// Copyright 2017 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.

/**
  DiskBlockCacheInterface specifies how to access a disk cache remotely.
  */
@namespace("kbgitkbfs.1")
protocol DiskBlockCache {

  enum PrefetchStatus {
      NO_PREFETCH_0,
      TRIGGERED_PREFETCH_1,
      FINISHED_PREFETCH_2
  }

  /**
    GetCachedBlockRes is the response from GetBlock.
    */
  record GetBlockRes {
    bytes buf;
    bytes serverHalf;
    PrefetchStatus prefetchStatus;
  }

  /**
    DeleteBlocksRes is the response from DeleteBlocks.
    */
  record DeleteBlocksRes {
    int numRemoved;
    long sizeRemoved;
  }

  /**
    GetBlock gets a block from the disk cache.
    */
  GetBlockRes GetBlock(bytes tlfID, bytes blockID);

  /**
   GetPrefetchStatus gets the prefetch status from the disk cache.
   */
  PrefetchStatus GetPrefetchStatus(bytes tlfID, bytes blockID);

  /**
    PutBlock puts a block into the disk cache.
    */
  void PutBlock(bytes tlfID, bytes blockID, bytes buf, bytes serverHalf);

  /**
    DeleteBlocks deletes a set of blocks from the disk cache.
    */
  DeleteBlocksRes DeleteBlocks(array<bytes> blockIDs);

  /**
    UpdateBlockMetadata updates the metadata for a block in the disk cache.
    */
  void UpdateBlockMetadata(bytes tlfID, bytes blockID, PrefetchStatus prefetchStatus);
}