//! Canonical definitions of `home_dir`, `cargo_home`, and `rustup_home`.

//!

//! The definition of `home_dir` provided by the standard library is

//! incorrect because it considers the `HOME` environment variable on

//! Windows. This causes surprising situations where a Rust program

//! will behave differently depending on whether it is run under a

//! Unix emulation environment like Cygwin or MinGW. Neither Cargo nor

//! rustup use the standard libraries definition - they use the

//! definition here.

//!

//! This crate provides two additional functions, `cargo_home` and

//! `rustup_home`, which are the canonical way to determine the

//! location that Cargo and rustup use to store their data.

//! The `env` module contains utilities for mocking the process environment

//! by Cargo and rustup.

//!

//! See also this [discussion].

//!

//! > This crate is maintained by the Cargo team, primarily for use by Cargo and Rustup

//! > and not intended for external use. This

//! > crate may make major changes to its APIs or be deprecated without warning.

//!

//! [discussion]: https://github.com/rust-lang/rust/pull/46799#issuecomment-361156935

#![allow(clippy::disallowed_methods)]

pub mod env;

#[cfg(target_os = "windows")]

mod windows;

use std::io;

use std::path::{Path, PathBuf};

/// Returns the path of the current user's home directory using environment

/// variables or OS-specific APIs.

///

/// # Unix

///

/// Returns the value of the `HOME` environment variable if it is set

/// **even** if it is an empty string. Otherwise, it tries to determine the

/// home directory by invoking the [`getpwuid_r`][getpwuid] function with

/// the UID of the current user.

///

/// [getpwuid]: https://linux.die.net/man/3/getpwuid_r

///

/// # Windows

///

/// Returns the value of the `USERPROFILE` environment variable if it is set

/// **and** it is not an empty string. Otherwise, it tries to determine the

/// home directory by invoking the [`SHGetKnownFolderPath`][shgkfp] function with

/// [`FOLDERID_Profile`][knownfolderid].

///

/// [shgkfp]: https://learn.microsoft.com/en-us/windows/win32/api/shlobj_core/nf-shlobj_core-shgetknownfolderpath

/// [knownfolderid]: https://learn.microsoft.com/en-us/windows/win32/shell/knownfolderid

///

/// # Examples

///

/// ```

/// match home::home_dir() {

///     Some(path) if !path.as_os_str().is_empty() => println!("{}", path.display()),

///     _ => println!("Unable to get your home dir!"),

/// }

/// ```

pub fn home_dir() -> Option<PathBuf> {

    env::home_dir_with_env(&env::OS_ENV)

}

#[cfg(windows)]

use windows::home_dir_inner;

#[cfg(unix)]

fn home_dir_inner() -> Option<PathBuf> {

    #[allow(deprecated)]

    std::env::home_dir()

}

/// Returns the storage directory used by Cargo, often known as

/// `.cargo` or `CARGO_HOME`.

///

/// It returns one of the following values, in this order of

/// preference:

///

/// - The value of the `CARGO_HOME` environment variable, if it is

///   an absolute path.

/// - The value of the current working directory joined with the value

///   of the `CARGO_HOME` environment variable, if `CARGO_HOME` is a

///   relative directory.

/// - The `.cargo` directory in the user's home directory, as reported

///   by the `home_dir` function.

///

/// # Errors

///

/// This function fails if it fails to retrieve the current directory,

/// or if the home directory cannot be determined.

///

/// # Examples

///

/// ```

/// match home::cargo_home() {

///     Ok(path) => println!("{}", path.display()),

///     Err(err) => eprintln!("Cannot get your cargo home dir: {:?}", err),

/// }

/// ```

pub fn cargo_home() -> io::Result<PathBuf> {

    env::cargo_home_with_env(&env::OS_ENV)

}

/// Returns the storage directory used by Cargo within `cwd`.

/// For more details, see [`cargo_home`](fn.cargo_home.html).

pub fn cargo_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {

    env::cargo_home_with_cwd_env(&env::OS_ENV, cwd)

}

/// Returns the storage directory used by rustup, often known as

/// `.rustup` or `RUSTUP_HOME`.

///

/// It returns one of the following values, in this order of

/// preference:

///

/// - The value of the `RUSTUP_HOME` environment variable, if it is

///   an absolute path.

/// - The value of the current working directory joined with the value

///   of the `RUSTUP_HOME` environment variable, if `RUSTUP_HOME` is a

///   relative directory.

/// - The `.rustup` directory in the user's home directory, as reported

///   by the `home_dir` function.

///

/// # Errors

///

/// This function fails if it fails to retrieve the current directory,

/// or if the home directory cannot be determined.

///

/// # Examples

///

/// ```

/// match home::rustup_home() {

///     Ok(path) => println!("{}", path.display()),

///     Err(err) => eprintln!("Cannot get your rustup home dir: {:?}", err),

/// }

/// ```

pub fn rustup_home() -> io::Result<PathBuf> {

    env::rustup_home_with_env(&env::OS_ENV)

}

/// Returns the storage directory used by rustup within `cwd`.

/// For more details, see [`rustup_home`](fn.rustup_home.html).

pub fn rustup_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {

    env::rustup_home_with_cwd_env(&env::OS_ENV, cwd)

}