sipp-sys 0.1.0

//! Shared deterministic helpers for `crates/sys` build-support tests.
//!
//! Provides temporary directories and serialized environment-variable mutation
//! so build-script helpers can be tested without depending on local machine state.

use std::env;
use std::ffi::OsString;
use std::fs;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::{Mutex, MutexGuard};

static NEXT_TEMP_ID: AtomicUsize = AtomicUsize::new(0);
static ENV_LOCK: Mutex<()> = Mutex::new(());

pub(crate) struct TempDir {
    path: PathBuf,
}

impl TempDir {
    pub(crate) fn new(label: &str) -> Self {
        let id = NEXT_TEMP_ID.fetch_add(1, Ordering::Relaxed);
        let path = env::temp_dir().join(format!("sipp-sys-{label}-{}-{id}", std::process::id()));
        if path.exists() {
            fs::remove_dir_all(&path).expect("remove stale temp dir");
        }
        fs::create_dir_all(&path).expect("create temp dir");
        Self { path }
    }

    pub(crate) fn path(&self) -> &Path {
        &self.path
    }

    pub(crate) fn join(&self, path: impl AsRef<Path>) -> PathBuf {
        self.path.join(path)
    }
}

impl Drop for TempDir {
    fn drop(&mut self) {
        let _ = fs::remove_dir_all(&self.path);
    }
}

pub(crate) struct EnvGuard {
    saved: Vec<(String, Option<OsString>)>,
    _lock: MutexGuard<'static, ()>,
}

impl EnvGuard {
    pub(crate) fn new(vars: &[(&str, Option<&str>)]) -> Self {
        let lock = ENV_LOCK
            .lock()
            .unwrap_or_else(|poisoned| poisoned.into_inner());
        let saved = vars
            .iter()
            .map(|(name, _)| ((*name).to_owned(), env::var_os(name)))
            .collect();

        for (name, value) in vars {
            if let Some(value) = value {
                env::set_var(name, value);
            } else {
                env::remove_var(name);
            }
        }

        Self { saved, _lock: lock }
    }
}

impl Drop for EnvGuard {
    fn drop(&mut self) {
        for (name, value) in &self.saved {
            if let Some(value) = value {
                env::set_var(name, value);
            } else {
                env::remove_var(name);
            }
        }
    }
}