// 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.

//

// TableBuilder provides the interface used to build a Table

// (an immutable and sorted map from keys to values).

//

// Multiple threads can invoke const methods on a TableBuilder without

// external synchronization, but if any of the threads may call a

// non-const method, all threads accessing the same TableBuilder must use

// external synchronization.

#ifndef STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_

#define STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_

#include <cstdint>

#include "leveldb/export.h"

#include "leveldb/options.h"

#include "leveldb/status.h"

namespace leveldb {

class BlockBuilder;

class BlockHandle;

class WritableFile;

class LEVELDB_EXPORT TableBuilder {

 public:

  // Create a builder that will store the contents of the table it is

  // building in *file.  Does not close the file.  It is up to the

  // caller to close the file after calling Finish().

  TableBuilder(const Options& options, WritableFile* file);

  TableBuilder(const TableBuilder&) = delete;

  TableBuilder& operator=(const TableBuilder&) = delete;

  // REQUIRES: Either Finish() or Abandon() has been called.

  ~TableBuilder();

  // Change the options used by this builder.  Note: only some of the

  // option fields can be changed after construction.  If a field is

  // not allowed to change dynamically and its value in the structure

  // passed to the constructor is different from its value in the

  // structure passed to this method, this method will return an error

  // without changing any fields.

  Status ChangeOptions(const Options& options);

  // Add key,value to the table being constructed.

  // REQUIRES: key is after any previously added key according to comparator.

  // REQUIRES: Finish(), Abandon() have not been called

  void Add(const Slice& key, const Slice& value);

  // Advanced operation: flush any buffered key/value pairs to file.

  // Can be used to ensure that two adjacent entries never live in

  // the same data block.  Most clients should not need to use this method.

  // REQUIRES: Finish(), Abandon() have not been called

  void Flush();

  // Return non-ok iff some error has been detected.

  Status status() const;

  // Finish building the table.  Stops using the file passed to the

  // constructor after this function returns.

  // REQUIRES: Finish(), Abandon() have not been called

  Status Finish();

  // Indicate that the contents of this builder should be abandoned.  Stops

  // using the file passed to the constructor after this function returns.

  // If the caller is not going to call Finish(), it must call Abandon()

  // before destroying this builder.

  // REQUIRES: Finish(), Abandon() have not been called

  void Abandon();

  // Number of calls to Add() so far.

  uint64_t NumEntries() const;

  // Size of the file generated so far.  If invoked after a successful

  // Finish() call, returns the size of the final generated file.

  uint64_t FileSize() const;

 private:

  bool ok() const { return status().ok(); }

  void WriteBlock(BlockBuilder* block, BlockHandle* handle);

  void WriteRawBlock(const Slice& data, CompressionType, BlockHandle* handle);

  struct Rep;

  Rep* rep_;

};

}  // namespace leveldb

#endif  // STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_