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diff --git a/src/rocksdb/include/rocksdb/iterator.h b/src/rocksdb/include/rocksdb/iterator.h
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+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// An iterator yields a sequence of key/value pairs from a source.
+// The following class defines the interface.  Multiple implementations
+// are provided by this library.  In particular, iterators are provided
+// to access the contents of a Table or a DB.
+//
+// Multiple threads can invoke const methods on an Iterator without
+// external synchronization, but if any of the threads may call a
+// non-const method, all threads accessing the same Iterator must use
+// external synchronization.
+
+#pragma once
+
+#include <string>
+#include "rocksdb/cleanable.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/status.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class Iterator : public Cleanable {
+ public:
+  Iterator() {}
+  // No copying allowed
+  Iterator(const Iterator&) = delete;
+  void operator=(const Iterator&) = delete;
+
+  virtual ~Iterator() {}
+
+  // An iterator is either positioned at a key/value pair, or
+  // not valid.  This method returns true iff the iterator is valid.
+  // Always returns false if !status().ok().
+  virtual bool Valid() const = 0;
+
+  // Position at the first key in the source.  The iterator is Valid()
+  // after this call iff the source is not empty.
+  virtual void SeekToFirst() = 0;
+
+  // Position at the last key in the source.  The iterator is
+  // Valid() after this call iff the source is not empty.
+  virtual void SeekToLast() = 0;
+
+  // Position at the first key in the source that at or past target.
+  // The iterator is Valid() after this call iff the source contains
+  // an entry that comes at or past target.
+  // All Seek*() methods clear any error status() that the iterator had prior to
+  // the call; after the seek, status() indicates only the error (if any) that
+  // happened during the seek, not any past errors.
+  virtual void Seek(const Slice& target) = 0;
+
+  // Position at the last key in the source that at or before target.
+  // The iterator is Valid() after this call iff the source contains
+  // an entry that comes at or before target.
+  virtual void SeekForPrev(const Slice& target) = 0;
+
+  // Moves to the next entry in the source.  After this call, Valid() is
+  // true iff the iterator was not positioned at the last entry in the source.
+  // REQUIRES: Valid()
+  virtual void Next() = 0;
+
+  // Moves to the previous entry in the source.  After this call, Valid() is
+  // true iff the iterator was not positioned at the first entry in source.
+  // REQUIRES: Valid()
+  virtual void Prev() = 0;
+
+  // Return the key for the current entry.  The underlying storage for
+  // the returned slice is valid only until the next modification of
+  // the iterator.
+  // REQUIRES: Valid()
+  virtual Slice key() const = 0;
+
+  // Return the value for the current entry.  The underlying storage for
+  // the returned slice is valid only until the next modification of
+  // the iterator.
+  // REQUIRES: Valid()
+  virtual Slice value() const = 0;
+
+  // If an error has occurred, return it.  Else return an ok status.
+  // If non-blocking IO is requested and this operation cannot be
+  // satisfied without doing some IO, then this returns Status::Incomplete().
+  virtual Status status() const = 0;
+
+  // If supported, renew the iterator to represent the latest state. The
+  // iterator will be invalidated after the call. Not supported if
+  // ReadOptions.snapshot is given when creating the iterator.
+  virtual Status Refresh() {
+    return Status::NotSupported("Refresh() is not supported");
+  }
+
+  // Property "rocksdb.iterator.is-key-pinned":
+  //   If returning "1", this means that the Slice returned by key() is valid
+  //   as long as the iterator is not deleted.
+  //   It is guaranteed to always return "1" if
+  //      - Iterator created with ReadOptions::pin_data = true
+  //      - DB tables were created with
+  //        BlockBasedTableOptions::use_delta_encoding = false.
+  // Property "rocksdb.iterator.super-version-number":
+  //   LSM version used by the iterator. The same format as DB Property
+  //   kCurrentSuperVersionNumber. See its comment for more information.
+  // Property "rocksdb.iterator.internal-key":
+  //   Get the user-key portion of the internal key at which the iteration
+  //   stopped.
+  virtual Status GetProperty(std::string prop_name, std::string* prop);
+};
+
+// Return an empty iterator (yields nothing).
+extern Iterator* NewEmptyIterator();
+
+// Return an empty iterator with the specified status.
+extern Iterator* NewErrorIterator(const Status& status);
+
+}  // namespace ROCKSDB_NAMESPACE