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use nom::multispace;
use nom::types::CompleteByteSlice;
use std::fmt;
use std::str;
use column::Column;
use common::{column_identifier_no_alias, opt_multispace};
use keywords::escape_if_keyword;
#[derive(Clone, Debug, Eq, Hash, PartialEq, Serialize, Deserialize)]
pub enum OrderType {
OrderAscending,
OrderDescending,
}
impl fmt::Display for OrderType {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
OrderType::OrderAscending => write!(f, "ASC"),
OrderType::OrderDescending => write!(f, "DESC"),
}
}
}
#[derive(Clone, Debug, Eq, Hash, PartialEq, Serialize, Deserialize)]
pub struct OrderClause {
pub columns: Vec<(Column, OrderType)>,
}
impl fmt::Display for OrderClause {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "ORDER BY ")?;
write!(
f,
"{}",
self.columns
.iter()
.map(|&(ref c, ref o)| format!("{} {}", escape_if_keyword(&c.name), o))
.collect::<Vec<_>>()
.join(", ")
)
}
}
named!(pub order_type<CompleteByteSlice, OrderType>,
alt!(
map!(tag_no_case!("desc"), |_| OrderType::OrderDescending)
| map!(tag_no_case!("asc"), |_| OrderType::OrderAscending)
)
);
named!(pub order_clause<CompleteByteSlice, OrderClause>,
do_parse!(
opt_multispace >>
tag_no_case!("order by") >>
multispace >>
order_expr: many0!(
do_parse!(
fieldname: column_identifier_no_alias >>
ordering: opt!(
do_parse!(
opt_multispace >>
ordering: order_type >>
(ordering)
)
) >>
opt!(
do_parse!(
opt_multispace >>
tag!(",") >>
opt_multispace >>
()
)
) >>
(fieldname, ordering.unwrap_or(OrderType::OrderAscending))
)
) >>
(OrderClause {
columns: order_expr,
})
)
);
#[cfg(test)]
mod tests {
use super::*;
use select::selection;
#[test]
fn order_clause() {
let qstring1 = "select * from users order by name desc\n";
let qstring2 = "select * from users order by name asc, age desc\n";
let qstring3 = "select * from users order by name\n";
let expected_ord1 = OrderClause {
columns: vec![("name".into(), OrderType::OrderDescending)],
};
let expected_ord2 = OrderClause {
columns: vec![
("name".into(), OrderType::OrderAscending),
("age".into(), OrderType::OrderDescending),
],
};
let expected_ord3 = OrderClause {
columns: vec![("name".into(), OrderType::OrderAscending)],
};
let res1 = selection(CompleteByteSlice(qstring1.as_bytes()));
let res2 = selection(CompleteByteSlice(qstring2.as_bytes()));
let res3 = selection(CompleteByteSlice(qstring3.as_bytes()));
assert_eq!(res1.unwrap().1.order, Some(expected_ord1));
assert_eq!(res2.unwrap().1.order, Some(expected_ord2));
assert_eq!(res3.unwrap().1.order, Some(expected_ord3));
}
}