Function ProjectConsume

src/execution_plan/ops/op_project.c:43–94

}

static Record ProjectConsume(OpBase *opBase) {
	OpProject *op = (OpProject *)opBase;

	if(op->op.childCount) {
		OpBase *child = op->op.children[0];
		op->r = OpBase_Consume(child);
		if(!op->r) return NULL;
	} else {
		// QUERY: RETURN 1+2
		// Return a single record followed by NULL on the second call.
		if(op->singleResponse) return NULL;
		op->singleResponse = true;
		op->r = OpBase_CreateRecord(opBase);
	}

	op->projection = OpBase_CreateRecord(opBase);

	for(uint i = 0; i < op->exp_count; i++) {
		AR_ExpNode *exp = op->exps[i];
		SIValue v = AR_EXP_Evaluate(exp, op->r);
		int rec_idx = op->record_offsets[i];

		// persisting a value is only necessary when
		// 'v' refers to a scalar held in Record 'r'
		// graph entities don't need to be persisted here as
		// Record_Add will copy them internally
		//
		// the RETURN projection here requires persistence:
		// MATCH (a) WITH toUpper(a.name) AS e RETURN e
		// TODO: this is a rare case;
		// the logic of when to persist can be improved

		if(!(v.type & SI_GRAPHENTITY)) SIValue_Persist(&v);
		Record_Add(op->projection, rec_idx, v);

		// if the value was a graph entity with its own allocation
		// as with a query like:
		// MATCH p = (src) RETURN nodes(p)[0]
		// ensure that the allocation is freed here
		if((v.type & SI_GRAPHENTITY)) {
			SIValue_Free(v);
		}
	}

	OpBase_DeleteRecord(op->r);
	op->r = NULL;

	// Emit the projected Record once.
	Record projection = op->projection;
	op->projection = NULL;
	return projection;
}

static OpResult ProjectReset(OpBase *opBase) {
	OpProject *op = (OpProject *)opBase;