In (Pooled|Unpooled)UnsafeDirectByteBuf copy memory directly to and from ByteBuffer

Motivation:

When moving bytes between a PooledUnsafeDirectByteBuf or an UnpooledUnsafeDirectByteBuf
and a ByteBuffer, a temp ByteBuffer is allocated and will need to be GCed. This is a
common case since a ByteBuffer is always needed when reading/writing on a file,
for example.

Modifications:

Use PlatformDependent.copyMemory() to avoid the need for the temp ByteBuffer

Result:

No temp ByteBuffer allocated and GCed.

buffer/src/main/java/io/netty/buffer/PooledUnsafeDirectByteBuf.java

@@ -16,7 +16,6 @@
 
 package io.netty.buffer;
 
-import io.netty.buffer.PooledByteBufAllocator.PoolThreadLocalCache;
 import io.netty.util.Recycler;
 import io.netty.util.internal.PlatformDependent;
 
@@ -149,29 +148,30 @@ final class PooledUnsafeDirectByteBuf extends PooledByteBuf<ByteBuffer> {
 
     @Override
     public ByteBuf getBytes(int index, ByteBuffer dst) {
-        getBytes(index, dst, false);
-        return this;
-    }
-
-    private void getBytes(int index, ByteBuffer dst, boolean internal) {
         checkIndex(index);
         int bytesToCopy = Math.min(capacity() - index, dst.remaining());
-        ByteBuffer tmpBuf;
+        if (bytesToCopy == 0) {
-        if (internal) {
+            return this;
-            tmpBuf = internalNioBuffer();
-        } else {
-            tmpBuf = memory.duplicate();
         }
-        index = idx(index);
+
-        tmpBuf.clear().position(index).limit(index + bytesToCopy);
+        if (dst.isDirect()) {
-        dst.put(tmpBuf);
+            // Copy to direct memory
+            long dstAddress = PlatformDependent.directBufferAddress(dst);
+            PlatformDependent.copyMemory(addr(index), dstAddress + dst.position(), bytesToCopy);
+        } else {
+            // Copy to array
+            PlatformDependent.copyMemory(addr(index), dst.array(), dst.arrayOffset() + dst.position(), bytesToCopy);
+        }
+
+        dst.position(dst.position() + bytesToCopy);
+        return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuffer dst) {
         int length = dst.remaining();
         checkReadableBytes(length);
-        getBytes(readerIndex, dst, true);
+        getBytes(readerIndex, dst);
         readerIndex += length;
         return this;
     }
@@ -280,14 +280,21 @@ final class PooledUnsafeDirectByteBuf extends PooledByteBuf<ByteBuffer> {
     @Override
     public ByteBuf setBytes(int index, ByteBuffer src) {
         checkIndex(index, src.remaining());
-        ByteBuffer tmpBuf = internalNioBuffer();
+
-        if (src == tmpBuf) {
+        int length = src.remaining();
-            src = src.duplicate();
+        if (length == 0) {
+            return this;
         }
 
-        index = idx(index);
+        if (src.isDirect()) {
-        tmpBuf.clear().position(index).limit(index + src.remaining());
+            // Copy from direct memory
-        tmpBuf.put(src);
+            long srcAddress = PlatformDependent.directBufferAddress(src);
+            PlatformDependent.copyMemory(srcAddress + src.position(), addr(index), src.remaining());
+        } else {
+            // Copy from array
+            PlatformDependent.copyMemory(src.array(), src.arrayOffset() + src.position(), addr(index), length);
+        }
+        src.position(src.position() + length);
         return this;
     }
 

buffer/src/main/java/io/netty/buffer/UnpooledUnsafeDirectByteBuf.java

@@ -285,32 +285,34 @@ public class UnpooledUnsafeDirectByteBuf extends AbstractReferenceCountedByteBuf
 
     @Override
     public ByteBuf getBytes(int index, ByteBuffer dst) {
-        getBytes(index, dst, false);
-        return this;
-    }
-
-    private void getBytes(int index, ByteBuffer dst, boolean internal) {
         checkIndex(index);
         if (dst == null) {
             throw new NullPointerException("dst");
         }
 
         int bytesToCopy = Math.min(capacity() - index, dst.remaining());
-        ByteBuffer tmpBuf;
+        if (bytesToCopy == 0) {
-        if (internal) {
+            return this;
-            tmpBuf = internalNioBuffer();
-        } else {
-            tmpBuf = buffer.duplicate();
         }
-        tmpBuf.clear().position(index).limit(index + bytesToCopy);
+
-        dst.put(tmpBuf);
+        if (dst.isDirect()) {
+            // Copy to direct memory
+            long dstAddress = PlatformDependent.directBufferAddress(dst);
+            PlatformDependent.copyMemory(addr(index), dstAddress + dst.position(), bytesToCopy);
+        } else {
+            // Copy to array
+            PlatformDependent.copyMemory(addr(index), dst.array(), dst.arrayOffset() + dst.position(), bytesToCopy);
+        }
+
+        dst.position(dst.position() + bytesToCopy);
+        return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuffer dst) {
         int length = dst.remaining();
         checkReadableBytes(length);
-        getBytes(readerIndex, dst, true);
+        getBytes(readerIndex, dst);
         readerIndex += length;
         return this;
     }
@@ -377,13 +379,20 @@ public class UnpooledUnsafeDirectByteBuf extends AbstractReferenceCountedByteBuf
     @Override
     public ByteBuf setBytes(int index, ByteBuffer src) {
         ensureAccessible();
-        ByteBuffer tmpBuf = internalNioBuffer();
+        int length = src.remaining();
-        if (src == tmpBuf) {
+        if (length == 0) {
-            src = src.duplicate();
+            return this;
         }
 
-        tmpBuf.clear().position(index).limit(index + src.remaining());
+        if (src.isDirect()) {
-        tmpBuf.put(src);
+            // Copy from direct memory
+            long srcAddress = PlatformDependent.directBufferAddress(src);
+            PlatformDependent.copyMemory(srcAddress + src.position(), addr(index), src.remaining());
+        } else {
+            // Copy from array
+            PlatformDependent.copyMemory(src.array(), src.arrayOffset() + src.position(), addr(index), length);
+        }
+        src.position(src.position() + length);
         return this;
     }