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lib.rs

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1//! Canonical definitions of `home_dir`, `cargo_home`, and `rustup_home`.
2//!
3//! The definition of `home_dir` provided by the standard library is
4//! incorrect because it considers the `HOME` environment variable on
5//! Windows. This causes surprising situations where a Rust program
6//! will behave differently depending on whether it is run under a
7//! Unix emulation environment like Cygwin or MinGW. Neither Cargo nor
8//! rustup use the standard libraries definition - they use the
9//! definition here.
10//!
11//! This crate provides two additional functions, `cargo_home` and
12//! `rustup_home`, which are the canonical way to determine the
13//! location that Cargo and rustup use to store their data.
14//! The `env` module contains utilities for mocking the process environment
15//! by Cargo and rustup.
16//!
17//! See also this [discussion].
18//!
19//! > This crate is maintained by the Cargo team, primarily for use by Cargo and Rustup
20//! > and not intended for external use. This
21//! > crate may make major changes to its APIs or be deprecated without warning.
22//!
23//! [discussion]: https://github.com/rust-lang/rust/pull/46799#issuecomment-361156935
24
25#![allow(clippy::disallowed_methods)]
26
27pub mod env;
28
29#[cfg(target_os = "windows")]
30mod windows;
31
32use std::io;
33use std::path::{Path, PathBuf};
34
35/// Returns the path of the current user's home directory using environment
36/// variables or OS-specific APIs.
37///
38/// # Unix
39///
40/// Returns the value of the `HOME` environment variable if it is set
41/// **even** if it is an empty string. Otherwise, it tries to determine the
42/// home directory by invoking the [`getpwuid_r`][getpwuid] function with
43/// the UID of the current user.
44///
45/// [getpwuid]: https://linux.die.net/man/3/getpwuid_r
46///
47/// # Windows
48///
49/// Returns the value of the `USERPROFILE` environment variable if it is set
50/// **and** it is not an empty string. Otherwise, it tries to determine the
51/// home directory by invoking the [`SHGetKnownFolderPath`][shgkfp] function with
52/// [`FOLDERID_Profile`][knownfolderid].
53///
54/// [shgkfp]: https://learn.microsoft.com/en-us/windows/win32/api/shlobj_core/nf-shlobj_core-shgetknownfolderpath
55/// [knownfolderid]: https://learn.microsoft.com/en-us/windows/win32/shell/knownfolderid
56///
57/// # Examples
58///
59/// ```
60/// match home::home_dir() {
61///     Some(path) if !path.as_os_str().is_empty() => println!("{}", path.display()),
62///     _ => println!("Unable to get your home dir!"),
63/// }
64/// ```
65pub fn home_dir() -> Option<PathBuf> {
66    env::home_dir_with_env(&env::OS_ENV)
67}
68
69#[cfg(windows)]
70use windows::home_dir_inner;
71
72#[cfg(any(unix, target_os = "redox"))]
73fn home_dir_inner() -> Option<PathBuf> {
74    #[allow(deprecated)]
75    std::env::home_dir()
76}
77
78/// Returns the storage directory used by Cargo, often knowns as
79/// `.cargo` or `CARGO_HOME`.
80///
81/// It returns one of the following values, in this order of
82/// preference:
83///
84/// - The value of the `CARGO_HOME` environment variable, if it is
85///   an absolute path.
86/// - The value of the current working directory joined with the value
87///   of the `CARGO_HOME` environment variable, if `CARGO_HOME` is a
88///   relative directory.
89/// - The `.cargo` directory in the user's home directory, as reported
90///   by the `home_dir` function.
91///
92/// # Errors
93///
94/// This function fails if it fails to retrieve the current directory,
95/// or if the home directory cannot be determined.
96///
97/// # Examples
98///
99/// ```
100/// match home::cargo_home() {
101///     Ok(path) => println!("{}", path.display()),
102///     Err(err) => eprintln!("Cannot get your cargo home dir: {:?}", err),
103/// }
104/// ```
105pub fn cargo_home() -> io::Result<PathBuf> {
106    env::cargo_home_with_env(&env::OS_ENV)
107}
108
109/// Returns the storage directory used by Cargo within `cwd`.
110/// For more details, see [`cargo_home`](fn.cargo_home.html).
111pub fn cargo_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {
112    env::cargo_home_with_cwd_env(&env::OS_ENV, cwd)
113}
114
115/// Returns the storage directory used by rustup, often knowns as
116/// `.rustup` or `RUSTUP_HOME`.
117///
118/// It returns one of the following values, in this order of
119/// preference:
120///
121/// - The value of the `RUSTUP_HOME` environment variable, if it is
122///   an absolute path.
123/// - The value of the current working directory joined with the value
124///   of the `RUSTUP_HOME` environment variable, if `RUSTUP_HOME` is a
125///   relative directory.
126/// - The `.rustup` directory in the user's home directory, as reported
127///   by the `home_dir` function.
128///
129/// # Errors
130///
131/// This function fails if it fails to retrieve the current directory,
132/// or if the home directory cannot be determined.
133///
134/// # Examples
135///
136/// ```
137/// match home::rustup_home() {
138///     Ok(path) => println!("{}", path.display()),
139///     Err(err) => eprintln!("Cannot get your rustup home dir: {:?}", err),
140/// }
141/// ```
142pub fn rustup_home() -> io::Result<PathBuf> {
143    env::rustup_home_with_env(&env::OS_ENV)
144}
145
146/// Returns the storage directory used by rustup within `cwd`.
147/// For more details, see [`rustup_home`](fn.rustup_home.html).
148pub fn rustup_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {
149    env::rustup_home_with_cwd_env(&env::OS_ENV, cwd)
150}
home/lib.rs

home/
lib.rs
