serenity/Userland/Libraries/LibSQL/Meta.h

/*
 * Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/ByteString.h>
#include <AK/NonnullRefPtr.h>
#include <AK/RefCounted.h>
#include <AK/Result.h>
#include <AK/Vector.h>
#include <LibCore/EventReceiver.h>
#include <LibSQL/Forward.h>
#include <LibSQL/Heap.h>
#include <LibSQL/Type.h>
#include <LibSQL/Value.h>

namespace SQL {

/**
 * This file declares objects describing tables, indexes, and columns.
 * It remains to be seen if this will survive in it's current form.
 */

class Relation : public RefCounted<Relation> {
public:
    virtual ~Relation() = default;

    ByteString const& name() const { return m_name; }
    Relation const* parent() const { return m_parent; }

    u32 hash() const;
    Block::Index block_index() const { return m_block_index; }
    void set_block_index(Block::Index block_index) { m_block_index = block_index; }
    virtual Key key() const = 0;

protected:
    Relation(ByteString name, Block::Index block_index, Relation* parent = nullptr)
        : m_name(move(name))
        , m_block_index(block_index)
        , m_parent(parent)
    {
    }

    explicit Relation(ByteString name, Relation* parent = nullptr)
        : Relation(move(name), 0, parent)
    {
    }

private:
    ByteString m_name;
    Block::Index m_block_index { 0 };
    Relation const* m_parent { nullptr };
};

class SchemaDef : public Relation {
public:
    static ErrorOr<NonnullRefPtr<SchemaDef>> create(ByteString name);
    static ErrorOr<NonnullRefPtr<SchemaDef>> create(Key const&);

    Key key() const override;
    static NonnullRefPtr<IndexDef> index_def();
    static Key make_key();

private:
    explicit SchemaDef(ByteString);
};

class ColumnDef : public Relation {
public:
    static ErrorOr<NonnullRefPtr<ColumnDef>> create(Relation*, size_t, ByteString, SQLType);

    Key key() const override;
    SQLType type() const { return m_type; }
    size_t column_number() const { return m_index; }
    void set_not_null(bool can_not_be_null) { m_not_null = can_not_be_null; }
    bool not_null() const { return m_not_null; }
    void set_default_value(Value const& default_value);
    Value const& default_value() const { return m_default; }

    static NonnullRefPtr<IndexDef> index_def();
    static Key make_key(TableDef const&);

protected:
    ColumnDef(Relation*, size_t, ByteString, SQLType);

private:
    size_t m_index;
    SQLType m_type { SQLType::Text };
    bool m_not_null { false };
    Value m_default;
};

class KeyPartDef : public ColumnDef {
public:
    static ErrorOr<NonnullRefPtr<KeyPartDef>> create(IndexDef*, ByteString, SQLType, Order = Order::Ascending);

    Order sort_order() const { return m_sort_order; }

private:
    KeyPartDef(IndexDef*, ByteString, SQLType, Order);

    Order m_sort_order { Order::Ascending };
};

class IndexDef : public Relation {
public:
    static ErrorOr<NonnullRefPtr<IndexDef>> create(TableDef*, ByteString, bool unique = true, u32 pointer = 0);
    static ErrorOr<NonnullRefPtr<IndexDef>> create(ByteString, bool unique = true, u32 pointer = 0);

    Vector<NonnullRefPtr<KeyPartDef>> const& key_definition() const { return m_key_definition; }
    bool unique() const { return m_unique; }
    [[nodiscard]] size_t size() const { return m_key_definition.size(); }
    void append_column(ByteString, SQLType, Order = Order::Ascending);
    Key key() const override;
    [[nodiscard]] NonnullRefPtr<TupleDescriptor> to_tuple_descriptor() const;
    static NonnullRefPtr<IndexDef> index_def();
    static Key make_key(TableDef const& table_def);

private:
    IndexDef(TableDef*, ByteString, bool unique, u32 pointer);

    Vector<NonnullRefPtr<KeyPartDef>> m_key_definition;
    bool m_unique { false };

    friend TableDef;
};

class TableDef : public Relation {
public:
    static ErrorOr<NonnullRefPtr<TableDef>> create(SchemaDef*, ByteString);

    Key key() const override;
    void append_column(ByteString, SQLType);
    void append_column(Key const&);
    size_t num_columns() { return m_columns.size(); }
    size_t num_indexes() { return m_indexes.size(); }
    Vector<NonnullRefPtr<ColumnDef>> const& columns() const { return m_columns; }
    Vector<NonnullRefPtr<IndexDef>> const& indexes() const { return m_indexes; }
    [[nodiscard]] NonnullRefPtr<TupleDescriptor> to_tuple_descriptor() const;

    static NonnullRefPtr<IndexDef> index_def();
    static Key make_key(SchemaDef const& schema_def);
    static Key make_key(Key const& schema_key);

private:
    explicit TableDef(SchemaDef*, ByteString);

    Vector<NonnullRefPtr<ColumnDef>> m_columns;
    Vector<NonnullRefPtr<IndexDef>> m_indexes;
};

}