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use std::{borrow::Cow, path::PathBuf};
use bstr::{BStr, BString, ByteSlice};
use gix_error::{ErrorExt, ExnResult, OptionExt, ResultExt, not_found, validation};
use crate::Path;
/// Types and functions used when expanding Git configuration paths.
pub mod interpolate {
use std::path::PathBuf;
/// Options for interpolating paths with [`Path::interpolate()`][crate::Path::interpolate()].
#[derive(Clone, Copy)]
pub struct Context<'a> {
/// The location where gitoxide or git is installed. If `None`, `%(prefix)` in paths will cause an error.
pub git_install_dir: Option<&'a std::path::Path>,
/// The home directory of the current user. If `None`, `~/` in paths will cause an error.
pub home_dir: Option<&'a std::path::Path>,
/// A function returning the home directory of a given user.
/// If `None`, `~name` or `~name/` in paths will cause an error.
pub home_for_user: Option<fn(&str) -> Option<PathBuf>>,
}
impl Default for Context<'_> {
fn default() -> Self {
Context {
git_install_dir: None,
home_dir: None,
home_for_user: Some(home_for_user),
}
}
}
/// Obtain the home directory for the given user `name` or return `None` if the user wasn't found
/// or any other error occurred.
/// It can be used as `home_for_user` parameter in [`Path::interpolate()`][crate::Path::interpolate()].
/// Returns `None` on Windows, Android, and WebAssembly targets other than Emscripten.
#[cfg_attr(windows, allow(unused_variables))]
#[cfg_attr(all(target_family = "wasm", not(target_os = "emscripten")), allow(unused_variables))]
pub fn home_for_user(name: &str) -> Option<PathBuf> {
#[cfg(not(any(
target_os = "android",
target_os = "windows",
all(target_family = "wasm", not(target_os = "emscripten"))
)))]
{
let cname = std::ffi::CString::new(name).ok()?;
// SAFETY: calling this in a threaded program that modifies the pw database is not actually safe.
// TODO: use the `*_r` version, but it's much harder to use.
#[expect(unsafe_code)]
let pwd = unsafe { libc::getpwnam(cname.as_ptr()) };
if pwd.is_null() {
None
} else {
use std::os::unix::ffi::OsStrExt;
// SAFETY: pw_dir is a cstr and it lives as long as… well, we hope nobody changes the pw database while we are at it
// from another thread. Otherwise it lives long enough.
#[expect(unsafe_code)]
let cstr = unsafe { std::ffi::CStr::from_ptr((*pwd).pw_dir) };
Some(std::ffi::OsStr::from_bytes(cstr.to_bytes()).into())
}
}
#[cfg(any(
target_os = "android",
target_os = "windows",
all(target_family = "wasm", not(target_os = "emscripten"))
))]
{
None
}
}
}
impl std::ops::Deref for Path {
type Target = BStr;
fn deref(&self) -> &Self::Target {
self.value.as_bstr()
}
}
impl AsRef<[u8]> for Path {
fn as_ref(&self) -> &[u8] {
self.value.as_ref()
}
}
impl AsRef<BStr> for Path {
fn as_ref(&self) -> &BStr {
self.value.as_bstr()
}
}
impl From<BString> for Path {
fn from(mut value: BString) -> Self {
/// The prefix used to mark a path as optional in Git configuration files.
const OPTIONAL_PREFIX: &[u8] = b":(optional)";
if value.starts_with(OPTIONAL_PREFIX) {
value.drain(..OPTIONAL_PREFIX.len());
Path {
value,
is_optional: true,
}
} else {
Path {
value,
is_optional: false,
}
}
}
}
impl From<Cow<'_, BStr>> for Path {
fn from(value: Cow<'_, BStr>) -> Self {
Path::from(value.into_owned())
}
}
impl From<&BStr> for Path {
fn from(value: &BStr) -> Self {
Path::from(value.to_owned())
}
}
impl From<&str> for Path {
fn from(value: &str) -> Self {
Path::from(BString::from(value))
}
}
impl Path {
/// Interpolates this path into a path usable on the file system.
///
/// If this path starts with `~/` or `~` or `~user` or `%(prefix)/`
/// - `~` or `~/` is expanded to the value of `home_dir`. The caller can use the [dirs](https://crates.io/crates/dirs) crate to obtain it.
/// If it is required but not set, an error is produced.
/// - `~user` or `~user/` to the specified user’s home directory, e.g `~alice` might get expanded to `/home/alice` on linux, but requires
/// the `home_for_user` function to be provided.
/// The default lookup uses `getpwnam` where available.
/// - `%(prefix)/` is expanded to the location where `gitoxide` is installed.
/// This location is not known at compile time and therefore need to be
/// optionally provided by the caller through `git_install_dir`.
///
/// Any other, non-empty path value is returned unchanged and error is returned in case of an empty path value or if the required
/// input wasn't provided.
/// UTF-8 conversion failures include the invalid path or username bytes as `input`
/// [metadata](gix_error::Exn::metadata()).
pub fn interpolate(
self,
interpolate::Context {
git_install_dir,
home_dir,
home_for_user,
}: interpolate::Context<'_>,
) -> ExnResult<PathBuf> {
if self.is_empty() {
return Err(not_found("path is missing").raise_erased());
}
const PREFIX: &[u8] = b"%(prefix)/";
if self.starts_with(PREFIX) {
let git_install_dir = git_install_dir.ok_or_raise_erased(|| not_found("git install dir is missing"))?;
let (_prefix, path_without_trailing_slash) = self.split_at(PREFIX.len());
let path_without_trailing_slash =
gix_path::try_from_bstring(path_without_trailing_slash).or_raise_erased(|| {
validation("Ill-formed UTF-8 in path past %(prefix)").with("input", path_without_trailing_slash)
})?;
Ok(git_install_dir.join(path_without_trailing_slash))
} else if let Some(val) = self.strip_prefix(b"~") {
let (username, path) = match val.split_once_str(b"/") {
Some((username, path)) => (username, Some(path)),
None => (val, None),
};
let (mut home, what) = if username.is_empty() {
(
home_dir
.ok_or_raise_erased(|| not_found("home dir is missing"))?
.to_path_buf(),
"path past ~/",
)
} else {
(
Self::home_for_username(
username,
home_for_user.ok_or_raise_erased(|| not_found("home for user lookup is missing"))?,
)?,
"path past ~user/",
)
};
if let Some(path) = path {
home.push(
gix_path::try_from_byte_slice(path)
.or_raise_erased(|| validation(format!("Ill-formed UTF-8 in {what}")).with("input", path))?,
);
}
Ok(home)
} else {
Ok(gix_path::from_bstr(self.value.as_bstr()).into_owned())
}
}
fn home_for_username(username: &[u8], home_for_user: fn(&str) -> Option<PathBuf>) -> ExnResult<PathBuf> {
let username = std::str::from_utf8(username)
.or_raise_erased(|| validation("Ill-formed UTF-8 in username").with("input", username))?;
home_for_user(username).ok_or_raise_erased(|| not_found("pwd user info is missing"))
}
}