Datum gin_consistent_agtype()

in src/backend/utils/adt/agtype_gin.c [309:388]

• 58 lines of code
• 14 McCabe index (conditional complexity)

Datum gin_consistent_agtype(PG_FUNCTION_ARGS)
{
    bool *check;
    StrategyNumber strategy;
    int32 nkeys;
    bool *recheck;
    bool res = true;
    int32 i;

    if (PG_ARGISNULL(0) || PG_ARGISNULL(1) ||
        PG_ARGISNULL(3) || PG_ARGISNULL(5))
    {
        PG_RETURN_NULL();
    }

    check = (bool *) PG_GETARG_POINTER(0);
    strategy = PG_GETARG_UINT16(1);
    nkeys = PG_GETARG_INT32(3);
    recheck = (bool *) PG_GETARG_POINTER(5);

    if (strategy == AGTYPE_CONTAINS_STRATEGY_NUMBER ||
        strategy == AGTYPE_CONTAINS_TOP_LEVEL_STRATEGY_NUMBER)
    {
        /*
         * We must always recheck, since we can't tell from the index whether
         * the positions of the matched items match the structure of the query
         * object.  (Even if we could, we'd also have to worry about hashed
         * keys and the index's failure to distinguish keys from string array
         * elements.)  However, the tuple certainly doesn't match unless it
         * contains all the query keys.
         */
        *recheck = true;
        for (i = 0; i < nkeys; i++)
        {
            if (!check[i])
            {
                res = false;
                break;
            }
        }
    }
    else if (strategy == AGTYPE_EXISTS_STRATEGY_NUMBER)
    {
        /*
         * Although the key is certainly present in the index, we must recheck
         * because (1) the key might be hashed, and (2) the index match might
         * be for a key that's not at top level of the JSON object.  For (1),
         * we could look at the query key to see if it's hashed and not
         * recheck if not, but the index lacks enough info to tell about (2).
         */
        *recheck = true;
        res = true;
    }
    else if (strategy == AGTYPE_EXISTS_ANY_STRATEGY_NUMBER)
    {
        /* As for plain exists, we must recheck */
        *recheck = true;
        res = true;
    }
    else if (strategy == AGTYPE_EXISTS_ALL_STRATEGY_NUMBER)
    {
        /* As for plain exists, we must recheck */
        *recheck = true;
        /* ... but unless all the keys are present, we can say "false" */
        for (i = 0; i < nkeys; i++)
        {
            if (!check[i])
            {
                res = false;
                break;
            }
        }
    }
    else
    {
        elog(ERROR, "unrecognized strategy number: %d", strategy);
    }

    PG_RETURN_BOOL(res);
}