rzmq 0.5.5

A high performance, fully asynchronous, safe pure-Rust implementation of ZeroMQ (ØMQ) messaging with io_uring and tcp cork acceleration on Linux.
Documentation 
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#![cfg(feature = "io-uring")]

use crate::ZmqError;
use bytes::BytesMut;
use io_uring::IoUring;
use io_uring_buf_ring::{BorrowedBuffer, IoUringBufRing};
use std::fmt;

/// Manages a ring of buffers registered with io_uring for efficient receives.
pub struct BufferRingManager {
  buf_ring_instance: IoUringBufRing<BytesMut>,
}

impl fmt::Debug for BufferRingManager {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    f.debug_struct("BufferRingManager")
      .field("bgid", &self.buf_ring_instance.buffer_group())
      .finish_non_exhaustive()
  }
}

impl BufferRingManager {
  pub fn new(
    ring: &IoUring,
    ring_entries: u16,
    bgid: u16,
    buffer_capacity: usize,
  ) -> Result<Self, ZmqError> {
    tracing::info!(
      "Initializing BufferRingManager with bgid: {}, requested_entries: {}, capacity_per_buffer: {}",
      bgid,
      ring_entries,
      buffer_capacity
    );

    // Create an iterator that yields `ring_entries` number of BytesMut buffers.
    let bufs_iter = (0..ring_entries).map(|_| BytesMut::with_capacity(buffer_capacity));

    // `IoUringBufRing::new_with_buffers` takes ownership of the iterator.
    // The actual number of entries in the ring will be `bufs_iter.count().next_power_of_two()`.
    // If `ring_entries` is already a power of two, it will be that.
    match IoUringBufRing::new_with_buffers(ring, bufs_iter, bgid) {
      Ok(buf_ring_instance) => {
        tracing::info!(
          "BufferRingManager: IoUringBufRing built and registered successfully for bgid: {}",
          bgid
        );
        Ok(Self { buf_ring_instance })
      }
      Err(e) => {
        tracing::error!("Failed to build and register IoUringBufRing: {:?}", e);
        Err(ZmqError::Internal(format!(
          "BufferRingManager build failed: {:?}",
          e
        )))
      }
    }
  }

  pub fn group_id(&self) -> u16 {
    self.buf_ring_instance.buffer_group()
  }

  pub unsafe fn borrow_kernel_filled_buffer(
    &self,
    buffer_id: u16,
    available_len: usize,
  ) -> Result<BorrowedBuffer<BytesMut>, ZmqError> {
    self
      .buf_ring_instance
      .get_buf(buffer_id, available_len)
      .ok_or_else(|| {
        ZmqError::Internal(format!(
          "Failed to borrow buffer ID {} from ring",
          buffer_id
        ))
      })
  }
}