use bstr::{BStr, ByteSlice}; /// Parse parts of a Git configuration key, like `remote.origin.url` or `core.bare`.pub trait AsKey: Copy {    /// Return a parsed key reference, containing all relevant parts of a key.    /// For instance, `remote.origin.url` such key would yield access to `("remote", Some("origin"), "url")`    /// while `user.name` would yield `("user", None, "name")`.    ///    /// # Panic    ///    /// If there is no valid `KeyRef` representation.    fn as_key(&self) -> KeyRef<'_>;     /// Return a parsed key reference, containing all relevant parts of a key.    /// For instance, `remote.origin.url` such key would yield access to `("remote", Some("origin"), "url")`    /// while `user.name` would yield `("user", None, "name")`.    fn try_as_key(&self) -> Option<KeyRef<'_>>;} mod impls {    use bstr::{BStr, BString, ByteSlice};     use crate::key::{AsKey, KeyRef};     impl AsKey for &String {        fn as_key(&self) -> KeyRef<'_> {            self.try_as_key()                .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            KeyRef::parse_unvalidated(self.as_str().into())        }    }     impl AsKey for &str {        fn as_key(&self) -> KeyRef<'_> {            self.try_as_key()                .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            KeyRef::parse_unvalidated((*self).into())        }    }     impl AsKey for &BString {        fn as_key(&self) -> KeyRef<'_> {            self.try_as_key()                .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            KeyRef::parse_unvalidated(self.as_bstr())        }    }     impl AsKey for &BStr {        fn as_key(&self) -> KeyRef<'_> {            self.try_as_key()                .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            KeyRef::parse_unvalidated(self)        }    }     impl<T> AsKey for &T    where        T: AsKey,    {        fn as_key(&self) -> KeyRef<'_> {            (*self).as_key()        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            (*self).try_as_key()        }    }     impl AsKey for KeyRef<'_> {        fn as_key(&self) -> KeyRef<'_> {            *self        }         fn try_as_key(&self) -> Option<KeyRef<'_>> {            Some(*self)        }    }} /// An unvalidated parse result of parsing input like `remote.origin.url` or `core.bare`.#[derive(Debug, PartialEq, Ord, PartialOrd, Eq, Hash, Clone, Copy)]pub struct KeyRef<'a> {    /// The name of the section, like `core` in `core.bare`.    pub section_name: &'a str,    /// The name of the subsection, like `origin` in `remote.origin.url`.    pub subsection_name: Option<&'a BStr>,    /// The name of the section key, like `url` in `remote.origin.url`.    pub value_name: &'a str,} /// Lifecycleimpl KeyRef<'_> {    /// Parse `input` like `core.bare` or `remote.origin.url` as a `Key` to make its fields available,    /// or `None` if there were not at least 2 tokens separated by `.`.    /// Note that `input` isn't validated, and is `str` as ascii is a subset of UTF-8 which is required for any valid keys.    pub fn parse_unvalidated(input: &BStr) -> Option<KeyRef<'_>> {        let mut tokens = input.splitn(2, |b| *b == b'.');        let section_name = tokens.next()?;        let subsection_or_key = tokens.next()?;        let mut tokens = subsection_or_key.rsplitn(2, |b| *b == b'.');        let (subsection_name, value_name) = match (tokens.next(), tokens.next()) {            (Some(key), Some(subsection)) => (Some(subsection.into()), key),            (Some(key), None) => (None, key),            (None, Some(_)) => unreachable!("iterator can't restart producing items"),            (None, None) => return None,        };         Some(KeyRef {            section_name: section_name.to_str().ok()?,            subsection_name,            value_name: value_name.to_str().ok()?,        })    }}