From 8b889a0e28faee02bfc1b128835a9ecbd3d3fe44 Mon Sep 17 00:00:00 2001
From: Santiago Pericasgeertsen <santiago.pericasgeertsen@oracle.com>
Date: Mon, 8 Jan 2024 17:19:03 -0500
Subject: [PATCH] Avoid buffer copies during writes.

Signed-off-by: Santiago Pericasgeertsen <santiago.pericasgeertsen@oracle.com>
---
 .../buffers/CompositeArrayBufferData.java     | 19 ++++++++++++++++++-
 .../buffers/CompositeListBufferData.java      | 19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/common/buffers/src/main/java/io/helidon/common/buffers/CompositeArrayBufferData.java b/common/buffers/src/main/java/io/helidon/common/buffers/CompositeArrayBufferData.java
index c9d33a6cccd..d3a31ea2b4a 100644
--- a/common/buffers/src/main/java/io/helidon/common/buffers/CompositeArrayBufferData.java
+++ b/common/buffers/src/main/java/io/helidon/common/buffers/CompositeArrayBufferData.java
@@ -38,7 +38,24 @@ public BufferData rewind() {
 
     @Override
     public void writeTo(OutputStream out) {
-        copy().writeTo(out);
+        /*
+        if (data.length == 1) {
+            data[0].writeTo(out);
+        } else {
+            copy().writeTo(out);
+        }
+         */
+        for (BufferData datum : data) {
+            if (datum instanceof CompositeBufferData) {
+                datum.writeTo(out);
+            } else {
+                int available = datum.available();
+                if (available > 0) {
+                    datum.writeTo(out);
+                    datum.skip(-available);
+                }
+            }
+        }
     }
 
     @Override
diff --git a/common/buffers/src/main/java/io/helidon/common/buffers/CompositeListBufferData.java b/common/buffers/src/main/java/io/helidon/common/buffers/CompositeListBufferData.java
index bf5fcdaefec..a7ec6ab353e 100644
--- a/common/buffers/src/main/java/io/helidon/common/buffers/CompositeListBufferData.java
+++ b/common/buffers/src/main/java/io/helidon/common/buffers/CompositeListBufferData.java
@@ -56,7 +56,24 @@ public BufferData rewind() {
 
     @Override
     public void writeTo(OutputStream out) {
-        copy().writeTo(out);
+        /*
+        if (data.size() == 1) {
+            data.get(0).writeTo(out);
+        } else {
+            copy().writeTo(out);
+        }
+        */
+        for (BufferData datum : data) {
+            if (datum instanceof CompositeBufferData) {
+                datum.writeTo(out);
+            } else {
+                int available = datum.available();
+                if (available > 0) {
+                    datum.writeTo(out);
+                    datum.skip(-available);
+                }
+            }
+        }
     }
 
     @Override