//!use std::convert::TryInto; use git_hash::ObjectId;use git_ref::FullNameRef; use crate::{    ext::{ObjectIdExt, ReferenceExt},    Head,}; /// Represents the kind of `HEAD` reference.#[derive(Clone)]pub enum Kind {    /// The existing reference the symbolic HEAD points to.    ///    /// This is the common case.    Symbolic(git_ref::Reference),    /// The yet-to-be-created reference the symbolic HEAD refers to.    ///    /// This is the case in a newly initialized repository.    Unborn(git_ref::FullName),    /// The head points to an object directly, not to a symbolic reference.    ///    /// This state is less common and can occur when checking out commits directly.    Detached {        /// The object to which the head points to        target: ObjectId,        /// Possibly the final destination of `target` after following the object chain from tag objects to commits.        peeled: Option<ObjectId>,    },} impl Kind {    /// Attach this instance to a `repo` to produce a [`Head`].    pub fn attach(self, repo: &crate::Repository) -> Head<'_> {        Head { kind: self, repo }    }} /// Accessimpl<'repo> Head<'repo> {    /// Returns the name of this references, always `HEAD`.    pub fn name(&self) -> &'static FullNameRef {        // TODO: use a statically checked version of this when available.        "HEAD".try_into().expect("HEAD is valid")    }     /// Returns the full reference name of this head if it is not detached, or `None` otherwise.    pub fn referent_name(&self) -> Option<&FullNameRef> {        Some(match &self.kind {            Kind::Symbolic(r) => r.name.as_ref(),            Kind::Unborn(name) => name.as_ref(),            Kind::Detached { .. } => return None,        })    }     /// Returns true if this instance is detached, and points to an object directly.    pub fn is_detached(&self) -> bool {        matches!(self.kind, Kind::Detached { .. })    }     /// Returns true if this instance is not yet born, hence it points to a ref that doesn't exist yet.    ///    /// This is the case in a newly initialized repository.    pub fn is_unborn(&self) -> bool {        matches!(self.kind, Kind::Unborn(_))    }     // TODO: tests    /// Returns the id the head points to, which isn't possible on unborn heads.    pub fn id(&self) -> Option<crate::Id<'repo>> {        match &self.kind {            Kind::Symbolic(r) => r.target.try_id().map(|oid| oid.to_owned().attach(self.repo)),            Kind::Detached { peeled, target } => {                (*peeled).unwrap_or_else(|| target.to_owned()).attach(self.repo).into()            }            Kind::Unborn(_) => None,        }    }     /// Try to transform this instance into the symbolic reference that it points to, or return `None` if head is detached or unborn.    pub fn try_into_referent(self) -> Option<crate::Reference<'repo>> {        match self.kind {            Kind::Symbolic(r) => r.attach(self.repo).into(),            _ => None,        }    }} mod remote {    use super::Head;    use crate::{remote, Remote};     /// Remote    impl<'repo> Head<'repo> {        /// Return the remote with which the currently checked our reference can be handled as configured by `branch.<name>.remote|pushRemote`        /// or fall back to the non-branch specific remote configuration. `None` is returned if the head is detached or unborn, so there is        /// no branch specific remote.        ///        /// This is equivalent to calling [`Reference::remote(…)`][crate::Reference::remote()] and        /// [`Repository::remote_default_name()`][crate::Repository::remote_default_name()] in order.        ///        /// Combine it with [`find_default_remote()`][crate::Repository::find_default_remote()] as fallback to handle detached heads,        /// i.e. obtain a remote even in case of detached heads.        pub fn into_remote(            self,            direction: remote::Direction,        ) -> Option<Result<Remote<'repo>, remote::find::existing::Error>> {            let repo = self.repo;            self.try_into_referent()?                .remote(direction)                .or_else(|| repo.find_default_remote(direction))        }    }} ///pub mod log; ///pub mod peel;