From 10a2d34c37957f103731f6dcd17a69f7a97afa5a Mon Sep 17 00:00:00 2001
From: Richard Startin <richard.startin@datadoghq.com>
Date: Thu, 30 Apr 2020 22:36:43 +0100
Subject: [PATCH] avoid allocating an array when getting first header value

---
 .../datadog/trace/core/propagation/HttpCodec.java    | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/core/propagation/HttpCodec.java b/dd-trace-core/src/main/java/datadog/trace/core/propagation/HttpCodec.java
index 62adeb63a8f..28dfcff3683 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/propagation/HttpCodec.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/propagation/HttpCodec.java
@@ -149,15 +149,11 @@ static String decode(final String value) {
   }
 
   static String firstHeaderValue(final String value) {
-    if (value == null || value.isEmpty()) {
-      return value;
+    if (value == null) {
+      return null;
     }
 
-    final String[] split = value.split(",");
-    if (split.length > 0) {
-      return split[0].trim();
-    } else {
-      return value;
-    }
+    int firstComma = value.indexOf(',');
+    return firstComma == -1 ? value : value.substring(0, firstComma).trim();
   }
 }