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-rw-r--r--crates/ra_toolchain/src/lib.rs64
1 files changed, 64 insertions, 0 deletions
diff --git a/crates/ra_toolchain/src/lib.rs b/crates/ra_toolchain/src/lib.rs
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1//! This crate contains a single public function
2//! [`get_path_for_executable`](fn.get_path_for_executable.html).
3//! See docs there for more information.
4use std::{env, iter, path::PathBuf};
5
6pub fn cargo() -> PathBuf {
7 get_path_for_executable("cargo")
8}
9
10pub fn rustc() -> PathBuf {
11 get_path_for_executable("rustc")
12}
13
14pub fn rustup() -> PathBuf {
15 get_path_for_executable("rustup")
16}
17
18/// Return a `PathBuf` to use for the given executable.
19///
20/// E.g., `get_path_for_executable("cargo")` may return just `cargo` if that
21/// gives a valid Cargo executable; or it may return a full path to a valid
22/// Cargo.
23fn get_path_for_executable(executable_name: &'static str) -> PathBuf {
24 // The current implementation checks three places for an executable to use:
25 // 1) Appropriate environment variable (erroring if this is set but not a usable executable)
26 // example: for cargo, this checks $CARGO environment variable; for rustc, $RUSTC; etc
27 // 2) `<executable_name>`
28 // example: for cargo, this tries just `cargo`, which will succeed if `cargo` is on the $PATH
29 // 3) `~/.cargo/bin/<executable_name>`
30 // example: for cargo, this tries ~/.cargo/bin/cargo
31 // It seems that this is a reasonable place to try for cargo, rustc, and rustup
32 let env_var = executable_name.to_ascii_uppercase();
33 if let Some(path) = env::var_os(&env_var) {
34 return path.into();
35 }
36
37 if lookup_in_path(executable_name) {
38 return executable_name.into();
39 }
40
41 if let Some(mut path) = home::home_dir() {
42 path.push(".cargo");
43 path.push("bin");
44 path.push(executable_name);
45 if path.is_file() {
46 return path;
47 }
48 }
49 executable_name.into()
50}
51
52fn lookup_in_path(exec: &str) -> bool {
53 let paths = env::var_os("PATH").unwrap_or_default();
54 let mut candidates = env::split_paths(&paths).flat_map(|path| {
55 let candidate = path.join(&exec);
56 let with_exe = if env::consts::EXE_EXTENSION == "" {
57 None
58 } else {
59 Some(candidate.with_extension(env::consts::EXE_EXTENSION))
60 };
61 iter::once(candidate).chain(with_exe)
62 });
63 candidates.any(|it| it.is_file())
64}