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- /*
- * Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <AK/NumericLimits.h>
- #include <LibSQL/AST/AST.h>
- #include <LibSQL/Database.h>
- #include <LibSQL/Meta.h>
- #include <LibSQL/ResultSet.h>
- #include <LibSQL/Row.h>
- namespace SQL::AST {
- RefPtr<SQLResult> Select::execute(ExecutionContext& context) const
- {
- NonnullRefPtrVector<ResultColumn> columns;
- for (auto& table_descriptor : table_or_subquery_list()) {
- if (!table_descriptor.is_table())
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::NotYetImplemented, "Sub-selects are not yet implemented");
- auto table_def_or_error = context.database->get_table(table_descriptor.schema_name(), table_descriptor.table_name());
- if (table_def_or_error.is_error())
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_def_or_error.error());
- auto table = table_def_or_error.value();
- if (!table) {
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::TableDoesNotExist, table_descriptor.table_name());
- }
- if (result_column_list().size() == 1 && result_column_list()[0].type() == ResultType::All) {
- for (auto& col : table->columns()) {
- columns.append(
- create_ast_node<ResultColumn>(
- create_ast_node<ColumnNameExpression>(table->parent()->name(), table->name(), col.name()),
- ""));
- }
- }
- }
- VERIFY(!result_column_list().is_empty());
- if (result_column_list().size() != 1 || result_column_list()[0].type() != ResultType::All) {
- for (auto& col : result_column_list()) {
- if (col.type() == ResultType::All)
- // FIXME can have '*' for example in conjunction with computed columns
- return SQLResult::construct(SQL::SQLCommand::Select, SQLErrorCode::SyntaxError, "*");
- columns.append(col);
- }
- }
- context.result = SQLResult::construct();
- AK::NonnullRefPtr<TupleDescriptor> descriptor = AK::adopt_ref(*new TupleDescriptor);
- Tuple tuple(descriptor);
- Vector<Tuple> rows;
- descriptor->empend("__unity__");
- tuple.append(Value(SQLType::Boolean, true));
- rows.append(tuple);
- for (auto& table_descriptor : table_or_subquery_list()) {
- if (!table_descriptor.is_table())
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::NotYetImplemented, "Sub-selects are not yet implemented");
- auto table_def_or_error = context.database->get_table(table_descriptor.schema_name(), table_descriptor.table_name());
- if (table_def_or_error.is_error())
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_def_or_error.error());
- auto table = table_def_or_error.value();
- if (table->num_columns() == 0)
- continue;
- auto old_descriptor_size = descriptor->size();
- descriptor->extend(table->to_tuple_descriptor());
- for (auto cartesian_row = rows.first(); cartesian_row.size() == old_descriptor_size; cartesian_row = rows.first()) {
- rows.remove(0);
- auto table_rows_or_error = context.database->select_all(*table);
- if (table_rows_or_error.is_error())
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::InternalError, table_rows_or_error.error());
- for (auto& table_row : table_rows_or_error.value()) {
- auto new_row = cartesian_row;
- new_row.extend(table_row);
- rows.append(new_row);
- }
- }
- }
- bool has_ordering { false };
- AK::NonnullRefPtr<TupleDescriptor> sort_descriptor = AK::adopt_ref(*new TupleDescriptor);
- for (auto& term : m_ordering_term_list) {
- sort_descriptor->append(TupleElementDescriptor { .order = term.order() });
- has_ordering = true;
- }
- Tuple sort_key(sort_descriptor);
- for (auto& row : rows) {
- context.current_row = &row;
- if (where_clause()) {
- auto where_result = where_clause()->evaluate(context);
- if (context.result->has_error())
- return context.result;
- if (!where_result)
- continue;
- }
- tuple.clear();
- for (auto& col : columns) {
- auto value = col.expression()->evaluate(context);
- if (context.result->has_error())
- return context.result;
- tuple.append(value);
- }
- if (has_ordering) {
- sort_key.clear();
- for (auto& term : m_ordering_term_list) {
- auto value = term.expression()->evaluate(context);
- if (context.result->has_error())
- return context.result;
- sort_key.append(value);
- }
- }
- context.result->insert(tuple, sort_key);
- }
- if (m_limit_clause != nullptr) {
- size_t limit_value = NumericLimits<size_t>::max();
- auto limit = m_limit_clause->limit_expression()->evaluate(context);
- if (!limit.is_null()) {
- auto limit_value_maybe = limit.to_u32();
- if (!limit_value_maybe.has_value()) {
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::SyntaxError, "LIMIT clause must evaluate to an integer value");
- }
- limit_value = limit_value_maybe.value();
- }
- size_t offset_value = 0;
- if (m_limit_clause->offset_expression() != nullptr) {
- auto offset = m_limit_clause->offset_expression()->evaluate(context);
- if (!offset.is_null()) {
- auto offset_value_maybe = offset.to_u32();
- if (!offset_value_maybe.has_value()) {
- return SQLResult::construct(SQLCommand::Select, SQLErrorCode::SyntaxError, "OFFSET clause must evaluate to an integer value");
- }
- offset_value = offset_value_maybe.value();
- }
- }
- context.result->limit(offset_value, limit_value);
- }
- return context.result;
- }
- }
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