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Diffstat (limited to 'third_party/rust/regex-automata/src/util/prefilter/mod.rs')
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diff --git a/third_party/rust/regex-automata/src/util/prefilter/mod.rs b/third_party/rust/regex-automata/src/util/prefilter/mod.rs new file mode 100644 index 0000000000..51fc922337 --- /dev/null +++ b/third_party/rust/regex-automata/src/util/prefilter/mod.rs @@ -0,0 +1,696 @@ +/*! +Defines a prefilter for accelerating regex searches. + +A prefilter can be created by building a [`Prefilter`] value. + +A prefilter represents one of the most important optimizations available for +accelerating regex searches. The idea of a prefilter is to very quickly find +candidate locations in a haystack where a regex _could_ match. Once a candidate +is found, it is then intended for the regex engine to run at that position to +determine whether the candidate is a match or a false positive. + +In the aforementioned description of the prefilter optimization also lay its +demise. Namely, if a prefilter has a high false positive rate and it produces +lots of candidates, then a prefilter can overall make a regex search slower. +It can run more slowly because more time is spent ping-ponging between the +prefilter search and the regex engine attempting to confirm each candidate as +a match. This ping-ponging has overhead that adds up, and is exacerbated by +a high false positive rate. + +Nevertheless, the optimization is still generally worth performing in most +cases. Particularly given just how much throughput can be improved. (It is not +uncommon for prefilter optimizations to improve throughput by one or two orders +of magnitude.) + +Typically a prefilter is used to find occurrences of literal prefixes from a +regex pattern, but this isn't required. A prefilter can be used to look for +suffixes or even inner literals. + +Note that as of now, prefilters throw away information about which pattern +each literal comes from. In other words, when a prefilter finds a match, +there's no way to know which pattern (or patterns) it came from. Therefore, +in order to confirm a match, you'll have to check all of the patterns by +running the full regex engine. +*/ + +mod aho_corasick; +mod byteset; +mod memchr; +mod memmem; +mod teddy; + +use core::{ + borrow::Borrow, + fmt::Debug, + panic::{RefUnwindSafe, UnwindSafe}, +}; + +#[cfg(feature = "alloc")] +use alloc::sync::Arc; + +#[cfg(feature = "syntax")] +use regex_syntax::hir::{literal, Hir}; + +use crate::util::search::{MatchKind, Span}; + +pub(crate) use crate::util::prefilter::{ + aho_corasick::AhoCorasick, + byteset::ByteSet, + memchr::{Memchr, Memchr2, Memchr3}, + memmem::Memmem, + teddy::Teddy, +}; + +/// A prefilter for accelerating regex searches. +/// +/// If you already have your literals that you want to search with, +/// then the vanilla [`Prefilter::new`] constructor is for you. But +/// if you have an [`Hir`] value from the `regex-syntax` crate, then +/// [`Prefilter::from_hir_prefix`] might be more convenient. Namely, it uses +/// the [`regex-syntax::hir::literal`](regex_syntax::hir::literal) module to +/// extract literal prefixes for you, optimize them and then select and build a +/// prefilter matcher. +/// +/// A prefilter must have **zero false negatives**. However, by its very +/// nature, it may produce false positives. That is, a prefilter will never +/// skip over a position in the haystack that corresponds to a match of the +/// original regex pattern, but it *may* produce a match for a position +/// in the haystack that does *not* correspond to a match of the original +/// regex pattern. If you use either the [`Prefilter::from_hir_prefix`] or +/// [`Prefilter::from_hirs_prefix`] constructors, then this guarantee is +/// upheld for you automatically. This guarantee is not preserved if you use +/// [`Prefilter::new`] though, since it is up to the caller to provide correct +/// literal strings with respect to the original regex pattern. +/// +/// # Cloning +/// +/// It is an API guarantee that cloning a prefilter is cheap. That is, cloning +/// it will not duplicate whatever heap memory is used to represent the +/// underlying matcher. +/// +/// # Example +/// +/// This example shows how to attach a `Prefilter` to the +/// [`PikeVM`](crate::nfa::thompson::pikevm::PikeVM) in order to accelerate +/// searches. +/// +/// ``` +/// use regex_automata::{ +/// nfa::thompson::pikevm::PikeVM, +/// util::prefilter::Prefilter, +/// Match, MatchKind, +/// }; +/// +/// let pre = Prefilter::new(MatchKind::LeftmostFirst, &["Bruce "]) +/// .expect("a prefilter"); +/// let re = PikeVM::builder() +/// .configure(PikeVM::config().prefilter(Some(pre))) +/// .build(r"Bruce \w+")?; +/// let mut cache = re.create_cache(); +/// assert_eq!( +/// Some(Match::must(0, 6..23)), +/// re.find(&mut cache, "Hello Bruce Springsteen!"), +/// ); +/// # Ok::<(), Box<dyn std::error::Error>>(()) +/// ``` +/// +/// But note that if you get your prefilter incorrect, it could lead to an +/// incorrect result! +/// +/// ``` +/// use regex_automata::{ +/// nfa::thompson::pikevm::PikeVM, +/// util::prefilter::Prefilter, +/// Match, MatchKind, +/// }; +/// +/// // This prefilter is wrong! +/// let pre = Prefilter::new(MatchKind::LeftmostFirst, &["Patti "]) +/// .expect("a prefilter"); +/// let re = PikeVM::builder() +/// .configure(PikeVM::config().prefilter(Some(pre))) +/// .build(r"Bruce \w+")?; +/// let mut cache = re.create_cache(); +/// // We find no match even though the regex does match. +/// assert_eq!( +/// None, +/// re.find(&mut cache, "Hello Bruce Springsteen!"), +/// ); +/// # Ok::<(), Box<dyn std::error::Error>>(()) +/// ``` +#[derive(Clone, Debug)] +pub struct Prefilter { + #[cfg(not(feature = "alloc"))] + _unused: (), + #[cfg(feature = "alloc")] + pre: Arc<dyn PrefilterI>, + #[cfg(feature = "alloc")] + is_fast: bool, +} + +impl Prefilter { + /// Create a new prefilter from a sequence of needles and a corresponding + /// match semantics. + /// + /// This may return `None` for a variety of reasons, for example, if + /// a suitable prefilter could not be constructed. That might occur + /// if they are unavailable (e.g., the `perf-literal-substring` and + /// `perf-literal-multisubstring` features aren't enabled), or it might + /// occur because of heuristics or other artifacts of how the prefilter + /// works. + /// + /// Note that if you have an [`Hir`] expression, it may be more convenient + /// to use [`Prefilter::from_hir_prefix`]. It will automatically handle the + /// task of extracting prefix literals for you. + /// + /// # Example + /// + /// This example shows how match semantics can impact the matching + /// algorithm used by the prefilter. For this reason, it is important to + /// ensure that the match semantics given here are consistent with the + /// match semantics intended for the regular expression that the literals + /// were extracted from. + /// + /// ``` + /// use regex_automata::{ + /// util::{prefilter::Prefilter, syntax}, + /// MatchKind, Span, + /// }; + /// + /// let hay = "Hello samwise"; + /// + /// // With leftmost-first, we find 'samwise' here because it comes + /// // before 'sam' in the sequence we give it.. + /// let pre = Prefilter::new(MatchKind::LeftmostFirst, &["samwise", "sam"]) + /// .expect("a prefilter"); + /// assert_eq!( + /// Some(Span::from(6..13)), + /// pre.find(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// // Still with leftmost-first but with the literals reverse, now 'sam' + /// // will match instead! + /// let pre = Prefilter::new(MatchKind::LeftmostFirst, &["sam", "samwise"]) + /// .expect("a prefilter"); + /// assert_eq!( + /// Some(Span::from(6..9)), + /// pre.find(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + pub fn new<B: AsRef<[u8]>>( + kind: MatchKind, + needles: &[B], + ) -> Option<Prefilter> { + Choice::new(kind, needles).and_then(Prefilter::from_choice) + } + + /// This turns a prefilter selection into a `Prefilter`. That is, in turns + /// the enum given into a trait object. + fn from_choice(choice: Choice) -> Option<Prefilter> { + #[cfg(not(feature = "alloc"))] + { + None + } + #[cfg(feature = "alloc")] + { + let pre: Arc<dyn PrefilterI> = match choice { + Choice::Memchr(p) => Arc::new(p), + Choice::Memchr2(p) => Arc::new(p), + Choice::Memchr3(p) => Arc::new(p), + Choice::Memmem(p) => Arc::new(p), + Choice::Teddy(p) => Arc::new(p), + Choice::ByteSet(p) => Arc::new(p), + Choice::AhoCorasick(p) => Arc::new(p), + }; + let is_fast = pre.is_fast(); + Some(Prefilter { pre, is_fast }) + } + } + + /// This attempts to extract prefixes from the given `Hir` expression for + /// the given match semantics, and if possible, builds a prefilter for + /// them. + /// + /// # Example + /// + /// This example shows how to build a prefilter directly from an [`Hir`] + /// expression, and use to find an occurrence of a prefix from the regex + /// pattern. + /// + /// ``` + /// use regex_automata::{ + /// util::{prefilter::Prefilter, syntax}, + /// MatchKind, Span, + /// }; + /// + /// let hir = syntax::parse(r"(Bruce|Patti) \w+")?; + /// let pre = Prefilter::from_hir_prefix(MatchKind::LeftmostFirst, &hir) + /// .expect("a prefilter"); + /// let hay = "Hello Patti Scialfa!"; + /// assert_eq!( + /// Some(Span::from(6..12)), + /// pre.find(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + #[cfg(feature = "syntax")] + pub fn from_hir_prefix(kind: MatchKind, hir: &Hir) -> Option<Prefilter> { + Prefilter::from_hirs_prefix(kind, &[hir]) + } + + /// This attempts to extract prefixes from the given `Hir` expressions for + /// the given match semantics, and if possible, builds a prefilter for + /// them. + /// + /// Note that as of now, prefilters throw away information about which + /// pattern each literal comes from. In other words, when a prefilter finds + /// a match, there's no way to know which pattern (or patterns) it came + /// from. Therefore, in order to confirm a match, you'll have to check all + /// of the patterns by running the full regex engine. + /// + /// # Example + /// + /// This example shows how to build a prefilter directly from multiple + /// `Hir` expressions expression, and use it to find an occurrence of a + /// prefix from the regex patterns. + /// + /// ``` + /// use regex_automata::{ + /// util::{prefilter::Prefilter, syntax}, + /// MatchKind, Span, + /// }; + /// + /// let hirs = syntax::parse_many(&[ + /// r"(Bruce|Patti) \w+", + /// r"Mrs?\. Doubtfire", + /// ])?; + /// let pre = Prefilter::from_hirs_prefix(MatchKind::LeftmostFirst, &hirs) + /// .expect("a prefilter"); + /// let hay = "Hello Mrs. Doubtfire"; + /// assert_eq!( + /// Some(Span::from(6..20)), + /// pre.find(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + #[cfg(feature = "syntax")] + pub fn from_hirs_prefix<H: Borrow<Hir>>( + kind: MatchKind, + hirs: &[H], + ) -> Option<Prefilter> { + prefixes(kind, hirs) + .literals() + .and_then(|lits| Prefilter::new(kind, lits)) + } + + /// Run this prefilter on `haystack[span.start..end]` and return a matching + /// span if one exists. + /// + /// The span returned is guaranteed to have a start position greater than + /// or equal to the one given, and an end position less than or equal to + /// the one given. + /// + /// # Example + /// + /// This example shows how to build a prefilter directly from an [`Hir`] + /// expression, and use it to find an occurrence of a prefix from the regex + /// pattern. + /// + /// ``` + /// use regex_automata::{ + /// util::{prefilter::Prefilter, syntax}, + /// MatchKind, Span, + /// }; + /// + /// let hir = syntax::parse(r"Bruce \w+")?; + /// let pre = Prefilter::from_hir_prefix(MatchKind::LeftmostFirst, &hir) + /// .expect("a prefilter"); + /// let hay = "Hello Bruce Springsteen!"; + /// assert_eq!( + /// Some(Span::from(6..12)), + /// pre.find(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + #[inline] + pub fn find(&self, haystack: &[u8], span: Span) -> Option<Span> { + #[cfg(not(feature = "alloc"))] + { + unreachable!() + } + #[cfg(feature = "alloc")] + { + self.pre.find(haystack, span) + } + } + + /// Returns the span of a prefix of `haystack[span.start..span.end]` if + /// the prefilter matches. + /// + /// The span returned is guaranteed to have a start position equivalent to + /// the one given, and an end position less than or equal to the one given. + /// + /// # Example + /// + /// This example shows how to build a prefilter directly from an [`Hir`] + /// expression, and use it to find an occurrence of a prefix from the regex + /// pattern that begins at the start of a haystack only. + /// + /// ``` + /// use regex_automata::{ + /// util::{prefilter::Prefilter, syntax}, + /// MatchKind, Span, + /// }; + /// + /// let hir = syntax::parse(r"Bruce \w+")?; + /// let pre = Prefilter::from_hir_prefix(MatchKind::LeftmostFirst, &hir) + /// .expect("a prefilter"); + /// let hay = "Hello Bruce Springsteen!"; + /// // Nothing is found here because 'Bruce' does + /// // not occur at the beginning of our search. + /// assert_eq!( + /// None, + /// pre.prefix(hay.as_bytes(), Span::from(0..hay.len())), + /// ); + /// // But if we change where we start the search + /// // to begin where 'Bruce ' begins, then a + /// // match will be found. + /// assert_eq!( + /// Some(Span::from(6..12)), + /// pre.prefix(hay.as_bytes(), Span::from(6..hay.len())), + /// ); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + #[inline] + pub fn prefix(&self, haystack: &[u8], span: Span) -> Option<Span> { + #[cfg(not(feature = "alloc"))] + { + unreachable!() + } + #[cfg(feature = "alloc")] + { + self.pre.prefix(haystack, span) + } + } + + /// Returns the heap memory, in bytes, used by the underlying prefilter. + #[inline] + pub fn memory_usage(&self) -> usize { + #[cfg(not(feature = "alloc"))] + { + unreachable!() + } + #[cfg(feature = "alloc")] + { + self.pre.memory_usage() + } + } + + /// Implementations might return true here if they believe themselves to + /// be "fast." The concept of "fast" is deliberately left vague, but in + /// practice this usually corresponds to whether it's believed that SIMD + /// will be used. + /// + /// Why do we care about this? Well, some prefilter tricks tend to come + /// with their own bits of overhead, and so might only make sense if we + /// know that a scan will be *much* faster than the regex engine itself. + /// Otherwise, the trick may not be worth doing. Whether something is + /// "much" faster than the regex engine generally boils down to whether + /// SIMD is used. (But not always. Even a SIMD matcher with a high false + /// positive rate can become quite slow.) + /// + /// Even if this returns true, it is still possible for the prefilter to + /// be "slow." Remember, prefilters are just heuristics. We can't really + /// *know* a prefilter will be fast without actually trying the prefilter. + /// (Which of course we cannot afford to do.) + #[inline] + pub(crate) fn is_fast(&self) -> bool { + #[cfg(not(feature = "alloc"))] + { + unreachable!() + } + #[cfg(feature = "alloc")] + { + self.is_fast + } + } +} + +/// A trait for abstracting over prefilters. Basically, a prefilter is +/// something that do an unanchored *and* an anchored search in a haystack +/// within a given span. +/// +/// This exists pretty much only so that we can use prefilters as a trait +/// object (which is what `Prefilter` is). If we ever move off of trait objects +/// and to an enum, then it's likely this trait could be removed. +pub(crate) trait PrefilterI: + Debug + Send + Sync + RefUnwindSafe + UnwindSafe + 'static +{ + /// Run this prefilter on `haystack[span.start..end]` and return a matching + /// span if one exists. + /// + /// The span returned is guaranteed to have a start position greater than + /// or equal to the one given, and an end position less than or equal to + /// the one given. + fn find(&self, haystack: &[u8], span: Span) -> Option<Span>; + + /// Returns the span of a prefix of `haystack[span.start..span.end]` if + /// the prefilter matches. + /// + /// The span returned is guaranteed to have a start position equivalent to + /// the one given, and an end position less than or equal to the one given. + fn prefix(&self, haystack: &[u8], span: Span) -> Option<Span>; + + /// Returns the heap memory, in bytes, used by the underlying prefilter. + fn memory_usage(&self) -> usize; + + /// Implementations might return true here if they believe themselves to + /// be "fast." See [`Prefilter::is_fast`] for more details. + fn is_fast(&self) -> bool; +} + +#[cfg(feature = "alloc")] +impl<P: PrefilterI + ?Sized> PrefilterI for Arc<P> { + #[cfg_attr(feature = "perf-inline", inline(always))] + fn find(&self, haystack: &[u8], span: Span) -> Option<Span> { + (&**self).find(haystack, span) + } + + #[cfg_attr(feature = "perf-inline", inline(always))] + fn prefix(&self, haystack: &[u8], span: Span) -> Option<Span> { + (&**self).prefix(haystack, span) + } + + #[cfg_attr(feature = "perf-inline", inline(always))] + fn memory_usage(&self) -> usize { + (&**self).memory_usage() + } + + #[cfg_attr(feature = "perf-inline", inline(always))] + fn is_fast(&self) -> bool { + (&**self).is_fast() + } +} + +/// A type that encapsulates the selection of a prefilter algorithm from a +/// sequence of needles. +/// +/// The existence of this type is a little tricky, because we don't (currently) +/// use it for performing a search. Instead, we really only consume it by +/// converting the underlying prefilter into a trait object, whether that be +/// `dyn PrefilterI` or `dyn Strategy` (for the meta regex engine). In order +/// to avoid re-copying the prefilter selection logic, we isolate it here, and +/// then force anything downstream that wants to convert it to a trait object +/// to do trivial case analysis on it. +/// +/// One wonders whether we *should* use an enum instead of a trait object. +/// At time of writing, I chose trait objects based on instinct because 1) I +/// knew I wasn't going to inline anything and 2) there would potentially be +/// many different choices. However, as of time of writing, I haven't actually +/// compared the trait object approach to the enum approach. That probably +/// should be litigated, but I ran out of steam. +/// +/// Note that if the `alloc` feature is disabled, then values of this type +/// are (and should) never be constructed. Also, in practice, for any of the +/// prefilters to be selected, you'll need at least one of the `perf-literal-*` +/// features enabled. +#[derive(Clone, Debug)] +pub(crate) enum Choice { + Memchr(Memchr), + Memchr2(Memchr2), + Memchr3(Memchr3), + Memmem(Memmem), + Teddy(Teddy), + ByteSet(ByteSet), + AhoCorasick(AhoCorasick), +} + +impl Choice { + /// Select what is believed to be the best prefilter algorithm for the + /// match semantics and sequence of needles given. + /// + /// This selection algorithm uses the needles as given without any + /// modification. For example, if `[bar]` is given, then this doesn't + /// try to select `memchr` for `b`. Instead, it would select `memmem` + /// for `bar`. If callers would want `memchr` selected for `[bar]`, then + /// callers should massages the literals themselves. That is, callers are + /// responsible for heuristics surrounding which sequence of literals is + /// best. + /// + /// What this selection algorithm does is attempt to use the fastest + /// prefilter that works for the literals given. So if `[a, b]`, is given, + /// then `memchr2` is selected. + /// + /// Of course, which prefilter is selected is also subject to what + /// is available. For example, if `alloc` isn't enabled, then + /// that limits which prefilters can be selected. Similarly, if + /// `perf-literal-substring` isn't enabled, then nothing from the `memchr` + /// crate can be returned. + pub(crate) fn new<B: AsRef<[u8]>>( + kind: MatchKind, + needles: &[B], + ) -> Option<Choice> { + // An empty set means the regex matches nothing, so no sense in + // building a prefilter. + if needles.len() == 0 { + debug!("prefilter building failed: found empty set of literals"); + return None; + } + // If the regex can match the empty string, then the prefilter + // will by definition match at every position. This is obviously + // completely ineffective. + if needles.iter().any(|n| n.as_ref().is_empty()) { + debug!("prefilter building failed: literals match empty string"); + return None; + } + // BREADCRUMBS: Perhaps the literal optimizer should special case + // sequences of length two or three if the leading bytes of each are + // "rare"? Or perhaps, if there are two or three total possible leading + // bytes, regardless of the number of literals, and all are rare... + // Then well, perhaps we should use memchr2 or memchr3 in those cases? + if let Some(pre) = Memchr::new(kind, needles) { + debug!("prefilter built: memchr"); + return Some(Choice::Memchr(pre)); + } + if let Some(pre) = Memchr2::new(kind, needles) { + debug!("prefilter built: memchr2"); + return Some(Choice::Memchr2(pre)); + } + if let Some(pre) = Memchr3::new(kind, needles) { + debug!("prefilter built: memchr3"); + return Some(Choice::Memchr3(pre)); + } + if let Some(pre) = Memmem::new(kind, needles) { + debug!("prefilter built: memmem"); + return Some(Choice::Memmem(pre)); + } + if let Some(pre) = Teddy::new(kind, needles) { + debug!("prefilter built: teddy"); + return Some(Choice::Teddy(pre)); + } + if let Some(pre) = ByteSet::new(kind, needles) { + debug!("prefilter built: byteset"); + return Some(Choice::ByteSet(pre)); + } + if let Some(pre) = AhoCorasick::new(kind, needles) { + debug!("prefilter built: aho-corasick"); + return Some(Choice::AhoCorasick(pre)); + } + debug!("prefilter building failed: no strategy could be found"); + None + } +} + +/// Extracts all of the prefix literals from the given HIR expressions into a +/// single `Seq`. The literals in the sequence are ordered with respect to the +/// order of the given HIR expressions and consistent with the match semantics +/// given. +/// +/// The sequence returned is "optimized." That is, they may be shrunk or even +/// truncated according to heuristics with the intent of making them more +/// useful as a prefilter. (Which translates to both using faster algorithms +/// and minimizing the false positive rate.) +/// +/// Note that this erases any connection between the literals and which pattern +/// (or patterns) they came from. +/// +/// The match kind given must correspond to the match semantics of the regex +/// that is represented by the HIRs given. The match semantics may change the +/// literal sequence returned. +#[cfg(feature = "syntax")] +pub(crate) fn prefixes<H>(kind: MatchKind, hirs: &[H]) -> literal::Seq +where + H: core::borrow::Borrow<Hir>, +{ + let mut extractor = literal::Extractor::new(); + extractor.kind(literal::ExtractKind::Prefix); + + let mut prefixes = literal::Seq::empty(); + for hir in hirs { + prefixes.union(&mut extractor.extract(hir.borrow())); + } + debug!( + "prefixes (len={:?}, exact={:?}) extracted before optimization: {:?}", + prefixes.len(), + prefixes.is_exact(), + prefixes + ); + match kind { + MatchKind::All => { + prefixes.sort(); + prefixes.dedup(); + } + MatchKind::LeftmostFirst => { + prefixes.optimize_for_prefix_by_preference(); + } + } + debug!( + "prefixes (len={:?}, exact={:?}) extracted after optimization: {:?}", + prefixes.len(), + prefixes.is_exact(), + prefixes + ); + prefixes +} + +/// Like `prefixes`, but for all suffixes of all matches for the given HIRs. +#[cfg(feature = "syntax")] +pub(crate) fn suffixes<H>(kind: MatchKind, hirs: &[H]) -> literal::Seq +where + H: core::borrow::Borrow<Hir>, +{ + let mut extractor = literal::Extractor::new(); + extractor.kind(literal::ExtractKind::Suffix); + + let mut suffixes = literal::Seq::empty(); + for hir in hirs { + suffixes.union(&mut extractor.extract(hir.borrow())); + } + debug!( + "suffixes (len={:?}, exact={:?}) extracted before optimization: {:?}", + suffixes.len(), + suffixes.is_exact(), + suffixes + ); + match kind { + MatchKind::All => { + suffixes.sort(); + suffixes.dedup(); + } + MatchKind::LeftmostFirst => { + suffixes.optimize_for_suffix_by_preference(); + } + } + debug!( + "suffixes (len={:?}, exact={:?}) extracted after optimization: {:?}", + suffixes.len(), + suffixes.is_exact(), + suffixes + ); + suffixes +} |