/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.channel.epoll;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.channel.AbstractChannel;
import io.netty.channel.Channel;
import io.netty.channel.ChannelMetadata;
import io.netty.channel.EventLoop;
import io.netty.channel.unix.FileDescriptor;
import io.netty.channel.unix.UnixChannel;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.OneTimeTask;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.UnresolvedAddressException;
abstract class AbstractEpollChannel extends AbstractChannel implements UnixChannel {
private static final ChannelMetadata DATA = new ChannelMetadata(false);
private final int readFlag;
private final FileDescriptor fileDescriptor;
protected int flags = Native.EPOLLET;
protected volatile boolean active;
AbstractEpollChannel(int fd, int flag) {
this(null, fd, flag, false);
}
AbstractEpollChannel(Channel parent, int fd, int flag, boolean active) {
this(parent, new FileDescriptor(fd), flag, active);
}
AbstractEpollChannel(Channel parent, FileDescriptor fd, int flag, boolean active) {
super(parent);
if (fd == null) {
throw new NullPointerException("fd");
}
readFlag = flag;
flags |= flag;
this.active = active;
fileDescriptor = fd;
}
void setFlag(int flag) {
if (!isFlagSet(flag)) {
flags |= flag;
modifyEvents();
}
}
void clearFlag(int flag) {
if (isFlagSet(flag)) {
flags &= ~flag;
modifyEvents();
}
}
boolean isFlagSet(int flag) {
return (flags & flag) != 0;
}
@Override
public final FileDescriptor fd() {
return fileDescriptor;
}
@Override
public abstract EpollChannelConfig config();
@Override
public boolean isActive() {
return active;
}
@Override
public ChannelMetadata metadata() {
return DATA;
}
@Override
protected void doClose() throws Exception {
active = false;
// deregister from epoll now
doDeregister();
FileDescriptor fd = fileDescriptor;
fd.close();
}
@Override
protected void doDisconnect() throws Exception {
doClose();
}
@Override
protected boolean isCompatible(EventLoop loop) {
return loop instanceof EpollEventLoop;
}
@Override
public boolean isOpen() {
return fileDescriptor.isOpen();
}
@Override
protected void doDeregister() throws Exception {
((EpollEventLoop) eventLoop()).remove(this);
}
@Override
protected void doBeginRead() throws Exception {
// Channel.read() or ChannelHandlerContext.read() was called
((AbstractEpollUnsafe) unsafe()).readPending = true;
setFlag(readFlag);
}
final void clearEpollIn() {
// Only clear if registered with an EventLoop as otherwise
if (isRegistered()) {
final EventLoop loop = eventLoop();
final AbstractEpollUnsafe unsafe = (AbstractEpollUnsafe) unsafe();
if (loop.inEventLoop()) {
unsafe.clearEpollIn0();
} else {
// schedule a task to clear the EPOLLIN as it is not safe to modify it directly
loop.execute(new OneTimeTask() {
@Override
public void run() {
if (!config().isAutoRead() && !unsafe.readPending) {
// Still no read triggered so clear it now
unsafe.clearEpollIn0();
}
}
});
}
} else {
// The EventLoop is not registered atm so just update the flags so the correct value
// will be used once the channel is registered
flags &= ~readFlag;
}
}
private void modifyEvents() {
if (isOpen() && isRegistered()) {
((EpollEventLoop) eventLoop()).modify(this);
}
}
@Override
protected void doRegister() throws Exception {
EpollEventLoop loop = (EpollEventLoop) eventLoop();
loop.add(this);
}
@Override
protected abstract AbstractEpollUnsafe newUnsafe();
/**
* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the original one.
*/
protected final ByteBuf newDirectBuffer(ByteBuf buf) {
return newDirectBuffer(buf, buf);
}
/**
* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the specified holder.
* The caller must ensure that the holder releases the original {@link ByteBuf} when the holder is released by
* this method.
*/
protected final ByteBuf newDirectBuffer(Object holder, ByteBuf buf) {
final int readableBytes = buf.readableBytes();
if (readableBytes == 0) {
ReferenceCountUtil.safeRelease(holder);
return Unpooled.EMPTY_BUFFER;
}
final ByteBufAllocator alloc = alloc();
if (alloc.isDirectBufferPooled()) {
return newDirectBuffer0(holder, buf, alloc, readableBytes);
}
final ByteBuf directBuf = ByteBufUtil.threadLocalDirectBuffer();
if (directBuf == null) {
return newDirectBuffer0(holder, buf, alloc, readableBytes);
}
directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
ReferenceCountUtil.safeRelease(holder);
return directBuf;
}
private static ByteBuf newDirectBuffer0(Object holder, ByteBuf buf, ByteBufAllocator alloc, int capacity) {
final ByteBuf directBuf = alloc.directBuffer(capacity);
directBuf.writeBytes(buf, buf.readerIndex(), capacity);
ReferenceCountUtil.safeRelease(holder);
return directBuf;
}
protected static void checkResolvable(InetSocketAddress addr) {
if (addr.isUnresolved()) {
throw new UnresolvedAddressException();
}
}
/**
* Read bytes into the given {@link ByteBuf} and return the amount.
*/
protected final int doReadBytes(ByteBuf byteBuf) throws Exception {
int writerIndex = byteBuf.writerIndex();
int localReadAmount;
if (byteBuf.hasMemoryAddress()) {
localReadAmount = Native.readAddress(
fileDescriptor.intValue(), byteBuf.memoryAddress(), writerIndex, byteBuf.capacity());
} else {
ByteBuffer buf = byteBuf.internalNioBuffer(writerIndex, byteBuf.writableBytes());
localReadAmount = Native.read(fileDescriptor.intValue(), buf, buf.position(), buf.limit());
}
if (localReadAmount > 0) {
byteBuf.writerIndex(writerIndex + localReadAmount);
}
return localReadAmount;
}
protected final int doWriteBytes(ByteBuf buf, int writeSpinCount) throws Exception {
int readableBytes = buf.readableBytes();
int writtenBytes = 0;
if (buf.hasMemoryAddress()) {
long memoryAddress = buf.memoryAddress();
int readerIndex = buf.readerIndex();
int writerIndex = buf.writerIndex();
for (int i = writeSpinCount - 1; i >= 0; i--) {
int localFlushedAmount = Native.writeAddress(
fileDescriptor.intValue(), memoryAddress, readerIndex, writerIndex);
if (localFlushedAmount > 0) {
writtenBytes += localFlushedAmount;
if (writtenBytes == readableBytes) {
return writtenBytes;
}
readerIndex += localFlushedAmount;
} else {
break;
}
}
} else {
ByteBuffer nioBuf;
if (buf.nioBufferCount() == 1) {
nioBuf = buf.internalNioBuffer(buf.readerIndex(), buf.readableBytes());
} else {
nioBuf = buf.nioBuffer();
}
for (int i = writeSpinCount - 1; i >= 0; i--) {
int pos = nioBuf.position();
int limit = nioBuf.limit();
int localFlushedAmount = Native.write(fileDescriptor.intValue(), nioBuf, pos, limit);
if (localFlushedAmount > 0) {
nioBuf.position(pos + localFlushedAmount);
writtenBytes += localFlushedAmount;
if (writtenBytes == readableBytes) {
return writtenBytes;
}
} else {
break;
}
}
}
if (writtenBytes < readableBytes) {
// Returned EAGAIN need to set EPOLLOUT
setFlag(Native.EPOLLOUT);
}
return writtenBytes;
}
protected abstract class AbstractEpollUnsafe extends AbstractUnsafe {
protected boolean readPending;
/**
* Called once EPOLLIN event is ready to be processed
*/
abstract void epollInReady();
/**
* Called once EPOLLRDHUP event is ready to be processed
*/
void epollRdHupReady() {
// NOOP
}
@Override
protected void flush0() {
// Flush immediately only when there's no pending flush.
// If there's a pending flush operation, event loop will call forceFlush() later,
// and thus there's no need to call it now.
if (isFlagSet(Native.EPOLLOUT)) {
return;
}
super.flush0();
}
/**
* Called once a EPOLLOUT event is ready to be processed
*/
void epollOutReady() {
// directly call super.flush0() to force a flush now
super.flush0();
}
protected final void clearEpollIn0() {
clearFlag(readFlag);
}
}
}