text: // Copyright 2018 The Fuchsia Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #pragma once
  
  #include <stdbool.h>
  #include <stdint.h>
  
  #include <blobfs/format.h>
  #include <zircon/types.h>
  
  namespace blobfs {
  
  // Interface for a class which may be used to iterate over a collection of extents.
  class ExtentIterator {
  public:
      virtual ~ExtentIterator() = default;
  
      // Returns true if there are no more extents to be consumed.
      virtual bool Done() const = 0;
  
      // On success, returns ZX_OK and the next extent in |out|.
      virtual zx_status_t Next(const Extent** out) = 0;
  
      // Returns the number of blocks iterated past already. Updated on each
      // call to |Next|.
      virtual uint64_t BlockIndex() const = 0;
  };
  
  // Interface to look up nodes.
  class NodeFinder {
  public:
      virtual ~NodeFinder() = default;
  
      // Returns a pointer to the requested node.
      //
      // TODO(smklein): Return a zx_status_t to allow for invalid |ino| values.
      virtual Inode* GetNode(uint32_t node_index) = 0;
  };
  
  } // namespace blobfs
  