AIFunction.java

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

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

import org.apache.doris.catalog.AIResource;
import org.apache.doris.catalog.Env;
import org.apache.doris.catalog.Resource;
import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
import org.apache.doris.nereids.trees.expressions.functions.scalar.ScalarFunction;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.util.ExpressionUtils;
import org.apache.doris.qe.ConnectContext;

import com.google.common.base.Strings;

/**
 * Base class for AI related functions.
 */
public abstract class AIFunction extends ScalarFunction
        implements PropagateNullable, ExplicitlyCastableSignature {
    /**
     * constructor with at least 1 argument.
     */
    public AIFunction(String name, Expression... expressions) {
        super(name, expressions);
        if (children.isEmpty()) {
            throw new AnalysisException(name + " requires at least 1 argument.");
        }
    }

    public abstract int getMaxArgsNum();

    @Override
    public void checkLegalityAfterRewrite() {
        // The rewrite has folded a constant resource name, unless constant folding is skipped
        // (debug_skip_fold_constant). The name FE can evaluate is resolved like the literal, and BE reads the name
        // it evaluates from the first row.
        if (arity() == getMaxArgsNum()) {
            checkResource(ExpressionUtils.foldConstantArgument(getArgument(0)));
        }
    }

    private void checkResource(Expression resourceNameArgument) {
        //The resource must be literal
        if (!resourceNameArgument.isLiteral()) {
            throw new AnalysisException("AI Function must accept literal for the resource name.");
        }

        //Check if the resource is valid
        String resourceName = resourceNameArgument.toString().replaceAll("^['\"]|['\"]$", "");
        Resource resource = Env.getCurrentEnv().getResourceMgr().getResource(resourceName);
        if (!(resource instanceof AIResource)) {
            throw new AnalysisException("AI resource '" + resourceName + "' does not exist");
        }
        if (!((AIResource) resource).hasCompleteGeneralProperties()) {
            throw new AnalysisException("AI resource '" + resourceName
                    + "' does not contain complete general AI properties");
        }
        Resource.registerUsedAIResourceName(resourceName);
    }

    /**
     *  If a user doesn't specify which resource to use when calling a function
     *  the current session variable will automatically allocate a resource.
     *  <p>
     *  1. First, attempt to use the user-specified argument passed to the function.
     *  2. If not available, try using the global default AI resource.
     */
    public static String getResourceName() throws AnalysisException {
        String resourceName = ConnectContext.get().getSessionVariable().defaultAIResource;
        if (Strings.isNullOrEmpty(resourceName)) {
            throw new AnalysisException("Please specify the AI Resource in argument "
                    + "or session variable.");
        }
        return resourceName;
    }

    @Override
    public void checkLegalityBeforeTypeCoercion() {
        // The rewrite folds a constant resource name before checkLegalityAfterRewrite resolves it. Resolve the
        // name FE can evaluate here too, because constant folding, e.g. of a NULL argument, may remove this
        // function before that check.
        if (arity() == getMaxArgsNum()) {
            checkResource(ExpressionUtils.foldConstantArgument(getArgument(0)));
        }
    }

    @Override
    public abstract <R, C> R accept(ExpressionVisitor<R, C> visitor, C context);
}