chromium/components/services/storage/indexed_db/transactional_leveldb/transactional_leveldb_transaction.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_SERVICES_STORAGE_INDEXED_DB_TRANSACTIONAL_LEVELDB_TRANSACTIONAL_LEVELDB_TRANSACTION_H_
#define COMPONENTS_SERVICES_STORAGE_INDEXED_DB_TRANSACTIONAL_LEVELDB_TRANSACTIONAL_LEVELDB_TRANSACTION_H_

#include <memory>
#include <set>
#include <string>
#include <string_view>

#include "base/containers/flat_set.h"
#include "base/functional/callback.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "components/services/storage/indexed_db/scopes/leveldb_scope_deletion_mode.h"
#include "third_party/leveldatabase/src/include/leveldb/status.h"

namespace content {
class TransactionalLevelDBDatabase;
class TransactionalLevelDBIterator;
class LevelDBScope;
class LevelDBWriteBatch;

// Represents a transaction on top of a TransactionalLevelDBDatabase, and is
// backed by a LevelDBScope. This class is not thread-safe.
// Isolation: Read committed
//   All changes written using this transaction are readable through the Get()
//   method and iterators returned by CreateIterator(). They are NOT invisible
//   to other readers - if a key is written to using this transaction and read
//   from in a different transaction or on the database, it might read what was
//   written here.
// Atomicity:
//   All changes in this transaction will be either fully written or fully
//   reverted. It uses the LevelDBScopes system to guarantee this. If this class
//   is destructed before Commit() is called, then it will be rolled back.
// Destruction:
//   On destruction, if the transaction is not committed, it will be rolled
//   back. In a single-sequence scopes setup, this can actually tear down the
//   whole IndexedDBOriginState! So be careful when destroying this object.
class TransactionalLevelDBTransaction
    : public base::RefCounted<TransactionalLevelDBTransaction> { … };

// Reads go straight to the database, ignoring any writes cached in
// write_batch_. Writes are accumulated in a leveldb::WriteBatch and written on
// |Commit()|.
// TODO(dmurph): Remove this and have users just use the database and a
// WriteBatch.
class LevelDBDirectTransaction { … };

}  // namespace content

#endif  // COMPONENTS_SERVICES_STORAGE_INDEXED_DB_TRANSACTIONAL_LEVELDB_TRANSACTIONAL_LEVELDB_TRANSACTION_H_