Trait Vfs 

pub trait Vfs: Send + Sync {
    // Required methods
    fn ensure_directory(&self, path: &Path, create: bool) -> Result<bool>;
    fn open(&self, path: &Path) -> Result<u64>;
    fn open_for_map(&self, path: &Path) -> Result<File>;
    fn read(&self, path: &Path) -> Result<Vec<u8>>;
    fn read_range(
        &self,
        path: &Path,
        offset: u64,
        length: usize,
    ) -> Result<Vec<u8>>;
    fn write(&self, path: &Path, bytes: &[u8]) -> Result<()>;
    fn open_append(&self, path: &Path) -> Result<Box<dyn VfsFile>>;
    fn rename(&self, from: &Path, to: &Path) -> Result<()>;
    fn sync(&self, path: &Path, kind: SyncKind) -> Result<()>;
    fn list(&self, directory: &Path) -> Result<Vec<PathBuf>>;
    fn for_each_direct_child(
        &self,
        directory: &Path,
        visitor: &mut dyn FnMut(&Path) -> Result<()>,
    ) -> Result<()>;
    fn delete(&self, path: &Path) -> Result<()>;

    // Provided methods
    fn create_directory(&self, _path: &Path) -> Result<()> { ... }
    fn remove_directory(&self, _path: &Path) -> Result<()> { ... }
    fn truncate(&self, _path: &Path, _length: u64) -> Result<()> { ... }
    fn create_new(&self, _path: &Path, _bytes: &[u8]) -> Result<()> { ... }
}

Minimal synchronous filesystem operations used by persisted commits.

Required Methods

fn ensure_directory(&self, path: &Path, create: bool) -> Result<bool>

Admits a store directory, creating missing ancestors when requested, and reports whether the resulting path is a directory.

fn open(&self, path: &Path) -> Result<u64>

Opens an existing path and returns its byte length.

fn open_for_map(&self, path: &Path) -> Result<File>

Opens an existing path as an owned file suitable for memory mapping.

Test filesystems without a native file descriptor return std::io::ErrorKind::Unsupported. Consequently MemoryVfs, CrashVfs, and memory-backed FaultVfs images cannot publish or reopen a sealed segment; use a path-backed VFS when exercising that lifecycle.

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

Reads an entire file.

fn read_range(&self, path: &Path, offset: u64, length: usize) -> Result<Vec<u8>>

Reads at most length bytes beginning at offset.

fn write(&self, path: &Path, bytes: &[u8]) -> Result<()>

Creates or truncates a file and writes all bytes.

fn open_append(&self, path: &Path) -> Result<Box<dyn VfsFile>>

Opens or creates one file for handle-oriented append-only writes.

fn rename(&self, from: &Path, to: &Path) -> Result<()>

Atomically renames one path over another according to platform semantics.

fn sync(&self, path: &Path, kind: SyncKind) -> Result<()>

Synchronizes a file or directory using an explicit platform primitive.

fn list(&self, directory: &Path) -> Result<Vec<PathBuf>>

Lists direct children of a directory.

fn for_each_direct_child( &self, directory: &Path, visitor: &mut dyn FnMut(&Path) -> Result<()>, ) -> Result<()>

Visits direct children one at a time without collecting the directory.

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

Deletes one file.

Provided Methods

fn create_directory(&self, _path: &Path) -> Result<()>

Exclusively creates one directory. Existing paths are preserved and reported as AlreadyExists; no ancestor is adopted implicitly.

fn remove_directory(&self, _path: &Path) -> Result<()>

Removes one empty directory. A non-empty directory is an error.

fn truncate(&self, _path: &Path, _length: u64) -> Result<()>

Removes a suffix without copying the retained file bytes.

fn create_new(&self, _path: &Path, _bytes: &[u8]) -> Result<()>

Exclusively creates a file and writes every byte without replacing any existing path. A failed write may leave a new partial file; callers must retain it as an uncommitted artifact until safe cleanup is established. Filesystems without atomic exclusive creation fail explicitly.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl Vfs for StdVfs

impl<V: Vfs> Vfs for CountingVfs<V>