Function BsonValueHashFuncCore

pg_documentdb_core/src/utils/hashset_utils.c:319–364

* Hashes a bson value for use in hash set. * * If no valid collation string is provided or collation is disabled, we simply * hash the bson value. * * If a collation string is provided, we need to consider the following: * (1) non-collation-aware bson value, just hash the value. * (2) utf8 bson value, create collation sort key and hash that. * (3) arrays and documents, recurse into them, a

 * The final hash value is the sum of all the hash values.
 */
static void
BsonValueHashFuncCore(const bson_value_t *bsonValue, const
					  char *collationString, uint32_t *hashValue)
{
	/* collation disabled or invalid collation string provided, */
	/* simply hash the bson value and return */
	if (!IsCollationApplicable(collationString))
	{
		*hashValue += BsonValueHashUint32(bsonValue);
		return;
	}

	/* base cases */
	/* (1) non-collation-aware bson value, just hash value */
	if (!IsBsonTypeCollationAware(bsonValue->value_type) ||
		!IsCollationApplicable(collationString))
	{
		*hashValue += BsonValueHashUint32(bsonValue);
		return;
	}

	/* (2) utf8 bson value, create collation sort key and hash that */
	if (bsonValue->value_type == BSON_TYPE_UTF8)
	{
		char *key = bsonValue->value.v_utf8.str;
		char *sortKey = GetCollationSortKey(collationString, key,
											bsonValue->value.v_utf8.len);

		*hashValue += hash_bytes((unsigned char *) sortKey, strlen(sortKey));
		pfree(sortKey);
		return;
	}

	/* recursive case: arrays and documents */
	/* process each element and recurse into array and document values */
	bson_iter_t arrayValueIterator;
	bson_iter_init_from_data(&arrayValueIterator,
							 bsonValue->value.v_doc.data,
							 bsonValue->value.v_doc.data_len);

	while (bson_iter_next(&arrayValueIterator))
	{
		const bson_value_t *value = bson_iter_value(&arrayValueIterator);
		BsonValueHashFuncCore(value, collationString, hashValue);
	}
}