Java Code Examples for io.netty.channel.ChannelConfig#isAutoRead()

The following examples show how to use io.netty.channel.ChannelConfig#isAutoRead() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: ServerBootstrap.java    From arcusplatform with Apache License 2.0 6 votes vote down vote up
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    final ChannelConfig config = ctx.channel().config();
    if (config.isAutoRead()) {
        // stop accept new connections for 1 second to allow the channel to recover
        // See https://github.com/netty/netty/issues/1328
        config.setAutoRead(false);
        ctx.channel().eventLoop().schedule(new Runnable() {
            @Override
            public void run() {
               config.setAutoRead(true);
            }
        }, 1, TimeUnit.SECONDS);
    }
    // still let the exceptionCaught event flow through the pipeline to give the user
    // a chance to do something with it
    ctx.fireExceptionCaught(cause);
}
 
Example 2
Source File: ServerBootstrap.java    From netty4.0.27Learn with Apache License 2.0 6 votes vote down vote up
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    final ChannelConfig config = ctx.channel().config();
    if (config.isAutoRead()) {
        // stop accept new connections for 1 second to allow the channel to recover
        // See https://github.com/netty/netty/issues/1328
        config.setAutoRead(false);
        ctx.channel().eventLoop().schedule(new Runnable() {
            @Override
            public void run() {
               config.setAutoRead(true);
            }
        }, 1, TimeUnit.SECONDS);
    }
    // still let the exceptionCaught event flow through the pipeline to give the user
    // a chance to do something with it
    ctx.fireExceptionCaught(cause);
}
 
Example 3
Source File: AbstractKQueueChannel.java    From netty-4.1.22 with Apache License 2.0 6 votes vote down vote up
final void readReadyFinally(ChannelConfig config) {
    maybeMoreDataToRead = allocHandle.maybeMoreDataToRead();
    // Check if there is a readPending which was not processed yet.
    // This could be for two reasons:
    // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
    // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
    //
    // See https://github.com/netty/netty/issues/2254
    if (!readPending && !config.isAutoRead()) {
        clearReadFilter0();
    } else if (readPending && maybeMoreDataToRead) {
        // trigger a read again as there may be something left to read and because of ET we
        // will not get notified again until we read everything from the socket
        //
        // It is possible the last fireChannelRead call could cause the user to call read() again, or if
        // autoRead is true the call to channelReadComplete would also call read, but maybeMoreDataToRead is set
        // to false before every read operation to prevent re-entry into readReady() we will not read from
        // the underlying OS again unless the user happens to call read again.
        executeReadReadyRunnable(config);
    }
}
 
Example 4
Source File: AbstractEpollChannel.java    From netty-4.1.22 with Apache License 2.0 6 votes vote down vote up
final void epollInFinally(ChannelConfig config) {
    maybeMoreDataToRead = allocHandle.isEdgeTriggered() && allocHandle.maybeMoreDataToRead();
    // Check if there is a readPending which was not processed yet.
    // This could be for two reasons:
    // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
    // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
    //
    // See https://github.com/netty/netty/issues/2254
    if (!readPending && !config.isAutoRead()) {
        clearEpollIn();
    } else if (readPending && maybeMoreDataToRead) {
        // trigger a read again as there may be something left to read and because of epoll ET we
        // will not get notified again until we read everything from the socket
        //
        // It is possible the last fireChannelRead call could cause the user to call read() again, or if
        // autoRead is true the call to channelReadComplete would also call read, but maybeMoreDataToRead is set
        // to false before every read operation to prevent re-entry into epollInReady() we will not read from
        // the underlying OS again unless the user happens to call read again.
        executeEpollInReadyRunnable(config);
    }
}
 
Example 5
Source File: AbstractTrafficShapingHandler.java    From netty-4.1.22 with Apache License 2.0 5 votes vote down vote up
@Override
public void run() {
    Channel channel = ctx.channel();
    ChannelConfig config = channel.config();
    if (!config.isAutoRead() && isHandlerActive(ctx)) {
        // If AutoRead is False and Active is True, user make a direct setAutoRead(false)
        // Then Just reset the status
        if (logger.isDebugEnabled()) {
            logger.debug("Not unsuspend: " + config.isAutoRead() + ':' +
                    isHandlerActive(ctx));
        }
        channel.attr(READ_SUSPENDED).set(false);
    } else {
        // Anything else allows the handler to reset the AutoRead
        if (logger.isDebugEnabled()) {
            if (config.isAutoRead() && !isHandlerActive(ctx)) {
                logger.debug("Unsuspend: " + config.isAutoRead() + ':' +
                        isHandlerActive(ctx));
            } else {
                logger.debug("Normal unsuspend: " + config.isAutoRead() + ':'
                        + isHandlerActive(ctx));
            }
        }
        channel.attr(READ_SUSPENDED).set(false);
        config.setAutoRead(true);
        channel.read();
    }
    if (logger.isDebugEnabled()) {
        logger.debug("Unsuspend final status => " + config.isAutoRead() + ':'
                + isHandlerActive(ctx));
    }
}
 
Example 6
Source File: LoadControlHandler.java    From tchannel-java with MIT License 5 votes vote down vote up
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
    if (msg instanceof Response) {
        ChannelConfig config = ctx.channel().config();
        if (--outstanding <= low && !config.isAutoRead()) {
            config.setAutoRead(true);
        }
    }
    ctx.write(msg, promise);
}
 
Example 7
Source File: LoadControlHandler.java    From tchannel-java with MIT License 5 votes vote down vote up
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
    if (msg instanceof Request) {
        ChannelConfig config = ctx.channel().config();
        if (++outstanding >= high && config.isAutoRead()) {
            config.setAutoRead(false);
        }
    }
    ctx.fireChannelRead(msg);
}
 
Example 8
Source File: AbstractTrafficShapingHandler.java    From netty4.0.27Learn with Apache License 2.0 5 votes vote down vote up
@Override
public void run() {
    ChannelConfig config = ctx.channel().config();
    if (!config.isAutoRead() && isHandlerActive(ctx)) {
        // If AutoRead is False and Active is True, user make a direct setAutoRead(false)
        // Then Just reset the status
        if (logger.isDebugEnabled()) {
            logger.debug("Not unsuspend: " + config.isAutoRead() + ':' +
                    isHandlerActive(ctx));
        }
        ctx.attr(READ_SUSPENDED).set(false);
    } else {
        // Anything else allows the handler to reset the AutoRead
        if (logger.isDebugEnabled()) {
            if (config.isAutoRead() && !isHandlerActive(ctx)) {
                logger.debug("Unsuspend: " + config.isAutoRead() + ':' +
                        isHandlerActive(ctx));
            } else {
                logger.debug("Normal unsuspend: " + config.isAutoRead() + ':'
                        + isHandlerActive(ctx));
            }
        }
        ctx.attr(READ_SUSPENDED).set(false);
        config.setAutoRead(true);
        ctx.channel().read();
    }
    if (logger.isDebugEnabled()) {
        logger.debug("Unsupsend final status => " + config.isAutoRead() + ':'
                + isHandlerActive(ctx));
    }
}
 
Example 9
Source File: ServerTransport.java    From reactor-netty with Apache License 2.0 5 votes vote down vote up
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
	ChannelConfig config = ctx.channel().config();
	if (config.isAutoRead()) {
		// stop accept new connections for 1 second to allow the channel to recover
		// See https://github.com/netty/netty/issues/1328
		config.setAutoRead(false);
		ctx.channel().eventLoop().schedule(enableAutoReadTask, 1, TimeUnit.SECONDS);
	}
	// still let the exceptionCaught event flow through the pipeline to give the user
	// a chance to do something with it
	ctx.fireExceptionCaught(cause);
}
 
Example 10
Source File: ServerBootstrap.java    From netty-4.1.22 with Apache License 2.0 5 votes vote down vote up
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    final ChannelConfig config = ctx.channel().config();
    if (config.isAutoRead()) {
        // stop accept new connections for 1 second to allow the channel to recover
        // See https://github.com/netty/netty/issues/1328
        config.setAutoRead(false);
        ctx.channel().eventLoop().schedule(enableAutoReadTask, 1, TimeUnit.SECONDS);
    }
    // still let the exceptionCaught event flow through the pipeline to give the user
    // a chance to do something with it
    ctx.fireExceptionCaught(cause);
}
 
Example 11
Source File: AbstractOioMessageChannel.java    From netty4.0.27Learn with Apache License 2.0 4 votes vote down vote up
@Override
protected void doRead() {
    final ChannelConfig config = config();
    final ChannelPipeline pipeline = pipeline();
    boolean closed = false;
    final int maxMessagesPerRead = config.getMaxMessagesPerRead();

    Throwable exception = null;
    int localRead = 0;
    int totalRead = 0;
    try {
        for (;;) {
            // Perform a read.
            localRead = doReadMessages(readBuf);
            if (localRead == 0) {
                break;
            }
            if (localRead < 0) {
                closed = true;
                break;
            }

            // Notify with the received messages and clear the buffer.
            int size = readBuf.size();
            for (int i = 0; i < size; i ++) {
                pipeline.fireChannelRead(readBuf.get(i));
            }
            readBuf.clear();

            // Do not read beyond maxMessagesPerRead.
            // Do not continue reading if autoRead has been turned off.
            totalRead += localRead;
            if (totalRead >= maxMessagesPerRead || !config.isAutoRead()) {
                break;
            }
        }
    } catch (Throwable t) {
        exception = t;
    }

    pipeline.fireChannelReadComplete();

    if (exception != null) {
        if (exception instanceof IOException) {
            closed = true;
        }

        pipeline().fireExceptionCaught(exception);
    }

    if (closed) {
        if (isOpen()) {
            unsafe().close(unsafe().voidPromise());
        }
    } else if (localRead == 0 && isActive()) {
        // If the read amount was 0 and the channel is still active we need to trigger a new read()
        // as otherwise we will never try to read again and the user will never know.
        // Just call read() is ok here as it will be submitted to the EventLoop as a task and so we are
        // able to process the rest of the tasks in the queue first.
        //
        // See https://github.com/netty/netty/issues/2404
        read();
    }
}
 
Example 12
Source File: AbstractNioByteChannel.java    From netty4.0.27Learn with Apache License 2.0 4 votes vote down vote up
@Override
public final void read() {
    final ChannelConfig config = config();
    if (!config.isAutoRead() && !isReadPending()) {
        // ChannelConfig.setAutoRead(false) was called in the meantime
        removeReadOp();
        return;
    }

    final ChannelPipeline pipeline = pipeline();
    final ByteBufAllocator allocator = config.getAllocator();
    final int maxMessagesPerRead = config.getMaxMessagesPerRead();
    RecvByteBufAllocator.Handle allocHandle = this.allocHandle;
    if (allocHandle == null) {
        this.allocHandle = allocHandle = config.getRecvByteBufAllocator().newHandle();
    }

    ByteBuf byteBuf = null;
    int messages = 0;
    boolean close = false;
    try {
        int totalReadAmount = 0;
        boolean readPendingReset = false;
        do {
            byteBuf = allocHandle.allocate(allocator);
            int writable = byteBuf.writableBytes();
            int localReadAmount = doReadBytes(byteBuf);
            if (localReadAmount <= 0) {
                // not was read release the buffer
                byteBuf.release();
                byteBuf = null;
                close = localReadAmount < 0;
                break;
            }
            if (!readPendingReset) {
                readPendingReset = true;
                setReadPending(false);
            }
            pipeline.fireChannelRead(byteBuf);
            byteBuf = null;

            if (totalReadAmount >= Integer.MAX_VALUE - localReadAmount) {
                // Avoid overflow.
                totalReadAmount = Integer.MAX_VALUE;
                break;
            }

            totalReadAmount += localReadAmount;

            // stop reading
            if (!config.isAutoRead()) {
                break;
            }

            if (localReadAmount < writable) {
                // Read less than what the buffer can hold,
                // which might mean we drained the recv buffer completely.
                break;
            }
        } while (++ messages < maxMessagesPerRead);

        pipeline.fireChannelReadComplete();
        allocHandle.record(totalReadAmount);

        if (close) {
            closeOnRead(pipeline);
            close = false;
        }
    } catch (Throwable t) {
        handleReadException(pipeline, byteBuf, t, close);
    } finally {
        // Check if there is a readPending which was not processed yet.
        // This could be for two reasons:
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
        //
        // See https://github.com/netty/netty/issues/2254
        if (!config.isAutoRead() && !isReadPending()) {
            removeReadOp();
        }
    }
}
 
Example 13
Source File: AbstractNioByteChannel.java    From netty-4.1.22 with Apache License 2.0 4 votes vote down vote up
@Override
public final void read() {
    final ChannelConfig config = config();
    final ChannelPipeline pipeline = pipeline();
    final ByteBufAllocator allocator = config.getAllocator();
    final RecvByteBufAllocator.Handle allocHandle = recvBufAllocHandle();
    allocHandle.reset(config);

    ByteBuf byteBuf = null;
    boolean close = false;
    try {
        do {
            byteBuf = allocHandle.allocate(allocator);
            allocHandle.lastBytesRead(doReadBytes(byteBuf));
            if (allocHandle.lastBytesRead() <= 0) {
                // nothing was read. release the buffer.
                byteBuf.release();
                byteBuf = null;
                close = allocHandle.lastBytesRead() < 0;
                if (close) {
                    // There is nothing left to read as we received an EOF.
                    readPending = false;
                }
                break;
            }

            allocHandle.incMessagesRead(1);
            readPending = false;
            pipeline.fireChannelRead(byteBuf);
            byteBuf = null;
        } while (allocHandle.continueReading());

        allocHandle.readComplete();
        pipeline.fireChannelReadComplete();

        if (close) {
            closeOnRead(pipeline);
        }
    } catch (Throwable t) {
        handleReadException(pipeline, byteBuf, t, close, allocHandle);
    } finally {
        // Check if there is a readPending which was not processed yet.
        // This could be for two reasons:
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
        //
        // See https://github.com/netty/netty/issues/2254
        if (!readPending && !config.isAutoRead()) {
            removeReadOp();
        }
    }
}
 
Example 14
Source File: AbstractEpollStreamChannel.java    From netty4.0.27Learn with Apache License 2.0 4 votes vote down vote up
@Override
void epollInReady() {
    final ChannelConfig config = config();
    boolean edgeTriggered = isFlagSet(Native.EPOLLET);

    if (!readPending && !edgeTriggered && !config.isAutoRead()) {
        // ChannelConfig.setAutoRead(false) was called in the meantime
        clearEpollIn0();
        return;
    }

    final ChannelPipeline pipeline = pipeline();
    final ByteBufAllocator allocator = config.getAllocator();
    RecvByteBufAllocator.Handle allocHandle = this.allocHandle;
    if (allocHandle == null) {
        this.allocHandle = allocHandle = config.getRecvByteBufAllocator().newHandle();
    }

    ByteBuf byteBuf = null;
    boolean close = false;
    try {
        // if edgeTriggered is used we need to read all messages as we are not notified again otherwise.
        final int maxMessagesPerRead = edgeTriggered
                ? Integer.MAX_VALUE : config.getMaxMessagesPerRead();
        int messages = 0;
        int totalReadAmount = 0;
        do {
            // we use a direct buffer here as the native implementations only be able
            // to handle direct buffers.
            byteBuf = allocHandle.allocate(allocator);
            int writable = byteBuf.writableBytes();
            int localReadAmount = doReadBytes(byteBuf);
            if (localReadAmount <= 0) {
                // not was read release the buffer
                byteBuf.release();
                close = localReadAmount < 0;
                break;
            }
            readPending = false;
            pipeline.fireChannelRead(byteBuf);
            byteBuf = null;

            if (totalReadAmount >= Integer.MAX_VALUE - localReadAmount) {
                allocHandle.record(totalReadAmount);

                // Avoid overflow.
                totalReadAmount = localReadAmount;
            } else {
                totalReadAmount += localReadAmount;
            }

            if (localReadAmount < writable) {
                // Read less than what the buffer can hold,
                // which might mean we drained the recv buffer completely.
                break;
            }
            if (!edgeTriggered && !config.isAutoRead()) {
                // This is not using EPOLLET so we can stop reading
                // ASAP as we will get notified again later with
                // pending data
                break;
            }
        } while (++ messages < maxMessagesPerRead);

        pipeline.fireChannelReadComplete();
        allocHandle.record(totalReadAmount);

        if (close) {
            closeOnRead(pipeline);
            close = false;
        }
    } catch (Throwable t) {
        boolean closed = handleReadException(pipeline, byteBuf, t, close);
        if (!closed) {
            // trigger a read again as there may be something left to read and because of epoll ET we
            // will not get notified again until we read everything from the socket
            eventLoop().execute(new Runnable() {
                @Override
                public void run() {
                    epollInReady();
                }
            });
        }
    } finally {
        // Check if there is a readPending which was not processed yet.
        // This could be for two reasons:
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
        //
        // See https://github.com/netty/netty/issues/2254
        if (!readPending && !config.isAutoRead()) {
            clearEpollIn0();
        }
    }
}
 
Example 15
Source File: AbstractOioMessageChannel.java    From netty-4.1.22 with Apache License 2.0 4 votes vote down vote up
@Override
protected void doRead() {
    if (!readPending) {
        // We have to check readPending here because the Runnable to read could have been scheduled and later
        // during the same read loop readPending was set to false.
        return;
    }
    // In OIO we should set readPending to false even if the read was not successful so we can schedule
    // another read on the event loop if no reads are done.
    readPending = false;

    final ChannelConfig config = config();
    final ChannelPipeline pipeline = pipeline();
    final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();
    allocHandle.reset(config);

    boolean closed = false;
    Throwable exception = null;
    try {
        do {
            // Perform a read.
            int localRead = doReadMessages(readBuf);
            if (localRead == 0) {
                break;
            }
            if (localRead < 0) {
                closed = true;
                break;
            }

            allocHandle.incMessagesRead(localRead);
        } while (allocHandle.continueReading());
    } catch (Throwable t) {
        exception = t;
    }

    boolean readData = false;
    int size = readBuf.size();
    if (size > 0) {
        readData = true;
        for (int i = 0; i < size; i++) {
            readPending = false;
            pipeline.fireChannelRead(readBuf.get(i));
        }
        readBuf.clear();
        allocHandle.readComplete();
        pipeline.fireChannelReadComplete();
    }

    if (exception != null) {
        if (exception instanceof IOException) {
            closed = true;
        }

        pipeline.fireExceptionCaught(exception);
    }

    if (closed) {
        if (isOpen()) {
            unsafe().close(unsafe().voidPromise());
        }
    } else if (readPending || config.isAutoRead() || !readData && isActive()) {
        // Reading 0 bytes could mean there is a SocketTimeout and no data was actually read, so we
        // should execute read() again because no data may have been read.
        read();
    }
}
 
Example 16
Source File: AbstractOioByteChannel.java    From netty-4.1.22 with Apache License 2.0 4 votes vote down vote up
@Override
protected void doRead() {
    final ChannelConfig config = config();
    if (isInputShutdown() || !readPending) {
        // We have to check readPending here because the Runnable to read could have been scheduled and later
        // during the same read loop readPending was set to false.
        return;
    }
    // In OIO we should set readPending to false even if the read was not successful so we can schedule
    // another read on the event loop if no reads are done.
    readPending = false;

    final ChannelPipeline pipeline = pipeline();
    final ByteBufAllocator allocator = config.getAllocator();
    final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();
    allocHandle.reset(config);

    ByteBuf byteBuf = null;
    boolean close = false;
    boolean readData = false;
    try {
        byteBuf = allocHandle.allocate(allocator);
        do {
            allocHandle.lastBytesRead(doReadBytes(byteBuf));
            if (allocHandle.lastBytesRead() <= 0) {
                if (!byteBuf.isReadable()) { // nothing was read. release the buffer.
                    byteBuf.release();
                    byteBuf = null;
                    close = allocHandle.lastBytesRead() < 0;
                    if (close) {
                        // There is nothing left to read as we received an EOF.
                        readPending = false;
                    }
                }
                break;
            } else {
                readData = true;
            }

            final int available = available();
            if (available <= 0) {
                break;
            }

            // Oio collects consecutive read operations into 1 ByteBuf before propagating up the pipeline.
            if (!byteBuf.isWritable()) {
                final int capacity = byteBuf.capacity();
                final int maxCapacity = byteBuf.maxCapacity();
                if (capacity == maxCapacity) {
                    allocHandle.incMessagesRead(1);
                    readPending = false;
                    pipeline.fireChannelRead(byteBuf);
                    byteBuf = allocHandle.allocate(allocator);
                } else {
                    final int writerIndex = byteBuf.writerIndex();
                    if (writerIndex + available > maxCapacity) {
                        byteBuf.capacity(maxCapacity);
                    } else {
                        byteBuf.ensureWritable(available);
                    }
                }
            }
        } while (allocHandle.continueReading());

        if (byteBuf != null) {
            // It is possible we allocated a buffer because the previous one was not writable, but then didn't use
            // it because allocHandle.continueReading() returned false.
            if (byteBuf.isReadable()) {
                readPending = false;
                pipeline.fireChannelRead(byteBuf);
            } else {
                byteBuf.release();
            }
            byteBuf = null;
        }

        if (readData) {
            allocHandle.readComplete();
            pipeline.fireChannelReadComplete();
        }

        if (close) {
            closeOnRead(pipeline);
        }
    } catch (Throwable t) {
        handleReadException(pipeline, byteBuf, t, close, allocHandle);
    } finally {
        if (readPending || config.isAutoRead() || !readData && isActive()) {
            // Reading 0 bytes could mean there is a SocketTimeout and no data was actually read, so we
            // should execute read() again because no data may have been read.
            read();
        }
    }
}
 
Example 17
Source File: AbstractXnioSocketChannel.java    From netty-xnio-transport with Apache License 2.0 4 votes vote down vote up
@Override
public void handleEvent(ConduitStreamSourceChannel channel) {
    final ChannelConfig config = config();
    final ChannelPipeline pipeline = pipeline();
    final ByteBufAllocator allocator = config.getAllocator();
    final int maxMessagesPerRead = config.getMaxMessagesPerRead();
    RecvByteBufAllocator.Handle allocHandle = this.allocHandle;
    if (allocHandle == null) {
        this.allocHandle = allocHandle = config.getRecvByteBufAllocator().newHandle();
    }

    ByteBuf byteBuf = null;
    int messages = 0;
    boolean close = false;
    try {
        int byteBufCapacity = allocHandle.guess();
        int totalReadAmount = 0;
        do {
            byteBuf = allocator.ioBuffer(byteBufCapacity);
            int writable = byteBuf.writableBytes();
            int localReadAmount = byteBuf.writeBytes(channel, byteBuf.writableBytes());
            if (localReadAmount <= 0) {
                // not was read release the buffer
                byteBuf.release();
                close = localReadAmount < 0;
                break;
            }
            ((AbstractXnioUnsafe) unsafe()).readPending = false;
            pipeline.fireChannelRead(byteBuf);
            byteBuf = null;

            if (totalReadAmount >= Integer.MAX_VALUE - localReadAmount) {
                // Avoid overflow.
                totalReadAmount = Integer.MAX_VALUE;
                break;
            }

            totalReadAmount += localReadAmount;

            // stop reading
            if (!config.isAutoRead()) {
                break;
            }

            if (localReadAmount < writable) {
                // Read less than what the buffer can hold,
                // which might mean we drained the recv buffer completely.
                break;
            }
        } while (++ messages < maxMessagesPerRead);

        pipeline.fireChannelReadComplete();
        allocHandle.record(totalReadAmount);

        if (close) {
            closeOnRead();
            close = false;
        }
    } catch (Throwable t) {
        handleReadException(pipeline, byteBuf, t, close);
    } finally {
        // Check if there is a readPending which was not processed yet.
        // This could be for two reasons:
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
        // * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
        //
        // See https://github.com/netty/netty/issues/2254
        if (!config.isAutoRead() && !((AbstractXnioUnsafe) unsafe()).readPending) {
            removeReadOp(channel);
        }
    }
}