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use std::collections::HashMap;
use std::cell::RefCell;
use std::sync::Arc;
use grep_matcher::{Match, Matcher, NoError};
use regex::bytes::{CaptureLocations, Regex};
use thread_local::CachedThreadLocal;
use config::ConfiguredHIR;
use error::Error;
use matcher::RegexCaptures;
/// A matcher for implementing "word match" semantics.
#[derive(Debug)]
pub struct WordMatcher {
/// The regex which is roughly `(?:^|\W)(<original pattern>)(?:$|\W)`.
regex: Regex,
/// A map from capture group name to capture group index.
names: HashMap<String, usize>,
/// A reusable buffer for finding the match location of the inner group.
locs: Arc<CachedThreadLocal<RefCell<CaptureLocations>>>,
}
impl Clone for WordMatcher {
fn clone(&self) -> WordMatcher {
// We implement Clone manually so that we get a fresh CachedThreadLocal
// such that it can set its own thread owner. This permits each thread
// usings `locs` to hit the fast path.
WordMatcher {
regex: self.regex.clone(),
names: self.names.clone(),
locs: Arc::new(CachedThreadLocal::new()),
}
}
}
impl WordMatcher {
/// Create a new matcher from the given pattern that only produces matches
/// that are considered "words."
///
/// The given options are used to construct the regular expression
/// internally.
pub fn new(expr: &ConfiguredHIR) -> Result<WordMatcher, Error> {
let word_expr = expr.with_pattern(|pat| {
format!(r"(?:(?m:^)|\W)({})(?:(?m:$)|\W)", pat)
})?;
let regex = word_expr.regex()?;
let locs = Arc::new(CachedThreadLocal::new());
let mut names = HashMap::new();
for (i, optional_name) in regex.capture_names().enumerate() {
if let Some(name) = optional_name {
names.insert(name.to_string(), i.checked_sub(1).unwrap());
}
}
Ok(WordMatcher { regex, names, locs })
}
}
impl Matcher for WordMatcher {
type Captures = RegexCaptures;
type Error = NoError;
fn find_at(
&self,
haystack: &[u8],
at: usize,
) -> Result<Option<Match>, NoError> {
// To make this easy to get right, we extract captures here instead of
// calling `find_at`. The actual match is at capture group `1` instead
// of `0`. We *could* use `find_at` here and then trim the match after
// the fact, but that's a bit harder to get right, and it's not clear
// if it's worth it.
let cell = self.locs.get_or(|| {
Box::new(RefCell::new(self.regex.capture_locations()))
});
let mut caps = cell.borrow_mut();
self.regex.captures_read_at(&mut caps, haystack, at);
Ok(caps.get(1).map(|m| Match::new(m.0, m.1)))
}
fn new_captures(&self) -> Result<RegexCaptures, NoError> {
Ok(RegexCaptures::with_offset(self.regex.capture_locations(), 1))
}
fn capture_count(&self) -> usize {
self.regex.captures_len().checked_sub(1).unwrap()
}
fn capture_index(&self, name: &str) -> Option<usize> {
self.names.get(name).map(|i| *i)
}
fn captures_at(
&self,
haystack: &[u8],
at: usize,
caps: &mut RegexCaptures,
) -> Result<bool, NoError> {
let r = self.regex.captures_read_at(caps.locations(), haystack, at);
Ok(r.is_some())
}
// We specifically do not implement other methods like find_iter or
// captures_iter. Namely, the iter methods are guaranteed to be correct
// by virtue of implementing find_at and captures_at above.
}
#[cfg(test)]
mod tests {
use grep_matcher::{Captures, Match, Matcher};
use config::Config;
use super::WordMatcher;
fn matcher(pattern: &str) -> WordMatcher {
let chir = Config::default().hir(pattern).unwrap();
WordMatcher::new(&chir).unwrap()
}
fn find(pattern: &str, haystack: &str) -> Option<(usize, usize)> {
matcher(pattern)
.find(haystack.as_bytes())
.unwrap()
.map(|m| (m.start(), m.end()))
}
fn find_by_caps(pattern: &str, haystack: &str) -> Option<(usize, usize)> {
let m = matcher(pattern);
let mut caps = m.new_captures().unwrap();
if !m.captures(haystack.as_bytes(), &mut caps).unwrap() {
None
} else {
caps.get(0).map(|m| (m.start(), m.end()))
}
}
// Test that the standard `find` API reports offsets correctly.
#[test]
fn various_find() {
assert_eq!(Some((0, 3)), find(r"foo", "foo"));
assert_eq!(Some((0, 3)), find(r"foo", "foo("));
assert_eq!(Some((1, 4)), find(r"foo", "!foo("));
assert_eq!(None, find(r"foo", "!afoo("));
assert_eq!(Some((0, 3)), find(r"foo", "foo☃"));
assert_eq!(None, find(r"foo", "fooб"));
// assert_eq!(Some((0, 3)), find(r"foo", "fooб"));
// See: https://github.com/BurntSushi/ripgrep/issues/389
assert_eq!(Some((0, 2)), find(r"-2", "-2"));
}
// Test that the captures API also reports offsets correctly, just as
// find does. This exercises a different path in the code since captures
// are handled differently.
#[test]
fn various_captures() {
assert_eq!(Some((0, 3)), find_by_caps(r"foo", "foo"));
assert_eq!(Some((0, 3)), find_by_caps(r"foo", "foo("));
assert_eq!(Some((1, 4)), find_by_caps(r"foo", "!foo("));
assert_eq!(None, find_by_caps(r"foo", "!afoo("));
assert_eq!(Some((0, 3)), find_by_caps(r"foo", "foo☃"));
assert_eq!(None, find_by_caps(r"foo", "fooб"));
// assert_eq!(Some((0, 3)), find_by_caps(r"foo", "fooб"));
// See: https://github.com/BurntSushi/ripgrep/issues/389
assert_eq!(Some((0, 2)), find_by_caps(r"-2", "-2"));
}
// Test that the capture reporting methods work as advertised.
#[test]
fn capture_indexing() {
let m = matcher(r"(a)(?P<foo>b)(c)");
assert_eq!(4, m.capture_count());
assert_eq!(Some(2), m.capture_index("foo"));
let mut caps = m.new_captures().unwrap();
assert_eq!(4, caps.len());
assert!(m.captures(b"abc", &mut caps).unwrap());
assert_eq!(caps.get(0), Some(Match::new(0, 3)));
assert_eq!(caps.get(1), Some(Match::new(0, 1)));
assert_eq!(caps.get(2), Some(Match::new(1, 2)));
assert_eq!(caps.get(3), Some(Match::new(2, 3)));
assert_eq!(caps.get(4), None);
assert!(m.captures(b"#abc#", &mut caps).unwrap());
assert_eq!(caps.get(0), Some(Match::new(1, 4)));
assert_eq!(caps.get(1), Some(Match::new(1, 2)));
assert_eq!(caps.get(2), Some(Match::new(2, 3)));
assert_eq!(caps.get(3), Some(Match::new(3, 4)));
assert_eq!(caps.get(4), None);
}
}
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