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Diffstat (limited to 'rust/src/push/utils.rs')
| -rw-r--r-- | rust/src/push/utils.rs | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/rust/src/push/utils.rs b/rust/src/push/utils.rs new file mode 100644 index 0000000000..8759340473 --- /dev/null +++ b/rust/src/push/utils.rs @@ -0,0 +1,215 @@ +// Copyright 2022 The Matrix.org Foundation C.I.C. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +use anyhow::bail; +use anyhow::Context; +use anyhow::Error; +use lazy_static::lazy_static; +use regex; +use regex::Regex; +use regex::RegexBuilder; + +lazy_static! { + /// Matches runs of non-wildcard characters followed by wildcard characters. + static ref WILDCARD_RUN: Regex = Regex::new(r"([^\?\*]*)([\?\*]*)").expect("valid regex"); +} + +/// Extract the localpart from a Matrix style ID +pub(crate) fn get_localpart_from_id(id: &str) -> Result<&str, Error> { + let (localpart, _) = id + .split_once(':') + .with_context(|| format!("ID does not contain colon: {id}"))?; + + // We need to strip off the first character, which is the ID type. + if localpart.is_empty() { + bail!("Invalid ID {id}"); + } + + Ok(&localpart[1..]) +} + +/// Used by `glob_to_regex` to specify what to match the regex against. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum GlobMatchType { + /// The generated regex will match against the entire input. + Whole, + /// The generated regex will match against words. + Word, +} + +/// Convert a "glob" style expression to a regex, anchoring either to the entire +/// input or to individual words. +pub fn glob_to_regex(glob: &str, match_type: GlobMatchType) -> Result<Regex, Error> { + let mut chunks = Vec::new(); + + // Patterns with wildcards must be simplified to avoid performance cliffs + // - The glob `?**?**?` is equivalent to the glob `???*` + // - The glob `???*` is equivalent to the regex `.{3,}` + for captures in WILDCARD_RUN.captures_iter(glob) { + if let Some(chunk) = captures.get(1) { + chunks.push(regex::escape(chunk.as_str())); + } + + if let Some(wildcards) = captures.get(2) { + if wildcards.as_str() == "" { + continue; + } + + let question_marks = wildcards.as_str().chars().filter(|c| *c == '?').count(); + + if wildcards.as_str().contains('*') { + chunks.push(format!(".{{{question_marks},}}")); + } else { + chunks.push(format!(".{{{question_marks}}}")); + } + } + } + + let joined = chunks.join(""); + + let regex_str = match match_type { + GlobMatchType::Whole => format!(r"\A{joined}\z"), + + // `^|\W` and `\W|$` handle the case where `pattern` starts or ends with a non-word + // character. + GlobMatchType::Word => format!(r"(?:^|\b|\W){joined}(?:\b|\W|$)"), + }; + + Ok(RegexBuilder::new(®ex_str) + .case_insensitive(true) + .build()?) +} + +/// Compiles the glob into a `Matcher`. +pub fn get_glob_matcher(glob: &str, match_type: GlobMatchType) -> Result<Matcher, Error> { + // There are a number of shortcuts we can make if the glob doesn't contain a + // wild card. + let matcher = if glob.contains(['*', '?']) { + let regex = glob_to_regex(glob, match_type)?; + Matcher::Regex(regex) + } else if match_type == GlobMatchType::Whole { + // If there aren't any wildcards and we're matching the whole thing, + // then we simply can do a case-insensitive string match. + Matcher::Whole(glob.to_lowercase()) + } else { + // Otherwise, if we're matching against words then can first check + // if the haystack contains the glob at all. + Matcher::Word { + word: glob.to_lowercase(), + regex: None, + } + }; + + Ok(matcher) +} + +/// Matches against a glob +pub enum Matcher { + /// Plain regex matching. + Regex(Regex), + + /// Case-insensitive equality. + Whole(String), + + /// Word matching. `regex` is a cache of calling [`glob_to_regex`] on word. + Word { word: String, regex: Option<Regex> }, +} + +impl Matcher { + /// Checks if the glob matches the given haystack. + pub fn is_match(&mut self, haystack: &str) -> Result<bool, Error> { + // We want to to do case-insensitive matching, so we convert to + // lowercase first. + let haystack = haystack.to_lowercase(); + + match self { + Matcher::Regex(regex) => Ok(regex.is_match(&haystack)), + Matcher::Whole(whole) => Ok(whole == &haystack), + Matcher::Word { word, regex } => { + // If we're looking for a literal word, then we first check if + // the haystack contains the word as a substring. + if !haystack.contains(&*word) { + return Ok(false); + } + + // If it does contain the word as a substring, then we need to + // check if it is an actual word by testing it against the regex. + let regex = if let Some(regex) = regex { + regex + } else { + let compiled_regex = glob_to_regex(word, GlobMatchType::Word)?; + regex.insert(compiled_regex) + }; + + Ok(regex.is_match(&haystack)) + } + } + } +} + +#[test] +fn test_get_domain_from_id() { + get_localpart_from_id("").unwrap_err(); + get_localpart_from_id(":").unwrap_err(); + get_localpart_from_id(":asd").unwrap_err(); + get_localpart_from_id("::as::asad").unwrap_err(); + + assert_eq!(get_localpart_from_id("@test:foo").unwrap(), "test"); + assert_eq!(get_localpart_from_id("@:").unwrap(), ""); + assert_eq!(get_localpart_from_id("@test:foo:907").unwrap(), "test"); +} + +#[test] +fn tset_glob() -> Result<(), Error> { + assert_eq!( + glob_to_regex("simple", GlobMatchType::Whole)?.as_str(), + r"\Asimple\z" + ); + assert_eq!( + glob_to_regex("simple*", GlobMatchType::Whole)?.as_str(), + r"\Asimple.{0,}\z" + ); + assert_eq!( + glob_to_regex("simple?", GlobMatchType::Whole)?.as_str(), + r"\Asimple.{1}\z" + ); + assert_eq!( + glob_to_regex("simple?*?*", GlobMatchType::Whole)?.as_str(), + r"\Asimple.{2,}\z" + ); + assert_eq!( + glob_to_regex("simple???", GlobMatchType::Whole)?.as_str(), + r"\Asimple.{3}\z" + ); + + assert_eq!( + glob_to_regex("escape.", GlobMatchType::Whole)?.as_str(), + r"\Aescape\.\z" + ); + + assert!(glob_to_regex("simple", GlobMatchType::Whole)?.is_match("simple")); + assert!(!glob_to_regex("simple", GlobMatchType::Whole)?.is_match("simples")); + assert!(glob_to_regex("simple*", GlobMatchType::Whole)?.is_match("simples")); + assert!(glob_to_regex("simple?", GlobMatchType::Whole)?.is_match("simples")); + assert!(glob_to_regex("simple*", GlobMatchType::Whole)?.is_match("simple")); + + assert!(glob_to_regex("simple", GlobMatchType::Word)?.is_match("some simple.")); + assert!(glob_to_regex("simple", GlobMatchType::Word)?.is_match("simple")); + assert!(!glob_to_regex("simple", GlobMatchType::Word)?.is_match("simples")); + + assert!(glob_to_regex("@user:foo", GlobMatchType::Word)?.is_match("Some @user:foo test")); + assert!(glob_to_regex("@user:foo", GlobMatchType::Word)?.is_match("@user:foo")); + + Ok(()) +} |