badmanners/maud
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Pre-allocate sufficient size for our output String

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This commit is contained in:
Coleman McFarland 2018-04-16 01:06:19 -07:00
parent 2d6558c769
commit f75da83a60
1 changed files with 4 additions and 6 deletions

10
maud_macros/src/lib.rs
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@ -10,7 +10,7 @@ extern crate proc_macro;
mod parse;
mod build;
use proc_macro::{Span, Term, TokenStream, TokenTree};
use proc_macro::{Literal, Span, Term, TokenStream, TokenTree};
use proc_macro::quote;
type ParseResult<T> = Result<T, String>;
@ -32,17 +32,15 @@ fn expand(input: TokenStream) -> TokenStream {
let output_ident = TokenTree::Term(Term::new("__maud_output", Span::def_site()));
// Heuristic: the size of the resulting markup tends to correlate with the
// code size of the template itself
//
// NOTE: can't get this to compile inside quote!
//let size_hint = Literal::u64_unsuffixed(size_hint as u64);
let size_hint = input.to_string().len();
let size_hint = TokenTree::Literal(Literal::u64_unsuffixed(size_hint as u64));
let stmts = match parse::parse(input, output_ident.clone()) {
Ok(stmts) => stmts,
Err(e) => panic!(e),
};
quote!({
extern crate maud;
//let mut $output_ident = String::with_capacity($size_hint as usize);
let mut $output_ident = String::new();
let mut $output_ident = String::with_capacity($size_hint as usize);
$stmts
maud::PreEscaped($output_ident)
})