netty5源码分析(5)--学习笔记

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上文中initAndRegist()返回的是new DefaultChannelPromise(channel, this),这里this是NioEventLoop，

DefaultChannelPromise维护的初始化和注册的结果,

        if (regFuture.isDone()) { //初始化顺利
            // At this point we know that the registration was complete and successful.
            ChannelPromise promise = channel.newPromise();
            doBind0(regFuture, channel, localAddress, promise);
            return promise;
        } else {
            // Registration future is almost always fulfilled already, but just in case it's not.
            final PendingRegistrationPromise promise = new PendingRegistrationPromise(channel);
            regFuture.addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    Throwable cause = future.cause();
                    if (cause != null) {
                        // Registration on the EventLoop failed so fail the ChannelPromise directly to not cause an
                        // IllegalStateException once we try to access the EventLoop of the Channel.
                        promise.setFailure(cause);
                    } else {
                        // Registration was successful, so set the correct executor to use.
                        // See https://github.com/netty/netty/issues/2586
                        promise.executor = channel.eventLoop();
                    }
                    doBind0(regFuture, channel, localAddress, promise);
                }
            });
            return promise;
        }

    private static void doBind0(
            final ChannelFuture regFuture, final Channel channel,
            final SocketAddress localAddress, final ChannelPromise promise) {

        // This method is invoked before channelRegistered() is triggered.  Give user handlers a chance to set up
        // the pipeline in its channelRegistered() implementation.
        channel.eventLoop().execute(new Runnable() {
            @Override
            public void run() {
                if (regFuture.isSuccess()) {
                    channel.bind(localAddress, promise).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
                } else {
                    promise.setFailure(regFuture.cause());
                }
            }
        });
    }

channel.bind(localAddress, promise)里最终是pipeline.bind(localAddress, promise);

    @Override
    public ChannelFuture bind(SocketAddress localAddress, ChannelPromise promise) {
        return tail.bind(localAddress, promise);
    }

    @Override
    public ChannelFuture bind(final SocketAddress localAddress, final ChannelPromise promise) {
        AbstractChannelHandlerContext next = findContextOutbound();
        next.invoker().invokeBind(next, localAddress, promise);
        return promise;
    }

    @Override
    public void invokeBind(
            final ChannelHandlerContext ctx, final SocketAddress localAddress, final ChannelPromise promise) {
        if (localAddress == null) {
            throw new NullPointerException("localAddress");
        }
        if (!validatePromise(ctx, promise, false)) {
            // promise cancelled
            return;
        }

        if (executor.inEventLoop()) {
            invokeBindNow(ctx, localAddress, promise);
        } else {
            safeExecuteOutbound(new OneTimeTask() {
                @Override
                public void run() {
                    invokeBindNow(ctx, localAddress, promise);
                }
            }, promise);
        }
    }

findContextOutbound来Bind(localAddress,promis),findContextOutbound是DefaultChannelPipeline的HeadContext

回到NioServerSocketChannel里的unsafe的bind

@Override
        public final void bind(final SocketAddress localAddress, final ChannelPromise promise) {
            if (!promise.setUncancellable() || !ensureOpen(promise)) {
                return;
            }

            // See: https://github.com/netty/netty/issues/576
            if (Boolean.TRUE.equals(config().getOption(ChannelOption.SO_BROADCAST)) &&
                localAddress instanceof InetSocketAddress &&
                !((InetSocketAddress) localAddress).getAddress().isAnyLocalAddress() &&
                !PlatformDependent.isWindows() && !PlatformDependent.isRoot()) {
                // Warn a user about the fact that a non-root user can't receive a
                // broadcast packet on *nix if the socket is bound on non-wildcard address.
                logger.warn(
                        "A non-root user can't receive a broadcast packet if the socket " +
                        "is not bound to a wildcard address; binding to a non-wildcard " +
                        "address (" + localAddress + ") anyway as requested.");
            }

            boolean wasActive = isActive();
            try {
                doBind(localAddress);
            } catch (Throwable t) {
                safeSetFailure(promise, t);
                closeIfClosed();
                return;
            }

            if (!wasActive && isActive()) {
                invokeLater(new OneTimeTask() {
                    @Override
                    public void run() {
                        pipeline.fireChannelActive();
                    }
                });
            }

            safeSetSuccess(promise);
        }

    @Override
    protected void doBind(SocketAddress localAddress) throws Exception {
        javaChannel().socket().bind(localAddress, config.getBacklog());
    }

完成NIo的端口监听,接下来应该看DefaultChannelPromise 的sync()