home/
env.rs

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1//! Lower-level utilities for mocking the process environment.
2
3use std::{
4    ffi::OsString,
5    io,
6    path::{Path, PathBuf},
7};
8
9/// Permits parameterizing the home functions via the _from variants - used for
10/// in-process unit testing by rustup.
11pub trait Env {
12    /// Return the path to the users home dir, or None if any error occurs:
13    /// see `home_inner`.
14    fn home_dir(&self) -> Option<PathBuf>;
15    /// Return the current working directory.
16    fn current_dir(&self) -> io::Result<PathBuf>;
17    /// Get an environment variable, as per `std::env::var_os`.
18    fn var_os(&self, key: &str) -> Option<OsString>;
19}
20
21/// Implements Env for the OS context, both Unix style and Windows.
22///
23/// This is trait permits in-process testing by providing a control point to
24/// allow in-process divergence on what is normally process wide state.
25///
26/// Implementations should be provided by whatever testing framework the caller
27/// is using. Code that is not performing in-process threaded testing requiring
28/// isolated rustup/cargo directories does not need this trait or the _from
29/// functions.
30pub struct OsEnv;
31impl Env for OsEnv {
32    fn home_dir(&self) -> Option<PathBuf> {
33        crate::home_dir_inner()
34    }
35    fn current_dir(&self) -> io::Result<PathBuf> {
36        std::env::current_dir()
37    }
38    fn var_os(&self, key: &str) -> Option<OsString> {
39        std::env::var_os(key)
40    }
41}
42
43pub const OS_ENV: OsEnv = OsEnv {};
44
45/// Returns the path of the current user's home directory from [`Env::home_dir`].
46pub fn home_dir_with_env(env: &dyn Env) -> Option<PathBuf> {
47    env.home_dir()
48}
49
50/// Variant of `cargo_home` where the environment source is parameterized.
51///
52/// This is
53/// specifically to support in-process testing scenarios as environment
54/// variables and user home metadata are normally process global state. See the
55/// [`Env`] trait.
56pub fn cargo_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
57    let cwd = env.current_dir()?;
58    cargo_home_with_cwd_env(env, &cwd)
59}
60
61/// Variant of `cargo_home_with_cwd` where the environment source is
62/// parameterized.
63///
64/// This is specifically to support in-process testing scenarios
65/// as environment variables and user home metadata are normally process global
66/// state. See the `OsEnv` trait.
67pub fn cargo_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
68    match env.var_os("CARGO_HOME").filter(|h| !h.is_empty()) {
69        Some(home) => {
70            let home = PathBuf::from(home);
71            if home.is_absolute() {
72                Ok(home)
73            } else {
74                Ok(cwd.join(&home))
75            }
76        }
77        _ => home_dir_with_env(env)
78            .map(|p| p.join(".cargo"))
79            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find cargo home dir")),
80    }
81}
82
83/// Variant of `cargo_home_with_cwd` where the environment source is
84/// parameterized.
85///
86/// This is specifically to support in-process testing scenarios
87/// as environment variables and user home metadata are normally process global
88/// state. See the `OsEnv` trait.
89pub fn rustup_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
90    let cwd = env.current_dir()?;
91    rustup_home_with_cwd_env(env, &cwd)
92}
93
94/// Variant of `cargo_home_with_cwd` where the environment source is
95/// parameterized.
96///
97/// This is specifically to support in-process testing scenarios
98/// as environment variables and user home metadata are normally process global
99/// state. See the `OsEnv` trait.
100pub fn rustup_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
101    match env.var_os("RUSTUP_HOME").filter(|h| !h.is_empty()) {
102        Some(home) => {
103            let home = PathBuf::from(home);
104            if home.is_absolute() {
105                Ok(home)
106            } else {
107                Ok(cwd.join(&home))
108            }
109        }
110        _ => home_dir_with_env(env)
111            .map(|d| d.join(".rustup"))
112            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find rustup home dir")),
113    }
114}
home/env.rs

home/
env.rs
