project_model/toolchain_info/
target_tuple.rs

1//! Functionality to discover the current build target(s).
2use std::path::Path;
3
4use anyhow::Context;
5use rustc_hash::FxHashMap;
6use toolchain::Tool;
7
8use crate::{
9    Sysroot, cargo_config_file::CargoConfigFile, toolchain_info::QueryConfig, utf8_stdout,
10};
11
12/// For cargo, runs `cargo -Zunstable-options config get build.target` to get the configured project target(s).
13/// For rustc, runs `rustc --print -vV` to get the host target.
14pub fn get(
15    config: QueryConfig<'_>,
16    target: Option<&str>,
17    extra_env: &FxHashMap<String, Option<String>>,
18) -> anyhow::Result<Vec<String>> {
19    let _p = tracing::info_span!("target_tuple::get").entered();
20    if let Some(target) = target {
21        return Ok(vec![target.to_owned()]);
22    }
23
24    let (sysroot, current_dir) = match config {
25        QueryConfig::Cargo(sysroot, cargo_toml, config_file) => {
26            match config_file.as_ref().and_then(cargo_config_build_target) {
27                Some(it) => return Ok(it),
28                None => (sysroot, cargo_toml.parent().as_ref()),
29            }
30        }
31        QueryConfig::Rustc(sysroot, current_dir) => (sysroot, current_dir),
32    };
33    rustc_discover_host_tuple(extra_env, sysroot, current_dir).map(|it| vec![it])
34}
35
36fn rustc_discover_host_tuple(
37    extra_env: &FxHashMap<String, Option<String>>,
38    sysroot: &Sysroot,
39    current_dir: &Path,
40) -> anyhow::Result<String> {
41    let mut cmd = sysroot.tool(Tool::Rustc, current_dir, extra_env);
42    cmd.arg("-vV");
43    let stdout = utf8_stdout(&mut cmd)
44        .with_context(|| format!("unable to discover host platform via `{cmd:?}`"))?;
45    let field = "host: ";
46    let target = stdout.lines().find_map(|l| l.strip_prefix(field));
47    if let Some(target) = target {
48        Ok(target.to_owned())
49    } else {
50        // If we fail to resolve the host platform, it's not the end of the world.
51        Err(anyhow::format_err!("rustc -vV did not report host platform, got:\n{}", stdout))
52    }
53}
54
55fn cargo_config_build_target(config: &CargoConfigFile) -> Option<Vec<String>> {
56    match parse_json_cargo_config_build_target(config) {
57        Ok(v) => v,
58        Err(e) => {
59            tracing::debug!("Failed to discover cargo config build target {e:?}");
60            None
61        }
62    }
63}
64
65// Parses `"build.target = [target-tuple, target-tuple, ...]"` or `"build.target = "target-tuple"`
66fn parse_json_cargo_config_build_target(
67    config: &CargoConfigFile,
68) -> anyhow::Result<Option<Vec<String>>> {
69    let target = config.get("build").and_then(|v| v.as_object()).and_then(|m| m.get("target"));
70    match target {
71        Some(serde_json::Value::String(s)) => Ok(Some(vec![s.to_owned()])),
72        Some(v) => serde_json::from_value(v.clone())
73            .map(Option::Some)
74            .context("Failed to parse `build.target` as an array of target"),
75        // t`error: config value `build.target` is not set`, in which case we
76        // don't wanna log the error
77        None => Ok(None),
78    }
79}
80
81#[cfg(test)]
82mod tests {
83    use paths::{AbsPathBuf, Utf8PathBuf};
84
85    use crate::{ManifestPath, Sysroot};
86
87    use super::*;
88
89    #[test]
90    fn cargo() {
91        let manifest_path = concat!(env!("CARGO_MANIFEST_DIR"), "/Cargo.toml");
92        let sysroot = Sysroot::empty();
93        let manifest_path =
94            ManifestPath::try_from(AbsPathBuf::assert(Utf8PathBuf::from(manifest_path))).unwrap();
95        let cfg = QueryConfig::Cargo(&sysroot, &manifest_path, &None);
96        assert!(get(cfg, None, &FxHashMap::default()).is_ok());
97    }
98
99    #[test]
100    fn rustc() {
101        let sysroot = Sysroot::empty();
102        let cfg = QueryConfig::Rustc(&sysroot, env!("CARGO_MANIFEST_DIR").as_ref());
103        assert!(get(cfg, None, &FxHashMap::default()).is_ok());
104    }
105}
project_model/toolchain_info/target_tuple.rs

project_model/toolchain_info/
target_tuple.rs
