mirror of
https://github.com/SerenityOS/serenity.git
synced 2025-01-23 18:02:05 -05:00
224804b424
Unfortunately this patch is quite large. The main functionality included are a BTree index implementation and the Heap class which manages persistent storage. Also included are a Key subclass of the Tuple class, which is a specialization for index key tuples. This "dragged in" the Meta layer, which has classes defining SQL objects like tables and indexes.
105 lines
2.6 KiB
C++
105 lines
2.6 KiB
C++
/*
|
|
* Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Debug.h>
|
|
#include <AK/HashMap.h>
|
|
#include <AK/String.h>
|
|
#include <AK/Vector.h>
|
|
#include <LibCore/File.h>
|
|
#include <LibCore/Object.h>
|
|
#include <LibSQL/Meta.h>
|
|
#include <LibSQL/Serialize.h>
|
|
|
|
namespace SQL {
|
|
|
|
constexpr static u32 BLOCKSIZE = 1024;
|
|
|
|
/**
|
|
* A Heap is a logical container for database (SQL) data. Conceptually a
|
|
* Heap can be a database file, or a memory block, or another storage medium.
|
|
* It contains datastructures, like B-Trees, hash_index tables, or tuple stores
|
|
* (basically a list of data tuples).
|
|
*
|
|
* A Heap can be thought of the backing storage of a single database. It's
|
|
* assumed that a single SQL database is backed by a single Heap.
|
|
*
|
|
* Currently only B-Trees and tuple stores are implemented.
|
|
*/
|
|
class Heap : public Core::Object {
|
|
C_OBJECT(Heap);
|
|
|
|
public:
|
|
explicit Heap(String);
|
|
virtual ~Heap() override { flush(); }
|
|
|
|
u32 size() const { return m_end_of_file; }
|
|
Result<ByteBuffer, String> read_block(u32);
|
|
bool write_block(u32, ByteBuffer&);
|
|
u32 new_record_pointer();
|
|
[[nodiscard]] bool has_block(u32 block) const { return block < size(); }
|
|
|
|
u32 schemas_root() const { return m_schemas_root; }
|
|
|
|
void set_schemas_root(u32 root)
|
|
{
|
|
m_schemas_root = root;
|
|
update_zero_block();
|
|
}
|
|
|
|
u32 tables_root() const { return m_tables_root; }
|
|
|
|
void set_tables_root(u32 root)
|
|
{
|
|
m_tables_root = root;
|
|
update_zero_block();
|
|
}
|
|
|
|
u32 table_columns_root() const { return m_table_columns_root; }
|
|
|
|
void set_table_columns_root(u32 root)
|
|
{
|
|
m_table_columns_root = root;
|
|
update_zero_block();
|
|
}
|
|
u32 version() const { return m_version; }
|
|
|
|
u32 user_value(size_t index) const
|
|
{
|
|
VERIFY(index < m_user_values.size());
|
|
return m_user_values[index];
|
|
}
|
|
|
|
void set_user_value(size_t index, u32 value)
|
|
{
|
|
VERIFY(index < m_user_values.size());
|
|
m_user_values[index] = value;
|
|
update_zero_block();
|
|
}
|
|
|
|
void add_to_wal(u32 block, ByteBuffer& buffer) { m_write_ahead_log.set(block, buffer); }
|
|
void flush();
|
|
|
|
private:
|
|
bool seek_block(u32);
|
|
void read_zero_block();
|
|
void initialize_zero_block();
|
|
void update_zero_block();
|
|
|
|
RefPtr<Core::File> m_file;
|
|
u32 m_free_list { 0 };
|
|
u32 m_next_block { 1 };
|
|
u32 m_end_of_file { 1 };
|
|
u32 m_schemas_root { 0 };
|
|
u32 m_tables_root { 0 };
|
|
u32 m_table_columns_root { 0 };
|
|
u32 m_version { 0x00000001 };
|
|
Array<u32, 16> m_user_values;
|
|
HashMap<u32, ByteBuffer> m_write_ahead_log;
|
|
};
|
|
|
|
}
|