rpc: move RPC record marking into GrizzlyRpcTransport

Motivation:
The grizzly pipeline built as:

  TransportFilter <-> RpcMessageParserTCP <-> RpcProtocolFilter <-> RpcDispatcher

which means, that every `Connection#write` called in RpcProtocolFilter and RpcDispatcher
calls RpcMessageParserTCP#handleWrite. The later one always adds RPC
frame marker, thus doesn't allow to use multiple writes within singe
frame.

Modification:
Move RPC message separation marker appending from RpcMessageParserTCP
into `GrizzlyRpcTransport#send`

Result:
The `GrizzlyRpcTransport#send` can use multiple `Connection#write` to
send a rpc message.

Acked-by: Albert Rossi
Target: master

oncrpc4j-core/src/main/java/org/dcache/oncrpc4j/grizzly/GrizzlyRpcTransport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009 - 2019 Deutsches Elektronen-Synchroton,
+ * Copyright (c) 2009 - 2022 Deutsches Elektronen-Synchroton,
  * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY
  *
  * This library is free software; you can redistribute it and/or modify
@@ -20,10 +20,14 @@
 package org.dcache.oncrpc4j.grizzly;
 
 
+import java.nio.ByteOrder;
 import org.dcache.oncrpc4j.rpc.ReplyQueue;
+import org.dcache.oncrpc4j.rpc.RpcMessageParserTCP;
 import org.dcache.oncrpc4j.xdr.Xdr;
 import java.net.InetSocketAddress;
 import java.nio.channels.CompletionHandler;
+import org.glassfish.grizzly.memory.BuffersBuffer;
+import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.glassfish.grizzly.Buffer;
@@ -48,6 +52,12 @@ public class GrizzlyRpcTransport implements RpcTransport {
     private final InetSocketAddress _localAddress;
     private final InetSocketAddress _remoteAddress;
 
+    /**
+     * If true, then underlying transport is stream-oriented (like TCP) and messages must be separated
+     * by record marking.
+     */
+    private final boolean _isStreaming;
+
     private final static Logger _log = LoggerFactory.getLogger(GrizzlyRpcTransport.class);
 
     public GrizzlyRpcTransport(Connection<InetSocketAddress> connection, ReplyQueue replyQueue) {
@@ -59,6 +69,7 @@ public GrizzlyRpcTransport(Connection<InetSocketAddress> connection, InetSocketA
         _replyQueue = replyQueue;
         _localAddress = _connection.getLocalAddress();
         _remoteAddress = remoteAddress;
+        _isStreaming = connection.getTransport() instanceof TCPNIOTransport;
     }
 
     @Override
@@ -68,10 +79,19 @@ public boolean isOpen() {
 
     @Override
     public <A> void send(final Xdr xdr, A attachment, CompletionHandler<Integer, ? super A> handler) {
-        final Buffer buffer = xdr.asBuffer();
-        buffer.allowBufferDispose(true);
 
         requireNonNull(handler, "CompletionHandler can't be null");
+        Buffer buffer = xdr.asBuffer();
+
+        // add record marker, if needed
+        if (_isStreaming) {
+            int len = buffer.remaining() | RpcMessageParserTCP.RPC_LAST_FRAG;
+            Buffer marker = _connection.getMemoryManager().allocate(Integer.BYTES);
+            marker.order(ByteOrder.BIG_ENDIAN);
+            marker.putInt(len);
+            marker.flip();
+            buffer = BuffersBuffer.create(_connection.getMemoryManager(), marker, buffer);
+        }
 
         // pass destination address to handle UDP connections as well
         _connection.write(_remoteAddress, buffer,

oncrpc4j-core/src/main/java/org/dcache/oncrpc4j/rpc/RpcMessageParserTCP.java

@@ -35,11 +35,11 @@ public class RpcMessageParserTCP extends BaseFilter {
     /**
      * RPC fragment record marker mask
      */
-    private final static int RPC_LAST_FRAG = 0x80000000;
+    public final static int RPC_LAST_FRAG = 0x80000000;
     /**
      * RPC fragment size mask
      */
-    private final static int RPC_SIZE_MASK = 0x7fffffff;
+    public final static int RPC_SIZE_MASK = 0x7fffffff;
 
     @Override
     public NextAction handleRead(FilterChainContext ctx) throws IOException {
@@ -61,24 +61,6 @@ public NextAction handleRead(FilterChainContext ctx) throws IOException {
         return ctx.getInvokeAction(reminder);
     }
 
-    @Override
-    public NextAction handleWrite(FilterChainContext ctx) throws IOException {
-
-        Buffer b = ctx.getMessage();
-        int len = b.remaining() | RPC_LAST_FRAG;
-
-        Buffer marker = ctx.getMemoryManager().allocate(4);
-        marker.order(ByteOrder.BIG_ENDIAN);
-        marker.putInt(len);
-        marker.flip();
-        marker.allowBufferDispose(true);
-        b.allowBufferDispose(true);
-        Buffer composite = BuffersBuffer.create(ctx.getMemoryManager(), marker, b);
-        composite.allowBufferDispose(true);
-        ctx.setMessage(composite);
-        return ctx.getInvokeAction();
-    }
-
     private boolean isAllFragmentsArrived(Buffer messageBuffer) {
         final Buffer buffer = messageBuffer.duplicate();
         buffer.order(ByteOrder.BIG_ENDIAN);