Struct WalReader 

pub struct WalReader { /* private fields */ }

Sequential WAL reader.

Implementations

impl WalReader

pub fn open(path: &Path, keys: Option<&KeyRing>) -> Result<Self>

Open a WAL file for replay.

Every record is decrypted on the way out: what the caller receives never has ENCRYPTED_FLAG set, and its checksum verifies against the plaintext. keys must be the key ring the segment was written under, or None for a segment that was never encrypted — an encrypted record met with no key is WalError::EncryptedRecordWithoutKey, never ciphertext handed to the caller.

pub fn open_raw(path: &Path) -> Result<Self>

Open a WAL file for structural scanning only.

Payloads may be ciphertext. Records come out exactly as they are on disk, ENCRYPTED_FLAG and all. This exists for code that reads nothing but record framing — LSNs, lengths, offsets — and specifically for crate::recovery::recover, which runs from WalWriter::open where no key ring exists and resuming an encrypted segment for appending must still work. Never use it for replay.

If the file begins with a valid WALP preamble (16 bytes), it is consumed and stored for use as AAD during decryption. Files without a preamble (unencrypted segments) start reading from offset 0 directly.

Automatically opens the companion double-write buffer file (*.dwb) if it exists alongside the WAL file.

pub fn committed_end(&self) -> u64

Byte offset just past the last fully consumed record.

This is where a writer resumes appending. It is not the same as Self::offset: it includes any alignment padding that followed the final record, and it excludes a partially-read damaged record whose header the reader had to consume before rejecting it.

pub fn stop_reason(&self) -> Option<StopReason>

Why iteration stopped, or None while records are still being read.

StopReason::Corruption does not by itself mean data was lost — it is the input to crate::torn_tail::verify_committed_prefix, which decides whether the damage is an unfsynced tail or a hole with committed records behind it.

pub fn segment_preamble(&self) -> Option<&SegmentPreamble>

The preamble read from this segment file, if present.

Returns None for unencrypted segments (no preamble written).

pub fn next_record(&mut self) -> Result<Option<WalRecord>>

Read the next record from the WAL.

Returns None at EOF (clean end) or at the first corruption point. Returns Err for I/O errors, unknown required record types, an oversized payload declaration, and a format version this build cannot read at the segment’s first record. A reader that returns Err for a header has consumed that header, so a caller must stop at the Err.

pub fn records(self) -> WalRecordIter

Iterator over all valid records in the WAL.

pub fn offset(&self) -> u64

Current read offset in the file.