mlua/src/util/short_names.rs

85 lines
3.1 KiB
Rust

//! Mostly copied from bevy_utils
//! <https://github.com/bevyengine/bevy/blob/main/crates/bevy_utils/src/short_names.rs>
use std::any::type_name;
/// Returns a short version of a type name `T` without all module paths.
///
/// The short name of a type is its full name as returned by
/// [`std::any::type_name`], but with the prefix of all paths removed. For
/// example, the short name of `alloc::vec::Vec<core::option::Option<u32>>`
/// would be `Vec<Option<u32>>`.
pub(crate) fn short_type_name<T: ?Sized>() -> String {
let full_name = type_name::<T>();
// Generics result in nested paths within <..> blocks.
// Consider "core::option::Option<alloc::string::String>".
// To tackle this, we parse the string from left to right, collapsing as we go.
let mut index: usize = 0;
let end_of_string = full_name.len();
let mut parsed_name = String::new();
while index < end_of_string {
let rest_of_string = full_name.get(index..end_of_string).unwrap_or_default();
// Collapse everything up to the next special character,
// then skip over it
if let Some(special_character_index) = rest_of_string
.find(|c: char| [' ', '<', '>', '(', ')', '[', ']', ',', ';'].contains(&c))
{
let segment_to_collapse = rest_of_string
.get(0..special_character_index)
.unwrap_or_default();
parsed_name += collapse_type_name(segment_to_collapse);
// Insert the special character
let special_character =
&rest_of_string[special_character_index..=special_character_index];
parsed_name.push_str(special_character);
match special_character {
">" | ")" | "]"
if rest_of_string[special_character_index + 1..].starts_with("::") =>
{
parsed_name.push_str("::");
// Move the index past the "::"
index += special_character_index + 3;
}
// Move the index just past the special character
_ => index += special_character_index + 1,
}
} else {
// If there are no special characters left, we're done!
parsed_name += collapse_type_name(rest_of_string);
index = end_of_string;
}
}
parsed_name
}
#[inline(always)]
fn collapse_type_name(string: &str) -> &str {
string.rsplit("::").next().unwrap()
}
#[cfg(test)]
mod tests {
use super::short_type_name;
use std::collections::HashMap;
#[test]
fn tests() {
assert_eq!(short_type_name::<String>(), "String");
assert_eq!(short_type_name::<Option<String>>(), "Option<String>");
assert_eq!(short_type_name::<(String, &str)>(), "(String, &str)");
assert_eq!(short_type_name::<[i32; 3]>(), "[i32; 3]");
assert_eq!(
short_type_name::<HashMap<String, Option<[i32; 3]>>>(),
"HashMap<String, Option<[i32; 3]>>"
);
assert_eq!(
short_type_name::<dyn Fn(i32) -> i32>(),
"dyn Fn(i32) -> i32"
);
}
}