Use temporary byte array when serializing Protobuf in Java

The previous attempt at avoiding unneeded memory allocation and
copying was futile because--obviously in retrospect--the underlying
byte buffer is fixed in size and not dynamically growable. This did
not manifest itself in any unit tests (too little data) or the set
of system tests that I ran manually.

It seems likely that we want to reconsider the encode/decode APIs
in the `DocumentProtocol` to allow for more optimal memory management.

1 files changed, 4 insertions, 7 deletions

diff --git a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories80.java b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories80.java
index a4dcd660ab8..2d29697717b 100644
--- a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories80.java
+++ b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories80.java
@@ -59,13 +59,10 @@ abstract class RoutableFactories80 {
         public boolean encode(Routable obj, DocumentSerializer out) {
             try {
                 var protoMsg = encoderFn.apply(apiClass.cast(obj));
-                var protoStream = CodedOutputStream.newInstance(out.getBuf().getByteBuffer()); // Not AutoCloseable...
-                try {
-                    protoMsg.writeTo(protoStream);
-                } finally {
-                    protoStream.flush();
-                }
-            } catch (IOException | UnsupportedOperationException e) {
+                // TODO avoid this buffer indirection by directly exposing an OutputStream to write into...!
+                //  ... or at the very least have a way to preallocate buffer output of protoMsg.getSerializedSize() bytes!
+                out.getBuf().put(protoMsg.toByteArray());
+            } catch (RuntimeException e) {
                 logCodecError("encoding", e);
                 return false;
             }