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use anyhow::{anyhow, Result};
use lazy_static::lazy_static;
use regex::Regex;
use std::fs;
use tree_sitter::{Language, Parser, Point};
lazy_static! {
static ref CAPTURE_NAME_REGEX: Regex = Regex::new("[\\w_\\-.]+").unwrap();
}
#[derive(Debug, Eq, PartialEq)]
pub struct CaptureInfo {
pub name: String,
pub start: Point,
pub end: Point,
}
#[derive(Debug, PartialEq, Eq)]
pub struct Assertion {
pub position: Point,
pub expected_capture_name: String,
}
/// Parse the given source code, finding all of the comments that contain
/// highlighting assertions. Return a vector of (position, expected highlight name)
/// pairs.
pub fn parse_position_comments(
parser: &mut Parser,
language: Language,
source: &[u8],
) -> Result<Vec<Assertion>> {
let mut result = Vec::new();
let mut assertion_ranges = Vec::new();
// Parse the code.
parser.set_included_ranges(&[]).unwrap();
parser.set_language(language).unwrap();
let tree = parser.parse(source, None).unwrap();
// Walk the tree, finding comment nodes that contain assertions.
let mut ascending = false;
let mut cursor = tree.root_node().walk();
loop {
if ascending {
let node = cursor.node();
// Find every comment node.
if node.kind().contains("comment") {
if let Ok(text) = node.utf8_text(source) {
let mut position = node.start_position();
if position.row > 0 {
// Find the arrow character ("^" or '<-") in the comment. A left arrow
// refers to the column where the comment node starts. An up arrow refers
// to its own column.
let mut has_left_caret = false;
let mut has_arrow = false;
let mut arrow_end = 0;
for (i, c) in text.char_indices() {
arrow_end = i + 1;
if c == '-' && has_left_caret {
has_arrow = true;
break;
}
if c == '^' {
has_arrow = true;
position.column += i;
break;
}
has_left_caret = c == '<';
}
// If the comment node contains an arrow and a highlight name, record the
// highlight name and the position.
if let (true, Some(mat)) =
(has_arrow, CAPTURE_NAME_REGEX.find(&text[arrow_end..]))
{
assertion_ranges.push((node.start_position(), node.end_position()));
result.push(Assertion {
position: position,
expected_capture_name: mat.as_str().to_string(),
});
}
}
}
}
// Continue walking the tree.
if cursor.goto_next_sibling() {
ascending = false;
} else if !cursor.goto_parent() {
break;
}
} else if !cursor.goto_first_child() {
ascending = true;
}
}
// Adjust the row number in each assertion's position to refer to the line of
// code *above* the assertion. There can be multiple lines of assertion comments,
// so the positions may have to be decremented by more than one row.
let mut i = 0;
for assertion in result.iter_mut() {
loop {
let on_assertion_line = assertion_ranges[i..]
.iter()
.any(|(start, _)| start.row == assertion.position.row);
if on_assertion_line {
assertion.position.row -= 1;
} else {
while i < assertion_ranges.len()
&& assertion_ranges[i].0.row < assertion.position.row
{
i += 1;
}
break;
}
}
}
// The assertions can end up out of order due to the line adjustments.
result.sort_unstable_by_key(|a| a.position);
Ok(result)
}
pub fn assert_expected_captures(
infos: Vec<CaptureInfo>,
path: String,
parser: &mut Parser,
language: Language,
) -> Result<()> {
let contents = fs::read_to_string(path)?;
let pairs = parse_position_comments(parser, language, contents.as_bytes())?;
for info in &infos {
if let Some(found) = pairs.iter().find(|p| {
p.position.row == info.start.row && p.position >= info.start && p.position < info.end
}) {
if found.expected_capture_name != info.name && info.name != "name" {
Err(anyhow!(
"Assertion failed: at {}, found {}, expected {}",
info.start,
found.expected_capture_name,
info.name
))?
}
}
}
Ok(())
}