Skip to main content

kevy_rt/
message_kinds.rs

1//! The small value types the messages carry: what a gather fetches, what it
2//! got back, which multi-key reduction it is, which set/zset algebra
3//! combination, how a keyspace-collection reply is shaped, and the per-write
4//! metadata the dispatch path hands to its housekeeping.
5//!
6//! Split out of `message.rs` to keep it under the 500-LOC house cap. These are
7//! parameters of the messages, not messages themselves — `Op` and `Part` stay
8//! next to the runtime that folds them.
9
10/// What to fetch per key in a cross-shard gather.
11#[derive(Clone, Copy)]
12pub(crate) enum GatherKind {
13    /// String value (for MGET).
14    Str,
15    /// String value, with a wrong-type key reported AS wrong-type
16    /// rather than as absent (for BITOP, which Redis errors on where
17    /// MGET answers nil).
18    StrStrict,
19    /// Set members (for SINTER/SUNION/SDIFF).
20    Set,
21    /// Scored members: zsets as-is, plain sets at score 1.0 (for the
22    /// zset algebra family — Redis lets sets participate).
23    Scored,
24}
25
26/// A single key's gathered payload.
27pub(crate) enum Gathered {
28    Str(Option<Vec<u8>>),
29    Members(Vec<Vec<u8>>),
30    /// `(member, score)` payload for [`GatherKind::Scored`].
31    Scored(Vec<(Vec<u8>, f64)>),
32    WrongType,
33}
34
35/// The multi-key gather reductions computed on the originating shard.
36/// Public: [`crate::Route::Gather`] carries it, and embedders' `route()`
37/// implementations construct it.
38#[derive(Debug, Clone, Copy, PartialEq, Eq)]
39pub enum MultiOp {
40    /// `MGET` — values gathered in request order.
41    Mget,
42    /// `SINTER`.
43    SInter,
44    /// `SUNION`.
45    SUnion,
46    /// `SDIFF`.
47    SDiff,
48    /// `ZINTERCARD numkeys key… [LIMIT n]` — read-only gathered count.
49    /// The `LIMIT` cap is parsed from the argv by the gather builder
50    /// (it sits after the keys), not carried here.
51    ZInterCard,
52}
53
54/// Which algebra combination a `*STORE` orchestrator runs after its
55/// gather completes. Public: [`crate::Route::ZAlgebraStore`]
56/// carries it, and embedders' `route()` implementations construct it.
57#[derive(Debug, Clone, Copy, PartialEq, Eq)]
58pub enum ZCombine {
59    /// `ZINTERSTORE`.
60    ZInter,
61    /// `ZUNIONSTORE`.
62    ZUnion,
63    /// `ZDIFFSTORE`.
64    ZDiff,
65    /// `SINTERSTORE`.
66    SInter,
67    /// `SUNIONSTORE`.
68    SUnion,
69    /// `SDIFFSTORE`.
70    SDiff,
71}
72
73/// Write-side facts the origin's `resolve()` already computed, carried
74/// with a dispatched command so the executing shard never re-parses the
75/// verb. Before this rode along, every forwarded write re-ran THREE
76/// full verb matches (`is_write` + `route` for the WATCH bump +
77/// `wake_idx`) on the owning shard — measurable at -c50 (SET trailed
78/// GET by the cost of those walks).
79#[derive(Clone, Copy)]
80pub(crate) struct DispatchMeta {
81    pub(crate) is_write: bool,
82    /// `Some(i)` = waking writes (LPUSH/RPUSH/XADD): argv[i] is the key
83    /// whose blocked waiters should be woken after the write.
84    pub(crate) wake_idx: Option<u8>,
85    /// `Some(i)` = argv[i] is the routed key (Route::Single) — the WATCH
86    /// version bump target. `None` for keyless `Route::Local` cmds.
87    pub(crate) key_idx: Option<u8>,
88}