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 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. This is
51/// specifically to support in-process testing scenarios as environment
52/// variables and user home metadata are normally process global state. See the
53/// [`Env`] trait.
54pub fn cargo_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
55 let cwd: PathBuf = env.current_dir()?;
56 cargo_home_with_cwd_env(env, &cwd)
57}
58
59/// Variant of cargo_home_with_cwd where the environment source is
60/// parameterized. This is specifically to support in-process testing scenarios
61/// as environment variables and user home metadata are normally process global
62/// state. See the OsEnv trait.
63pub fn cargo_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
64 match env.var_os(key:"CARGO_HOME").filter(|h: &OsString| !h.is_empty()) {
65 Some(home: OsString) => {
66 let home: PathBuf = PathBuf::from(home);
67 if home.is_absolute() {
68 Ok(home)
69 } else {
70 Ok(cwd.join(&home))
71 }
72 }
73 _ => home_dir_with_env(env)
74 .map(|p| p.join(".cargo"))
75 .ok_or_else(|| io::Error::new(kind:io::ErrorKind::Other, error:"could not find cargo home dir")),
76 }
77}
78
79/// Variant of cargo_home_with_cwd where the environment source is
80/// parameterized. This is specifically to support in-process testing scenarios
81/// as environment variables and user home metadata are normally process global
82/// state. See the OsEnv trait.
83pub fn rustup_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
84 let cwd: PathBuf = env.current_dir()?;
85 rustup_home_with_cwd_env(env, &cwd)
86}
87
88/// Variant of cargo_home_with_cwd where the environment source is
89/// parameterized. This is specifically to support in-process testing scenarios
90/// as environment variables and user home metadata are normally process global
91/// state. See the OsEnv trait.
92pub fn rustup_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
93 match env.var_os(key:"RUSTUP_HOME").filter(|h: &OsString| !h.is_empty()) {
94 Some(home: OsString) => {
95 let home: PathBuf = PathBuf::from(home);
96 if home.is_absolute() {
97 Ok(home)
98 } else {
99 Ok(cwd.join(&home))
100 }
101 }
102 _ => home_dir_with_env(env)
103 .map(|d| d.join(".rustup"))
104 .ok_or_else(|| io::Error::new(kind:io::ErrorKind::Other, error:"could not find rustup home dir")),
105 }
106}
107