SpatialFunctionSignature.java

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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.types.GeographyType;
import org.apache.doris.nereids.types.GeometryType;

/** Helpers for preserving parameterized spatial types in function signatures. */
final class SpatialFunctionSignature {
    private SpatialFunctionSignature() {
    }

    static FunctionSignature unary(Expression argument, DataType returnType) {
        if (!isSpatial(argument)) {
            return null;
        }
        return FunctionSignature.ret(returnType).args(argument.getDataType());
    }

    static FunctionSignature binary(Expression left, Expression right, DataType returnType) {
        return spatialArguments(returnType, left, right);
    }

    static FunctionSignature ternary(Expression first, Expression second, Expression third, DataType returnType) {
        return spatialArguments(returnType, first, second, third);
    }

    private static FunctionSignature spatialArguments(DataType returnType, Expression... arguments) {
        DataType inferredType = null;
        for (Expression argument : arguments) {
            if (isSpatial(argument)) {
                inferredType = argument.getDataType();
                break;
            }
        }
        if (inferredType == null) {
            return null;
        }
        DataType[] inputTypes = new DataType[arguments.length];
        for (int i = 0; i < arguments.length; i++) {
            Expression argument = arguments[i];
            if (isSpatial(argument)) {
                inputTypes[i] = argument.getDataType();
            } else if (argument.getDataType().isNullType()) {
                inputTypes[i] = inferredType;
            } else {
                return null;
            }
        }
        return FunctionSignature.ret(returnType).args(inputTypes);
    }

    private static boolean isSpatial(Expression expression) {
        return expression.getDataType() instanceof GeometryType
                || expression.getDataType() instanceof GeographyType;
    }
}