/*
    * Copyright 2024 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:
    *
    *   https://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.uring;
  
  
  final class RingBuffer {
      private final SubmissionQueue ioUringSubmissionQueue;
      private final CompletionQueue ioUringCompletionQueue;
      private final int features;
  
      RingBuffer(SubmissionQueue ioUringSubmissionQueue,
                 CompletionQueue ioUringCompletionQueue, int features) {
          this.ioUringSubmissionQueue = ioUringSubmissionQueue;
          this.ioUringCompletionQueue = ioUringCompletionQueue;
          this.features = features;
      }
  
      /**
       * Enable ring. This method must be called from the same method that will call {@link SubmissionQueue#submit()} and
       * {@link SubmissionQueue#submitAndWait()}.
       */
      void enable() {
          // We create our ring in disabled mode and so need to enable it first.
          Native.ioUringRegisterEnableRings(fd());
          // Now also register the ring filedescriptor itself. This needs to happen in the same thread
          // that will also call the io_uring_enter(...)
          ioUringSubmissionQueue.tryRegisterRingFd();
      }
  
      int fd() {
          return ioUringCompletionQueue.ringFd;
      }
  
      int features() {
          return features;
      }
  
      SubmissionQueue ioUringSubmissionQueue() {
          return this.ioUringSubmissionQueue;
      }
  
      CompletionQueue ioUringCompletionQueue() {
          return this.ioUringCompletionQueue;
      }
  
      void close() {
          Native.ioUringExit(
                  ioUringSubmissionQueue.submissionQueueArrayAddress,
                  ioUringSubmissionQueue.ringEntries,
                  ioUringSubmissionQueue.ringAddress,
                  ioUringSubmissionQueue.ringSize,
                  ioUringCompletionQueue.ringAddress,
                  ioUringCompletionQueue.ringSize,
                  ioUringSubmissionQueue.ringFd,
                  ioUringSubmissionQueue.enterRingFd);
      }
  }