yog 0.0.43

//! The production [`FileIo`] impl — the thin `std::fs` shell behind every
//! editor's pure view-model. Covered the way `cli_outbound`/`lock_probe` are:
//! a real tempdir, no fakes.

use super::FileIo;
use std::path::{Path, PathBuf};

/// `std::fs`-backed filesystem seam. Missing paths fold to the empty case
/// (`read` ⇒ `None`, `list_dir` ⇒ empty), matching the trait contract.
#[derive(Debug, Clone, Copy, Default)]
pub struct RealFileIo;

impl FileIo for RealFileIo {
    fn read(&self, path: &Path) -> std::io::Result<Option<Vec<u8>>> {
        match std::fs::read(path) {
            Ok(bytes) => Ok(Some(bytes)),
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
            Err(e) => Err(e),
        }
    }

    fn write(&self, path: &Path, bytes: &[u8]) -> std::io::Result<()> {
        std::fs::write(path, bytes)
    }

    fn rename(&self, from: &Path, to: &Path) -> std::io::Result<()> {
        std::fs::rename(from, to)
    }

    fn remove(&self, path: &Path) -> std::io::Result<()> {
        std::fs::remove_file(path)
    }

    fn list_dir(&self, dir: &Path) -> std::io::Result<Vec<PathBuf>> {
        match std::fs::read_dir(dir) {
            // An unreadable individual entry is dropped, not fatal — the same
            // forgiveness `read` gives a missing file.
            Ok(entries) => Ok(entries.flatten().map(|e| e.path()).collect()),
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(Vec::new()),
            Err(e) => Err(e),
        }
    }
}

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

    #[test]
    fn read_write_rename_remove_roundtrip() {
        let dir = tempdir().unwrap();
        let io = RealFileIo;
        let a = dir.path().join("a");
        let b = dir.path().join("b");
        // read of a missing file → None (fold identity), which is also how
        // absence is asked now that the seam carries no `exists` (bl-dba3: its
        // one caller was the credential probe, and the probe was a second
        // derivation of a column brazen already answers).
        assert_eq!(io.read(&a).unwrap(), None);
        io.write(&a, b"hello").unwrap();
        assert_eq!(io.read(&a).unwrap(), Some(b"hello".to_vec()));
        io.rename(&a, &b).unwrap();
        assert_eq!(io.read(&a).unwrap(), None);
        assert_eq!(io.read(&b).unwrap(), Some(b"hello".to_vec()));
        io.remove(&b).unwrap();
        assert_eq!(io.read(&b).unwrap(), None);
    }

    #[test]
    fn read_surfaces_non_notfound_errors() {
        // Reading a directory as a file is an error that is NOT NotFound —
        // it must propagate, not fold to None.
        let dir = tempdir().unwrap();
        assert!(RealFileIo.read(dir.path()).is_err());
    }

    #[test]
    fn list_dir_lists_children_and_absent_is_empty() {
        let dir = tempdir().unwrap();
        let io = RealFileIo;
        // An absent directory folds to an empty listing, not an error.
        assert!(io.list_dir(&dir.path().join("nope")).unwrap().is_empty());
        io.write(&dir.path().join("a.yaml"), b"1").unwrap();
        io.write(&dir.path().join("b.txt"), b"2").unwrap();
        let mut got = io.list_dir(dir.path()).unwrap();
        got.sort();
        assert_eq!(
            got,
            vec![dir.path().join("a.yaml"), dir.path().join("b.txt")]
        );
    }

    #[test]
    fn list_dir_surfaces_non_notfound_errors() {
        // Listing a regular file (ENOTDIR) is an error, not NotFound.
        let dir = tempdir().unwrap();
        let f = dir.path().join("f");
        RealFileIo.write(&f, b"x").unwrap();
        assert!(RealFileIo.list_dir(&f).is_err());
    }
}