EpollServerSocketUnsafe Class — netty Architecture

Source Code

transport-classes-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollServerChannel.java lines 71–128

    final class EpollServerSocketUnsafe extends AbstractEpollUnsafe {
        // Will hold the remote address after accept(...) was successful.
        // We need 24 bytes for the address as maximum + 1 byte for storing the length.
        private final byte[] acceptedAddress = new byte[25];

        @Override
        public void connect(SocketAddress socketAddress, SocketAddress socketAddress2, ChannelPromise channelPromise) {
            // Connect not supported by ServerChannel implementations
            channelPromise.setFailure(new UnsupportedOperationException());
        }

        @Override
        void epollInReady() {
            assert eventLoop().inEventLoop();
            final ChannelConfig config = config();
            if (shouldBreakEpollInReady(config)) {
                clearEpollIn0();
                return;
            }
            final EpollRecvByteAllocatorHandle allocHandle = recvBufAllocHandle();
            final ChannelPipeline pipeline = pipeline();
            allocHandle.reset(config);
            allocHandle.attemptedBytesRead(1);

            Throwable exception = null;
            try {
                try {
                    do {
                        // lastBytesRead represents the fd. We use lastBytesRead because it must be set so that the
                        // EpollRecvByteAllocatorHandle knows if it should try to read again or not when autoRead is
                        // enabled.
                        allocHandle.lastBytesRead(socket.accept(acceptedAddress));
                        if (allocHandle.lastBytesRead() == -1) {
                            // this means everything was handled for now
                            break;
                        }
                        allocHandle.incMessagesRead(1);

                        readPending = false;
                        pipeline.fireChannelRead(newChildChannel(allocHandle.lastBytesRead(), acceptedAddress, 1,
                                                                 acceptedAddress[0]));
                    } while (allocHandle.continueReading());
                } catch (Throwable t) {
                    exception = t;
                }
                allocHandle.readComplete();
                pipeline.fireChannelReadComplete();

                if (exception != null) {
                    pipeline.fireExceptionCaught(exception);
                }
            } finally {
                if (shouldStopReading(config)) {
                    clearEpollIn();
                }
            }
        }
    }