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