Function bson_update_document

pg_documentdb/src/update/bson_update.c:168–272

* bson_update_document processes the update operation on a given document. * The first argument is the source document to apply the updates on. * If an empty document is specified, it is assumed to be an 'upsert' * The second argument is a bson element that is the update spec. This is of the form: * { "": }. * The third argument is the query spec used to form this up

 * This is the C entry point for the update_bson_document SQL UDF, which returns a scalar bson value.
 */
Datum
bson_update_document(PG_FUNCTION_ARGS)
{
	/* Validate scalar bson return type (update_bson_document UDF). */
	TupleDesc tupleDescriptor = NULL;
	Oid resultTypeId = InvalidOid;
	if (get_call_result_type(fcinfo, &resultTypeId, &tupleDescriptor) != TYPEFUNC_SCALAR)
	{
		elog(ERROR, "return type must be a scalar type");
	}

	if (resultTypeId != BsonTypeId())
	{
		elog(ERROR, "return type must be a single bson value");
	}

	if (PG_ARGISNULL(0) || PG_ARGISNULL(1) || PG_ARGISNULL(2))
	{
		/* be on the safe side fwiw */
		ereport(ERROR, (errmsg("sourceDocument / updateSpec / querySpec "
							   "cannot be NULL")));
	}

	pgbson *sourceDocument = PG_GETARG_PGBSON(0);
	pgbson *updateSpecDoc = PG_GETARG_PGBSON(1);
	pgbson *querySpecDoc = PG_GETARG_PGBSON(2);
	pgbson *arrayFiltersDoc = PG_GETARG_MAYBE_NULL_PGBSON(3);

	bson_value_t variableSpec = { 0 };
	if (PG_NARGS() > 4 && !PG_ARGISNULL(4))
	{
		pgbson *variableSpecDoc = PG_GETARG_PGBSON(4);
		variableSpec = ConvertPgbsonToBsonValue(variableSpecDoc);
	}

	pgbsonelement updateSpecElement;
	PgbsonToSinglePgbsonElement(updateSpecDoc, &updateSpecElement);
	bson_value_t querySpec = ConvertPgbsonToBsonValue(querySpecDoc);
	pgbsonelement arrayFiltersBase = { 0 };
	bson_value_t *arrayFilters = NULL;

	if (arrayFiltersDoc != NULL)
	{
		PgbsonToSinglePgbsonElement(arrayFiltersDoc, &arrayFiltersBase);
		arrayFilters = &arrayFiltersBase.bsonValue;
	}

	BsonUpdateSource updateSource = { 0 };
	if (PG_NARGS() > 7)
	{
		if (!PG_ARGISNULL(6))
		{
			updateSource.ctid = (ItemPointer) DatumGetPointer(PG_GETARG_DATUM(6));
		}
		if (!PG_ARGISNULL(7) && PG_GETARG_OID(7) != InvalidOid)
		{
			updateSource.tableOid = PG_GETARG_OID(7);
		}