#include "tensorflow/core/platform/status.h"

namespace tensorflow {

// Abstract interface to a TensorHandle.
//
// A TensorHandle is management class around a Tensor which may track additional
// metadata and synchronization.
//
// This allows us to hide concrete implementations of TensorHandle from header
// files. The interface lists the common functionality that must be provided by

 *       {@code equals()}, {@code hashCode()}, and graph equivalence</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#synchronization">
 *       Synchronization policy</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#notes-for-implementors">Notes
 *       for implementors</a>
 * </ul>
 *
 * @author James Sexton

 *       {@code equals()}, {@code hashCode()}, and graph equivalence</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#synchronization">
 *       Synchronization policy</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#notes-for-implementors">Notes
 *       for implementors</a>
 * </ul>
 *
 * @author James Sexton

        default:
          throw new AssertionError("unexpected state: " + state);
      }
    }
  }

  abstract static class OldAbstractFuture<V> implements ListenableFuture<V> {

    /** Synchronization control for AbstractFutures. */
    private final Sync<V> sync = new Sync<V>();

    // The execution list to hold our executors.
    private final ExecutionList executionList = new ExecutionList();

 *       {@code equals()}, {@code hashCode()}, and graph equivalence</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#synchronization">
 *       Synchronization policy</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#notes-for-implementors">Notes
 *       for implementors</a>
 * </ul>
 *
 * @author James Sexton

 *       {@code equals()}, {@code hashCode()}, and graph equivalence</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#synchronization">
 *       Synchronization policy</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#notes-for-implementors">Notes
 *       for implementors</a>
 * </ul>
 *
 * @author James Sexton

  // A sequence of thread wrappers, one per device, for executing operations in
  // parallel.
  //
  // Conceptually this is a thread pool with one thread per device. It requires
  // less synchronization than a thread pool would for this task, since Execute
  // acquires each thread in order (and so only one Execute will schedule
  // blocking collective operations at a time), and avoids some dynamic

 *       {@code equals()}, {@code hashCode()}, and graph equivalence</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#synchronization">
 *       Synchronization policy</a>
 *   <li><a href="https://github.com/google/guava/wiki/GraphsExplained#notes-for-implementors">Notes
 *       for implementors</a>
 * </ul>
 *
 * @author James Sexton

      }
    }

    private static class RunnableExecutorPair {
      final Runnable runnable;
      final Executor executor;
      // Volatile because this is written on one thread and read on another with no synchronization.
      @Nullable volatile RunnableExecutorPair next;

      RunnableExecutorPair(@Nullable Runnable runnable, @Nullable Executor executor) {
        this.runnable = runnable;
        this.executor = executor;

 * guarantee that the new value will be fully visible to the other threads. To guarantee that
 * modifications are visible, synchronize access to the table. Unlike other {@code Table}
 * implementations, synchronization is unnecessary between a thread that writes to one cell and a
 * thread that reads from another.
 *
 * <p>See the Guava User Guide article on <a href=