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: PathBuf = 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(key:"CARGO_HOME").filter(|h: &OsString| !h.is_empty()) {
69 Some(home: OsString) => {
70 let home: PathBuf = 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(kind:io::ErrorKind::Other, error:"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: PathBuf = 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(key:"RUSTUP_HOME").filter(|h: &OsString| !h.is_empty()) {
102 Some(home: OsString) => {
103 let home: PathBuf = 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(kind:io::ErrorKind::Other, error:"could not find rustup home dir")),
113 }
114}
115