/*
 *  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.groovy.parser.antlr4.internal.atnmanager;

import org.antlr.v4.runtime.atn.ATNDeserializer;
import org.apache.groovy.parser.antlr4.GroovyLangLexer;
import org.apache.groovy.util.SystemUtil;

/**
 * Manage ATN for lexer to avoid memory leak
 */
public class LexerAtnManager extends AtnManager {
    private static final String GROOVY_CLEAR_LEXER_DFA_CACHE = "groovy.antlr4.clear.lexer.dfa.cache";
    private static final boolean TO_CLEAR_LEXER_DFA_CACHE;
    public static final LexerAtnManager INSTANCE = new LexerAtnManager();

    static {
        TO_CLEAR_LEXER_DFA_CACHE = SystemUtil.getBooleanSafe(GROOVY_CLEAR_LEXER_DFA_CACHE);
    }

    @Override
    protected AtnWrapper createAtnWrapper() {
        // Dropping is opt-in for the lexer (its DFA stays in the hundreds of states), so by
        // default the wrapper shares the static ATN and the warm lexer cache persists.
        return new AtnWrapper(droppingEnabled()
                ? new ATNDeserializer().deserialize(GroovyLangLexer._serializedATN)
                : GroovyLangLexer._ATN);
    }

    @Override
    protected boolean shouldClearDfaCache() {
        return TO_CLEAR_LEXER_DFA_CACHE;
    }

    private LexerAtnManager() {}
}
