org.neo4j.codegen.bytecode.ByteCodeGenerator Maven / Gradle / Ivy

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Simple library for generating code.
There is a newer version: 5.25.1
/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [https://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.neo4j.codegen.bytecode;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.neo4j.codegen.ByteCodes;
import org.neo4j.codegen.ClassWriter;
import org.neo4j.codegen.CodeGenerator;
import org.neo4j.codegen.CompilationFailureException;
import org.neo4j.codegen.TypeReference;

/**
 * {@link CodeGenerator} that generates classes dy direct bytecode generation using {@link org.objectweb.asm.ClassWriter}.
 */
class ByteCodeGenerator extends CodeGenerator {
    private final Configuration configuration;
    private final Map classes = new HashMap<>();

    ByteCodeGenerator(ClassLoader parentClassLoader, Configuration configuration) {
        super(parentClassLoader);
        this.configuration = configuration;
    }

    @Override
    protected ClassWriter generate(TypeReference type, TypeReference base, TypeReference... interfaces) {
        ByteCodeClassWriter codeWriter = new ByteCodeClassWriter(type, base, interfaces);
        synchronized (this) {
            ByteCodeClassWriter old = classes.put(type, codeWriter);
            if (old != null) {
                classes.put(type, old);
                throw new IllegalStateException("Trying to generate class twice: " + type);
            }
        }

        return codeWriter;
    }

    @Override
    protected Iterable compile(ClassLoader classpathLoader) throws CompilationFailureException {
        List byteCodes;
        synchronized (this) {
            byteCodes = new ArrayList<>(classes.size());
            for (ByteCodeClassWriter writer : classes.values()) {
                byteCodes.add(writer.toByteCodes());
            }
            ByteCodeChecker checker = configuration.bytecodeChecker();
            if (checker != null) {
                checker.check(classpathLoader, byteCodes);
            }
            classes.clear();
        }
        return byteCodes;
    }
}