DateTimeWithPrecision.java

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//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees.expressions.functions;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.scalar.ScalarFunction;
import org.apache.doris.nereids.trees.expressions.literal.IntegerLikeLiteral;
import org.apache.doris.nereids.types.DateTimeV2Type;

import java.util.List;

/**
 * TimeWithPrecision. fill precision to the return type.
 *
 * e.g. now(1) return datetime v2(1)
 */
public abstract class DateTimeWithPrecision extends ScalarFunction {

    public DateTimeWithPrecision(String name, Expression... arguments) {
        super(name, arguments);
    }

    public DateTimeWithPrecision(String name, List<Expression> arguments) {
        super(name, arguments);
    }

    @Override
    public FunctionSignature computeSignature(FunctionSignature signature) {
        if (arity() == 1 && signature.returnType instanceof DateTimeV2Type) {
            // For functions in TIME_FUNCTIONS_WITH_PRECISION, we can't figure out which function should be use when
            // searching in FunctionSet. So we adjust the return type by hand here.
            if (getArgument(0) instanceof IntegerLikeLiteral) {
                IntegerLikeLiteral integerLikeLiteral = (IntegerLikeLiteral) getArgument(0);
                signature = signature.withReturnType(DateTimeV2Type.of(integerLikeLiteral.getIntValue()));
            } else {
                signature = signature.withReturnType(DateTimeV2Type.of(6));
            }
        }
        return super.computeSignature(signature);
    }
}