Function _RdbSaveKeySchema

src/serializers/encoder/v13/encode_graph.c:113–169

this function saves the key content schema and returns it so the encoder can know how to encode the key

// this function saves the key content schema
// and returns it so the encoder can know how to encode the key
static PayloadInfo *_RdbSaveKeySchema
(
	RedisModuleIO *rdb,
	GraphContext *gc
) {
	//  Format:
	//  #Number of payloads info - N
	//  N * Payload info:
	//      Encode state
	//      Number of entities encoded in this state

	PayloadInfo *payloads = array_new(PayloadInfo, 1);

	// get current encoding state
	EncodeState current_state = GraphEncodeContext_GetEncodeState(gc->encoding_context);

	// if this is the start of the encodeing, set the state to be NODES
	if(current_state == ENCODE_STATE_INIT) current_state = ENCODE_STATE_NODES;

	uint64_t remaining_entities;
	Config_Option_get(Config_VKEY_MAX_ENTITY_COUNT, &remaining_entities);

	// check if this is the last key
	bool last_key = GraphEncodeContext_GetProcessedKeyCount(gc->encoding_context) ==
					(GraphEncodeContext_GetKeyCount(gc->encoding_context) - 1);
	if(last_key) remaining_entities = VKEY_ENTITY_COUNT_UNLIMITED;

	// get the current state encoded entities count
	uint64_t offset = GraphEncodeContext_GetProcessedEntitiesOffset(gc->encoding_context);

	// while there are still remaining entities to encode in this key
	// and the state is valid
	while(remaining_entities > 0 && current_state < ENCODE_STATE_FINAL) {
		// get the current state payload info, with respect to offset
		PayloadInfo current_state_payload_info = _StatePayloadInfo(gc,
				current_state, offset, remaining_entities);
		array_append(payloads, current_state_payload_info);
		if(!last_key) remaining_entities -= current_state_payload_info.entities_count;
		if(remaining_entities > 0) {
			offset = 0; // new state offset is 0
			current_state++; // advance in the states
		}
	}

	// save the number of payloads
	uint payloads_count = array_len(payloads);
	RedisModule_SaveUnsigned(rdb, payloads_count);
	for(uint i = 0; i < payloads_count; i++) {
		// for each payload
		// save its type and the number of entities it contains
		PayloadInfo payload_info = payloads[i];
		RedisModule_SaveUnsigned(rdb, payload_info.state);
		RedisModule_SaveUnsigned(rdb, payload_info.entities_count);
	}

	return payloads;
}