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//! Inbound event handling: socket-readable, cross-core ring drain, and
//! connection teardown. The event loop (`run`), transport setup
//! (accept_ready, flush_conn, flush_dirty, maybe_auto_rewrite_aof), and
//! cross-shard send/backlog plumbing live in [`crate::shard`]; the
//! *semantics* (routing, execution, reduction) live in [`crate::exec`].
//! Split out so each file stays under the 500-LOC house rule without
//! breaking the established two-impl-block layering.
use std::io;
use kevy_resp::parse_command_borrowed;
use crate::Commands;
use crate::message::{Inbound, Op};
use crate::shard::Shard;
impl<C: Commands> Shard<C> {
/// Socket readable: read until WouldBlock, then parse out every full
/// RESP command and dispatch it.
///
/// The local fast path dispatches straight from an `ArgvBorrowed` view
/// into the connection's read buffer — no per-cmd memcpy. We swap
/// `conn.input` onto the stack (`mem::take`) for the parse-and-dispatch
/// loop so the borrowed argv doesn't conflict with `&mut self`; after
/// each command we `drain(..consumed)` on the local buf, and finally
/// swap the buf back into the connection (if it still exists). Cross-
/// shard / MULTI queue / AOF call `args.to_argv()` at the handoff
/// juncture; only those paths still materialise an owned `Argv`.
pub(crate) fn conn_readable(&mut self, conn_id: u64) -> io::Result<()> {
{
let Some(conn) = self.conns.get_mut(&conn_id) else {
return Ok(());
};
loop {
match conn.sock.read(&mut self.read_buf) {
Ok(0) => {
conn.closing = true;
break;
}
Ok(n) => conn.input.extend_from_slice(&self.read_buf[..n]),
Err(e) if e.kind() == io::ErrorKind::WouldBlock => break,
Err(e) if e.kind() == io::ErrorKind::Interrupted => continue,
Err(_) => {
conn.closing = true;
break;
}
}
}
}
// Swap conn.input onto the stack so parse_command_borrowed can lend
// it to ArgvBorrowed without colliding with &mut self in dispatch.
let mut input_buf = match self.conns.get_mut(&conn_id) {
Some(c) => std::mem::take(&mut c.input),
None => return Ok(()),
};
let mut had_protocol_error = false;
// Group-commit window for `appendfsync always`: the writes dispatched
// from this pipelined read batch buffer their AOF appends and fsync
// once in `aof_end_group`, BEFORE `flush_conn` sends their replies.
self.aof_begin_group();
loop {
let parse = parse_command_borrowed(&input_buf);
let (argv, consumed) = match parse {
Ok(Some(t)) => t,
Ok(None) => break,
Err(_) => {
had_protocol_error = true;
break;
}
};
if let Some(key) = argv.get(1) {
self.store.prefetch_for_key(key);
}
self.handle_command(conn_id, &argv);
drop(argv);
input_buf.drain(..consumed);
if !self.conns.contains_key(&conn_id) {
// Connection was closed mid-batch; drop the rest of the buf.
self.aof_end_group()?;
return Ok(());
}
}
// fsync the batch's buffered writes before any reply leaves the shard.
self.aof_end_group()?;
if let Some(c) = self.conns.get_mut(&conn_id) {
c.input = input_buf;
}
if had_protocol_error {
self.protocol_error(conn_id);
}
self.flush_conn(conn_id)
}
/// Open the AOF group-commit window (no-op unless AOF is on + policy is
/// `always`). Bracket a batch of writes with this and [`Self::aof_end_group`]
/// so an `always` policy fsyncs once per batch instead of per command,
/// still before the batch's replies are sent.
#[inline]
pub(crate) fn aof_begin_group(&mut self) {
if let Some(aof) = &mut self.aof {
aof.begin_group();
}
}
/// Close the group-commit window: one fsync for the batch (if any writes
/// buffered), before replies leave. Errors propagate like other flush
/// failures.
#[inline]
pub(crate) fn aof_end_group(&mut self) -> io::Result<()> {
if let Some(aof) = &mut self.aof {
aof.end_group()?;
}
Ok(())
}
/// Drain inbound cross-core messages from every peer ring; returns
/// whether any were processed.
pub(crate) fn drain_inbound(&mut self) -> io::Result<bool> {
let mut did = false;
for src in 0..self.nshards {
if src == self.id {
continue; // no self-ring
}
while let Some(msg) = self.inboxes[src].as_mut().expect("peer inbox").pop() {
did = true;
match msg {
Inbound::Request {
origin,
conn,
seq,
op,
} => {
let part = self.exec_op(op);
self.send_to(origin, Inbound::Response { conn, seq, part });
}
Inbound::Response { conn, seq, part } => {
self.fold(conn, seq, part);
self.flush_conn(conn)?;
}
// Batched single-key dispatches to this (owning) shard:
// exec each locally, reply as one `ResponseBatch` to the
// origin.
Inbound::RequestBatch { origin, reqs } => {
let mut resps = Vec::with_capacity(reqs.len());
self.aof_begin_group();
for (conn, seq, argv, proto) in reqs {
let part = self.exec_op(Op::Dispatch(argv, proto));
resps.push((conn, seq, part));
}
// fsync the batch's forwarded writes before replying.
self.aof_end_group()?;
self.send_to(origin, Inbound::ResponseBatch(resps));
}
// Batched replies: fold each by seq, then flush each
// touched conn once (dedup — pipelined replies share a
// conn).
Inbound::ResponseBatch(resps) => {
let mut to_flush: Vec<u64> = Vec::new();
for (conn, seq, part) in resps {
self.fold(conn, seq, part);
if !to_flush.contains(&conn) {
to_flush.push(conn);
}
}
for conn in to_flush {
self.flush_conn(conn)?;
}
}
// Fire-and-forget batched pub/sub delivery; appended
// subscriber output is flushed via `flush_dirty`.
Inbound::DeliverPublish(batch) => {
for m in &batch {
self.deliver_publish(&m.0, &m.1);
}
}
// ── Cross-shard BLOCK arbiter (see `block_xshard`) ──
Inbound::BlockArm {
origin,
conn,
key,
kind,
serve_argv,
proto,
} => self.target_arm(origin, conn, key, kind, serve_argv, proto),
Inbound::BlockReady { conn, key } => self.origin_on_ready(conn, &key),
Inbound::BlockServeReq { origin, conn, key } => {
let reply = self.target_serve(origin, conn, &key);
self.send_to(origin, Inbound::BlockServeResp { conn, key, reply });
}
Inbound::BlockServeResp { conn, key, reply } => {
self.origin_on_serve_resp(conn, key, reply);
self.flush_conn(conn)?;
}
Inbound::BlockCancel { origin, conn } => self.target_cancel(origin, conn),
}
}
}
Ok(did)
}
/// Tear down a closing connection: deregister from the poller, drop
/// its channel + pattern subscriptions from the shared registries
/// and the per-shard tables, and release its `Socket` (closing the
/// fd).
pub(crate) fn close_conn(&mut self, conn_id: u64) {
if let Some(conn) = self.conns.remove(&conn_id) {
let fd = conn.sock.raw();
let _ = self.poller.delete(fd);
self.fd_to_conn.remove(&fd);
// Drop any BLPOP / BRPOP / XREAD BLOCK waiter the closing conn
// was parked in, across all its watched keys. Cheap fast-out
// when nothing is blocked (the common case).
self.blocked.drop_for_conn(conn_id);
// Cancel any cross-shard block this conn was the origin of, so
// target shards drop their registrations.
self.cancel_xshard_on_close(conn_id);
self.unregister_subs(&conn.sub);
// Drop the conn's psub local table entries first (`unregister_psubs`
// reads `psub_local` to decide if our shard bit should be cleared).
for pat in &conn.psub {
if let Some(ids) = self.psub_local.get_mut(pat) {
ids.retain(|&id| id != conn_id);
if ids.is_empty() {
self.psub_local.remove(pat);
}
}
}
self.unregister_psubs(&conn.psub);
// conn (and its Socket) dropped here → fd closed.
}
}
}