DefaultIoUringIoRegistration Class — netty Architecture

Source Code

transport-classes-io_uring/src/main/java/io/netty/channel/uring/IoUringIoHandler.java lines 497–607

    private final class DefaultIoUringIoRegistration implements IoRegistration {
        private final AtomicBoolean canceled = new AtomicBoolean();
        private final ThreadAwareExecutor executor;
        private final IoUringIoEvent event = new IoUringIoEvent(0, 0, (byte) 0, (short) 0);
        final IoUringIoHandle handle;

        private boolean removeLater;
        private int outstandingCompletions;
        private int id;

        DefaultIoUringIoRegistration(ThreadAwareExecutor executor, IoUringIoHandle handle) {
            this.executor = executor;
            this.handle = handle;
        }

        void setId(int id) {
            this.id = id;
        }

        @Override
        public long submit(IoOps ops) {
            IoUringIoOps ioOps = (IoUringIoOps) ops;
            if (!isValid()) {
                return INVALID_ID;
            }
            if ((ioOps.flags() & Native.IOSQE_CQE_SKIP_SUCCESS) != 0) {
                // Because we expect at least 1 completion per submission we can't support IOSQE_CQE_SKIP_SUCCESS
                // as it will only produce a completion on failure.
                throw new IllegalArgumentException("IOSQE_CQE_SKIP_SUCCESS not supported");
            }
            long udata = UserData.encode(id, ioOps.opcode(), ioOps.data());
            if (executor.isExecutorThread(Thread.currentThread())) {
                submit0(ioOps, udata);
            } else {
                executor.execute(() -> submit0(ioOps, udata));
            }
            return udata;
        }

        private void submit0(IoUringIoOps ioOps, long udata) {
            ringBuffer.ioUringSubmissionQueue().enqueueSqe(ioOps.opcode(), ioOps.flags(), ioOps.ioPrio(),
                    ioOps.fd(), ioOps.union1(), ioOps.union2(), ioOps.len(), ioOps.union3(), udata,
                    ioOps.union4(), ioOps.personality(), ioOps.union5(), ioOps.union6()
            );
            outstandingCompletions++;
        }

        @SuppressWarnings("unchecked")
        @Override
        public <T> T attachment() {
            return (T) IoUringIoHandler.this;
        }

        @Override
        public boolean isValid() {
            return !canceled.get();
        }

        @Override
        public boolean cancel() {
            if (!canceled.compareAndSet(false, true)) {
                // Already cancelled.
                return false;
            }
            if (executor.isExecutorThread(Thread.currentThread())) {
                tryRemove();
            } else {
                executor.execute(this::tryRemove);
            }
            return true;
        }

        private void tryRemove() {
            if (outstandingCompletions > 0) {
                // We have some completions outstanding, we will remove the id <-> registration mapping
                // once these are done.
                removeLater = true;
                return;
            }
            remove();
        }