use std::{borrow::Cow, ffi::OsStr, path::Path}; use crate::{DOT_GIT_DIR, MODULES}; /// Returns true if the given `git_dir` seems to be a bare repository.////// Please note that repositories without an index generally _look_ bare, even though they might also be uninitialized.pub fn bare(git_dir_candidate: impl AsRef<Path>) -> bool {    let git_dir = git_dir_candidate.as_ref();    !(git_dir.join("index").exists() || (git_dir.file_name() == Some(OsStr::new(DOT_GIT_DIR)) && git_dir.is_file()))} /// Returns true if `git_dir` is is located within a `.git/modules` directory, indicating it's a submodule clone.pub fn submodule_git_dir(git_dir: impl AsRef<Path>) -> bool {    let git_dir = git_dir.as_ref();     let mut last_comp = None;    git_dir.file_name() != Some(OsStr::new(DOT_GIT_DIR))        && git_dir.components().rev().any(|c| {            if c.as_os_str() == OsStr::new(DOT_GIT_DIR) {                true            } else {                last_comp = Some(c.as_os_str());                false            }        })        && last_comp == Some(OsStr::new(MODULES))} /// What constitutes a valid git repository, returning the guessed repository kind/// purely based on the presence of files. Note that the git-config ultimately decides what's bare.////// Returns the `Kind` of git directory that was passed, possibly alongside the supporting private worktree git dir.////// Note that `.git` files are followed to a valid git directory, which then requires…//////   * …a valid head///   * …an objects directory///   * …a refs directory///pub fn git(git_dir: impl AsRef<Path>) -> Result<crate::repository::Kind, crate::is_git::Error> {    #[derive(Eq, PartialEq)]    enum Kind {        MaybeRepo,        Submodule,        LinkedWorkTreeDir,        WorkTreeGitDir { work_dir: std::path::PathBuf },    }    let git_dir = git_dir.as_ref();    let (dot_git, common_dir, kind) = if git_dir.metadata()?.is_file() {        let private_git_dir = crate::path::from_gitdir_file(git_dir)?;        let common_dir = private_git_dir.join("commondir");        match crate::path::from_plain_file(&common_dir) {            Some(Err(err)) => {                return Err(crate::is_git::Error::MissingCommonDir {                    missing: common_dir,                    source: err,                })            }            Some(Ok(common_dir)) => {                let common_dir = private_git_dir.join(common_dir);                (                    Cow::Owned(private_git_dir),                    Cow::Owned(common_dir),                    Kind::LinkedWorkTreeDir,                )            }            None => (                Cow::Owned(private_git_dir.clone()),                Cow::Owned(private_git_dir),                Kind::Submodule,            ),        }    } else {        let common_dir = git_dir.join("commondir");        let worktree_and_common_dir = crate::path::from_plain_file(common_dir)            .and_then(Result::ok)            .and_then(|cd| {                crate::path::from_plain_file(git_dir.join("gitdir"))                    .and_then(Result::ok)                    .map(|worktree_gitfile| (crate::path::without_dot_git_dir(worktree_gitfile), cd))            });        match worktree_and_common_dir {            Some((work_dir, common_dir)) => {                let common_dir = git_dir.join(common_dir);                (                    Cow::Borrowed(git_dir),                    Cow::Owned(common_dir),                    Kind::WorkTreeGitDir { work_dir },                )            }            None => (Cow::Borrowed(git_dir), Cow::Borrowed(git_dir), Kind::MaybeRepo),        }    };     {        // We expect to be able to parse any ref-hash, so we shouldn't have to know the repos hash here.        // With ref-table, the has is probably stored as part of the ref-db itself, so we can handle it from there.        // In other words, it's important not to fail on detached heads here because we guessed the hash kind wrongly.        let object_hash_should_not_matter_here = git_hash::Kind::Sha1;        let refs = git_ref::file::Store::at(            dot_git.as_ref(),            git_ref::store::WriteReflog::Normal,            object_hash_should_not_matter_here,        );        let head = refs.find_loose("HEAD")?;        if head.name.as_bstr() != "HEAD" {            return Err(crate::is_git::Error::MisplacedHead {                name: head.name.into_inner(),            });        }    }     {        let objects_path = common_dir.join("objects");        if !objects_path.is_dir() {            return Err(crate::is_git::Error::MissingObjectsDirectory { missing: objects_path });        }    }    {        let refs_path = common_dir.join("refs");        if !refs_path.is_dir() {            return Err(crate::is_git::Error::MissingRefsDirectory { missing: refs_path });        }    }     Ok(match kind {        Kind::LinkedWorkTreeDir => crate::repository::Kind::WorkTree {            linked_git_dir: Some(dot_git.into_owned()),        },        Kind::WorkTreeGitDir { work_dir } => crate::repository::Kind::WorkTreeGitDir { work_dir },        Kind::Submodule => crate::repository::Kind::Submodule {            git_dir: dot_git.into_owned(),        },        Kind::MaybeRepo => {            if bare(git_dir) {                crate::repository::Kind::Bare            } else if submodule_git_dir(git_dir) {                crate::repository::Kind::SubmoduleGitDir            } else {                crate::repository::Kind::WorkTree { linked_git_dir: None }            }        }    })}