1 files changed, 88 insertions, 0 deletions
diff --git a/third_party/rust/clap/src/build/regex.rs b/third_party/rust/clap/src/build/regex.rs
new file mode 100644
index 0000000000..bf3a78e0c2
--- /dev/null
+++ b/third_party/rust/clap/src/build/regex.rs
@@ -0,0 +1,88 @@
+use ::regex::{Error, Regex, RegexSet};
+
+use core::{convert::TryFrom, ops::Deref, str::FromStr};
+use std::borrow::Cow;
+
+/// Contains either a regular expression or a set of them or a reference to one.
+///
+/// See [Arg::validator_regex(][crate::Arg::validator_regex] to set this on an argument.
+#[derive(Debug, Clone)]
+pub enum RegexRef<'a> {
+    /// Used if the underlying is a regex set
+    RegexSet(Cow<'a, RegexSet>),
+    /// Used if the underlying is a regex
+    Regex(Cow<'a, Regex>),
+}
+
+impl<'a> RegexRef<'a> {
+    pub(crate) fn is_match(&self, text: &str) -> bool {
+        match self {
+            Self::Regex(r) => r.deref().is_match(text),
+            Self::RegexSet(r) => r.deref().is_match(text),
+        }
+    }
+}
+
+impl<'a> From<&'a Regex> for RegexRef<'a> {
+    fn from(r: &'a Regex) -> Self {
+        Self::Regex(Cow::Borrowed(r))
+    }
+}
+
+impl<'a> From<Regex> for RegexRef<'a> {
+    fn from(r: Regex) -> Self {
+        Self::Regex(Cow::Owned(r))
+    }
+}
+
+impl<'a> From<&'a RegexSet> for RegexRef<'a> {
+    fn from(r: &'a RegexSet) -> Self {
+        Self::RegexSet(Cow::Borrowed(r))
+    }
+}
+
+impl<'a> From<RegexSet> for RegexRef<'a> {
+    fn from(r: RegexSet) -> Self {
+        Self::RegexSet(Cow::Owned(r))
+    }
+}
+
+impl<'a> TryFrom<&'a str> for RegexRef<'a> {
+    type Error = <Self as FromStr>::Err;
+
+    fn try_from(r: &'a str) -> Result<Self, Self::Error> {
+        Self::from_str(r)
+    }
+}
+
+impl<'a> FromStr for RegexRef<'a> {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Regex::from_str(s).map(|v| Self::Regex(Cow::Owned(v)))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use core::convert::TryInto;
+
+    #[test]
+    fn test_try_from_with_valid_string() {
+        let t: Result<RegexRef, _> = "^Hello, World$".try_into();
+        assert!(t.is_ok())
+    }
+
+    #[test]
+    fn test_try_from_with_invalid_string() {
+        let t: Result<RegexRef, _> = "^Hello, World)$".try_into();
+        assert!(t.is_err());
+    }
+
+    #[test]
+    fn from_str() {
+        let t: Result<RegexRef, _> = RegexRef::from_str("^Hello, World");
+        assert!(t.is_ok());
+    }
+}