pub trait AsyncSeek {
// Required methods
fn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>;
fn poll_complete(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<u64>>;
}Expand description
Seek bytes asynchronously.
This trait is analogous to the std::io::Seek trait, but integrates
with the asynchronous task system. In particular, the start_seek
method, unlike Seek::seek, will not block the calling thread.
Utilities for working with AsyncSeek values are provided by
AsyncSeekExt.
Required Methods§
sourcefn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>
fn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>
Attempts to seek to an offset, in bytes, in a stream.
A seek beyond the end of a stream is allowed, but behavior is defined by the implementation.
If this function returns successfully, then the job has been submitted.
To find out when it completes, call poll_complete.
Errors
This function can return io::ErrorKind::Other in case there is
another seek in progress. To avoid this, it is advisable that any call
to start_seek is preceded by a call to poll_complete to ensure all
pending seeks have completed.
sourcefn poll_complete(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<u64>>
fn poll_complete( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<u64>>
Waits for a seek operation to complete.
If the seek operation completed successfully,
this method returns the new position from the start of the stream.
That position can be used later with SeekFrom::Start. Repeatedly
calling this function without calling start_seek might return the
same result.
Errors
Seeking to a negative offset is considered an error.