query-forge 0.9.0

use crate::QueryResult;
use crate::value::display_value;

use super::utils::escape_csv_field;

pub fn write_csv<W: std::io::Write + ?Sized>(
    result: &QueryResult,
    writer: &mut W,
) -> std::io::Result<()> {
    write_csv_row(result.columns.iter().map(String::as_str), writer)?;

    for row in &result.rows {
        writer.write_all(b"\n")?;
        write_csv_row(row.iter().map(display_value), writer)?;
    }

    Ok(())
}

pub fn render_csv(result: &QueryResult) -> String {
    let mut output = Vec::new();
    write_csv(result, &mut output).expect("writing to memory cannot fail");
    String::from_utf8(output).expect("CSV output should always be valid UTF-8")
}

fn write_csv_row<I, S, W>(fields: I, writer: &mut W) -> std::io::Result<()>
where
    I: IntoIterator<Item = S>,
    S: AsRef<str>,
    W: std::io::Write + ?Sized,
{
    for (index, field) in fields.into_iter().enumerate() {
        if index > 0 {
            writer.write_all(b",")?;
        }
        writer.write_all(escape_csv_field(field.as_ref()).as_bytes())?;
    }
    Ok(())
}