fn consume()

in integrations/virtiofs/src/virtiofs_util.rs [58:97]

• 40 lines of code
• 7 McCabe index (conditional complexity)

    fn consume<F>(&mut self, count: usize, f: F) -> Result<usize>
    where
        F: FnOnce(&[&VolatileSlice<B>]) -> Result<usize>,
    {
        let mut len = 0;
        let mut bufs = Vec::with_capacity(self.buffers.len());
        for vs in &self.buffers {
            if len >= count {
                break;
            }
            bufs.push(vs);
            let remain = count - len;
            if remain < vs.len() {
                len += remain;
            } else {
                len += vs.len();
            }
        }
        if bufs.is_empty() {
            return Ok(0);
        }
        let bytes_consumed = f(&bufs)?;
        let total_bytes_consumed =
            self.bytes_consumed
                .checked_add(bytes_consumed)
                .ok_or(new_vhost_user_fs_error(
                    "the combined length of all the buffers in DescriptorChain would overflow",
                    None,
                ))?;
        let mut remain = bytes_consumed;
        while let Some(vs) = self.buffers.pop_front() {
            if remain < vs.len() {
                self.buffers.push_front(vs.offset(remain).unwrap());
                break;
            }
            remain -= vs.len();
        }
        self.bytes_consumed = total_bytes_consumed;
        Ok(bytes_consumed)
    }