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#![cfg(feature = "frunk")]
use frunk::{hlist::h_cons, prelude::HList};
pub use frunk::{HCons, HNil};
use super::{FromRow, FromRowError};
use crate::{
row::{new_row_raw, Row},
value::{
convert::{ConvIr, FromValue, FromValueError},
Value,
},
};
impl FromRow for HNil {
fn from_row_opt(row: Row) -> Result<Self, FromRowError>
where
Self: Sized,
{
if !row.is_empty() {
return Err(FromRowError(row));
}
Ok(HNil)
}
}
impl<H, T> FromRow for HCons<H, T>
where
H: FromValue,
T: FromRow + sealed::HlistFromRow,
T: HList,
{
fn from_row_opt(row: Row) -> Result<Self, FromRowError>
where
Self: Sized,
{
use sealed::HlistFromRow;
if row.len() != Self::LEN {
return Err(FromRowError(row));
}
let columns = row.columns();
let values = row.unwrap_raw();
Self::hlist_from_row_opt(values)
.map_err(|values| FromRowError(new_row_raw(values, columns)))
}
}
mod sealed {
use super::*;
pub trait HlistFromRow: Sized {
fn hlist_from_row_opt(values: Vec<Option<Value>>) -> Result<Self, Vec<Option<Value>>>;
}
impl HlistFromRow for HNil {
fn hlist_from_row_opt(values: Vec<Option<Value>>) -> Result<Self, Vec<Option<Value>>> {
debug_assert_eq!(values.len(), Self::LEN);
Ok(HNil)
}
}
impl<H, T> HlistFromRow for HCons<H, T>
where
H: FromValue,
T: HlistFromRow,
T: HList,
{
fn hlist_from_row_opt(mut values: Vec<Option<Value>>) -> Result<Self, Vec<Option<Value>>>
where
Self: Sized,
{
debug_assert_eq!(values.len(), Self::LEN);
if values[0].is_none() {
return Err(values);
}
let head = values.remove(0).expect("must be here");
let ir = match H::get_intermediate(head) {
Ok(ir) => ir,
Err(FromValueError(value)) => {
values.insert(0, Some(value));
return Err(values);
}
};
let tail = match T::hlist_from_row_opt(values) {
Ok(t) => t,
Err(mut values) => {
values.insert(0, Some(ir.rollback()));
return Err(values);
}
};
Ok(h_cons(ir.commit(), tail))
}
}
}
#[test]
fn hlist_from_row() {
use crate::{
constants::ColumnType::{MYSQL_TYPE_LONG, MYSQL_TYPE_VARCHAR},
packets::Column,
row::{convert::from_row, new_row},
value::Value::*,
};
let row = new_row(
vec![
Int(0),
Bytes(vec![b'0']),
Int(1),
Bytes(vec![b'1']),
Int(2),
Bytes(vec![b'2']),
Int(3),
Bytes(vec![b'3']),
Int(4),
Bytes(vec![b'4']),
Int(5),
Bytes(vec![b'5']),
Int(6),
Bytes(vec![b'6']),
Int(7),
Bytes(vec![b'7']),
],
vec![
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
Column::new(MYSQL_TYPE_LONG),
Column::new(MYSQL_TYPE_VARCHAR),
]
.into_boxed_slice()
.into(),
);
let val: frunk::HList![
u8,
Vec<u8>,
u16,
String,
u8,
u8,
u8,
u8,
u8,
u8,
u8,
u8,
u8,
u8,
u8,
u8
] = from_row(row);
assert_eq!(
val.into_tuple2(),
(
0,
(
vec![b'0'],
(
1,
(
String::from("1"),
(2, (2, (3, (3, (4, (4, (5, (5, (6, (6, (7, 7)))))))))))
)
)
)
)
);
}