Struct WriteAheadLog 

pub struct WriteAheadLog {
    pub max_entries: usize,
    pub stats: WalStats,
    /* private fields */
}

In-memory write-ahead log providing crash-recovery for block store writes.

Example

use ipfrs_storage::wal::{WriteAheadLog, WalOp};

let wal = WriteAheadLog::new(1000);
let seq = wal.append(WalOp::Put { cid: "bafytest".into(), data_len: 128 }).unwrap();
assert_eq!(seq, 1);
let ops = wal.replay_ops();
assert_eq!(ops.len(), 1);

Fields

max_entries: usize

Maximum number of entries allowed in the log before truncation is required.

stats: WalStats

Live statistics.

Implementations

impl WriteAheadLog

pub fn new(max_entries: usize) -> Self

Creates a new WriteAheadLog with the given maximum entry count.

pub fn with_defaults() -> Self

Creates a WriteAheadLog with the default maximum of 10 000 entries.

pub fn append(&self, op: WalOp) -> Result<u64, WalError>

Appends an operation to the WAL.

Assigns the next sequence number, computes the CRC-32 (FNV-1a) of the serialized op, and stores the entry. Returns the assigned sequence number.

Errors

Returns WalError::CapacityExceeded when the number of stored entries already equals or exceeds max_entries.

pub fn checkpoint(&self) -> Result<u64, WalError>

Appends a WalOp::Checkpoint entry and updates checkpoint_sequence.

Returns the sequence number of the checkpoint entry.

pub fn entries_since_checkpoint(&self) -> Vec<WalEntry>

Returns all entries whose sequence number is strictly greater than the last checkpointed sequence.

pub fn truncate_before(&self, sequence: u64) -> usize

Removes all entries whose sequence number is strictly less than sequence. Returns the number of entries removed.

pub fn entry_count(&self) -> usize

Returns the number of entries currently in the log.

pub fn replay_ops(&self) -> Vec<WalOp>

Returns the ops from entries since the last checkpoint, excluding WalOp::Checkpoint ops themselves (those are metadata, not data ops).

pub fn checkpoint_sequence(&self) -> u64

Returns the current checkpoint sequence number.

pub fn next_sequence(&self) -> u64

Returns the next sequence number that will be assigned (without consuming it).

Trait Implementations

impl Debug for WriteAheadLog

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.