Function execute_select_statement

crates/gitql-engine/src/engine_executor.rs:78–168

(
    env: &mut Environment,
    statement: &SelectStatement,
    alias_table: &HashMap<String, String>,
    data_provider: &Box<dyn DataProvider>,
    gitql_object: &mut GitQLObject,
    hidden_selec

#[allow(clippy::borrowed_box)]
fn execute_select_statement(
    env: &mut Environment,
    statement: &SelectStatement,
    alias_table: &HashMap<String, String>,
    data_provider: &Box<dyn DataProvider>,
    gitql_object: &mut GitQLObject,
    hidden_selections: &HashMap<String, Vec<String>>,
) -> Result<(), String> {
    let mut selected_rows_per_table: HashMap<String, Vec<Row>> = HashMap::new();
    let mut hidden_selection_count_per_table: HashMap<String, usize> = HashMap::new();

    let mut titles: Vec<String> = vec![];
    let mut hidden_sum = 0;

    for table_selection in &statement.table_selections {
        // Select objects from the target table
        let table_name = &table_selection.table_name;
        let selected_columns = &mut table_selection.columns_names.to_owned();

        // Insert Hidden selection items for this table first
        let mut hidden_selection_count = 0;
        if let Some(table_hidden_selection) = hidden_selections.get(table_name) {
            for hidden_selection in table_hidden_selection {
                if !selected_columns.contains(hidden_selection) {
                    selected_columns.insert(0, hidden_selection.to_string());
                    hidden_selection_count += 1;
                }
            }
        }

        hidden_selection_count_per_table.insert(table_name.to_string(), hidden_selection_count);

        // Calculate list of titles once per table
        let mut table_titles = vec![];
        for selected_column in selected_columns.iter_mut() {
            table_titles.push(resolve_actual_column_name(alias_table, selected_column));
        }

        // Call the provider only if table name is not empty
        let selected_rows: Vec<Row> = if table_name.is_empty() {
            vec![Row { values: vec![] }]
        } else {
            data_provider.provide(table_name, selected_columns)?
        };

        selected_rows_per_table.insert(table_name.to_string(), selected_rows);

        // Append hidden selection in the right position
        // at the end all hidden selections will be first
        let hidden_selection_titles = &table_titles[..hidden_selection_count];
        titles.splice(hidden_sum..hidden_sum, hidden_selection_titles.to_vec());

        // Non hidden selection should be inserted at the end
        let selection_titles = &table_titles[hidden_selection_count..];
        titles.extend_from_slice(selection_titles);
        hidden_sum += hidden_selection_count;
    }