Struct OverlayFs 

pub struct OverlayFs { /* private fields */ }

A copy-on-write filesystem: reads from a real directory, writes to memory.

The lower layer (a real directory on disk) is treated as read-only. All mutations go to the upper InMemoryFs layer. Deletions are tracked via a whiteout set so deleted lower-layer entries appear as removed.

Example

use rust_bash::{RustBashBuilder, OverlayFs};
use std::sync::Arc;

let overlay = OverlayFs::new("./my_project").unwrap();
let mut shell = RustBashBuilder::new()
    .fs(Arc::new(overlay))
    .cwd("/")
    .build()
    .unwrap();

let result = shell.exec("cat /src/main.rs").unwrap(); // reads from disk
shell.exec("echo new > /src/main.rs").unwrap();       // writes to memory only

Implementations

impl OverlayFs

pub fn new(lower: impl Into<PathBuf>) -> Result<Self>

Create an overlay filesystem with lower as the read-only base.

The lower directory must exist and be a directory. It is canonicalized on construction so symlinks in the lower path itself are resolved once.

Trait Implementations

impl VirtualFs for OverlayFs

fn read_file(&self, path: &Path) -> Result<Vec<u8>, VfsError>

fn write_file(&self, path: &Path, content: &[u8]) -> Result<(), VfsError>

fn append_file(&self, path: &Path, content: &[u8]) -> Result<(), VfsError>

fn remove_file(&self, path: &Path) -> Result<(), VfsError>

fn mkdir(&self, path: &Path) -> Result<(), VfsError>

fn mkdir_p(&self, path: &Path) -> Result<(), VfsError>

fn readdir(&self, path: &Path) -> Result<Vec<DirEntry>, VfsError>

fn remove_dir(&self, path: &Path) -> Result<(), VfsError>

fn remove_dir_all(&self, path: &Path) -> Result<(), VfsError>

fn exists(&self, path: &Path) -> bool

fn stat(&self, path: &Path) -> Result<Metadata, VfsError>

fn lstat(&self, path: &Path) -> Result<Metadata, VfsError>

fn chmod(&self, path: &Path, mode: u32) -> Result<(), VfsError>

fn utimes(&self, path: &Path, mtime: SystemTime) -> Result<(), VfsError>

fn symlink(&self, target: &Path, link: &Path) -> Result<(), VfsError>

fn hardlink(&self, src: &Path, dst: &Path) -> Result<(), VfsError>

fn readlink(&self, path: &Path) -> Result<PathBuf, VfsError>

fn canonicalize(&self, path: &Path) -> Result<PathBuf, VfsError>

fn copy(&self, src: &Path, dst: &Path) -> Result<(), VfsError>

fn rename(&self, src: &Path, dst: &Path) -> Result<(), VfsError>

fn glob(&self, pattern: &str, cwd: &Path) -> Result<Vec<PathBuf>, VfsError>

fn deep_clone(&self) -> Arc<dyn VirtualFs>

Create an independent deep copy for subshell isolation.

fn glob_with_opts( &self, pattern: &str, cwd: &Path, _opts: &GlobOptions, ) -> Result<Vec<PathBuf>, VfsError>

Glob expansion with shopt-controlled options (dotglob, nocaseglob, globstar).