ruff/crates/ruff_python_ast/src/token/tokens.rs

517 lines
18 KiB
Rust

use std::{iter::FusedIterator, ops::Deref};
use super::{Token, TokenKind};
use ruff_python_trivia::CommentRanges;
use ruff_text_size::{Ranged as _, TextRange, TextSize};
/// Tokens represents a vector of lexed [`Token`].
#[derive(Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "get-size", derive(get_size2::GetSize))]
pub struct Tokens {
raw: Vec<Token>,
}
impl Tokens {
pub fn new(tokens: Vec<Token>) -> Tokens {
Tokens { raw: tokens }
}
/// Returns an iterator over all the tokens that provides context.
pub fn iter_with_context(&self) -> TokenIterWithContext<'_> {
TokenIterWithContext::new(&self.raw)
}
/// Performs a binary search to find the index of the **first** token that starts at the given `offset`.
///
/// Unlike `binary_search_by_key`, this method ensures that if multiple tokens start at the same offset,
/// it returns the index of the first one. Multiple tokens can start at the same offset in cases where
/// zero-length tokens are involved (like `Dedent` or `Newline` at the end of the file).
pub fn binary_search_by_start(&self, offset: TextSize) -> Result<usize, usize> {
let partition_point = self.partition_point(|token| token.start() < offset);
let after = &self[partition_point..];
if after.first().is_some_and(|first| first.start() == offset) {
Ok(partition_point)
} else {
Err(partition_point)
}
}
/// Returns a slice of [`Token`] that are within the given `range`.
///
/// The start and end offset of the given range should be either:
/// 1. Token boundary
/// 2. Gap between the tokens
///
/// For example, considering the following tokens and their corresponding range:
///
/// | Token | Range |
/// |---------------------|-----------|
/// | `Def` | `0..3` |
/// | `Name` | `4..7` |
/// | `Lpar` | `7..8` |
/// | `Rpar` | `8..9` |
/// | `Colon` | `9..10` |
/// | `Newline` | `10..11` |
/// | `Comment` | `15..24` |
/// | `NonLogicalNewline` | `24..25` |
/// | `Indent` | `25..29` |
/// | `Pass` | `29..33` |
///
/// Here, for (1) a token boundary is considered either the start or end offset of any of the
/// above tokens. For (2), the gap would be any offset between the `Newline` and `Comment`
/// token which are 12, 13, and 14.
///
/// Examples:
/// 1) `4..10` would give `Name`, `Lpar`, `Rpar`, `Colon`
/// 2) `11..25` would give `Comment`, `NonLogicalNewline`
/// 3) `12..25` would give same as (2) and offset 12 is in the "gap"
/// 4) `9..12` would give `Colon`, `Newline` and offset 12 is in the "gap"
/// 5) `18..27` would panic because both the start and end offset is within a token
///
/// ## Note
///
/// The returned slice can contain the [`TokenKind::Unknown`] token if there was a lexical
/// error encountered within the given range.
///
/// # Panics
///
/// If either the start or end offset of the given range is within a token range.
pub fn in_range(&self, range: TextRange) -> &[Token] {
let tokens_after_start = self.after(range.start());
Self::before_impl(tokens_after_start, range.end())
}
/// Searches the token(s) at `offset`.
///
/// Returns [`TokenAt::Between`] if `offset` points directly inbetween two tokens
/// (the left token ends at `offset` and the right token starts at `offset`).
pub fn at_offset(&self, offset: TextSize) -> TokenAt {
match self.binary_search_by_start(offset) {
// The token at `index` starts exactly at `offset.
// ```python
// object.attribute
// ^ OFFSET
// ```
Ok(index) => {
let token = self[index];
// `token` starts exactly at `offset`. Test if the offset is right between
// `token` and the previous token (if there's any)
if let Some(previous) = index.checked_sub(1).map(|idx| self[idx]) {
if previous.end() == offset {
return TokenAt::Between(previous, token);
}
}
TokenAt::Single(token)
}
// No token found that starts exactly at the given offset. But it's possible that
// the token starting before `offset` fully encloses `offset` (it's end range ends after `offset`).
// ```python
// object.attribute
// ^ OFFSET
// # or
// if True:
// print("test")
// ^ OFFSET
// ```
Err(index) => {
if let Some(previous) = index.checked_sub(1).map(|idx| self[idx]) {
if previous.range().contains_inclusive(offset) {
return TokenAt::Single(previous);
}
}
TokenAt::None
}
}
}
/// Returns a slice of tokens before the given [`TextSize`] offset.
///
/// If the given offset is between two tokens, the returned slice will end just before the
/// following token. In other words, if the offset is between the end of previous token and
/// start of next token, the returned slice will end just before the next token.
///
/// # Panics
///
/// If the given offset is inside a token range at any point
/// other than the start of the range.
pub fn before(&self, offset: TextSize) -> &[Token] {
Self::before_impl(&self.raw, offset)
}
fn before_impl(tokens: &[Token], offset: TextSize) -> &[Token] {
let partition_point = tokens.partition_point(|token| token.start() < offset);
let before = &tokens[..partition_point];
if let Some(last) = before.last() {
// If it's equal to the end offset, then it's at a token boundary which is
// valid. If it's greater than the end offset, then it's in the gap between
// the tokens which is valid as well.
assert!(
offset >= last.end(),
"Offset {offset:?} is inside token `{last:?}`",
);
}
before
}
/// Returns a slice of tokens after the given [`TextSize`] offset.
///
/// If the given offset is between two tokens, the returned slice will start from the following
/// token. In other words, if the offset is between the end of previous token and start of next
/// token, the returned slice will start from the next token.
///
/// # Panics
///
/// If the given offset is inside a token range at any point
/// other than the start of the range.
pub fn after(&self, offset: TextSize) -> &[Token] {
let partition_point = self.partition_point(|token| token.end() <= offset);
let after = &self[partition_point..];
if let Some(first) = after.first() {
// valid. If it's greater than the end offset, then it's in the gap between
// the tokens which is valid as well.
assert!(
offset <= first.start(),
"Offset {offset:?} is inside token `{first:?}`",
);
}
after
}
}
impl<'a> IntoIterator for &'a Tokens {
type Item = &'a Token;
type IntoIter = std::slice::Iter<'a, Token>;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
impl Deref for Tokens {
type Target = [Token];
fn deref(&self) -> &Self::Target {
&self.raw
}
}
/// A token that encloses a given offset or ends exactly at it.
#[derive(Debug, Clone)]
pub enum TokenAt {
/// There's no token at the given offset
None,
/// There's a single token at the given offset.
Single(Token),
/// The offset falls exactly between two tokens. E.g. `CURSOR` in `call<CURSOR>(arguments)` is
/// positioned exactly between the `call` and `(` tokens.
Between(Token, Token),
}
impl Iterator for TokenAt {
type Item = Token;
fn next(&mut self) -> Option<Self::Item> {
match *self {
TokenAt::None => None,
TokenAt::Single(token) => {
*self = TokenAt::None;
Some(token)
}
TokenAt::Between(first, second) => {
*self = TokenAt::Single(second);
Some(first)
}
}
}
}
impl FusedIterator for TokenAt {}
impl From<&Tokens> for CommentRanges {
fn from(tokens: &Tokens) -> Self {
let mut ranges = vec![];
for token in tokens {
if token.kind() == TokenKind::Comment {
ranges.push(token.range());
}
}
CommentRanges::new(ranges)
}
}
/// An iterator over the [`Token`]s with context.
///
/// This struct is created by the [`iter_with_context`] method on [`Tokens`]. Refer to its
/// documentation for more details.
///
/// [`iter_with_context`]: Tokens::iter_with_context
#[derive(Debug, Clone)]
pub struct TokenIterWithContext<'a> {
inner: std::slice::Iter<'a, Token>,
nesting: u32,
}
impl<'a> TokenIterWithContext<'a> {
fn new(tokens: &'a [Token]) -> TokenIterWithContext<'a> {
TokenIterWithContext {
inner: tokens.iter(),
nesting: 0,
}
}
/// Return the nesting level the iterator is currently in.
pub const fn nesting(&self) -> u32 {
self.nesting
}
/// Returns `true` if the iterator is within a parenthesized context.
pub const fn in_parenthesized_context(&self) -> bool {
self.nesting > 0
}
/// Returns the next [`Token`] in the iterator without consuming it.
pub fn peek(&self) -> Option<&'a Token> {
self.clone().next()
}
}
impl<'a> Iterator for TokenIterWithContext<'a> {
type Item = &'a Token;
fn next(&mut self) -> Option<Self::Item> {
let token = self.inner.next()?;
match token.kind() {
TokenKind::Lpar | TokenKind::Lbrace | TokenKind::Lsqb => self.nesting += 1,
TokenKind::Rpar | TokenKind::Rbrace | TokenKind::Rsqb => {
self.nesting = self.nesting.saturating_sub(1);
}
// This mimics the behavior of re-lexing which reduces the nesting level on the lexer.
// We don't need to reduce it by 1 because unlike the lexer we see the final token
// after recovering from every unclosed parenthesis.
TokenKind::Newline if self.nesting > 0 => {
self.nesting = 0;
}
_ => {}
}
Some(token)
}
}
impl FusedIterator for TokenIterWithContext<'_> {}
#[cfg(test)]
mod tests {
use std::ops::Range;
use ruff_text_size::TextSize;
use crate::token::{Token, TokenFlags, TokenKind};
use super::*;
/// Test case containing a "gap" between two tokens.
///
/// Code: <https://play.ruff.rs/a3658340-6df8-42c5-be80-178744bf1193>
const TEST_CASE_WITH_GAP: [(TokenKind, Range<u32>); 10] = [
(TokenKind::Def, 0..3),
(TokenKind::Name, 4..7),
(TokenKind::Lpar, 7..8),
(TokenKind::Rpar, 8..9),
(TokenKind::Colon, 9..10),
(TokenKind::Newline, 10..11),
// Gap ||..||
(TokenKind::Comment, 15..24),
(TokenKind::NonLogicalNewline, 24..25),
(TokenKind::Indent, 25..29),
(TokenKind::Pass, 29..33),
// No newline at the end to keep the token set full of unique tokens
];
/// Helper function to create [`Tokens`] from an iterator of (kind, range).
fn new_tokens(tokens: impl Iterator<Item = (TokenKind, Range<u32>)>) -> Tokens {
Tokens::new(
tokens
.map(|(kind, range)| {
Token::new(
kind,
TextRange::new(TextSize::new(range.start), TextSize::new(range.end)),
TokenFlags::empty(),
)
})
.collect(),
)
}
#[test]
fn tokens_after_offset_at_token_start() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let after = tokens.after(TextSize::new(8));
assert_eq!(after.len(), 7);
assert_eq!(after.first().unwrap().kind(), TokenKind::Rpar);
}
#[test]
fn tokens_after_offset_at_token_end() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let after = tokens.after(TextSize::new(11));
assert_eq!(after.len(), 4);
assert_eq!(after.first().unwrap().kind(), TokenKind::Comment);
}
#[test]
fn tokens_after_offset_between_tokens() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let after = tokens.after(TextSize::new(13));
assert_eq!(after.len(), 4);
assert_eq!(after.first().unwrap().kind(), TokenKind::Comment);
}
#[test]
fn tokens_after_offset_at_last_token_end() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let after = tokens.after(TextSize::new(33));
assert_eq!(after.len(), 0);
}
#[test]
#[should_panic(expected = "Offset 5 is inside token `Name 4..7`")]
fn tokens_after_offset_inside_token() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
tokens.after(TextSize::new(5));
}
#[test]
fn tokens_before_offset_at_first_token_start() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(0));
assert_eq!(before.len(), 0);
}
#[test]
fn tokens_before_offset_after_first_token_gap() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(3));
assert_eq!(before.len(), 1);
assert_eq!(before.last().unwrap().kind(), TokenKind::Def);
}
#[test]
fn tokens_before_offset_at_second_token_start() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(4));
assert_eq!(before.len(), 1);
assert_eq!(before.last().unwrap().kind(), TokenKind::Def);
}
#[test]
fn tokens_before_offset_at_token_start() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(8));
assert_eq!(before.len(), 3);
assert_eq!(before.last().unwrap().kind(), TokenKind::Lpar);
}
#[test]
fn tokens_before_offset_at_token_end() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(11));
assert_eq!(before.len(), 6);
assert_eq!(before.last().unwrap().kind(), TokenKind::Newline);
}
#[test]
fn tokens_before_offset_between_tokens() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(13));
assert_eq!(before.len(), 6);
assert_eq!(before.last().unwrap().kind(), TokenKind::Newline);
}
#[test]
fn tokens_before_offset_at_last_token_end() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let before = tokens.before(TextSize::new(33));
assert_eq!(before.len(), 10);
assert_eq!(before.last().unwrap().kind(), TokenKind::Pass);
}
#[test]
#[should_panic(expected = "Offset 5 is inside token `Name 4..7`")]
fn tokens_before_offset_inside_token() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
tokens.before(TextSize::new(5));
}
#[test]
fn tokens_in_range_at_token_offset() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let in_range = tokens.in_range(TextRange::new(4.into(), 10.into()));
assert_eq!(in_range.len(), 4);
assert_eq!(in_range.first().unwrap().kind(), TokenKind::Name);
assert_eq!(in_range.last().unwrap().kind(), TokenKind::Colon);
}
#[test]
fn tokens_in_range_start_offset_at_token_end() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let in_range = tokens.in_range(TextRange::new(11.into(), 29.into()));
assert_eq!(in_range.len(), 3);
assert_eq!(in_range.first().unwrap().kind(), TokenKind::Comment);
assert_eq!(in_range.last().unwrap().kind(), TokenKind::Indent);
}
#[test]
fn tokens_in_range_end_offset_at_token_start() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let in_range = tokens.in_range(TextRange::new(8.into(), 15.into()));
assert_eq!(in_range.len(), 3);
assert_eq!(in_range.first().unwrap().kind(), TokenKind::Rpar);
assert_eq!(in_range.last().unwrap().kind(), TokenKind::Newline);
}
#[test]
fn tokens_in_range_start_offset_between_tokens() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let in_range = tokens.in_range(TextRange::new(13.into(), 29.into()));
assert_eq!(in_range.len(), 3);
assert_eq!(in_range.first().unwrap().kind(), TokenKind::Comment);
assert_eq!(in_range.last().unwrap().kind(), TokenKind::Indent);
}
#[test]
fn tokens_in_range_end_offset_between_tokens() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
let in_range = tokens.in_range(TextRange::new(9.into(), 13.into()));
assert_eq!(in_range.len(), 2);
assert_eq!(in_range.first().unwrap().kind(), TokenKind::Colon);
assert_eq!(in_range.last().unwrap().kind(), TokenKind::Newline);
}
#[test]
#[should_panic(expected = "Offset 5 is inside token `Name 4..7`")]
fn tokens_in_range_start_offset_inside_token() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
tokens.in_range(TextRange::new(5.into(), 10.into()));
}
#[test]
#[should_panic(expected = "Offset 6 is inside token `Name 4..7`")]
fn tokens_in_range_end_offset_inside_token() {
let tokens = new_tokens(TEST_CASE_WITH_GAP.into_iter());
tokens.in_range(TextRange::new(0.into(), 6.into()));
}
}