blob: 971c03048d41e943e0a5b02a8dc213032986216f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
extern crate proc_macro;
use proc_macro::TokenStream;
#[proc_macro]
pub fn _cssparser_internal_max_len(input: TokenStream) -> TokenStream {
struct Input {
max_length: usize,
}
impl syn::parse::Parse for Input {
fn parse(input: syn::parse::ParseStream) -> syn::parse::Result<Self> {
let mut max_length = 0;
while !input.is_empty() {
if input.peek(syn::Token![_]) {
input.parse::<syn::Token![_]>().unwrap();
continue;
}
let lit: syn::LitStr = input.parse()?;
let value = lit.value();
if value.to_ascii_lowercase() != value {
return Err(syn::Error::new(lit.span(), "must be ASCII-lowercase"));
}
max_length = max_length.max(value.len());
}
Ok(Input { max_length })
}
}
let Input { max_length } = syn::parse_macro_input!(input);
quote::quote!(
pub(super) const MAX_LENGTH: usize = #max_length;
)
.into()
}
|
