/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2011 INRIA, France Telecom

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holders nor the names of its

 *    contributors may be used to endorse or promote products derived from

 *    this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package jdk.internal.org.objectweb.asm.commons;

import jdk.internal.org.objectweb.asm.ClassVisitor;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.internal.org.objectweb.asm.Opcodes;

/**

 * A {@link ClassVisitor} that merges <clinit> methods into a single one. All the existing

 * <clinit> methods are renamed, and a new one is created, which calls all the renamed

 * methods.

 *

 * @author Eric Bruneton

 */

public class StaticInitMerger extends ClassVisitor {

    /** The internal name of the visited class. */

    private String owner;

    /** The prefix to use to rename the existing <clinit> methods. */

    private final String renamedClinitMethodPrefix;

    /** The number of <clinit> methods visited so far. */

    private int numClinitMethods;

    /** The MethodVisitor for the merged <clinit> method. */

    private MethodVisitor mergedClinitVisitor;

    /**

      * Constructs a new {@link StaticInitMerger}. <i>Subclasses must not use this constructor</i>.

      * Instead, they must use the {@link #StaticInitMerger(int, String, ClassVisitor)} version.

      *

      * @param prefix the prefix to use to rename the existing <clinit> methods.

      * @param classVisitor the class visitor to which this visitor must delegate method calls. May be

      *     null.

      */

    public StaticInitMerger(final String prefix, final ClassVisitor classVisitor) {

        this(/* latest api = */ Opcodes.ASM8, prefix, classVisitor);

    }

    /**

      * Constructs a new {@link StaticInitMerger}.

      *

      * @param api the ASM API version implemented by this visitor. Must be one of {@link

      *     Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6}, {@link Opcodes#ASM7} or {@link

      *     Opcodes#ASM8}.

      * @param prefix the prefix to use to rename the existing <clinit> methods.

      * @param classVisitor the class visitor to which this visitor must delegate method calls. May be

      *     null.

      */

    protected StaticInitMerger(final int api, final String prefix, final ClassVisitor classVisitor) {

        super(api, classVisitor);

        this.renamedClinitMethodPrefix = prefix;

    }

    @Override

    public void visit(

            final int version,

            final int access,

            final String name,

            final String signature,

            final String superName,

            final String[] interfaces) {

        super.visit(version, access, name, signature, superName, interfaces);

        this.owner = name;

    }

    @Override

    public MethodVisitor visitMethod(

            final int access,

            final String name,

            final String descriptor,

            final String signature,

            final String[] exceptions) {

        MethodVisitor methodVisitor;

        if ("<clinit>".equals(name)) {

            int newAccess = Opcodes.ACC_PRIVATE + Opcodes.ACC_STATIC;

            String newName = renamedClinitMethodPrefix + numClinitMethods++;

            methodVisitor = super.visitMethod(newAccess, newName, descriptor, signature, exceptions);

            if (mergedClinitVisitor == null) {

                mergedClinitVisitor = super.visitMethod(newAccess, name, descriptor, null, null);

            }

            mergedClinitVisitor.visitMethodInsn(Opcodes.INVOKESTATIC, owner, newName, descriptor, false);

        } else {

            methodVisitor = super.visitMethod(access, name, descriptor, signature, exceptions);

        }

        return methodVisitor;

    }

    @Override

    public void visitEnd() {

        if (mergedClinitVisitor != null) {

            mergedClinitVisitor.visitInsn(Opcodes.RETURN);

            mergedClinitVisitor.visitMaxs(0, 0);

        }

        super.visitEnd();

    }

}