset(mt, _)      ⇒ ContentType(mt)
+        }
+        throw UnacceptableResponseContentTypeException(supportedContentTypes.toSet)
+      })
+      def choose(acc: MarshallingWeight, mt: MediaType, cs: HttpCharset, marshal: () ⇒ HttpResponse) = {
+        val weight = math.min(qValueMT(mt), qValueCS(cs))
+        if (weight > acc.weight) new MarshallingWeight(weight, marshal) else acc
+      }
       val best = marshallings.foldLeft(defaultMarshallingWeight) {
         case (acc, Marshalling.WithFixedCharset(mt, cs, marshal)) ⇒
-          val w = weight(mt, cs)
-          if (w > acc.weight) new MarshallingWeight(w, marshal) else acc
-
+          choose(acc, mt, cs, marshal)
         case (acc, Marshalling.WithOpenCharset(mt, marshal)) ⇒
-          def withCharset(cs: HttpCharset) = {
-            val w = weight(mt, cs)
-            if (w > acc.weight) new MarshallingWeight(w, () ⇒ marshal(cs)) else acc
-          }
+          def withCharset(cs: HttpCharset) = choose(acc, mt, cs, () ⇒ marshal(cs))
           // logic for choosing the charset adapted from http://tools.ietf.org/html/rfc7231#section-5.3.3
           if (qValueCS(`UTF-8`) == 1f) withCharset(`UTF-8`) // prefer UTF-8 if fully accepted
-          else charsetRanges match { // ranges are sorted by descending q-value,
-            case (HttpCharsetRange.One(cs, qValue)) :: _ ⇒ // so we only need to look at the first one
-              if (qValue == 1f) withCharset(cs) // if the client has high preference for this charset, pick it
-              else if (qValue > 0f) withCharset(cs) // ok, simply choose the first one if the client doesn't reject it
-              else acc
+          else charsetRanges match {
+            // pick the charset which the highest q-value (head of charsetRanges) if it isn't explicitly rejected
+            case (HttpCharsetRange.One(cs, qValue)) :: _ if qValue > 0f ⇒ withCharset(cs)
             case _ ⇒ acc
           }