Module journal 

Append-only framed journal.

Persistence is kept orthogonal to serialization. The journal moves opaque versioned, checksummed frames to and from a file and handles the durability concerns — append, fsync, bounded recovery, and recovery of a torn trailing frame after a crash. How a record turns into a payload is entirely the FrameCodec’s business, so the Raft log store can frame protobuf while the WAL engine frames JSON over the exact same code.

Structs

JournalWriter

An append handle over a single journal file.

JsonCodec

JSON frame codec for any owned, serde-serializable record.

Constants

MAX_FRAME_PAYLOAD_BYTES

Maximum encoded payload accepted from disk or written as one journal frame.

Traits

FrameCodec

Serialization seam: how one record becomes a frame payload and back.

Functions

decode_frames

Decode framed records from an in-memory buffer, returning the records and the byte length of the valid (fully-written) prefix. A torn trailing frame ends the scan.

migrate_legacy

Migrate the legacy [length][payload] journal format to the current checksummed format, retaining a hard-linked .v0.bak rollback copy.

replay

Read every record from path, decoding with C. A torn trailing frame left by a crash mid-write is truncated away and ignored, leaving the file at its last clean record boundary.

replay_each

Stream every valid record from path through visit without retaining the entire journal in memory. A torn trailing frame is truncated with the same recovery semantics as replay.

truncate_to

Truncate path to valid_len bytes, dropping a torn trailing frame, then fsync.