zccache-core 1.5.0

//! Configuration types for zccache.

use crate::NormalizedPath;
use std::ffi::OsString;
use std::path::Path;

/// Environment variable used to override the zccache cache root.
pub const CACHE_DIR_ENV: &str = "ZCCACHE_CACHE_DIR";

/// Top-level configuration for zccache.
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
#[serde(default)]
pub struct Config {
    /// Path to the artifact cache directory.
    pub cache_dir: NormalizedPath,
    /// Maximum artifact cache size in bytes.
    pub max_cache_size: u64,
    /// Daemon idle timeout in seconds before auto-shutdown.
    pub idle_timeout_secs: u64,
    /// Whether to enable the file watcher.
    pub enable_watcher: bool,
    /// Whether to use polling fallback for file watching.
    pub watcher_poll_fallback: bool,
    /// Log level filter (e.g., "info", "debug", "trace").
    pub log_level: String,
    /// Maximum in-memory cache budget in bytes (default: 1 GB).
    pub max_memory_bytes: u64,
    /// How often (in seconds) the memory eviction background task runs (default: 30).
    pub eviction_interval_secs: u64,
    /// How often (in seconds) the disk artifact GC task runs (default: 300).
    pub disk_gc_interval_secs: u64,
}

impl Default for Config {
    fn default() -> Self {
        Self {
            cache_dir: default_cache_dir(),
            max_cache_size: 10 * 1024 * 1024 * 1024, // 10 GB
            idle_timeout_secs: 3600,
            enable_watcher: true,
            watcher_poll_fallback: false,
            log_level: String::from("info"),
            max_memory_bytes: 1_073_741_824, // 1 GB
            eviction_interval_secs: 30,
            disk_gc_interval_secs: 300,
        }
    }
}

/// Returns the configured cache directory path.
///
/// If `ZCCACHE_CACHE_DIR` is set and non-empty, it is used as the cache root.
/// Relative override paths are made absolute against the current working
/// directory so the daemon and CLI derive the same subpaths when spawned
/// together. If unset, this falls back to `~/.zccache` on all platforms.
#[must_use]
pub fn default_cache_dir() -> NormalizedPath {
    default_cache_dir_from_env_value(std::env::var_os(CACHE_DIR_ENV))
}

fn default_cache_dir_from_env_value(value: Option<OsString>) -> NormalizedPath {
    cache_dir_from_env_value(value).unwrap_or_else(|| dirs_fallback().join(".zccache"))
}

/// Returns the cache directory override from `ZCCACHE_CACHE_DIR`, if set.
#[must_use]
pub fn cache_dir_override() -> Option<NormalizedPath> {
    cache_dir_from_env_value(std::env::var_os(CACHE_DIR_ENV))
}

/// Returns the directory for content-addressed compiled outputs.
#[must_use]
pub fn artifacts_dir() -> NormalizedPath {
    artifacts_dir_from_cache_dir(&default_cache_dir())
}

/// Returns the directory for in-progress artifact writes (cleaned on startup).
#[must_use]
pub fn tmp_dir() -> NormalizedPath {
    tmp_dir_from_cache_dir(&default_cache_dir())
}

/// Returns the base directory for compiler-injected depfiles.
///
/// Each daemon instance creates a `{pid}-{instance}` subdirectory here.
/// Stale subdirectories from dead daemon processes are cleaned on startup.
#[must_use]
pub fn depfile_dir() -> NormalizedPath {
    depfile_dir_from_cache_dir(&default_cache_dir())
}

/// Remove legacy zccache state left directly under the OS temp directory.
///
/// Older builds stored the full cache root at `%TEMP%/.zccache` and created
/// depfile directories as `%TEMP%/zccache-depfiles-*`. Those paths are safe to
/// remove only when they are exact legacy matches and do not point at the
/// current cache directory.
pub fn cleanup_legacy_temp_root_state<F>(
    temp_root: &Path,
    current_cache_dir: &Path,
    is_alive: F,
) -> usize
where
    F: Fn(u32) -> bool,
{
    let mut cleaned = cleanup_legacy_temp_cache_dir(temp_root, current_cache_dir);
    cleaned += cleanup_legacy_temp_depfile_dirs(temp_root, is_alive);
    cleaned
}

/// Remove stale depfile directories from previous (dead) daemon instances.
///
/// Scans [`depfile_dir()`] for subdirectories matching `{pid}-{instance}`.
/// If the PID is no longer alive (per `is_alive`), removes the directory.
/// Returns the number of directories cleaned up.
pub fn cleanup_stale_depfile_dirs<F>(is_alive: F) -> usize
where
    F: Fn(u32) -> bool,
{
    let base = depfile_dir();
    let entries = match std::fs::read_dir(&base) {
        Ok(entries) => entries,
        Err(_) => return 0,
    };

    let mut cleaned = 0;
    for entry in entries.flatten() {
        let path = entry.path();
        if !path.is_dir() {
            continue;
        }
        let name = match path.file_name().and_then(|n| n.to_str()) {
            Some(n) => n,
            None => continue,
        };
        let pid: u32 = match name.split('-').next().and_then(|s| s.parse().ok()) {
            Some(p) => p,
            None => continue,
        };
        if !is_alive(pid) {
            match std::fs::remove_dir_all(&path) {
                Ok(()) => {
                    cleaned += 1;
                    tracing::info!(path = %path.display(), "removed stale depfile dir");
                }
                Err(e) => {
                    tracing::warn!(
                        path = %path.display(),
                        "failed to remove stale depfile dir: {e}"
                    );
                }
            }
        }
    }
    cleaned
}

fn cleanup_legacy_temp_cache_dir(temp_root: &Path, current_cache_dir: &Path) -> usize {
    let legacy_cache_dir = temp_root.join(".zccache");
    if path_is_or_contains(&legacy_cache_dir, current_cache_dir) {
        return 0;
    }

    if !is_real_dir(&legacy_cache_dir) {
        return 0;
    }

    match std::fs::remove_dir_all(&legacy_cache_dir) {
        Ok(()) => {
            tracing::info!(path = %legacy_cache_dir.display(), "removed legacy temp cache dir");
            1
        }
        Err(e) => {
            tracing::warn!(
                path = %legacy_cache_dir.display(),
                "failed to remove legacy temp cache dir: {e}"
            );
            0
        }
    }
}

fn cleanup_legacy_temp_depfile_dirs<F>(temp_root: &Path, is_alive: F) -> usize
where
    F: Fn(u32) -> bool,
{
    let entries = match std::fs::read_dir(temp_root) {
        Ok(entries) => entries,
        Err(_) => return 0,
    };

    let mut cleaned = 0;
    for entry in entries.flatten() {
        let path = entry.path();
        let file_name = entry.file_name();
        let name = match file_name.to_str() {
            Some(name) if name.starts_with("zccache-depfiles-") => name,
            _ => continue,
        };

        if !is_real_dir(&path) {
            continue;
        }

        let pid = match legacy_temp_depfile_pid(name) {
            Some(pid) => pid,
            None => continue,
        };

        if is_alive(pid) {
            continue;
        }

        match std::fs::remove_dir_all(&path) {
            Ok(()) => {
                cleaned += 1;
                tracing::info!(path = %path.display(), "removed legacy temp depfile dir");
            }
            Err(e) => {
                tracing::warn!(
                    path = %path.display(),
                    "failed to remove legacy temp depfile dir: {e}"
                );
            }
        }
    }
    cleaned
}

fn legacy_temp_depfile_pid(name: &str) -> Option<u32> {
    let suffix = name.strip_prefix("zccache-depfiles-")?;
    suffix.split('-').next()?.parse().ok()
}

fn is_real_dir(path: &Path) -> bool {
    std::fs::symlink_metadata(path)
        .map(|meta| meta.file_type().is_dir())
        .unwrap_or(false)
}

fn path_is_or_contains(parent: &Path, child: &Path) -> bool {
    if child.starts_with(parent) {
        return true;
    }

    let parent = match std::fs::canonicalize(parent) {
        Ok(parent) => parent,
        Err(_) => return false,
    };
    std::fs::canonicalize(child)
        .map(|child| child.starts_with(parent))
        .unwrap_or(false)
}

/// Returns the directory for serialized dependency graph storage (future).
#[must_use]
pub fn depgraph_dir() -> NormalizedPath {
    depgraph_dir_from_cache_dir(&default_cache_dir())
}

/// Returns the path to the artifact index database.
#[must_use]
pub fn index_path() -> NormalizedPath {
    index_path_from_cache_dir(&default_cache_dir())
}

/// Returns the directory for crash dump files.
#[must_use]
pub fn crash_dump_dir() -> NormalizedPath {
    crash_dump_dir_from_cache_dir(&default_cache_dir())
}

/// Returns the directory for daemon log files.
#[must_use]
pub fn log_dir() -> NormalizedPath {
    log_dir_from_cache_dir(&default_cache_dir())
}

fn artifacts_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("artifacts")
}

fn tmp_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("tmp")
}

fn depfile_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    tmp_dir_from_cache_dir(cache_dir).join("depfiles")
}

fn depgraph_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("depgraph")
}

fn index_path_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("index.redb")
}

fn crash_dump_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("crashes")
}

fn log_dir_from_cache_dir(cache_dir: &NormalizedPath) -> NormalizedPath {
    cache_dir.join("logs")
}

fn dirs_fallback() -> NormalizedPath {
    std::env::var("HOME")
        .or_else(|_| std::env::var("USERPROFILE"))
        .map(NormalizedPath::from)
        .unwrap_or_else(|_| ".".into())
}

fn cache_dir_from_env_value(value: Option<OsString>) -> Option<NormalizedPath> {
    let value = value?;
    if value.is_empty() {
        return None;
    }
    Some(normalize_cache_dir_override(std::path::Path::new(&value)))
}

fn normalize_cache_dir_override(path: &std::path::Path) -> NormalizedPath {
    if path.is_absolute() {
        path.into()
    } else {
        std::env::current_dir()
            .unwrap_or_default()
            .join(path)
            .into()
    }
}

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

    #[test]
    fn default_cache_dir_ends_with_zccache() {
        let dir = default_cache_dir_from_env_value(None);
        assert!(dir.ends_with(".zccache"));
    }

    #[test]
    fn cache_dir_override_uses_non_empty_env_value() {
        let root = tempfile::tempdir().unwrap();
        let override_dir = root.path().join("zc");
        let cache_dir =
            default_cache_dir_from_env_value(Some(override_dir.clone().into_os_string()));

        assert_eq!(cache_dir, override_dir);
        assert_eq!(
            artifacts_dir_from_cache_dir(&cache_dir),
            override_dir.join("artifacts")
        );
        assert_eq!(tmp_dir_from_cache_dir(&cache_dir), override_dir.join("tmp"));
        assert_eq!(
            depgraph_dir_from_cache_dir(&cache_dir),
            override_dir.join("depgraph")
        );
        assert_eq!(
            index_path_from_cache_dir(&cache_dir),
            override_dir.join("index.redb")
        );
        assert_eq!(
            crash_dump_dir_from_cache_dir(&cache_dir),
            override_dir.join("crashes")
        );
        assert_eq!(
            log_dir_from_cache_dir(&cache_dir),
            override_dir.join("logs")
        );
    }

    #[test]
    fn cache_dir_override_ignores_empty_env_value() {
        assert!(cache_dir_from_env_value(Some(OsString::new())).is_none());
    }

    #[test]
    fn relative_cache_dir_override_is_made_absolute() {
        let override_dir = cache_dir_from_env_value(Some(OsString::from("target/../zc"))).unwrap();
        assert!(override_dir.is_absolute());
        assert!(override_dir.ends_with("zc"));
    }

    #[test]
    fn crash_dump_dir_ends_with_crashes() {
        let (_temp, cache) = temp_cache_dir();
        let dir = crash_dump_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("crashes"));
    }

    #[test]
    fn crash_dump_dir_is_under_cache_dir() {
        let (_temp, cache) = temp_cache_dir();
        let crashes = crash_dump_dir_from_cache_dir(&cache);
        assert!(crashes.starts_with(&cache));
    }

    #[test]
    fn log_dir_ends_with_logs() {
        let (_temp, cache) = temp_cache_dir();
        let dir = log_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("logs"));
    }

    #[test]
    fn log_dir_is_under_cache_dir() {
        let (_temp, cache) = temp_cache_dir();
        let logs = log_dir_from_cache_dir(&cache);
        assert!(logs.starts_with(&cache));
    }

    #[test]
    fn artifacts_dir_ends_with_artifacts() {
        let (_temp, cache) = temp_cache_dir();
        let dir = artifacts_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("artifacts"));
        assert!(dir.starts_with(cache));
    }

    #[test]
    fn tmp_dir_ends_with_tmp() {
        let (_temp, cache) = temp_cache_dir();
        let dir = tmp_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("tmp"));
        assert!(dir.starts_with(cache));
    }

    #[test]
    fn depgraph_dir_ends_with_depgraph() {
        let (_temp, cache) = temp_cache_dir();
        let dir = depgraph_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("depgraph"));
        assert!(dir.starts_with(cache));
    }

    #[test]
    fn depfile_dir_under_tmp() {
        let (_temp, cache) = temp_cache_dir();
        let tmp = tmp_dir_from_cache_dir(&cache);
        let dir = depfile_dir_from_cache_dir(&cache);
        assert!(dir.ends_with("depfiles"));
        assert!(dir.starts_with(tmp));
    }

    #[test]
    fn cleanup_stale_depfile_dirs_removes_dead() {
        let base = tempfile::tempdir().unwrap();
        let depfiles = base.path().join("depfiles");
        std::fs::create_dir_all(&depfiles).unwrap();

        // Create a "dead" dir (PID 99999999 unlikely alive).
        std::fs::create_dir(depfiles.join("99999999-0")).unwrap();
        // Create a non-matching dir (should be left alone).
        std::fs::create_dir(depfiles.join("not-a-pid")).unwrap();

        let entries = std::fs::read_dir(&depfiles).unwrap();
        let dirs: Vec<_> = entries.flatten().collect();
        assert_eq!(dirs.len(), 2);

        // Use a custom is_alive that says nothing is alive.
        let cleaned = cleanup_stale_with_base(&depfiles, |_| false);
        assert_eq!(cleaned, 1); // only the parseable one removed

        // "not-a-pid" should still exist.
        assert!(depfiles.join("not-a-pid").is_dir());
        assert!(!depfiles.join("99999999-0").exists());
    }

    #[test]
    fn cleanup_stale_depfile_dirs_skips_alive() {
        let base = tempfile::tempdir().unwrap();
        let depfiles = base.path().join("depfiles");
        std::fs::create_dir_all(&depfiles).unwrap();
        std::fs::create_dir(depfiles.join("12345-0")).unwrap();

        let cleaned = cleanup_stale_with_base(&depfiles, |_| true);
        assert_eq!(cleaned, 0);
        assert!(depfiles.join("12345-0").is_dir());
    }

    #[test]
    fn cleanup_stale_depfile_dirs_empty() {
        // Non-existent directory returns 0.
        let cleaned = cleanup_stale_with_base(std::path::Path::new("/nonexistent/path"), |_| false);
        assert_eq!(cleaned, 0);
    }

    #[test]
    fn cleanup_legacy_temp_root_state_removes_legacy_dirs() {
        let temp_root = tempfile::tempdir().unwrap();
        let current_cache_dir = tempfile::tempdir().unwrap();

        let legacy_cache = temp_root.path().join(".zccache");
        std::fs::create_dir_all(&legacy_cache).unwrap();
        std::fs::write(legacy_cache.join("sentinel"), "legacy").unwrap();

        let dead_depfile = temp_root.path().join("zccache-depfiles-1234-0");
        std::fs::create_dir_all(&dead_depfile).unwrap();
        std::fs::write(dead_depfile.join("sentinel"), "dead").unwrap();

        let live_depfile = temp_root.path().join("zccache-depfiles-4321-0");
        std::fs::create_dir_all(&live_depfile).unwrap();

        let unrelated = temp_root.path().join("not-legacy");
        std::fs::create_dir_all(&unrelated).unwrap();

        let cleaned =
            cleanup_legacy_temp_root_state(temp_root.path(), current_cache_dir.path(), |pid| {
                pid != 1234
            });

        assert_eq!(cleaned, 2);
        assert!(!legacy_cache.exists());
        assert!(!dead_depfile.exists());
        assert!(live_depfile.exists());
        assert!(unrelated.exists());
    }

    #[test]
    fn cleanup_legacy_temp_root_state_skips_current_cache_dir() {
        let temp_root = tempfile::tempdir().unwrap();
        let current_cache_dir = temp_root.path().join(".zccache");
        std::fs::create_dir_all(&current_cache_dir).unwrap();
        std::fs::write(current_cache_dir.join("sentinel"), "keep").unwrap();

        let cleaned =
            cleanup_legacy_temp_root_state(temp_root.path(), &current_cache_dir, |_| false);

        assert_eq!(cleaned, 0);
        assert!(current_cache_dir.exists());
        assert_eq!(
            std::fs::read_to_string(current_cache_dir.join("sentinel")).unwrap(),
            "keep"
        );
    }

    #[test]
    fn cleanup_legacy_temp_root_state_skips_parent_of_current_cache_dir() {
        let temp_root = tempfile::tempdir().unwrap();
        let current_cache_dir = temp_root.path().join(".zccache").join("current");
        std::fs::create_dir_all(&current_cache_dir).unwrap();
        std::fs::write(current_cache_dir.join("sentinel"), "keep").unwrap();

        let cleaned =
            cleanup_legacy_temp_root_state(temp_root.path(), &current_cache_dir, |_| false);

        assert_eq!(cleaned, 0);
        assert!(current_cache_dir.exists());
        assert_eq!(
            std::fs::read_to_string(current_cache_dir.join("sentinel")).unwrap(),
            "keep"
        );
    }

    /// Test helper: runs cleanup logic against an arbitrary base dir.
    fn cleanup_stale_with_base<F>(base: &std::path::Path, is_alive: F) -> usize
    where
        F: Fn(u32) -> bool,
    {
        let entries = match std::fs::read_dir(base) {
            Ok(entries) => entries,
            Err(_) => return 0,
        };
        let mut cleaned = 0;
        for entry in entries.flatten() {
            let path = entry.path();
            if !path.is_dir() {
                continue;
            }
            let name = match path.file_name().and_then(|n| n.to_str()) {
                Some(n) => n,
                None => continue,
            };
            let pid: u32 = match name.split('-').next().and_then(|s| s.parse().ok()) {
                Some(p) => p,
                None => continue,
            };
            if !is_alive(pid) && std::fs::remove_dir_all(&path).is_ok() {
                cleaned += 1;
            }
        }
        cleaned
    }

    #[test]
    fn disk_gc_interval_default() {
        let config = Config::default();
        assert_eq!(config.disk_gc_interval_secs, 300);
    }

    #[test]
    fn index_path_ends_with_redb() {
        let (_temp, cache) = temp_cache_dir();
        let p = index_path_from_cache_dir(&cache);
        assert!(p.ends_with("index.redb"));
        assert!(p.starts_with(cache));
    }

    fn temp_cache_dir() -> (tempfile::TempDir, NormalizedPath) {
        let temp = tempfile::tempdir().unwrap();
        let cache = NormalizedPath::from(temp.path());
        (temp, cache)
    }
}