Trait ReaderPolicy

pub trait ReaderPolicy {
    // Provided methods
    fn before_read(&mut self, buffer: &mut Buffer) -> DoRead { ... }
    fn after_consume(&mut self, _buffer: &mut Buffer, _amt: usize) { ... }
}

Trait that governs BufReader’s behavior.

Provided Methods

fn before_read(&mut self, buffer: &mut Buffer) -> DoRead

Consulted before attempting to read into the buffer.

Return DoRead(true) to issue a read into the buffer before reading data out of it, or DoRead(false) to read from the buffer as it is, even if it’s empty. do_read!() is provided as a shorthand.

If there is no room in the buffer after this method is called, the buffer will not be read into (so if the buffer is full but you want more data you should call .make_room() or reserve more space). If there is room, BufReader will attempt to read into the buffer. If successful (Ok(x) where x > 0 is returned), this method will be consulted again for another read attempt.

By default, this implements std::io::BufReader’s behavior: only read into the buffer if it is empty.

Note

If the read will ignore the buffer entirely (if the buffer is empty and the amount to be read matches or exceeds its capacity) or if BufReader::read_into_buf() was called to force a read into the buffer manually, this method will not be called.

fn after_consume(&mut self, _buffer: &mut Buffer, _amt: usize)

Called after bytes are consumed from the buffer.

Supplies the true amount consumed if the amount passed to BufReader::consume was in excess.

This is a no-op by default.

Implementors

impl ReaderPolicy for MinBuffered

impl ReaderPolicy for StdPolicy

Behavior of std::io::BufReader: the buffer will only be read into if it is empty.