From 65a1538dd149a6b343a1ebb69062ed5b332271aa Mon Sep 17 00:00:00 2001 From: Lukas Wirth Date: Sun, 2 Jan 2022 03:25:47 +0100 Subject: [PATCH] internal: Use basic NonEmptyVec in mbe::syntax_bridge --- crates/mbe/src/syntax_bridge.rs | 103 ++++++++++++++++--------------- crates/stdx/src/lib.rs | 1 + crates/stdx/src/non_empty_vec.rs | 45 ++++++++++++++ 3 files changed, 98 insertions(+), 51 deletions(-) create mode 100644 crates/stdx/src/non_empty_vec.rs diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs index 3b97bc8ba6..066b305205 100644 --- a/crates/mbe/src/syntax_bridge.rs +++ b/crates/mbe/src/syntax_bridge.rs @@ -1,6 +1,7 @@ //! Conversions between [`SyntaxNode`] and [`tt::TokenTree`]. use rustc_hash::{FxHashMap, FxHashSet}; +use stdx::non_empty_vec::NonEmptyVec; use syntax::{ ast::{self, make::tokens::doc_comment}, AstToken, Parse, PreorderWithTokens, SmolStr, SyntaxElement, SyntaxKind, @@ -141,25 +142,26 @@ fn convert_tokens(conv: &mut C) -> tt::Subtree { idx: !0, open_range: TextRange::empty(TextSize::of('.')), }; - let mut stack = vec![entry]; + let mut stack = NonEmptyVec::new(entry); loop { - let entry = stack.last_mut().unwrap(); - let result = &mut entry.subtree.token_trees; + let StackEntry { subtree, .. } = stack.last_mut(); + let result = &mut subtree.token_trees; let (token, range) = match conv.bump() { Some(it) => it, None => break, }; - let k: SyntaxKind = token.kind(&conv); - if k == COMMENT { + let kind = token.kind(&conv); + if kind == COMMENT { if let Some(tokens) = conv.convert_doc_comment(&token) { // FIXME: There has to be a better way to do this // Add the comments token id to the converted doc string let id = conv.id_alloc().alloc(range); result.extend(tokens.into_iter().map(|mut tt| { if let tt::TokenTree::Subtree(sub) = &mut tt { - if let tt::TokenTree::Leaf(tt::Leaf::Literal(lit)) = &mut sub.token_trees[2] + if let Some(tt::TokenTree::Leaf(tt::Leaf::Literal(lit))) = + sub.token_trees.get_mut(2) { lit.id = id } @@ -169,26 +171,26 @@ fn convert_tokens(conv: &mut C) -> tt::Subtree { } continue; } - - result.push(if k.is_punct() && k != UNDERSCORE { + let tt = if kind.is_punct() && kind != UNDERSCORE { assert_eq!(range.len(), TextSize::of('.')); - if let Some(delim) = entry.subtree.delimiter { + if let Some(delim) = subtree.delimiter { let expected = match delim.kind { tt::DelimiterKind::Parenthesis => T![')'], tt::DelimiterKind::Brace => T!['}'], tt::DelimiterKind::Bracket => T![']'], }; - if k == expected { - let entry = stack.pop().unwrap(); - conv.id_alloc().close_delim(entry.idx, Some(range)); - stack.last_mut().unwrap().subtree.token_trees.push(entry.subtree.into()); + if kind == expected { + if let Some(entry) = stack.pop() { + conv.id_alloc().close_delim(entry.idx, Some(range)); + stack.last_mut().subtree.token_trees.push(entry.subtree.into()); + } continue; } } - let delim = match k { + let delim = match kind { T!['('] => Some(tt::DelimiterKind::Parenthesis), T!['{'] => Some(tt::DelimiterKind::Brace), T!['['] => Some(tt::DelimiterKind::Bracket), @@ -201,36 +203,35 @@ fn convert_tokens(conv: &mut C) -> tt::Subtree { subtree.delimiter = Some(tt::Delimiter { id, kind }); stack.push(StackEntry { subtree, idx, open_range: range }); continue; - } else { - let spacing = match conv.peek() { - Some(next) - if next.kind(&conv).is_trivia() - || next.kind(&conv) == T!['['] - || next.kind(&conv) == T!['{'] - || next.kind(&conv) == T!['('] => - { - tt::Spacing::Alone - } - Some(next) if next.kind(&conv).is_punct() && next.kind(&conv) != UNDERSCORE => { - tt::Spacing::Joint - } - _ => tt::Spacing::Alone, - }; - let char = match token.to_char(&conv) { - Some(c) => c, - None => { - panic!("Token from lexer must be single char: token = {:#?}", token); - } - }; - tt::Leaf::from(tt::Punct { char, spacing, id: conv.id_alloc().alloc(range) }).into() } + + let spacing = match conv.peek().map(|next| next.kind(&conv)) { + Some(kind) + if !kind.is_trivia() + && kind.is_punct() + && kind != T!['['] + && kind != T!['{'] + && kind != T!['('] + && kind != UNDERSCORE => + { + tt::Spacing::Joint + } + _ => tt::Spacing::Alone, + }; + let char = match token.to_char(&conv) { + Some(c) => c, + None => { + panic!("Token from lexer must be single char: token = {:#?}", token); + } + }; + tt::Leaf::from(tt::Punct { char, spacing, id: conv.id_alloc().alloc(range) }).into() } else { macro_rules! make_leaf { ($i:ident) => { tt::$i { id: conv.id_alloc().alloc(range), text: token.to_text(conv) }.into() }; } - let leaf: tt::Leaf = match k { + let leaf: tt::Leaf = match kind { T![true] | T![false] => make_leaf!(Ident), IDENT => make_leaf!(Ident), UNDERSCORE => make_leaf!(Ident), @@ -258,15 +259,15 @@ fn convert_tokens(conv: &mut C) -> tt::Subtree { }; leaf.into() - }); + }; + result.push(tt); } // If we get here, we've consumed all input tokens. // We might have more than one subtree in the stack, if the delimiters are improperly balanced. // Merge them so we're left with one. - while stack.len() > 1 { - let entry = stack.pop().unwrap(); - let parent = stack.last_mut().unwrap(); + while let Some(entry) = stack.pop() { + let parent = stack.last_mut(); conv.id_alloc().close_delim(entry.idx, None); let leaf: tt::Leaf = tt::Punct { @@ -283,13 +284,12 @@ fn convert_tokens(conv: &mut C) -> tt::Subtree { parent.subtree.token_trees.extend(entry.subtree.token_trees); } - let subtree = stack.pop().unwrap().subtree; - if subtree.token_trees.len() == 1 { - if let tt::TokenTree::Subtree(first) = &subtree.token_trees[0] { - return first.clone(); - } + let subtree = stack.into_first().subtree; + if let [tt::TokenTree::Subtree(first)] = &*subtree.token_trees { + first.clone() + } else { + subtree } - subtree } /// Returns the textual content of a doc comment block as a quoted string @@ -320,7 +320,8 @@ fn convert_doc_comment(token: &syntax::SyntaxToken) -> Option let meta_tkns = vec![mk_ident("doc"), mk_punct('='), mk_doc_literal(&comment)]; // Make `#![]` - let mut token_trees = vec![mk_punct('#')]; + let mut token_trees = Vec::with_capacity(3); + token_trees.push(mk_punct('#')); if let ast::CommentPlacement::Inner = doc { token_trees.push(mk_punct('!')); } @@ -439,8 +440,8 @@ impl<'a> SrcToken> for usize { impl<'a> TokenConvertor for RawConvertor<'a> { type Token = usize; - fn convert_doc_comment(&self, token: &usize) -> Option> { - let text = self.lexed.text(*token); + fn convert_doc_comment(&self, &token: &usize) -> Option> { + let text = self.lexed.text(token); convert_doc_comment(&doc_comment(text)) } @@ -568,9 +569,9 @@ impl TokenConvertor for Convertor<'_> { } self.current = Self::next_token(&mut self.preorder, self.censor); let token = if curr.kind().is_punct() { + self.punct_offset = Some((curr.clone(), 0.into())); let range = curr.text_range(); let range = TextRange::at(range.start(), TextSize::of('.')); - self.punct_offset = Some((curr.clone(), 0.into())); (SynToken::Punch(curr, 0.into()), range) } else { self.punct_offset = None; diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs index e33b45cc8e..16b8558f41 100644 --- a/crates/stdx/src/lib.rs +++ b/crates/stdx/src/lib.rs @@ -5,6 +5,7 @@ use std::{cmp::Ordering, ops, time::Instant}; mod macros; pub mod process; pub mod panic_context; +pub mod non_empty_vec; pub use always_assert::{always, never}; diff --git a/crates/stdx/src/non_empty_vec.rs b/crates/stdx/src/non_empty_vec.rs new file mode 100644 index 0000000000..199ee18b94 --- /dev/null +++ b/crates/stdx/src/non_empty_vec.rs @@ -0,0 +1,45 @@ +//! A [`Vec`] that is guaranteed to at least contain one element. + +pub struct NonEmptyVec(Vec); + +impl NonEmptyVec { + #[inline] + pub fn new(initial: T) -> Self { + NonEmptyVec(vec![initial]) + } + + #[inline] + pub fn last_mut(&mut self) -> &mut T { + match self.0.last_mut() { + Some(it) => it, + None => unreachable!(), + } + } + + #[inline] + pub fn pop(&mut self) -> Option { + if self.0.len() <= 1 { + None + } else { + self.0.pop() + } + } + + #[inline] + pub fn push(&mut self, value: T) { + self.0.push(value) + } + + #[inline] + pub fn len(&self) -> usize { + self.0.len() + } + + #[inline] + pub fn into_first(mut self) -> T { + match self.0.pop() { + Some(it) => it, + None => unreachable!(), + } + } +}