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Merge pull request #340 from dtolnay/extend
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Reduce make_mut calls in FromIterator and Extend impls
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dtolnay authored Jul 25, 2022
2 parents f66898b + c5db3d6 commit ee0e583
Showing 1 changed file with 40 additions and 41 deletions.
81 changes: 40 additions & 41 deletions src/fallback.rs
Original file line number Diff line number Diff line change
Expand Up @@ -65,47 +65,45 @@ impl TokenStream {
fn take_inner(&mut self) -> Vec<TokenTree> {
mem::replace(Rc::make_mut(&mut self.inner), Vec::new())
}
}

fn push_token_from_proc_macro(&mut self, token: TokenTree) {
// https://github.com/dtolnay/proc-macro2/issues/235
match token {
#[cfg(not(no_bind_by_move_pattern_guard))]
TokenTree::Literal(crate::Literal {
#[cfg(wrap_proc_macro)]
inner: crate::imp::Literal::Fallback(literal),
#[cfg(not(wrap_proc_macro))]
inner: literal,
..
}) if literal.repr.starts_with('-') => {
push_negative_literal(self, literal);
}
#[cfg(no_bind_by_move_pattern_guard)]
TokenTree::Literal(crate::Literal {
#[cfg(wrap_proc_macro)]
inner: crate::imp::Literal::Fallback(literal),
#[cfg(not(wrap_proc_macro))]
inner: literal,
..
}) => {
if literal.repr.starts_with('-') {
push_negative_literal(self, literal);
} else {
Rc::make_mut(&mut self.inner)
.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
}
fn push_token_from_proc_macro(vec: &mut Vec<TokenTree>, token: TokenTree) {
// https://github.com/dtolnay/proc-macro2/issues/235
match token {
#[cfg(not(no_bind_by_move_pattern_guard))]
TokenTree::Literal(crate::Literal {
#[cfg(wrap_proc_macro)]
inner: crate::imp::Literal::Fallback(literal),
#[cfg(not(wrap_proc_macro))]
inner: literal,
..
}) if literal.repr.starts_with('-') => {
push_negative_literal(vec, literal);
}
#[cfg(no_bind_by_move_pattern_guard)]
TokenTree::Literal(crate::Literal {
#[cfg(wrap_proc_macro)]
inner: crate::imp::Literal::Fallback(literal),
#[cfg(not(wrap_proc_macro))]
inner: literal,
..
}) => {
if literal.repr.starts_with('-') {
push_negative_literal(vec, literal);
} else {
vec.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
}
_ => Rc::make_mut(&mut self.inner).push(token),
}
_ => vec.push(token),
}

#[cold]
fn push_negative_literal(stream: &mut TokenStream, mut literal: Literal) {
literal.repr.remove(0);
let mut punct = crate::Punct::new('-', Spacing::Alone);
punct.set_span(crate::Span::_new_stable(literal.span));
let inner = Rc::make_mut(&mut stream.inner);
inner.push(TokenTree::Punct(punct));
inner.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
}
#[cold]
fn push_negative_literal(vec: &mut Vec<TokenTree>, mut literal: Literal) {
literal.repr.remove(0);
let mut punct = crate::Punct::new('-', Spacing::Alone);
punct.set_span(crate::Span::_new_stable(literal.span));
vec.push(TokenTree::Punct(punct));
vec.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
}
}

Expand Down Expand Up @@ -246,9 +244,9 @@ impl From<TokenStream> for proc_macro::TokenStream {

impl From<TokenTree> for TokenStream {
fn from(tree: TokenTree) -> TokenStream {
let mut stream = TokenStream::new();
stream.push_token_from_proc_macro(tree);
stream
let mut stream = TokenStreamBuilder::new();
push_token_from_proc_macro(&mut stream.inner, tree);
stream.build()
}
}

Expand All @@ -274,9 +272,10 @@ impl FromIterator<TokenStream> for TokenStream {

impl Extend<TokenTree> for TokenStream {
fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, tokens: I) {
let vec = Rc::make_mut(&mut self.inner);
tokens
.into_iter()
.for_each(|token| self.push_token_from_proc_macro(token));
.for_each(|token| push_token_from_proc_macro(vec, token));
}
}

Expand Down

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