FileObject

kernel::object::capability::file

Trait FileObject 

Source 
pub trait FileObject:
    StreamOps
    + ControlOps
    + MemoryMappingOps
    + Selectable {
    // Required methods
    fn seek(&self, whence: SeekFrom) -> Result<u64, StreamError>;
    fn metadata(&self) -> Result<FileMetadata, StreamError>;
    fn as_any(&self) -> &dyn Any;

    // Provided methods
    fn read_at(
        &self,
        offset: u64,
        buffer: &mut [u8],
    ) -> Result<usize, StreamError> { ... }
    fn write_at(&self, offset: u64, buffer: &[u8]) -> Result<usize, StreamError> { ... }
    fn truncate(&self, size: u64) -> Result<(), StreamError> { ... }
    fn sync(&self) -> Result<(), StreamError> { ... }
}
Expand description

Trait for file objects

This trait represents a file-like object that supports stream operations, file-specific operations like seeking and metadata access, control operations for device-specific functionality, and memory mapping operations. Directory reading is handled through normal read() operations.

Required Methods§

Source

fn seek(&self, whence: SeekFrom) -> Result<u64, StreamError>

Seek to a position in the file stream

Source

fn metadata(&self) -> Result<FileMetadata, StreamError>

Get metadata about the file

Source

fn as_any(&self) -> &dyn Any

Provided Methods§

Source

fn read_at(&self, offset: u64, buffer: &mut [u8]) -> Result<usize, StreamError>

Read data from a specific offset without changing internal position

This method performs a random-access read operation that must not modify the file’s current seek position. Filesystems that cannot support position-independent reads may return StreamError::NotSupported.

Source

fn write_at(&self, offset: u64, buffer: &[u8]) -> Result<usize, StreamError>

Write data to a specific offset without changing internal position

Similar to [read_at], this operation must not adjust the file’s internal cursor. Implementations can default to returning StreamError::NotSupported when random-access writes are unavailable.

Source

fn truncate(&self, size: u64) -> Result<(), StreamError>

Truncate the file to the specified size

This method changes the size of the file to the specified length. If the new size is smaller than the current size, the file is truncated. If the new size is larger, the file is extended with zero bytes.

§Arguments
  • size - New size of the file in bytes
§Returns
  • Result<(), StreamError> - Ok if the file was truncated successfully
§Errors
  • StreamError - If the file is a directory or the operation is not supported
Source

fn sync(&self) -> Result<(), StreamError>

Synchronize file content to storage

This method ensures that any buffered changes to the file are written to the underlying storage device. This is important for filesystems that cache file content in memory.

§Returns
  • Result<(), StreamError> - Ok if the sync was successful
§Errors
  • StreamError - If the sync operation fails or is not supported

Implementors§