Struct RecordHeader 

pub struct RecordHeader {
    pub kind: u8,
    pub flags: u8,
    pub prev: u64,
    pub ttl_ms: u64,
}

A record about to be written.

Fields

kind: u8

What the value is. A raw byte rather than a RecordKind so that a future version can be written by a build that predates it, which is not as strange as it sounds: compaction copies records it does not interpret.

flags: u8

See record_flags.

prev: u64

The previous address in this key’s chain, or 0.

ttl_ms: u64

Unix milliseconds, meaningful only when record_flags::HAS_TTL is set.

Implementations

impl RecordHeader

pub const fn new(kind: RecordKind) -> RecordHeader

A header for a live value with no TTL, checksummed.

pub const fn with_ttl(self, unix_ms: u64) -> RecordHeader

Sets the TTL and the flag that says it is there.

pub const fn after(self, prev: u64) -> RecordHeader

Chains this record to the previous version of the same key.

pub fn fill(&self, buf: &mut [u8], key: &[u8], value: &[u8]) -> Result<usize>

Writes everything except len, and returns the exact record length.

The first four bytes are left untouched, which is the point. 06 section 3 requires len to be stored last with a release store, so that a reader either sees a whole record or sees a zero and stops. Writing it here would put a length in front of a body that is not there yet, and a crash in between produces a record that claims bytes it does not have.

The caller finishes with seal_len, which is the release store’s payload. Ordering is the caller’s job because this crate does not know what memory the buffer is in.

Errors

Code::Invalid for an oversized key, Code::Full if buf is too small for the record.

Trait Implementations

impl Clone for RecordHeader

fn clone(&self) -> RecordHeader

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RecordHeader

impl Debug for RecordHeader

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

Formats the value using the given formatter.

impl Eq for RecordHeader

impl PartialEq for RecordHeader

fn eq(&self, other: &RecordHeader) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for RecordHeader