[#2653] Remove unnecessary ensureAccessible() calls

Motivation:

I introduced ensureAccessible() class as part of 6c47cc9711 in some places. Unfortunally I also added some where these are not needed and so caused a performance regression.

Modification:

Remove calls where not needed.

Result:

Fixed performance regression.

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

@@ -229,7 +229,6 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf ensureWritable(int minWritableBytes) {
-        ensureAccessible();
         if (minWritableBytes < 0) {
             throw new IllegalArgumentException(String.format(
                     "minWritableBytes: %d (expected: >= 0)", minWritableBytes));
@@ -759,13 +758,15 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeByte(int value) {
+        ensureAccessible();
         ensureWritable(1);
-        setByte(writerIndex++, value);
+        _setByte(writerIndex++, value);
         return this;
     }
 
     @Override
     public ByteBuf writeShort(int value) {
+        ensureAccessible();
         ensureWritable(2);
         _setShort(writerIndex, value);
         writerIndex += 2;
@@ -774,6 +775,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeMedium(int value) {
+        ensureAccessible();
         ensureWritable(3);
         _setMedium(writerIndex, value);
         writerIndex += 3;
@@ -782,6 +784,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeInt(int value) {
+        ensureAccessible();
         ensureWritable(4);
         _setInt(writerIndex, value);
         writerIndex += 4;
@@ -790,6 +793,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeLong(long value) {
+        ensureAccessible();
         ensureWritable(8);
         _setLong(writerIndex, value);
         writerIndex += 8;
@@ -816,6 +820,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeBytes(byte[] src, int srcIndex, int length) {
+        ensureAccessible();
         ensureWritable(length);
         setBytes(writerIndex, src, srcIndex, length);
         writerIndex += length;
@@ -847,6 +852,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeBytes(ByteBuf src, int srcIndex, int length) {
+        ensureAccessible();
         ensureWritable(length);
         setBytes(writerIndex, src, srcIndex, length);
         writerIndex += length;
@@ -855,6 +861,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public ByteBuf writeBytes(ByteBuffer src) {
+        ensureAccessible();
         int length = src.remaining();
         ensureWritable(length);
         setBytes(writerIndex, src);
@@ -865,6 +872,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
     @Override
     public int writeBytes(InputStream in, int length)
             throws IOException {
+        ensureAccessible();
         ensureWritable(length);
         int writtenBytes = setBytes(writerIndex, in, length);
         if (writtenBytes > 0) {
@@ -875,6 +883,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public int writeBytes(ScatteringByteChannel in, int length) throws IOException {
+        ensureAccessible();
         ensureWritable(length);
         int writtenBytes = setBytes(writerIndex, in, length);
         if (writtenBytes > 0) {

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

@@ -129,6 +129,7 @@ final class UnsafeDirectSwappedByteBuf extends SwappedByteBuf {
 
     @Override
     public ByteBuf writeShort(int value) {
+        wrapped.ensureAccessible();
         wrapped.ensureWritable(2);
         _setShort(wrapped.writerIndex, value);
         wrapped.writerIndex += 2;
@@ -137,6 +138,7 @@ final class UnsafeDirectSwappedByteBuf extends SwappedByteBuf {
 
     @Override
     public ByteBuf writeInt(int value) {
+        wrapped.ensureAccessible();
         wrapped.ensureWritable(4);
         _setInt(wrapped.writerIndex, value);
         wrapped.writerIndex += 4;
@@ -145,6 +147,7 @@ final class UnsafeDirectSwappedByteBuf extends SwappedByteBuf {
 
     @Override
     public ByteBuf writeLong(long value) {
+        wrapped.ensureAccessible();
         wrapped.ensureWritable(8);
         _setLong(wrapped.writerIndex, value);
         wrapped.writerIndex += 8;

buffer/src/test/java/io/netty/buffer/SlicedByteBufTest.java

@@ -15,8 +15,10 @@
  */
 package io.netty.buffer;
 
+import io.netty.util.IllegalReferenceCountException;
 import org.junit.Test;
 
+import java.io.IOException;
 import java.util.Random;
 
 import static org.junit.Assert.*;
@@ -95,6 +97,18 @@ public class SlicedByteBufTest extends AbstractByteBufTest {
         super.testNioBufferExposeOnlyRegion();
     }
 
+    @Test(expected = IndexOutOfBoundsException.class)
+    @Override
+    public void testEnsureWritableAfterRelease() {
+        super.testEnsureWritableAfterRelease();
+    }
+
+    @Test(expected = IndexOutOfBoundsException.class)
+    @Override
+    public void testWriteZeroAfterRelease() throws IOException {
+        super.testWriteZeroAfterRelease();
+    }
+
     @Test
     @Override
     public void testLittleEndianWithExpand() {