Struct fuchsia_fs::file::BufferedAsyncReadAt

pub struct BufferedAsyncReadAt<T> { /* private fields */ }

Wraps an AsyncReadAt with an in-memory buffer of size fidl_fuchsia_io::MAX_TRANSFER_SIZE in which it stores the results of poll_read_at calls made to the wrapped AsyncReadAt.

Calls to poll_read_at that begin in the buffer will be serviced only from the buffer without interacting with the wrapped AsyncReadAt, therefore the read will be short if the buffer ends before the requested range.

Calls to poll_read_at that do not begin in the buffer will be forwarded to the wrapped AsyncReadAt with the length of the forwarded buffer always exactly fidl_fuchsia_io::MAX_TRANSFER_SIZE, therefore calls to poll_read_at requesting more than fidl_fuchsia_io::MAX_TRANSFER_SIZE bytes will always be short.

Implementations

impl<T> BufferedAsyncReadAt<T>

pub fn new(wrapped: T) -> Self

Trait Implementations

impl<T: AsyncGetSize> AsyncGetSize for BufferedAsyncReadAt<T>

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

Attempt to get the size of the file, on success returns the file size.

impl<T: AsyncReadAt> AsyncReadAt for BufferedAsyncReadAt<T>

fn poll_read_at( self: Pin<&mut Self>, cx: &mut Context<'_>, offset_u64: u64, buf: &mut [u8], ) -> Poll<Result<usize>>

Attempt to read at most buf.len() bytes starting at offset into buf. On success returns the number of bytes read. Contents of buf are only altered on success. Reads of more than zero but fewer than buf.len() bytes do NOT indicate EOF. Reads of zero bytes only occur if buf.len() == 0 or EOF.

impl<'pin, T> Unpin for BufferedAsyncReadAt<T>

where __BufferedAsyncReadAt<'pin, T>: Unpin,