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enve/itconfig/src/envstr.rs

92 lines
1.6 KiB
Rust

use std::ops::Deref;
use std::str::FromStr;
#[doc(hidden)]
pub trait ToEnvString {
fn to_env_string(&self) -> EnvString;
}
#[doc(hidden)]
pub trait FromEnvString: Sized {
type Err;
fn from_env_string(s: &EnvString) -> Result<Self, Self::Err>;
}
impl<T> ToEnvString for T
where
T: ToString
{
#[inline]
fn to_env_string(&self) -> EnvString {
EnvString(self.to_string())
}
}
#[doc(hidden)]
macro_rules! from_env_string_numbers_impl {
($($ty:ty),+) => {
$(
impl FromEnvString for $ty {
type Err = <$ty as FromStr>::Err;
#[inline]
fn from_env_string(s: &EnvString) -> Result<Self, Self::Err> {
s.0.parse::<Self>()
}
}
)+
};
}
from_env_string_numbers_impl![
i8, i16, i32, i64, i128, isize,
u8, u16, u32, u64, u128, usize,
f32, f64
];
impl FromEnvString for bool {
type Err = ();
fn from_env_string(s: &EnvString) -> Result<Self, Self::Err> {
match s.to_lowercase().as_str() {
"true" | "t" | "yes" | "y" | "on" | "1" => Ok(true),
_ => Ok(false)
}
}
}
impl FromEnvString for String {
type Err = ();
fn from_env_string(s: &EnvString) -> Result<Self, Self::Err> {
Ok(s.0.clone())
}
}
#[doc(hidden)]
#[derive(Debug, PartialEq, Clone)]
pub struct EnvString(String);
impl EnvString {
pub fn parse<T: FromEnvString>(&self) -> Result<T, T::Err> {
FromEnvString::from_env_string(self)
}
}
impl Deref for EnvString {
type Target = String;
fn deref(&self) -> &Self::Target {
&self.0
}
}