Struct FileCursor 

pub struct FileCursor { /* private fields */ }

An owned cursor over a File implementing AsyncRead + AsyncWrite + AsyncSeek, built entirely on File::read_at/File::write_at. Multiple cursors over one File are safe; each carries its own position and the underlying I/O is positioned, so there is no shared seek pointer.

One operation is in flight at a time per cursor (it is driven by &mut self like every async-io adapter); starting a seek while a read or write is pending is rejected with io::ErrorKind::Other.

Implementations

impl FileCursor

pub fn position(&self) -> u64

The cursor’s current absolute byte offset.

Trait Implementations

impl AsyncRead for FileCursor

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf.

impl AsyncSeek for FileCursor

fn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>

Attempts to seek to an offset, in bytes, in a stream.

fn poll_complete( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<u64>>

Waits for a seek operation to complete.

impl AsyncWrite for FileCursor

fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempts to flush the object, ensuring that any buffered data reach their destination.

fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down.

fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Like poll_write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

Determines if this writer has an efficient poll_write_vectored implementation.