text: /*
   *ServerCheckpoint.actor.h
   *
   * This source file is part of the FoundationDB open source project
   *
   * Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #pragma once
  #if defined(NO_INTELLISENSE) && !defined(FDBSERVER_SERVER_CHECKPOINT_ACTOR_G_H)
  #define FDBSERVER_SERVER_CHECKPOINT_ACTOR_G_H
  #include "fdbserver/ServerCheckpoint.actor.g.h"
  #elif !defined(FDBSERVER_SERVER_CHECKPOINT_ACTOR_H)
  #define FDBSERVER_SERVER_CHECKPOINT_ACTOR_H
  
  #include "fdbclient/NativeAPI.actor.h"
  #include "fdbclient/StorageCheckpoint.h"
  #include "flow/flow.h"
  
  #include "flow/actorcompiler.h" // has to be last include
  
  // An ICheckpointReader can read the contents of a checkpoint created from a KV store,
  // i.e., by IKeyValueStore::checkpoint().
  class ICheckpointReader {
  public:
  	// `token` is a serialized object defined by each derived ICheckpointReader class, to specify the
  	// starting point for the underlying checkpoint.
  	virtual Future<Void> init(StringRef token) = 0;
  
  	// Scans the checkpoint, and returns the key-value pairs.
  	virtual Future<RangeResult> nextKeyValues(const int rowLimit, const int ByteLimit) = 0;
  
  	// Returns the next chunk of the serialized checkpoint.
  	virtual Future<Standalone<StringRef>> nextChunk(const int ByteLimit) = 0;
  
  	virtual Future<Void> close() = 0;
  
  protected:
  	virtual ~ICheckpointReader() {}
  };
  
  ICheckpointReader* newCheckpointReader(const CheckpointMetaData& checkpoint, UID logID);
  
  // Delete a checkpoint.
  ACTOR Future<Void> deleteCheckpoint(CheckpointMetaData checkpoint);
  
  // Fetchs checkpoint to a local `dir`, `initialState` provides the checkpoint formats, location, restart point, etc.
  // If cFun is provided, the progress can be checkpointed.
  // Returns a CheckpointMetaData, which could contain KVS-specific results, e.g., the list of fetched checkpoint files.
  ACTOR Future<CheckpointMetaData> fetchCheckpoint(Database cx,
                                                   CheckpointMetaData initialState,
                                                   std::string dir,
                                                   std::function<Future<Void>(const CheckpointMetaData&)> cFun = nullptr);
  #endif