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3dcb3f3abf
MozReview-Commit-ID: 39oowMlDBon
99 lines
4.1 KiB
Rust
99 lines
4.1 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#[macro_use] extern crate procedural_masquerade;
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extern crate phf_codegen;
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extern crate proc_macro;
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extern crate proc_macro2;
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#[macro_use] extern crate quote;
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extern crate syn;
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#[allow(unused_imports)] use std::ascii::AsciiExt;
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use std::iter;
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use proc_macro2::{TokenStream, TokenTree};
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define_proc_macros! {
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/// Input: the arms of a `match` expression.
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///
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/// Output: a `MAX_LENGTH` constant with the length of the longest string pattern.
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///
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/// Panic if the arms contain non-string patterns,
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/// or string patterns that contains ASCII uppercase letters.
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#[allow(non_snake_case)]
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pub fn cssparser_internal__assert_ascii_lowercase__max_len(input: &str) -> String {
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let expr = syn::parse_str(&format!("match x {{ {} }}", input)).unwrap();
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let arms = match expr {
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syn::Expr::Match(syn::ExprMatch { arms, .. }) => arms,
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_ => panic!("expected a match expression, got {:?}", expr)
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};
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max_len(arms.into_iter().flat_map(|arm| arm.pats).filter_map(|pattern| {
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let expr = match pattern {
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syn::Pat::Lit(expr) => expr,
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syn::Pat::Wild(_) => return None,
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_ => panic!("expected string or wildcard pattern, got {:?}", pattern)
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};
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match *expr.expr {
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syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Str(ref lit), .. }) => {
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assert_eq!(lit.value(), lit.value().to_ascii_lowercase(),
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"string patterns must be given in ASCII lowercase");
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Some(lit.value().len())
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}
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_ => panic!("expected string pattern, got {:?}", expr)
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}
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}))
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}
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/// Input: string literals with no separator
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///
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/// Output: a `MAX_LENGTH` constant with the length of the longest string.
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#[allow(non_snake_case)]
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pub fn cssparser_internal__max_len(input: &str) -> String {
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max_len(syn::parse_str::<TokenStream>(input).unwrap().into_iter().map(|tt| string_literal(&tt).len()))
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}
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/// Input: parsed as token trees. The first TT is a type. (Can be wrapped in parens.)
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/// following TTs are grouped in pairs, each pair being a key as a string literal
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/// and the corresponding value as a const expression.
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///
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/// Output: a rust-phf map, with keys ASCII-lowercased:
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/// ```text
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/// static MAP: &'static ::cssparser::phf::Map<&'static str, $ValueType> = …;
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/// ```
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#[allow(non_snake_case)]
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pub fn cssparser_internal__phf_map(input: &str) -> String {
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let token_trees: Vec<TokenTree> = syn::parse_str::<TokenStream>(input).unwrap().into_iter().collect();
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let value_type = &token_trees[0];
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let pairs: Vec<_> = token_trees[1..].chunks(2).map(|chunk| {
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let key = string_literal(&chunk[0]);
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let value = &chunk[1];
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(key.to_ascii_lowercase(), quote!(#value).to_string())
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}).collect();
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let mut map = phf_codegen::Map::new();
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map.phf_path("::cssparser::_internal__phf");
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for &(ref key, ref value) in &pairs {
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map.entry(&**key, &**value);
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}
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let mut tokens = quote! {
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static MAP: ::cssparser::_internal__phf::Map<&'static str, #value_type> =
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};
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let mut initializer_bytes = Vec::new();
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map.build(&mut initializer_bytes).unwrap();
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tokens.append_all(syn::parse_str::<syn::Expr>(::std::str::from_utf8(&initializer_bytes).unwrap()));
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tokens.append_all(quote!(;));
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tokens.to_string()
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}
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}
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fn max_len<I: Iterator<Item=usize>>(lengths: I) -> String {
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let max_length = lengths.max().expect("expected at least one string");
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quote!( const MAX_LENGTH: usize = #max_length; ).to_string()
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}
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fn string_literal(token: &TokenTree) -> String {
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let lit: syn::LitStr = syn::parse2(iter::once(token.clone()).collect()).expect(&format!("expected string literal, got {:?}", token));
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lit.value()
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}
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