io.rsocket.core.StreamIdSupplier Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of rsocket-core Show documentation

Core functionality for the RSocket library

The newest version!

/*
 * Copyright 2015-2020 the original author or authors.
 *
 * Licensed 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
 *
 *     http://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.rsocket.core;

import io.netty.util.collection.IntObjectMap;

/** This API is not thread-safe and must be strictly used in serialized fashion */
final class StreamIdSupplier {
  private static final int MASK = 0x7FFFFFFF;

  private long streamId;

  // Visible for testing
  StreamIdSupplier(int streamId) {
    this.streamId = streamId;
  }

  static StreamIdSupplier clientSupplier() {
    return new StreamIdSupplier(-1);
  }

  static StreamIdSupplier serverSupplier() {
    return new StreamIdSupplier(0);
  }

  /**
   * This methods provides new stream id and ensures there is no intersections with already running
   * streams. This methods is not thread-safe.
   *
   * @param streamIds currently running streams store
   * @return next stream id
   */
  int nextStreamId(IntObjectMap streamIds) {
    int streamId;
    do {
      this.streamId += 2;
      streamId = (int) (this.streamId & MASK);
    } while (streamId == 0 || streamIds.containsKey(streamId));
    return streamId;
  }

  boolean isBeforeOrCurrent(int streamId) {
    return this.streamId >= streamId && streamId > 0;
  }
}