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/// The set of user configurable options for compiling zero or more regexes. #[derive(Clone, Debug)] #[allow(missing_docs)] pub struct RegexOptions { pub pats: Vec<String>, pub size_limit: usize, pub dfa_size_limit: usize, pub nest_limit: u32, pub case_insensitive: bool, pub multi_line: bool, pub dot_matches_new_line: bool, pub swap_greed: bool, pub ignore_whitespace: bool, pub unicode: bool, pub octal: bool, } impl Default for RegexOptions { fn default() -> Self { RegexOptions { pats: vec![], size_limit: 10 * (1 << 20), dfa_size_limit: 2 * (1 << 20), nest_limit: 250, case_insensitive: false, multi_line: false, dot_matches_new_line: false, swap_greed: false, ignore_whitespace: false, unicode: true, octal: false, } } } macro_rules! define_builder { ($name:ident, $regex_mod:ident, $only_utf8:expr) => { pub mod $name { use super::RegexOptions; use error::Error; use exec::ExecBuilder; use $regex_mod::Regex; /// A configurable builder for a regular expression. /// /// A builder can be used to configure how the regex is built, for example, by /// setting the default flags (which can be overridden in the expression /// itself) or setting various limits. pub struct RegexBuilder(RegexOptions); impl RegexBuilder { /// Create a new regular expression builder with the given pattern. /// /// If the pattern is invalid, then an error will be returned when /// `build` is called. pub fn new(pattern: &str) -> RegexBuilder { let mut builder = RegexBuilder(RegexOptions::default()); builder.0.pats.push(pattern.to_owned()); builder } /// Consume the builder and compile the regular expression. /// /// Note that calling `as_str` on the resulting `Regex` will produce the /// pattern given to `new` verbatim. Notably, it will not incorporate any /// of the flags set on this builder. pub fn build(&self) -> Result<Regex, Error> { ExecBuilder::new_options(self.0.clone()) .only_utf8($only_utf8) .build() .map(Regex::from) } /// Set the value for the case insensitive (`i`) flag. /// /// When enabled, letters in the pattern will match both upper case and /// lower case variants. pub fn case_insensitive( &mut self, yes: bool, ) -> &mut RegexBuilder { self.0.case_insensitive = yes; self } /// Set the value for the multi-line matching (`m`) flag. /// /// When enabled, `^` matches the beginning of lines and `$` matches the /// end of lines. /// /// By default, they match beginning/end of the input. pub fn multi_line(&mut self, yes: bool) -> &mut RegexBuilder { self.0.multi_line = yes; self } /// Set the value for the any character (`s`) flag, where in `.` matches /// anything when `s` is set and matches anything except for new line when /// it is not set (the default). /// /// N.B. "matches anything" means "any byte" when Unicode is disabled and /// means "any valid UTF-8 encoding of any Unicode scalar value" when /// Unicode is enabled. pub fn dot_matches_new_line( &mut self, yes: bool, ) -> &mut RegexBuilder { self.0.dot_matches_new_line = yes; self } /// Set the value for the greedy swap (`U`) flag. /// /// When enabled, a pattern like `a*` is lazy (tries to find shortest /// match) and `a*?` is greedy (tries to find longest match). /// /// By default, `a*` is greedy and `a*?` is lazy. pub fn swap_greed(&mut self, yes: bool) -> &mut RegexBuilder { self.0.swap_greed = yes; self } /// Set the value for the ignore whitespace (`x`) flag. /// /// When enabled, whitespace such as new lines and spaces will be ignored /// between expressions of the pattern, and `#` can be used to start a /// comment until the next new line. pub fn ignore_whitespace( &mut self, yes: bool, ) -> &mut RegexBuilder { self.0.ignore_whitespace = yes; self } /// Set the value for the Unicode (`u`) flag. /// /// Enabled by default. When disabled, character classes such as `\w` only /// match ASCII word characters instead of all Unicode word characters. pub fn unicode(&mut self, yes: bool) -> &mut RegexBuilder { self.0.unicode = yes; self } /// Whether to support octal syntax or not. /// /// Octal syntax is a little-known way of uttering Unicode codepoints in /// a regular expression. For example, `a`, `\x61`, `\u0061` and /// `\141` are all equivalent regular expressions, where the last example /// shows octal syntax. /// /// While supporting octal syntax isn't in and of itself a problem, it does /// make good error messages harder. That is, in PCRE based regex engines, /// syntax like `\0` invokes a backreference, which is explicitly /// unsupported in Rust's regex engine. However, many users expect it to /// be supported. Therefore, when octal support is disabled, the error /// message will explicitly mention that backreferences aren't supported. /// /// Octal syntax is disabled by default. pub fn octal(&mut self, yes: bool) -> &mut RegexBuilder { self.0.octal = yes; self } /// Set the approximate size limit of the compiled regular expression. /// /// This roughly corresponds to the number of bytes occupied by a single /// compiled program. If the program exceeds this number, then a /// compilation error is returned. pub fn size_limit( &mut self, limit: usize, ) -> &mut RegexBuilder { self.0.size_limit = limit; self } /// Set the approximate size of the cache used by the DFA. /// /// This roughly corresponds to the number of bytes that the DFA will /// use while searching. /// /// Note that this is a *per thread* limit. There is no way to set a global /// limit. In particular, if a regex is used from multiple threads /// simultaneously, then each thread may use up to the number of bytes /// specified here. pub fn dfa_size_limit( &mut self, limit: usize, ) -> &mut RegexBuilder { self.0.dfa_size_limit = limit; self } /// Set the nesting limit for this parser. /// /// The nesting limit controls how deep the abstract syntax tree is allowed /// to be. If the AST exceeds the given limit (e.g., with too many nested /// groups), then an error is returned by the parser. /// /// The purpose of this limit is to act as a heuristic to prevent stack /// overflow for consumers that do structural induction on an `Ast` using /// explicit recursion. While this crate never does this (instead using /// constant stack space and moving the call stack to the heap), other /// crates may. /// /// This limit is not checked until the entire Ast is parsed. Therefore, /// if callers want to put a limit on the amount of heap space used, then /// they should impose a limit on the length, in bytes, of the concrete /// pattern string. In particular, this is viable since this parser /// implementation will limit itself to heap space proportional to the /// length of the pattern string. /// /// Note that a nest limit of `0` will return a nest limit error for most /// patterns but not all. For example, a nest limit of `0` permits `a` but /// not `ab`, since `ab` requires a concatenation, which results in a nest /// depth of `1`. In general, a nest limit is not something that manifests /// in an obvious way in the concrete syntax, therefore, it should not be /// used in a granular way. pub fn nest_limit(&mut self, limit: u32) -> &mut RegexBuilder { self.0.nest_limit = limit; self } } } }; } define_builder!(bytes, re_bytes, false); define_builder!(unicode, re_unicode, true); macro_rules! define_set_builder { ($name:ident, $regex_mod:ident, $only_utf8:expr) => { pub mod $name { use super::RegexOptions; use error::Error; use exec::ExecBuilder; use re_set::$regex_mod::RegexSet; /// A configurable builder for a set of regular expressions. /// /// A builder can be used to configure how the regexes are built, for example, /// by setting the default flags (which can be overridden in the expression /// itself) or setting various limits. pub struct RegexSetBuilder(RegexOptions); impl RegexSetBuilder { /// Create a new regular expression builder with the given pattern. /// /// If the pattern is invalid, then an error will be returned when /// `build` is called. pub fn new<I, S>(patterns: I) -> RegexSetBuilder where S: AsRef<str>, I: IntoIterator<Item = S>, { let mut builder = RegexSetBuilder(RegexOptions::default()); for pat in patterns { builder.0.pats.push(pat.as_ref().to_owned()); } builder } /// Consume the builder and compile the regular expressions into a set. pub fn build(&self) -> Result<RegexSet, Error> { ExecBuilder::new_options(self.0.clone()) .only_utf8($only_utf8) .build() .map(RegexSet::from) } /// Set the value for the case insensitive (`i`) flag. pub fn case_insensitive( &mut self, yes: bool, ) -> &mut RegexSetBuilder { self.0.case_insensitive = yes; self } /// Set the value for the multi-line matching (`m`) flag. pub fn multi_line( &mut self, yes: bool, ) -> &mut RegexSetBuilder { self.0.multi_line = yes; self } /// Set the value for the any character (`s`) flag, where in `.` matches /// anything when `s` is set and matches anything except for new line when /// it is not set (the default). /// /// N.B. "matches anything" means "any byte" for `regex::bytes::RegexSet` /// expressions and means "any Unicode scalar value" for `regex::RegexSet` /// expressions. pub fn dot_matches_new_line( &mut self, yes: bool, ) -> &mut RegexSetBuilder { self.0.dot_matches_new_line = yes; self } /// Set the value for the greedy swap (`U`) flag. pub fn swap_greed( &mut self, yes: bool, ) -> &mut RegexSetBuilder { self.0.swap_greed = yes; self } /// Set the value for the ignore whitespace (`x`) flag. pub fn ignore_whitespace( &mut self, yes: bool, ) -> &mut RegexSetBuilder { self.0.ignore_whitespace = yes; self } /// Set the value for the Unicode (`u`) flag. pub fn unicode(&mut self, yes: bool) -> &mut RegexSetBuilder { self.0.unicode = yes; self } /// Whether to support octal syntax or not. /// /// Octal syntax is a little-known way of uttering Unicode codepoints in /// a regular expression. For example, `a`, `\x61`, `\u0061` and /// `\141` are all equivalent regular expressions, where the last example /// shows octal syntax. /// /// While supporting octal syntax isn't in and of itself a problem, it does /// make good error messages harder. That is, in PCRE based regex engines, /// syntax like `\0` invokes a backreference, which is explicitly /// unsupported in Rust's regex engine. However, many users expect it to /// be supported. Therefore, when octal support is disabled, the error /// message will explicitly mention that backreferences aren't supported. /// /// Octal syntax is disabled by default. pub fn octal(&mut self, yes: bool) -> &mut RegexSetBuilder { self.0.octal = yes; self } /// Set the approximate size limit of the compiled regular expression. /// /// This roughly corresponds to the number of bytes occupied by a single /// compiled program. If the program exceeds this number, then a /// compilation error is returned. pub fn size_limit( &mut self, limit: usize, ) -> &mut RegexSetBuilder { self.0.size_limit = limit; self } /// Set the approximate size of the cache used by the DFA. /// /// This roughly corresponds to the number of bytes that the DFA will /// use while searching. /// /// Note that this is a *per thread* limit. There is no way to set a global /// limit. In particular, if a regex is used from multiple threads /// simultaneously, then each thread may use up to the number of bytes /// specified here. pub fn dfa_size_limit( &mut self, limit: usize, ) -> &mut RegexSetBuilder { self.0.dfa_size_limit = limit; self } /// Set the nesting limit for this parser. /// /// The nesting limit controls how deep the abstract syntax tree is allowed /// to be. If the AST exceeds the given limit (e.g., with too many nested /// groups), then an error is returned by the parser. /// /// The purpose of this limit is to act as a heuristic to prevent stack /// overflow for consumers that do structural induction on an `Ast` using /// explicit recursion. While this crate never does this (instead using /// constant stack space and moving the call stack to the heap), other /// crates may. /// /// This limit is not checked until the entire Ast is parsed. Therefore, /// if callers want to put a limit on the amount of heap space used, then /// they should impose a limit on the length, in bytes, of the concrete /// pattern string. In particular, this is viable since this parser /// implementation will limit itself to heap space proportional to the /// length of the pattern string. /// /// Note that a nest limit of `0` will return a nest limit error for most /// patterns but not all. For example, a nest limit of `0` permits `a` but /// not `ab`, since `ab` requires a concatenation, which results in a nest /// depth of `1`. In general, a nest limit is not something that manifests /// in an obvious way in the concrete syntax, therefore, it should not be /// used in a granular way. pub fn nest_limit( &mut self, limit: u32, ) -> &mut RegexSetBuilder { self.0.nest_limit = limit; self } } } }; } define_set_builder!(set_bytes, bytes, false); define_set_builder!(set_unicode, unicode, true);