Auto merge of #11359 - LucioFranco:lucio/home-crate, r=ehuss

Add `home` crate to cargo crates

### What does this PR try to resolve?

The `home` crate is the crate used by both `rustup` and `cargo` to define their home directories. The crate is quite small but plays an important role in gluing rust tooling together. This PR adds this crate the `crates` folder within cargo to allow the cargo team and the rust project to maintain this small crate.

### Additional information

I've also added both `rust-lang-owners` and `ehuss` as owners of the crate. Once, merged I will archive the old repo.

Reference zulip conversation: https://rust-lang.zulipchat.com/#narrow/stream/246057-t-cargo/topic/Moving.20the.20home.20crate.20into.20rust-lang.20and.20under.20cargo/near/299975263

cc `@weihanglo` `@ehuss`

.github/workflows/main.yml

@@ -99,6 +99,7 @@ jobs:
         CARGO_TARGET_DIR: target
     - run: cargo test -p cargo-platform
     - run: cargo test -p cargo-util
+    - run: cargo test --manifest-path crates/home/Cargo.toml
     - run: cargo test --manifest-path crates/mdman/Cargo.toml
     - run: cargo build --manifest-path crates/credential/cargo-credential-1password/Cargo.toml
     - run: cargo build --manifest-path crates/credential/cargo-credential-gnome-secret/Cargo.toml

crates/home/CHANGELOG.md

@@ -0,0 +1,46 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+<!-- ## [Unreleased] -->
+
+## [0.5.4] - 2022-10-10
+- Add `_with_env` variants of functions to support in-process threaded tests for
+  rustup.
+
+## [0.5.3] - 2020-01-07
+
+Use Rust 1.36.0 as minimum Rust version.
+
+## [0.5.2] - 2020-01-05
+
+*YANKED since it cannot be built on Rust 1.36.0*
+
+### Changed
+- Check for emptiness of `CARGO_HOME` and `RUSTUP_HOME` environment variables.
+- Windows: Use `SHGetFolderPath` to replace `GetUserProfileDirectory` syscall.
+  * Remove `scopeguard` dependency.
+
+## [0.5.1] - 2019-10-12
+### Changed
+- Disable unnecessary features for `scopeguard`. Thanks @mati865.
+
+## [0.5.0] - 2019-08-21
+### Added
+- Add `home_dir` implementation for Windows UWP platforms.
+
+### Fixed
+- Fix `rustup_home` implementation when `RUSTUP_HOME` is an absolute directory.
+- Fix `cargo_home` implementation when `CARGO_HOME` is an absolute directory.
+
+### Removed
+- Remove support for `multirust` folder used in old version of `rustup`.
+
+[Unreleased]: https://github.com/brson/home/compare/v0.5.4...HEAD
+[0.5.4]: https://github.com/brson/home/compare/v0.5.3...v0.5.4
+[0.5.3]: https://github.com/brson/home/compare/v0.5.2...v0.5.3
+[0.5.2]: https://github.com/brson/home/compare/v0.5.1...v0.5.2
+[0.5.1]: https://github.com/brson/home/compare/v0.5.0...v0.5.1
+[0.5.0]: https://github.com/brson/home/compare/0.4.2...v0.5.0

crates/home/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "home"
+version = "0.5.4" # also update `html_root_url` in `src/lib.rs`
+authors = [ "Brian Anderson <andersrb@gmail.com>" ]
+documentation = "https://docs.rs/home"
+edition = "2018"
+include = [
+    "/src",
+    "/Cargo.toml",
+    "/CHANGELOG",
+    "/LICENSE-*",
+    "/README.md",
+]
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+repository = "https://github.com/brson/home"
+description = "Shared definitions of home directories"
+
+[target."cfg(windows)".dependencies.winapi]
+version = "0.3"
+features = [
+    "shlobj",
+    "std",
+    "winerror",
+]

crates/home/LICENSE-APACHE

@@ -0,0 +1 @@
+../../LICENSE-APACHE

crates/home/LICENSE-MIT

@@ -0,0 +1 @@
+../../LICENSE-MIT

crates/home/README.md

@@ -0,0 +1,27 @@
+[![Documentation](https://docs.rs/home/badge.svg)](https://docs.rs/home)
+[![Crates.io](https://img.shields.io/crates/v/home.svg)](https://crates.io/crates/home)
+
+Canonical definitions of `home_dir`, `cargo_home`, and `rustup_home`.
+
+This provides the definition of `home_dir` used by Cargo and rustup,
+as well functions to find the correct value of `CARGO_HOME` and
+`RUSTUP_HOME`.
+
+The definition of `home_dir` provided by the standard library is
+incorrect because it considers the `HOME` environment variable on
+Windows. This causes surprising situations where a Rust program will
+behave differently depending on whether it is run under a Unix
+emulation environment like Cygwin or MinGW. Neither Cargo nor rustup
+use the standard libraries definition - they use the definition here.
+
+This crate further provides two functions, `cargo_home` and
+`rustup_home`, which are the canonical way to determine the location
+that Cargo and rustup store their data.
+
+See [rust-lang/rust#43321].
+
+[rust-lang/rust#43321]: https://github.com/rust-lang/rust/issues/43321
+
+## License
+
+MIT OR Apache-2.0

crates/home/src/env.rs

@@ -0,0 +1,106 @@
+//! Lower-level utilities for mocking the process environment.
+
+use std::{
+    ffi::OsString,
+    io,
+    path::{Path, PathBuf},
+};
+
+/// Permits parameterizing the home functions via the _from variants - used for
+/// in-process unit testing by rustup.
+pub trait Env {
+    /// Return the path to the the users home dir, or None if any error occurs:
+    /// see home_inner.
+    fn home_dir(&self) -> Option<PathBuf>;
+    /// Return the current working directory.
+    fn current_dir(&self) -> io::Result<PathBuf>;
+    /// Get an environment variable, as per std::env::var_os.
+    fn var_os(&self, key: &str) -> Option<OsString>;
+}
+
+/// Implements Env for the OS context, both Unix style and Windows.
+///
+/// This is trait permits in-process testing by providing a control point to
+/// allow in-process divergence on what is normally process wide state.
+///
+/// Implementations should be provided by whatever testing framework the caller
+/// is using. Code that is not performing in-process threaded testing requiring
+/// isolated rustup/cargo directories does not need this trait or the _from
+/// functions.
+pub struct OsEnv;
+impl Env for OsEnv {
+    fn home_dir(&self) -> Option<PathBuf> {
+        crate::home_dir_inner()
+    }
+    fn current_dir(&self) -> io::Result<PathBuf> {
+        std::env::current_dir()
+    }
+    fn var_os(&self, key: &str) -> Option<OsString> {
+        std::env::var_os(key)
+    }
+}
+
+pub const OS_ENV: OsEnv = OsEnv {};
+
+/// Returns the path of the current user's home directory from [`Env::home_dir`].
+pub fn home_dir_with_env(env: &dyn Env) -> Option<PathBuf> {
+    env.home_dir()
+}
+
+/// Variant of cargo_home where the environment source is parameterized. This is
+/// specifically to support in-process testing scenarios as environment
+/// variables and user home metadata are normally process global state. See the
+/// [`Env`] trait.
+pub fn cargo_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
+    let cwd = env.current_dir()?;
+    cargo_home_with_cwd_env(env, &cwd)
+}
+
+/// Variant of cargo_home_with_cwd where the environment source is
+/// parameterized. This is specifically to support in-process testing scenarios
+/// as environment variables and user home metadata are normally process global
+/// state. See the OsEnv trait.
+pub fn cargo_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
+    match env.var_os("CARGO_HOME").filter(|h| !h.is_empty()) {
+        Some(home) => {
+            let home = PathBuf::from(home);
+            if home.is_absolute() {
+                Ok(home)
+            } else {
+                Ok(cwd.join(&home))
+            }
+        }
+        _ => home_dir_with_env(env)
+            .map(|p| p.join(".cargo"))
+            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find cargo home dir")),
+    }
+}
+
+/// Variant of cargo_home_with_cwd where the environment source is
+/// parameterized. This is specifically to support in-process testing scenarios
+/// as environment variables and user home metadata are normally process global
+/// state. See the OsEnv trait.
+pub fn rustup_home_with_env(env: &dyn Env) -> io::Result<PathBuf> {
+    let cwd = env.current_dir()?;
+    rustup_home_with_cwd_env(env, &cwd)
+}
+
+/// Variant of cargo_home_with_cwd where the environment source is
+/// parameterized. This is specifically to support in-process testing scenarios
+/// as environment variables and user home metadata are normally process global
+/// state. See the OsEnv trait.
+pub fn rustup_home_with_cwd_env(env: &dyn Env, cwd: &Path) -> io::Result<PathBuf> {
+    match env.var_os("RUSTUP_HOME").filter(|h| !h.is_empty()) {
+        Some(home) => {
+            let home = PathBuf::from(home);
+            if home.is_absolute() {
+                Ok(home)
+            } else {
+                Ok(cwd.join(&home))
+            }
+        }
+        _ => home_dir_with_env(env)
+            .map(|d| d.join(".rustup"))
+            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find rustup home dir")),
+    }
+}

crates/home/src/lib.rs

@@ -0,0 +1,149 @@
+//! Canonical definitions of `home_dir`, `cargo_home`, and `rustup_home`.
+//!
+//! This provides the definition of `home_dir` used by Cargo and
+//! rustup, as well functions to find the correct value of
+//! `CARGO_HOME` and `RUSTUP_HOME`.
+//!
+//! See also the [`dirs`](https://docs.rs/dirs) crate.
+//!
+//! _Note that as of 2019/08/06 it appears that cargo uses this crate. And
+//! rustup has used this crate since 2019/08/21._
+//!
+//! The definition of `home_dir` provided by the standard library is
+//! incorrect because it considers the `HOME` environment variable on
+//! Windows. This causes surprising situations where a Rust program
+//! will behave differently depending on whether it is run under a
+//! Unix emulation environment like Cygwin or MinGW. Neither Cargo nor
+//! rustup use the standard libraries definition - they use the
+//! definition here.
+//!
+//! This crate further provides two functions, `cargo_home` and
+//! `rustup_home`, which are the canonical way to determine the
+//! location that Cargo and rustup store their data.
+//!
+//! See also this [discussion].
+//!
+//! [discussion]: https://github.com/rust-lang/rust/pull/46799#issuecomment-361156935
+
+#![doc(html_root_url = "https://docs.rs/home/0.5.4")]
+#![deny(rust_2018_idioms)]
+
+pub mod env;
+
+#[cfg(windows)]
+mod windows;
+
+use std::io;
+use std::path::{Path, PathBuf};
+
+/// Returns the path of the current user's home directory if known.
+///
+/// # Unix
+///
+/// Returns the value of the `HOME` environment variable if it is set
+/// and not equal to the empty string. Otherwise, it tries to determine the
+/// home directory by invoking the `getpwuid_r` function on the UID of the
+/// current user.
+///
+/// # Windows
+///
+/// Returns the value of the `USERPROFILE` environment variable if it
+/// is set and not equal to the empty string. If both do not exist,
+/// [`SHGetFolderPathW`][msdn] is used to return the appropriate path.
+///
+/// [msdn]: https://docs.microsoft.com/en-us/windows/win32/api/shlobj_core/nf-shlobj_core-shgetfolderpathw
+///
+/// # Examples
+///
+/// ```
+/// match home::home_dir() {
+///     Some(path) => println!("{}", path.display()),
+///     None => println!("Impossible to get your home dir!"),
+/// }
+/// ```
+pub fn home_dir() -> Option<PathBuf> {
+    env::home_dir_with_env(&env::OS_ENV)
+}
+
+#[cfg(windows)]
+use windows::home_dir_inner;
+
+#[cfg(any(unix, target_os = "redox"))]
+fn home_dir_inner() -> Option<PathBuf> {
+    #[allow(deprecated)]
+    std::env::home_dir()
+}
+
+/// Returns the storage directory used by Cargo, often knowns as
+/// `.cargo` or `CARGO_HOME`.
+///
+/// It returns one of the following values, in this order of
+/// preference:
+///
+/// - The value of the `CARGO_HOME` environment variable, if it is
+///   an absolute path.
+/// - The value of the current working directory joined with the value
+///   of the `CARGO_HOME` environment variable, if `CARGO_HOME` is a
+///   relative directory.
+/// - The `.cargo` directory in the user's home directory, as reported
+///   by the `home_dir` function.
+///
+/// # Errors
+///
+/// This function fails if it fails to retrieve the current directory,
+/// or if the home directory cannot be determined.
+///
+/// # Examples
+///
+/// ```
+/// match home::cargo_home() {
+///     Ok(path) => println!("{}", path.display()),
+///     Err(err) => eprintln!("Cannot get your cargo home dir: {:?}", err),
+/// }
+/// ```
+pub fn cargo_home() -> io::Result<PathBuf> {
+    env::cargo_home_with_env(&env::OS_ENV)
+}
+
+/// Returns the storage directory used by Cargo within `cwd`.
+/// For more details, see [`cargo_home`](fn.cargo_home.html).
+pub fn cargo_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {
+    env::cargo_home_with_cwd_env(&env::OS_ENV, cwd)
+}
+
+/// Returns the storage directory used by rustup, often knowns as
+/// `.rustup` or `RUSTUP_HOME`.
+///
+/// It returns one of the following values, in this order of
+/// preference:
+///
+/// - The value of the `RUSTUP_HOME` environment variable, if it is
+///   an absolute path.
+/// - The value of the current working directory joined with the value
+///   of the `RUSTUP_HOME` environment variable, if `RUSTUP_HOME` is a
+///   relative directory.
+/// - The `.rustup` directory in the user's home directory, as reported
+///   by the `home_dir` function.
+///
+/// # Errors
+///
+/// This function fails if it fails to retrieve the current directory,
+/// or if the home directory cannot be determined.
+///
+/// # Examples
+///
+/// ```
+/// match home::rustup_home() {
+///     Ok(path) => println!("{}", path.display()),
+///     Err(err) => eprintln!("Cannot get your rustup home dir: {:?}", err),
+/// }
+/// ```
+pub fn rustup_home() -> io::Result<PathBuf> {
+    env::rustup_home_with_env(&env::OS_ENV)
+}
+
+/// Returns the storage directory used by rustup within `cwd`.
+/// For more details, see [`rustup_home`](fn.rustup_home.html).
+pub fn rustup_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {
+    env::rustup_home_with_cwd_env(&env::OS_ENV, cwd)
+}