API reference › @evolu/common › local‑first/Protocol › ProtocolMessageBuffer

Defined in: packages/common/src/local-first/Protocol.ts:774

Mutable builder for constructing ProtocolMessage respecting size limits.

A frame never exceeds totalMaxSize. Make ordinary writes inside tryWrite, which keeps them only if the frame can still be closed. A write outside a trial is a closing write: addMessage and addRange assert that the frame fits totalMaxSize.

The builder references each change, which unwrap copies into the frame it returns, so a change must not be modified while the builder is in use. unwrap leaves the builder unchanged, so it can be called again.

Properties

addMessage

readonly addMessage: (message: EncryptedCrdtMessage) => void;

Defined in: packages/common/src/local-first/Protocol.ts:775

addRange

readonly addRange: (range:
  | SkipRange
  | FingerprintRange
  | TimestampsRangeWithTimestampsBuffer) => void;

Defined in: packages/common/src/local-first/Protocol.ts:777

getSize

readonly getSize: () => number & Brand<"NonNaN"> & Brand<"Finite"> & Brand<"Int"> & Brand<"NonNegative"> & Brand<"Positive">;

Defined in: packages/common/src/local-first/Protocol.ts:801

Returns the exact encoded size of the frame.

tryWrite

readonly tryWrite: (write: () => void, reserve?: number & Brand<"NonNaN"> & Brand<"Finite"> & Brand<"Int"> & Brand<"NonNegative">) => boolean;

Defined in: packages/common/src/local-first/Protocol.ts:796

Runs write and keeps what it wrote only if the frame can still be closed, returning whether it was kept.

The frame can be closed when its exact size plus the bytes needed to append one Fingerprint range with InfiniteUpperBound plus reserve is at most totalMaxSize, and its ranges section plus the same bytes is at most rangesMaxSize. Nothing is needed to close a broadcast, which holds no ranges, or a frame whose last range has InfiniteUpperBound. Use reserve for bytes the caller adds later, such as a range it is still collecting.

When the frame cannot be closed, or write throws, everything write wrote is undone, so the frame is as if write never ran. Inside write, addMessage and addRange do not assert the size limit.

unwrap

readonly unwrap: () => ProtocolMessage;

Defined in: packages/common/src/local-first/Protocol.ts:798

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