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use std::{borrow::Cow, path::PathBuf};
use bstr::BStr;
use crate::Path;
///
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/` 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),
}
}
}
/// The error returned by [`Path::interpolate()`][crate::Path::interpolate()].
#[derive(Debug, thiserror::Error)]
#[allow(missing_docs)]
pub enum Error {
#[error("{} is missing", .what)]
Missing { what: &'static str },
#[error("Ill-formed UTF-8 in {}", .what)]
Utf8Conversion {
what: &'static str,
#[source]
err: gix_path::Utf8Error,
},
#[error("Ill-formed UTF-8 in username")]
UsernameConversion(#[from] std::str::Utf8Error),
#[error("User interpolation is not available on this platform")]
UserInterpolationUnsupported,
}
/// 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()].
#[cfg_attr(windows, allow(unused_variables))]
pub fn home_for_user(name: &str) -> Option<PathBuf> {
#[cfg(not(any(target_os = "android", target_os = "windows")))]
{
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.
#[allow(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.
#[allow(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"))]
{
None
}
}
}
impl<'a> std::ops::Deref for Path<'a> {
type Target = BStr;
fn deref(&self) -> &Self::Target {
self.value.as_ref()
}
}
impl<'a> AsRef<[u8]> for Path<'a> {
fn as_ref(&self) -> &[u8] {
self.value.as_ref()
}
}
impl<'a> AsRef<BStr> for Path<'a> {
fn as_ref(&self) -> &BStr {
self.value.as_ref()
}
}
impl<'a> From<Cow<'a, BStr>> for Path<'a> {
fn from(value: Cow<'a, BStr>) -> Self {
Path { value }
}
}
impl<'a> Path<'a> {
/// Interpolates this path into a path usable on the file system.
///
/// If this path starts with `~/` or `~user/` or `%(prefix)/`
/// - `~/` 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/` 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 interpolation uses `getpwnam` sys call and is therefore not available on windows.
/// - `%(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 required input
/// wasn't provided.
pub fn interpolate(
self,
interpolate::Context {
git_install_dir,
home_dir,
home_for_user,
}: interpolate::Context<'_>,
) -> Result<Cow<'a, std::path::Path>, interpolate::Error> {
if self.is_empty() {
return Err(interpolate::Error::Missing { what: "path" });
}
const PREFIX: &[u8] = b"%(prefix)/";
const USER_HOME: &[u8] = b"~/";
if self.starts_with(PREFIX) {
let git_install_dir = git_install_dir.ok_or(interpolate::Error::Missing {
what: "git install dir",
})?;
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).map_err(|err| {
interpolate::Error::Utf8Conversion {
what: "path past %(prefix)",
err,
}
})?;
Ok(git_install_dir.join(path_without_trailing_slash).into())
} else if self.starts_with(USER_HOME) {
let home_path = home_dir.ok_or(interpolate::Error::Missing { what: "home dir" })?;
let (_prefix, val) = self.split_at(USER_HOME.len());
let val = gix_path::try_from_byte_slice(val).map_err(|err| interpolate::Error::Utf8Conversion {
what: "path past ~/",
err,
})?;
Ok(home_path.join(val).into())
} else if self.starts_with(b"~") && self.contains(&b'/') {
self.interpolate_user(home_for_user.ok_or(interpolate::Error::Missing {
what: "home for user lookup",
})?)
} else {
Ok(gix_path::from_bstr(self.value))
}
}
#[cfg(any(target_os = "windows", target_os = "android"))]
fn interpolate_user(
self,
_home_for_user: fn(&str) -> Option<PathBuf>,
) -> Result<Cow<'a, std::path::Path>, interpolate::Error> {
Err(interpolate::Error::UserInterpolationUnsupported)
}
#[cfg(not(any(target_os = "windows", target_os = "android")))]
fn interpolate_user(
self,
home_for_user: fn(&str) -> Option<PathBuf>,
) -> Result<Cow<'a, std::path::Path>, interpolate::Error> {
let (_prefix, val) = self.split_at("/".len());
let i = val
.iter()
.position(|&e| e == b'/')
.ok_or(interpolate::Error::Missing { what: "/" })?;
let (username, path_with_leading_slash) = val.split_at(i);
let username = std::str::from_utf8(username)?;
let home = home_for_user(username).ok_or(interpolate::Error::Missing { what: "pwd user info" })?;
let path_past_user_prefix =
gix_path::try_from_byte_slice(&path_with_leading_slash["/".len()..]).map_err(|err| {
interpolate::Error::Utf8Conversion {
what: "path past ~user/",
err,
}
})?;
Ok(home.join(path_past_user_prefix).into())
}
}
|
