use crate::Source;use std::borrow::Cow;use std::ffi::OsString;use std::path::{Path, PathBuf}; /// The category of a [`Source`], in order of ascending precedence.#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]pub enum Kind {    /// A source shared for the entire system.    System,    /// Application specific configuration unique for each user of the `System`.    Global,    /// Configuration relevant only to the repository, possibly including the worktree.    Repository,    /// Configuration specified after all other configuration was loaded for the purpose of overrides.    Override,} impl Kind {    /// Return a list of sources associated with this `Kind` of source, in order of ascending precedence.    pub fn sources(self) -> &'static [Source] {        let src = match self {            Kind::System => &[Source::System] as &[_],            Kind::Global => &[Source::Git, Source::User],            Kind::Repository => &[Source::Local, Source::Worktree],            Kind::Override => &[Source::Env, Source::Cli, Source::Api],        };        debug_assert!(            src.iter().all(|src| src.kind() == self),            "BUG: classification of source has to match the ordering here, see `Source::kind()`"        );        src    }} impl Source {    /// Return true if the source indicates a location within a file of a repository.    pub const fn kind(self) -> Kind {        use Source::*;        match self {            System => Kind::System,            Git | User => Kind::Global,            Local | Worktree => Kind::Repository,            Env | Cli | Api => Kind::Override,        }    }     /// Returns the location at which a file of this type would be stored, or `None` if    /// there is no notion of persistent storage for this source, with `env_var` to obtain environment variables.    /// Note that the location can be relative for repository-local sources like `Local` and `Worktree`,    /// and the caller has to known which base it it relative to, namely the `common_dir` in the `Local` case    /// and the `git_dir` in the `Worktree` case.    /// Be aware that depending on environment overrides, multiple scopes might return the same path, which should    /// only be loaded once nonetheless.    ///    /// With `env_var` it becomes possible to prevent accessing environment variables entirely to comply with `git-sec`    /// permissions for example.    pub fn storage_location(self, env_var: &mut dyn FnMut(&str) -> Option<OsString>) -> Option<Cow<'static, Path>> {        use Source::*;        match self {            System => env_var("GIT_CONFIG_NO_SYSTEM")                .is_none()                .then(|| PathBuf::from(env_var("GIT_CONFIG_SYSTEM").unwrap_or_else(|| "/etc/gitconfig".into())).into()),            Git => match env_var("GIT_CONFIG_GLOBAL") {                Some(global_override) => Some(PathBuf::from(global_override).into()),                None => env_var("XDG_CONFIG_HOME")                    .map(|home| {                        let mut p = PathBuf::from(home);                        p.push("git");                        p.push("config");                        p                    })                    .or_else(|| {                        env_var("HOME").map(|home| {                            let mut p = PathBuf::from(home);                            p.push(".config");                            p.push("git");                            p.push("config");                            p                        })                    })                    .map(Cow::Owned),            },            User => env_var("GIT_CONFIG_GLOBAL")                .map(|global_override| PathBuf::from(global_override).into())                .or_else(|| {                    env_var("HOME").map(|home| {                        let mut p = PathBuf::from(home);                        p.push(".gitconfig");                        p.into()                    })                }),            Local => Some(Path::new("config").into()),            Worktree => Some(Path::new("config.worktree").into()),            Env | Cli | Api => None,        }    }}