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use std::error::Error;
use std::fmt;
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum ValueRef<'a> {
Null,
Integer(i64),
Real(f64),
Text(&'a [u8]),
Blob(&'a [u8]),
}
impl<'a> ValueRef<'a> {
pub fn as_str(&self) -> FromSqlResult<&'a str, &'a &'a str> {
match *self {
ValueRef::Text(t) => {
std::str::from_utf8(t).map_err(|_| FromSqlError::InvalidType).map(|x| (x, &x))
}
_ => Err(FromSqlError::InvalidType),
}
}
}
#[derive(Debug)]
#[non_exhaustive]
pub enum FromSqlError {
InvalidType
}
impl fmt::Display for FromSqlError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "InvalidType")
}
}
impl Error for FromSqlError {}
pub type FromSqlResult<T, K> = Result<(T, K), FromSqlError>;
pub trait FromSql: Sized {
fn column_result(value: ValueRef<'_>) -> FromSqlResult<Self, &Self>;
}
impl FromSql for &str {
fn column_result(value: ValueRef<'_>) -> FromSqlResult<&str, &&str> {
//~^ ERROR `impl` item signature doesn't match `trait` item signature
value.as_str()
}
}
pub fn main() {
println!("{}", "Hello World");
}
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