1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

use std::path::PathBuf;
use std::process::Command;

use rustc_version::{Version, VersionMeta};

use crate::errors::*;
use crate::extensions::{env_program, CommandExt};
use crate::shell::MessageInfo;
use crate::{Host, Target};

#[derive(Debug)]
pub struct TargetList {
    pub triples: Vec<String>,
}

impl TargetList {
    #[must_use]
    pub fn contains(&self, triple: &str) -> bool {
        self.triples.iter().any(|t| t == triple)
    }
}

pub trait VersionMetaExt {
    fn host(&self) -> Host;
    fn needs_interpreter(&self) -> bool;
    fn commit_hash(&self) -> String;
}

impl VersionMetaExt for VersionMeta {
    fn host(&self) -> Host {
        Host::from(&*self.host)
    }

    fn needs_interpreter(&self) -> bool {
        self.semver < Version::new(1, 19, 0)
    }

    fn commit_hash(&self) -> String {
        self.commit_hash.as_ref().map_or_else(
            || hash_from_version_string(&self.short_version_string, 2),
            |x| short_commit_hash(x),
        )
    }
}

fn short_commit_hash(hash: &str) -> String {
    // short version hashes are always 9 digits
    //  https://github.com/rust-lang/cargo/pull/10579
    const LENGTH: usize = 9;

    hash.get(..LENGTH)
        .unwrap_or_else(|| panic!("commit hash must be at least {LENGTH} characters long"))
        .to_owned()
}

#[must_use]
pub fn hash_from_version_string(version: &str, index: usize) -> String {
    let is_hash = |x: &str| x.chars().all(|c| c.is_ascii_hexdigit());
    let is_date = |x: &str| x.chars().all(|c| matches!(c, '-' | '0'..='9'));

    // the version can be one of two forms:
    //   multirust channel string: `"1.61.0 (fe5b13d68 2022-05-18)"`
    //   short version string: `"rustc 1.61.0 (fe5b13d68 2022-05-18)"`
    // want to extract the commit hash if we can, if not, just hash the string.
    if let Some((commit, date)) = version
        .splitn(index + 1, ' ')
        .nth(index)
        .and_then(|meta| meta.strip_prefix('('))
        .and_then(|meta| meta.strip_suffix(')'))
        .and_then(|meta| meta.split_once(' '))
    {
        if is_hash(commit) && is_date(date) {
            return short_commit_hash(commit);
        }
    }

    // fallback: can't extract the hash. just create a hash of the version string.
    let buffer = const_sha1::ConstBuffer::from_slice(version.as_bytes());
    short_commit_hash(&const_sha1::sha1(&buffer).to_string())
}

#[must_use]
pub fn rustc_command() -> Command {
    Command::new(env_program("RUSTC", "rustc"))
}

pub fn target_list(msg_info: &mut MessageInfo) -> Result<TargetList> {
    rustc_command()
        .args(&["--print", "target-list"])
        .run_and_get_stdout(msg_info)
        .map(|s| TargetList {
            triples: s.lines().map(|l| l.to_owned()).collect(),
        })
}

pub fn sysroot(host: &Host, target: &Target, msg_info: &mut MessageInfo) -> Result<PathBuf> {
    let mut stdout = rustc_command()
        .args(&["--print", "sysroot"])
        .run_and_get_stdout(msg_info)?
        .trim()
        .to_owned();

    // On hosts other than Linux, specify the correct toolchain path.
    if host != &Host::X86_64UnknownLinuxGnu && target.needs_docker() {
        stdout = stdout.replacen(host.triple(), Host::X86_64UnknownLinuxGnu.triple(), 1);
    }

    Ok(PathBuf::from(stdout))
}

pub fn get_sysroot(
    host: &Host,
    target: &Target,
    channel: Option<&str>,
    msg_info: &mut MessageInfo,
) -> Result<(String, PathBuf)> {
    let mut sysroot = sysroot(host, target, msg_info)?;
    let default_toolchain = sysroot
        .file_name()
        .and_then(|file_name| file_name.to_str())
        .ok_or_else(|| eyre::eyre!("couldn't get toolchain name"))?;
    let toolchain = if let Some(channel) = channel {
        [channel]
            .iter()
            .cloned()
            .chain(default_toolchain.splitn(2, '-').skip(1))
            .collect::<Vec<_>>()
            .join("-")
    } else {
        default_toolchain.to_owned()
    };
    sysroot.set_file_name(&toolchain);

    Ok((toolchain, sysroot))
}

pub fn version_meta() -> Result<rustc_version::VersionMeta> {
    rustc_version::version_meta().wrap_err("couldn't fetch the `rustc` version")
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn hash_from_rustc() {
        assert_eq!(
            hash_from_version_string("1.61.0 (fe5b13d68 2022-05-18)", 1),
            "fe5b13d68"
        );
        assert_eq!(
            hash_from_version_string("rustc 1.61.0 (fe5b13d68 2022-05-18)", 2),
            "fe5b13d68"
        );
    }
}