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// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
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// modification, are permitted provided that the following conditions
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// 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
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package org.objectweb.asm.commons;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import 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}. Subclasses must not use this constructor.
* 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.ASM9, prefix, classVisitor);
}
/**
* Constructs a new {@link StaticInitMerger}.
*
* @param api the ASM API version implemented by this visitor. Must be one of the {@code
* ASM}x values in {@link Opcodes}.
* @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 ("".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();
}
}