continuwuity/src/macros/utils.rs
Jason Volk fd4c447a2d move attribute argument extractor to utils
Signed-off-by: Jason Volk <jason@zemos.net>
2024-11-24 07:11:26 +00:00

87 lines
1.9 KiB
Rust

use std::collections::HashMap;
use syn::{parse_str, Expr, ExprLit, Generics, Lit, Meta, MetaNameValue};
use crate::Result;
pub(crate) fn get_simple_settings(args: &[Meta]) -> HashMap<String, String> {
args.iter().fold(HashMap::new(), |mut map, arg| {
let Meta::NameValue(MetaNameValue {
path,
value,
..
}) = arg
else {
return map;
};
let Expr::Lit(
ExprLit {
lit: Lit::Str(str),
..
},
..,
) = value
else {
return map;
};
if let Some(key) = path.segments.iter().next().map(|s| s.ident.clone()) {
map.insert(key.to_string(), str.value());
}
map
})
}
pub(crate) fn is_cargo_build() -> bool {
std::env::args()
.find(|flag| flag.starts_with("--emit"))
.as_ref()
.and_then(|flag| flag.split_once('='))
.map(|val| val.1.split(','))
.and_then(|mut vals| vals.find(|elem| *elem == "link"))
.is_some()
}
pub(crate) fn get_named_generics(args: &[Meta], name: &str) -> Result<Generics> {
const DEFAULT: &str = "<>";
parse_str::<Generics>(&get_named_string(args, name).unwrap_or_else(|| DEFAULT.to_owned()))
}
pub(crate) fn get_named_string(args: &[Meta], name: &str) -> Option<String> {
args.iter().find_map(|arg| {
let value = arg.require_name_value().ok()?;
let Expr::Lit(ref lit) = value.value else {
return None;
};
let Lit::Str(ref str) = lit.lit else {
return None;
};
value.path.is_ident(name).then_some(str.value())
})
}
#[must_use]
pub(crate) fn camel_to_snake_string(s: &str) -> String {
let mut output = String::with_capacity(
s.chars()
.fold(s.len(), |a, ch| a.saturating_add(usize::from(ch.is_ascii_uppercase()))),
);
let mut state = false;
s.chars().for_each(|ch| {
let m = ch.is_ascii_uppercase();
let s = exchange(&mut state, !m);
if m && s {
output.push('_');
}
output.push(ch.to_ascii_lowercase());
});
output
}
#[inline]
pub(crate) fn exchange<T>(state: &mut T, source: T) -> T { std::mem::replace(state, source) }