1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
//! `Shard::fold` — the seq-ordered result reducer — plus its small
//! free-fn helpers. Same `impl<C: Commands> Shard<C>` as [`crate::exec`];
//! split out so that file stays under the 500-LOC house rule.
use crate::message::{Agg, Part, PendingSlot, SmallReply};
use crate::reduce::{drain_front, materialize};
use crate::shard::Shard;
use crate::Commands;
use kevy_resp::ArgvView;
impl<C: Commands> Shard<C> {
/// Fold a sub-result into its slot; emit completed replies in seq order.
/// The `WatchCollect` / `ExecPrep` accumulators don't materialise to RESP
/// bytes — they hand off to [`crate::exec_watch`] for the conn-state
/// mutation + downstream dispatch they require.
// LOC-WAIVER: data-driven aggregation match table — one arm per
// (Agg, Part) pairing + the finalize dispatch over orchestrator aggs.
pub(crate) fn fold(&mut self, conn_id: u64, seq: u64, part: Part) {
let watch_agg: Option<Agg> = {
let Some(conn) = self.conns.get_mut(&conn_id) else {
return;
};
if seq < conn.next_emit {
return; // already emitted (defensive — shouldn't happen)
}
let idx = (seq - conn.next_emit) as usize;
let Some(slot) = conn.pending.get_mut(idx) else {
return;
};
// (Agg::AllOk, Part::Ok) `{}` body matches the catch-all `_ => {}`
// body but documents the *expected* aggregator/part pairing — the
// wildcard arm is the fallback for impossible combinations after
// the dispatcher arms. match_same_arms would collapse the two and
// hide the contract; keep them separate.
#[allow(clippy::match_same_arms)]
match (&mut slot.agg, part) {
(Agg::First(dst), Part::Reply(b)) => *dst = Some(b),
(Agg::SumInt(acc), Part::Int(n)) => *acc += n,
// v3.16 D1 WAIT: reply = MIN over per-shard acked counts.
(Agg::MinInt(acc), Part::Int(n)) => *acc = (*acc).min(n),
// v3.16 D2 REPL.WAIT: every shard must report 1 (met).
(Agg::ReplBarrier { ok, .. }, Part::Int(n)) => *ok &= n > 0,
// v3.16 D2 REPL.TOKEN: pairs drop in by shard id.
(
Agg::ReplTokens { slots },
Part::ReplToken { shard, generation, next_offset },
) => {
if let Some(s) = slots.get_mut(shard as usize) {
*s = Some((generation, next_offset));
}
}
(Agg::AllOk, Part::Ok) => {}
(Agg::ExtensionGather { chunks, .. }, Part::ExtensionChunk(c)) => {
chunks.push(c);
}
(Agg::Gather { got, .. }, Part::Gathered(items))
| (Agg::ZStoreGather { got, .. }, Part::Gathered(items)) => {
for (k, g) in items {
got.insert(k, g);
}
}
(Agg::Keys { acc, .. }, Part::Keys(ks)) => acc.extend(ks),
(
Agg::PrefixStats { keys, expires },
Part::PrefixStats { keys: k, expires: e },
) => {
*keys += k;
*expires += e;
}
(Agg::SlowlogGet { entries, .. }, Part::SlowlogEntries(es)) => {
entries.extend(es);
}
(Agg::WatchCollect { pairs }, Part::WatchVersions(items)) => {
pairs.extend(items);
}
// Cross-shard XREAD gather: drop each stream's element into
// its request-order slot.
(Agg::XReadGather { slots }, Part::XReadElement { index, element }) => {
if let Some(slot) = slots.get_mut(index as usize) {
*slot = element;
}
}
(Agg::ExecPrep { dirty, .. }, Part::Int(n)) => *dirty |= n != 0,
// Cross-shard RENAME orchestrator: buffer the step-1
// result in the agg so finalize can ship step 2.
(
Agg::RenameOrchestrator { taken, .. },
Part::RenameTaken { value, ttl_ms },
) => *taken = Some((value, ttl_ms)),
// Step 2's put result: `refused = None` → stored; `Some`
// → NX-blocked, and the handed-back value lands in `taken`
// so finalize can restore src before the `:0` reply.
(
Agg::RenameOrchestrator { put_stored, taken, .. },
Part::RenamePutDone { refused },
) => {
*put_stored = Some(refused.is_none());
if refused.is_some() {
*taken = refused;
}
}
// The terminal step-1 miss (RenameNoSuchSrc) leaves
// `taken == None`; finalize reads that as "missing src".
_ => {}
}
slot.remaining -= 1;
if slot.remaining == 0 {
let proto = slot.proto;
let agg = std::mem::replace(&mut slot.agg, Agg::AllOk);
if matches!(
agg,
Agg::WatchCollect { .. }
| Agg::ExecPrep { .. }
| Agg::RenameOrchestrator { .. }
| Agg::ZStoreGather { .. }
| Agg::ExtensionGather { .. }
) {
Some(agg)
} else {
slot.done = Some(materialize(agg, proto));
drain_front(conn);
None
}
} else {
None
}
};
if let Some(agg) = watch_agg {
match agg {
Agg::WatchCollect { .. } | Agg::ExecPrep { .. } => {
self.finalize_watch_agg(conn_id, seq, agg);
}
Agg::RenameOrchestrator { .. } => self.finalize_rename_agg(conn_id, seq, agg),
Agg::ZStoreGather { .. } => self.finalize_zstore_agg(conn_id, seq, agg),
Agg::ExtensionGather { argv, chunks } => {
let proto = self
.conns
.get(&conn_id)
.map_or(kevy_resp::RespVersion::V2, |c| c.proto);
let reply = self.commands.extension_reduce_v3(&argv, chunks, proto);
// v2.6: a reply starting with 0x00 is a CONTINUATION —
// the remainder encodes a second fan-out argv
// (length-prefixed items). RESP replies never start
// with NUL, so the convention is unambiguous. Phase
// state rides inside the continuation argv itself
// (stateless two-phase, no new agg variant).
if reply.first() == Some(&0) {
if let Some(argv2) = decode_continuation(&reply[1..]) {
self.start_extension_phase(conn_id, seq, argv2);
} else {
self.fill_extension_slot(
conn_id,
seq,
b"-ERR internal: bad extension continuation\r\n".to_vec(),
);
}
} else {
self.fill_extension_slot(conn_id, seq, reply);
}
}
// The match above is exhaustive over what fold ever puts
// into `watch_agg` (only the orchestrator aggs). Anything
// else is a bug; ignore so a stray slot doesn't crash
// the reactor.
_ => {}
}
}
}
pub(crate) fn protocol_error(&mut self, conn_id: u64) {
let seq = match self.conns.get_mut(&conn_id) {
Some(c) => {
let s = c.next_seq;
c.next_seq += 1;
c.closing = true;
let proto = c.proto;
c.pending.push_back(PendingSlot {
remaining: 1,
agg: Agg::First(None),
done: None,
proto,
});
s
}
None => return,
};
self.fold(
conn_id,
seq,
Part::Reply(SmallReply::from_slice(b"-ERR Protocol error\r\n")),
);
}
}
/// Does `args` set a TTL via a *relative* duration (vs absolute `*AT`)? Such
/// writes need an absolute `PEXPIREAT` follow-up in the AOF — see
/// [`Shard::log_write`]. `SET … EXAT|PXAT` aren't parsed by the server's SET,
/// so only `EX`/`PX` count here.
pub(crate) fn relative_ttl_write<A: ArgvView + ?Sized>(args: &A) -> bool {
if args.len() < 3 {
return false;
}
let verb = &args[0];
if verb.eq_ignore_ascii_case(b"EXPIRE")
|| verb.eq_ignore_ascii_case(b"PEXPIRE")
|| verb.eq_ignore_ascii_case(b"SETEX")
|| verb.eq_ignore_ascii_case(b"PSETEX")
{
return true;
}
if verb.eq_ignore_ascii_case(b"SET") {
return (3..args.len())
.any(|i| args[i].eq_ignore_ascii_case(b"EX") || args[i].eq_ignore_ascii_case(b"PX"));
}
false
}
/// Decode a continuation payload: `[n: u32 LE][(len: u32 LE, bytes)*]`.
fn decode_continuation(b: &[u8]) -> Option<Vec<Vec<u8>>> {
let mut pos = 0usize;
let n = u32::from_le_bytes(b.get(pos..pos + 4)?.try_into().ok()?) as usize;
pos += 4;
let mut out = Vec::with_capacity(n);
for _ in 0..n {
let len = u32::from_le_bytes(b.get(pos..pos + 4)?.try_into().ok()?) as usize;
pos += 4;
out.push(b.get(pos..pos + len)?.to_vec());
pos += len;
}
Some(out)
}