Function readInto

apps/desktop/src/utils/shared-frame-buffer.ts:387–473

(target: Uint8Array, timeoutMs: number = 100)

		},

		readInto(target: Uint8Array, timeoutMs: number = 100): number | null {
			const MAX_CAS_RETRIES = 3;

			for (let attempt = 0; attempt < MAX_CAS_RETRIES; attempt++) {
				const shutdownFlag = Atomics.load(controlView, CONTROL_SHUTDOWN);
				if (shutdownFlag) {
					return null;
				}

				const readIdx = Atomics.load(controlView, CONTROL_READ_INDEX);
				const slotMetaIdx =
					(metadataOffset + readIdx * METADATA_ENTRY_SIZE) / 4;

				let state = Atomics.load(metadataView, slotMetaIdx + META_SLOT_STATE);

				if (state !== SLOT_STATE.READY) {
					const waitResult = Atomics.wait(
						metadataView,
						slotMetaIdx + META_SLOT_STATE,
						state,
						timeoutMs,
					);
					if (waitResult === "timed-out") {
						return null;
					}

					const shutdownCheck = Atomics.load(controlView, CONTROL_SHUTDOWN);
					if (shutdownCheck) {
						return null;
					}

					state = Atomics.load(metadataView, slotMetaIdx + META_SLOT_STATE);
					if (state !== SLOT_STATE.READY) {
						continue;
					}
				}

				const exchangedState = Atomics.compareExchange(
					metadataView,
					slotMetaIdx + META_SLOT_STATE,
					SLOT_STATE.READY,
					SLOT_STATE.READING,
				);
				if (exchangedState !== SLOT_STATE.READY) {
					continue;
				}

				const frameSize = Atomics.load(
					metadataView,
					slotMetaIdx + META_FRAME_SIZE,
				);
				const slotDataOffset = dataOffset + readIdx * slotSize;

				if (
					!Number.isInteger(frameSize) ||
					frameSize < 0 ||
					frameSize > slotSize ||
					slotDataOffset < 0 ||