peat_lite/protocol/
error.rs

1//! Message encoding/decoding errors.
2
3/// Errors that can occur when encoding or decoding a Peat-Lite message.
4///
5/// Marked `#[non_exhaustive]` so future protocol amendments can add
6/// variants without breaking exhaustive-match consumers.
7#[derive(Debug, Clone, Copy, PartialEq, Eq)]
8#[non_exhaustive]
9pub enum MessageError {
10    /// Output buffer is too small for the encoded message.
11    BufferTooSmall,
12    /// Input buffer is shorter than the minimum header size.
13    TooShort,
14    /// Magic bytes do not match.
15    InvalidMagic,
16    /// Protocol version is not supported.
17    UnsupportedVersion,
18    /// Message type byte is not recognised.
19    InvalidMessageType,
20    /// Payload exceeds `MAX_PAYLOAD_SIZE`.
21    PayloadTooLarge,
22    /// A length-prefixed field declared more bytes than remain in the
23    /// input — truncated wire encoding.
24    TruncatedField,
25    /// A length-prefixed string field is not valid UTF-8. peat-lite
26    /// declares collection names + document ids as UTF-8 by spec; non-
27    /// UTF-8 bytes indicate corruption or a non-conforming sender.
28    InvalidUtf8,
29    /// A length-prefixed field exceeded its declared maximum
30    /// (collection over 255 bytes, doc_id or body over 65535 bytes).
31    /// The wire format uses fixed-width length prefixes per field;
32    /// oversized values must be rejected at encode time so receivers
33    /// can trust the fixed widths.
34    FieldTooLarge,
35    /// A `MessageType::Document` envelope's collection name was
36    /// empty (`coll_len = 0`). Empty collection is structurally
37    /// invalid — receivers can't route the document. Distinct from
38    /// [`Self::FieldTooLarge`] (which is for length-cap violations)
39    /// and from [`Self::TruncatedField`] (which is for buffer-shorter-
40    /// than-declared cases). Round-2 of peat-lite#26 introduced this
41    /// to fix an asymmetric-variant trap where encoder and decoder
42    /// reported the same condition with different error names.
43    EmptyCollection,
44    /// A reserved or not-yet-implemented flag bit was set on a
45    /// `MessageType::Document` envelope. Today's encoder rejects any
46    /// flag with reserved bits 2–7 set, and additionally bit 1
47    /// (`DOC_FLAG_ENCRYPTED`) which is reserved for a future
48    /// per-document encryption layer not yet wired through. Lets us
49    /// add features without older encoders silently shipping invalid
50    /// frames.
51    InvalidFlags,
52    /// `MessageType::Document` envelope had `DOC_FLAG_TOMBSTONE` set
53    /// AND a non-empty body. Per the envelope spec, a tombstone is a
54    /// deletion sentinel; carrying body bytes alongside it is a
55    /// publisher contract violation that downstream consumers might
56    /// process write-then-delete races against. Rejected at encode
57    /// time so the bug doesn't reach the wire.
58    TombstoneWithBody,
59}
peat_lite/protocol/error.rs

peat_lite/protocol/
error.rs
