rust/crates/syntax/src/ast/token_ext.rs
2020-08-12 18:30:53 +02:00

539 lines
20 KiB
Rust

//! There are many AstNodes, but only a few tokens, so we hand-write them here.
use std::{
borrow::Cow,
convert::{TryFrom, TryInto},
};
use rustc_lexer::unescape::{unescape_literal, Mode};
use crate::{
ast::{AstToken, Comment, RawString, String, Whitespace},
TextRange, TextSize,
};
impl Comment {
pub fn kind(&self) -> CommentKind {
kind_by_prefix(self.text())
}
pub fn prefix(&self) -> &'static str {
for (prefix, k) in COMMENT_PREFIX_TO_KIND.iter() {
if *k == self.kind() && self.text().starts_with(prefix) {
return prefix;
}
}
unreachable!()
}
}
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct CommentKind {
pub shape: CommentShape,
pub doc: Option<CommentPlacement>,
}
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum CommentShape {
Line,
Block,
}
impl CommentShape {
pub fn is_line(self) -> bool {
self == CommentShape::Line
}
pub fn is_block(self) -> bool {
self == CommentShape::Block
}
}
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum CommentPlacement {
Inner,
Outer,
}
const COMMENT_PREFIX_TO_KIND: &[(&str, CommentKind)] = {
use {CommentPlacement::*, CommentShape::*};
&[
("////", CommentKind { shape: Line, doc: None }),
("///", CommentKind { shape: Line, doc: Some(Outer) }),
("//!", CommentKind { shape: Line, doc: Some(Inner) }),
("/**", CommentKind { shape: Block, doc: Some(Outer) }),
("/*!", CommentKind { shape: Block, doc: Some(Inner) }),
("//", CommentKind { shape: Line, doc: None }),
("/*", CommentKind { shape: Block, doc: None }),
]
};
fn kind_by_prefix(text: &str) -> CommentKind {
if text == "/**/" {
return CommentKind { shape: CommentShape::Block, doc: None };
}
for (prefix, kind) in COMMENT_PREFIX_TO_KIND.iter() {
if text.starts_with(prefix) {
return *kind;
}
}
panic!("bad comment text: {:?}", text)
}
impl Whitespace {
pub fn spans_multiple_lines(&self) -> bool {
let text = self.text();
text.find('\n').map_or(false, |idx| text[idx + 1..].contains('\n'))
}
}
pub struct QuoteOffsets {
pub quotes: (TextRange, TextRange),
pub contents: TextRange,
}
impl QuoteOffsets {
fn new(literal: &str) -> Option<QuoteOffsets> {
let left_quote = literal.find('"')?;
let right_quote = literal.rfind('"')?;
if left_quote == right_quote {
// `literal` only contains one quote
return None;
}
let start = TextSize::from(0);
let left_quote = TextSize::try_from(left_quote).unwrap() + TextSize::of('"');
let right_quote = TextSize::try_from(right_quote).unwrap();
let end = TextSize::of(literal);
let res = QuoteOffsets {
quotes: (TextRange::new(start, left_quote), TextRange::new(right_quote, end)),
contents: TextRange::new(left_quote, right_quote),
};
Some(res)
}
}
pub trait HasQuotes: AstToken {
fn quote_offsets(&self) -> Option<QuoteOffsets> {
let text = self.text().as_str();
let offsets = QuoteOffsets::new(text)?;
let o = self.syntax().text_range().start();
let offsets = QuoteOffsets {
quotes: (offsets.quotes.0 + o, offsets.quotes.1 + o),
contents: offsets.contents + o,
};
Some(offsets)
}
fn open_quote_text_range(&self) -> Option<TextRange> {
self.quote_offsets().map(|it| it.quotes.0)
}
fn close_quote_text_range(&self) -> Option<TextRange> {
self.quote_offsets().map(|it| it.quotes.1)
}
fn text_range_between_quotes(&self) -> Option<TextRange> {
self.quote_offsets().map(|it| it.contents)
}
}
impl HasQuotes for String {}
impl HasQuotes for RawString {}
pub trait HasStringValue: HasQuotes {
fn value(&self) -> Option<Cow<'_, str>>;
}
impl HasStringValue for String {
fn value(&self) -> Option<Cow<'_, str>> {
let text = self.text().as_str();
let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
let mut buf = std::string::String::with_capacity(text.len());
let mut has_error = false;
unescape_literal(text, Mode::Str, &mut |_, unescaped_char| match unescaped_char {
Ok(c) => buf.push(c),
Err(_) => has_error = true,
});
if has_error {
return None;
}
// FIXME: don't actually allocate for borrowed case
let res = if buf == text { Cow::Borrowed(text) } else { Cow::Owned(buf) };
Some(res)
}
}
impl HasStringValue for RawString {
fn value(&self) -> Option<Cow<'_, str>> {
let text = self.text().as_str();
let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
Some(Cow::Borrowed(text))
}
}
impl RawString {
pub fn map_range_up(&self, range: TextRange) -> Option<TextRange> {
let contents_range = self.text_range_between_quotes()?;
assert!(TextRange::up_to(contents_range.len()).contains_range(range));
Some(range + contents_range.start())
}
}
#[derive(Debug)]
pub enum FormatSpecifier {
Open,
Close,
Integer,
Identifier,
Colon,
Fill,
Align,
Sign,
NumberSign,
Zero,
DollarSign,
Dot,
Asterisk,
QuestionMark,
}
pub trait HasFormatSpecifier: AstToken {
fn char_ranges(
&self,
) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>>;
fn lex_format_specifier<F>(&self, mut callback: F)
where
F: FnMut(TextRange, FormatSpecifier),
{
let char_ranges = if let Some(char_ranges) = self.char_ranges() {
char_ranges
} else {
return;
};
let mut chars = char_ranges.iter().peekable();
while let Some((range, first_char)) = chars.next() {
match first_char {
Ok('{') => {
// Format specifier, see syntax at https://doc.rust-lang.org/std/fmt/index.html#syntax
if let Some((_, Ok('{'))) = chars.peek() {
// Escaped format specifier, `{{`
chars.next();
continue;
}
callback(*range, FormatSpecifier::Open);
// check for integer/identifier
match chars
.peek()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default()
{
'0'..='9' => {
// integer
read_integer(&mut chars, &mut callback);
}
c if c == '_' || c.is_alphabetic() => {
// identifier
read_identifier(&mut chars, &mut callback);
}
_ => {}
}
if let Some((_, Ok(':'))) = chars.peek() {
skip_char_and_emit(&mut chars, FormatSpecifier::Colon, &mut callback);
// check for fill/align
let mut cloned = chars.clone().take(2);
let first = cloned
.next()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default();
let second = cloned
.next()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default();
match second {
'<' | '^' | '>' => {
// alignment specifier, first char specifies fillment
skip_char_and_emit(
&mut chars,
FormatSpecifier::Fill,
&mut callback,
);
skip_char_and_emit(
&mut chars,
FormatSpecifier::Align,
&mut callback,
);
}
_ => match first {
'<' | '^' | '>' => {
skip_char_and_emit(
&mut chars,
FormatSpecifier::Align,
&mut callback,
);
}
_ => {}
},
}
// check for sign
match chars
.peek()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default()
{
'+' | '-' => {
skip_char_and_emit(
&mut chars,
FormatSpecifier::Sign,
&mut callback,
);
}
_ => {}
}
// check for `#`
if let Some((_, Ok('#'))) = chars.peek() {
skip_char_and_emit(
&mut chars,
FormatSpecifier::NumberSign,
&mut callback,
);
}
// check for `0`
let mut cloned = chars.clone().take(2);
let first = cloned.next().and_then(|next| next.1.as_ref().ok()).copied();
let second = cloned.next().and_then(|next| next.1.as_ref().ok()).copied();
if first == Some('0') && second != Some('$') {
skip_char_and_emit(&mut chars, FormatSpecifier::Zero, &mut callback);
}
// width
match chars
.peek()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default()
{
'0'..='9' => {
read_integer(&mut chars, &mut callback);
if let Some((_, Ok('$'))) = chars.peek() {
skip_char_and_emit(
&mut chars,
FormatSpecifier::DollarSign,
&mut callback,
);
}
}
c if c == '_' || c.is_alphabetic() => {
read_identifier(&mut chars, &mut callback);
// can be either width (indicated by dollar sign, or type in which case
// the next sign has to be `}`)
let next =
chars.peek().and_then(|next| next.1.as_ref().ok()).copied();
match next {
Some('$') => skip_char_and_emit(
&mut chars,
FormatSpecifier::DollarSign,
&mut callback,
),
Some('}') => {
skip_char_and_emit(
&mut chars,
FormatSpecifier::Close,
&mut callback,
);
continue;
}
_ => continue,
};
}
_ => {}
}
// precision
if let Some((_, Ok('.'))) = chars.peek() {
skip_char_and_emit(&mut chars, FormatSpecifier::Dot, &mut callback);
match chars
.peek()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default()
{
'*' => {
skip_char_and_emit(
&mut chars,
FormatSpecifier::Asterisk,
&mut callback,
);
}
'0'..='9' => {
read_integer(&mut chars, &mut callback);
if let Some((_, Ok('$'))) = chars.peek() {
skip_char_and_emit(
&mut chars,
FormatSpecifier::DollarSign,
&mut callback,
);
}
}
c if c == '_' || c.is_alphabetic() => {
read_identifier(&mut chars, &mut callback);
if chars.peek().and_then(|next| next.1.as_ref().ok()).copied()
!= Some('$')
{
continue;
}
skip_char_and_emit(
&mut chars,
FormatSpecifier::DollarSign,
&mut callback,
);
}
_ => {
continue;
}
}
}
// type
match chars
.peek()
.and_then(|next| next.1.as_ref().ok())
.copied()
.unwrap_or_default()
{
'?' => {
skip_char_and_emit(
&mut chars,
FormatSpecifier::QuestionMark,
&mut callback,
);
}
c if c == '_' || c.is_alphabetic() => {
read_identifier(&mut chars, &mut callback);
}
_ => {}
}
}
if let Some((_, Ok('}'))) = chars.peek() {
skip_char_and_emit(&mut chars, FormatSpecifier::Close, &mut callback);
} else {
continue;
}
}
_ => {
while let Some((_, Ok(next_char))) = chars.peek() {
match next_char {
'{' => break,
_ => {}
}
chars.next();
}
}
};
}
fn skip_char_and_emit<'a, I, F>(
chars: &mut std::iter::Peekable<I>,
emit: FormatSpecifier,
callback: &mut F,
) where
I: Iterator<Item = &'a (TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>,
F: FnMut(TextRange, FormatSpecifier),
{
let (range, _) = chars.next().unwrap();
callback(*range, emit);
}
fn read_integer<'a, I, F>(chars: &mut std::iter::Peekable<I>, callback: &mut F)
where
I: Iterator<Item = &'a (TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>,
F: FnMut(TextRange, FormatSpecifier),
{
let (mut range, c) = chars.next().unwrap();
assert!(c.as_ref().unwrap().is_ascii_digit());
while let Some((r, Ok(next_char))) = chars.peek() {
if next_char.is_ascii_digit() {
chars.next();
range = range.cover(*r);
} else {
break;
}
}
callback(range, FormatSpecifier::Integer);
}
fn read_identifier<'a, I, F>(chars: &mut std::iter::Peekable<I>, callback: &mut F)
where
I: Iterator<Item = &'a (TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>,
F: FnMut(TextRange, FormatSpecifier),
{
let (mut range, c) = chars.next().unwrap();
assert!(c.as_ref().unwrap().is_alphabetic() || *c.as_ref().unwrap() == '_');
while let Some((r, Ok(next_char))) = chars.peek() {
if *next_char == '_' || next_char.is_ascii_digit() || next_char.is_alphabetic() {
chars.next();
range = range.cover(*r);
} else {
break;
}
}
callback(range, FormatSpecifier::Identifier);
}
}
}
impl HasFormatSpecifier for String {
fn char_ranges(
&self,
) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>> {
let text = self.text().as_str();
let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
let offset = self.text_range_between_quotes()?.start() - self.syntax().text_range().start();
let mut res = Vec::with_capacity(text.len());
unescape_literal(text, Mode::Str, &mut |range, unescaped_char| {
res.push((
TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap())
+ offset,
unescaped_char,
))
});
Some(res)
}
}
impl HasFormatSpecifier for RawString {
fn char_ranges(
&self,
) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>> {
let text = self.text().as_str();
let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
let offset = self.text_range_between_quotes()?.start() - self.syntax().text_range().start();
let mut res = Vec::with_capacity(text.len());
for (idx, c) in text.char_indices() {
res.push((TextRange::at(idx.try_into().unwrap(), TextSize::of(c)) + offset, Ok(c)));
}
Some(res)
}
}