*       divided into segments, each of which does LRU internally)
 *   <li>time-based expiration of entries, measured since last access or last write
 *   <li>keys automatically wrapped in {@code WeakReference}
 *   <li>values automatically wrapped in {@code WeakReference} or {@code SoftReference}
 *   <li>notification of evicted (or otherwise removed) entries
 *   <li>accumulation of cache access statistics
 * </ul>
 *

 *       divided into segments, each of which does LRU internally)
 *   <li>time-based expiration of entries, measured since last access or last write
 *   <li>keys automatically wrapped in {@code WeakReference}
 *   <li>values automatically wrapped in {@code WeakReference} or {@code SoftReference}
 *   <li>notification of evicted (or otherwise removed) entries
 *   <li>accumulation of cache access statistics
 * </ul>
 *

 * limitations under the License.
 */
package okhttp3.internal.connection

import java.io.IOException
import java.io.InterruptedIOException
import java.lang.ref.WeakReference
import java.net.Socket
import java.util.concurrent.CopyOnWriteArrayList
import java.util.concurrent.ExecutorService
import java.util.concurrent.RejectedExecutionException
import java.util.concurrent.TimeUnit.MILLISECONDS

      // TODO(cpovirk): Should we use a simpler (presumably cheaper) data structure?
      /*
       * Using weak references here could let us release exceptions earlier, but:
       *
       * 1. On Android, querying a WeakReference blocks if the GC is doing an otherwise-concurrent
       * pass.
       *
       * 2. We would probably choose to compare exceptions using == instead of equals() (for

      // TODO(cpovirk): Should we use a simpler (presumably cheaper) data structure?
      /*
       * Using weak references here could let us release exceptions earlier, but:
       *
       * 1. On Android, querying a WeakReference blocks if the GC is doing an otherwise-concurrent
       * pass.
       *
       * 2. We would probably choose to compare exceptions using == instead of equals() (for

   * entries in thread-specific maps when the ThreadLocal object itself is no longer referenced,
   * ThreadLocal is usually implemented with a WeakReference, which can have negative performance
   * properties; for example, calling WeakReference.get() on Android will block during an
   * otherwise-concurrent GC cycle.
   */
  private static final class TaskNonReentrantExecutor extends AtomicReference<RunningState>

import com.google.common.collect.MapMaker;
import com.google.common.math.IntMath;
import com.google.common.primitives.Ints;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.math.RoundingMode;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Semaphore;

   * entries in thread-specific maps when the ThreadLocal object itself is no longer referenced,
   * ThreadLocal is usually implemented with a WeakReference, which can have negative performance
   * properties; for example, calling WeakReference.get() on Android will block during an
   * otherwise-concurrent GC cycle.
   */
  private static final class TaskNonReentrantExecutor extends AtomicReference<RunningState>

      clearReferenceQueue(queueForKeys);
    }
  }

  static final class CleanupMapTask implements Runnable {
    final WeakReference<MapMakerInternalMap<?, ?, ?, ?>> mapReference;

    public CleanupMapTask(MapMakerInternalMap<?, ?, ?, ?> map) {
      this.mapReference = new WeakReference<>(map);
    }

    @Override
    public void run() {
      MapMakerInternalMap<?, ?, ?, ?> map = mapReference.get();

    int iterations = 10;
    WeakReference<Object> ref = new WeakReference<>(null);
    int expectedComputations = 0;
    for (int i = 0; i < iterations; i++) {
      // The entry should get garbage collected and recomputed.
      Object oldValue = ref.get();
      if (oldValue == null) {
        expectedComputations++;
      }
      ref = new WeakReference<>(cache.getUnchecked(1));
      oldValue = null;