src/ledger/bin/storage/impl/btree/builder.h

// Copyright 2017 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.

#ifndef SRC_LEDGER_BIN_STORAGE_IMPL_BTREE_BUILDER_H_
#define SRC_LEDGER_BIN_STORAGE_IMPL_BTREE_BUILDER_H_

#include <lib/fit/function.h>

#include <memory>
#include <set>

#include "src/ledger/bin/storage/public/iterator.h"
#include "src/ledger/bin/storage/public/page_storage.h"
#include "src/ledger/bin/storage/public/types.h"
#include "src/ledger/lib/coroutine/coroutine.h"

namespace storage {
namespace btree {

struct NodeLevelCalculator {
  // Returns the level in the tree where a node containing |key| must be
  // located. The leaves are located on level 0.
  uint8_t (*GetNodeLevel)(convert::ExtendedStringView key);
};

// Returns the default algorithm to compute the node level.
const NodeLevelCalculator* GetDefaultNodeLevelCalculator();

// Applies changes provided by |changes| to the B-Tree starting at
// |root_identifier|. |changes| must provide |EntryChange| objects sorted by
// their key. |new_root_identifier| will contain the id of the new root and
// |new_identifiers| the list of ids of all new nodes created after the changes.
// Existing elements inside |new_identifiers| will be deleted.
Status ApplyChanges(
    coroutine::CoroutineHandler* coroutine_handler, PageStorage* page_storage,
    ObjectIdentifier root_identifier, std::vector<EntryChange> changes,
    ObjectIdentifier* new_root_identifier, std::set<ObjectIdentifier>* new_identifiers,
    const NodeLevelCalculator* node_level_calculator = GetDefaultNodeLevelCalculator());

}  // namespace btree
}  // namespace storage

#endif  // SRC_LEDGER_BIN_STORAGE_IMPL_BTREE_BUILDER_H_