LibSQL: Database layer

This patch implements the beginnings of a database API allowing for the
creation of tables, inserting rows in those tables, and retrieving those
rows.

1 files changed, 54 insertions, 0 deletions

diff --git a/Userland/Libraries/LibSQL/Database.h b/Userland/Libraries/LibSQL/Database.h
new file mode 100644
index 0000000000..5603dcc2e1
--- /dev/null
+++ b/Userland/Libraries/LibSQL/Database.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/RefPtr.h>
+#include <AK/String.h>
+#include <LibCore/Object.h>
+#include <LibSQL/Forward.h>
+#include <LibSQL/Heap.h>
+
+namespace SQL {
+
+/**
+ * A Database object logically connects a Heap with the SQL data we want
+ * to store in it. It has BTree pointers for B-Trees holding the definitions
+ * of tables, columns, indexes, and other SQL objects.
+ */
+class Database : public Core::Object {
+    C_OBJECT(Database);
+
+public:
+    explicit Database(String);
+    ~Database() override = default;
+
+    void commit() { m_heap->flush(); }
+
+    void add_schema(SchemaDef const&);
+    static Key get_schema_key(String const&);
+    RefPtr<SchemaDef> get_schema(String const&);
+
+    void add_table(TableDef& table);
+    static Key get_table_key(String const&, String const&);
+    RefPtr<TableDef> get_table(String const&, String const&);
+
+    Vector<Row> select_all(TableDef const&);
+    Vector<Row> match(TableDef const&, Key const&);
+    bool insert(Row&);
+    bool update(Row&);
+
+private:
+    RefPtr<Heap> m_heap;
+    RefPtr<BTree> m_schemas;
+    RefPtr<BTree> m_tables;
+    RefPtr<BTree> m_table_columns;
+
+    HashMap<u32, RefPtr<SchemaDef>> m_schema_cache;
+    HashMap<u32, RefPtr<TableDef>> m_table_cache;
+};
+
+}