From a2bd9a4399929f862ae5c6d773b72e4915b1c682 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Wed, 7 Jun 2017 17:12:19 +0200
Subject: [PATCH] Correctly handle ByteBuf implementations which have no
 memoryAddress when writing to native transport

Motivation:

Commit 3c4dfed08ae2ce300f6ac1d0794d42a14c344b79 introduced a regression in handling buffers that have no memoryAddress.

Modifications:

Fix regression and also add unit tests.

Result:

It's possible again to write buffers without memory address.
---
 .../transport/socket/DatagramUnicastTest.java | 25 ++++++++++++-------
 .../netty/channel/epoll/UnixChannelUtil.java  |  2 +-
 .../channel/epoll/UnixChannelUtilTest.java    |  3 +++
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/socket/DatagramUnicastTest.java b/testsuite/src/main/java/io/netty/testsuite/transport/socket/DatagramUnicastTest.java
index c5701e8360..b234bf5f81 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/socket/DatagramUnicastTest.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/socket/DatagramUnicastTest.java
@@ -37,7 +37,7 @@ public class DatagramUnicastTest extends AbstractDatagramTest {
 
     private static final byte[] BYTES = {0, 1, 2, 3};
     private enum WrapType {
-        NONE, DUP, SLICE,
+        NONE, DUP, SLICE, READ_ONLY
     }
 
     @Test
@@ -189,14 +189,21 @@ public class DatagramUnicastTest extends AbstractDatagramTest {
         }
 
         for (int i = 0; i < count; i++) {
-            if (wrapType == WrapType.DUP) {
-                cc.write(new DatagramPacket(buf.retain().duplicate(), addr));
-            } else if (wrapType == WrapType.SLICE) {
-                cc.write(new DatagramPacket(buf.retain().slice(), addr));
-            } else if (wrapType == WrapType.NONE) {
-                cc.write(new DatagramPacket(buf.retain(), addr));
-            } else {
-                throw new Exception("unknown wrap type: " + wrapType);
+            switch (wrapType) {
+                case DUP:
+                    cc.write(new DatagramPacket(buf.retain().duplicate(), addr));
+                    break;
+                case SLICE:
+                    cc.write(new DatagramPacket(buf.retain().slice(), addr));
+                    break;
+                case READ_ONLY:
+                    cc.write(new DatagramPacket(Unpooled.unmodifiableBuffer(buf.retain()), addr));
+                    break;
+                case NONE:
+                    cc.write(new DatagramPacket(buf.retain(), addr));
+                    break;
+                default:
+                    throw new Error("unknown wrap type: " + wrapType);
             }
         }
         // release as we used buf.retain() before
diff --git a/transport-native-epoll/src/main/java/io/netty/channel/epoll/UnixChannelUtil.java b/transport-native-epoll/src/main/java/io/netty/channel/epoll/UnixChannelUtil.java
index 713b85d7c4..25fc4e376c 100644
--- a/transport-native-epoll/src/main/java/io/netty/channel/epoll/UnixChannelUtil.java
+++ b/transport-native-epoll/src/main/java/io/netty/channel/epoll/UnixChannelUtil.java
@@ -27,6 +27,6 @@ public final class UnixChannelUtil {
      * (We check this because otherwise we need to make it a new direct buffer.)
      */
     public static boolean isBufferCopyNeededForWrite(ByteBuf byteBuf) {
-        return !(byteBuf.hasMemoryAddress() || byteBuf.isDirect() && byteBuf.nioBufferCount() <= Native.IOV_MAX);
+        return !byteBuf.hasMemoryAddress() || !byteBuf.isDirect() || byteBuf.nioBufferCount() > Native.IOV_MAX;
     }
 }
diff --git a/transport-native-epoll/src/test/java/io/netty/channel/epoll/UnixChannelUtilTest.java b/transport-native-epoll/src/test/java/io/netty/channel/epoll/UnixChannelUtilTest.java
index ba5a098fa5..b3edc61d0e 100644
--- a/transport-native-epoll/src/test/java/io/netty/channel/epoll/UnixChannelUtilTest.java
+++ b/transport-native-epoll/src/test/java/io/netty/channel/epoll/UnixChannelUtilTest.java
@@ -47,10 +47,13 @@ public class UnixChannelUtilTest {
     private static void testIsBufferCopyNeededForWrite(ByteBufAllocator alloc) {
         ByteBuf byteBuf = alloc.directBuffer();
         assertFalse(isBufferCopyNeededForWrite(byteBuf));
+        assertTrue(isBufferCopyNeededForWrite(byteBuf.asReadOnly()));
+
         assertTrue(byteBuf.release());
 
         byteBuf = alloc.heapBuffer();
         assertTrue(isBufferCopyNeededForWrite(byteBuf));
+        assertTrue(isBufferCopyNeededForWrite(byteBuf.asReadOnly()));
         assertTrue(byteBuf.release());
 
         assertCompositeByteBufIsBufferCopyNeededForWrite(alloc, 2, 0, false);