Java tutorial
/* * Cobertura - http://cobertura.sourceforge.net/ * * Copyright (C) 2011 Piotr Tabor * * Note: This file is dual licensed under the GPL and the Apache * Source License (so that it can be used from both the main * Cobertura classes and the ant tasks). * * Cobertura 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 2 of the License, * or (at your option) any later version. * * Cobertura 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 Cobertura; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 * USA */ package net.sourceforge.cobertura.instrument.pass1; import net.sourceforge.cobertura.instrument.AbstractFindTouchPointsClassInstrumenter; import org.objectweb.asm.ClassVisitor; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; import org.objectweb.asm.util.CheckClassAdapter; import java.util.HashMap; import java.util.Map; import java.util.concurrent.atomic.AtomicInteger; /** * The same line can cause generation of many byte-code blocks connected to the same line. * <p/> * This especially occurs in case of 'finally' blocks. For example: * <p/> * <pre> * 173: public void methodWithFinishBlock(FinishReturnTypeEnum f){ * 174: try { * 175: switch (f) { * 176: case BY_RETURN: * 177: System.out.println("will return"); * 178: return; * 179: case BY_THROW: * 180: System.out.println("will throw"); * 181: throw new IllegalStateException("Expected exception"); * 182: default: * 183: System.out.println("default"); * 184: } * 185: } finally { * 186: if (f != null) { //This piece of code is generated in ASM 3 times. We should merge it into one block * 187: System.out.println("Finish with: f="+f); * 188: } * 189: } * 190} * </pre> * <p/> * effects in generation such a JVM code: * <p/> * <pre> * // access flags 1 * public methodWithFinishBlock(Ltest/performance/Test1$FinishReturnTypeEnum;)V * TRYCATCHBLOCK L0 L1 L2 * TRYCATCHBLOCK L3 L2 L2 * L0 * LINENUMBER 175 L0 * INVOKESTATIC test/performance/Test1.$SWITCH_TABLE$test$performance$Test1$FinishReturnTypeEnum()[I * ALOAD 1 * INVOKEVIRTUAL test/performance/Test1$FinishReturnTypeEnum.ordinal()I * IALOAD * TABLESWITCH * 1: L4 * 2: L3 * default: L5 * L4 * LINENUMBER 177 L4 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * LDC "will return" * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * L1 * LINENUMBER 186 L1 * ALOAD 1 * IFNULL L6 * L7 * LINENUMBER 187 L7 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * NEW java/lang/StringBuilder * DUP * LDC "Finish with: f=" * INVOKESPECIAL java/lang/StringBuilder.<init>(Ljava/lang/String;)V * ALOAD 1 * INVOKEVIRTUAL java/lang/StringBuilder.append(Ljava/lang/Object;)Ljava/lang/StringBuilder; * INVOKEVIRTUAL java/lang/StringBuilder.toString()Ljava/lang/String; * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * L6 * LINENUMBER 178 L6 * RETURN * L3 * LINENUMBER 180 L3 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * LDC "will throw" * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * L8 * LINENUMBER 181 L8 * NEW java/lang/IllegalStateException * DUP * LDC "Expected exception" * INVOKESPECIAL java/lang/IllegalStateException.<init>(Ljava/lang/String;)V * ATHROW * L5 * LINENUMBER 183 L5 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * LDC "default" * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * GOTO L9 * L2 * LINENUMBER 185 L2 * ASTORE 2 * L10 * LINENUMBER 186 L10 * ALOAD 1 * IFNULL L11 * L12 * LINENUMBER 187 L12 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * NEW java/lang/StringBuilder * DUP * LDC "Finish with: f=" * INVOKESPECIAL java/lang/StringBuilder.<init>(Ljava/lang/String;)V * ALOAD 1 * INVOKEVIRTUAL java/lang/StringBuilder.append(Ljava/lang/Object;)Ljava/lang/StringBuilder; * INVOKEVIRTUAL java/lang/StringBuilder.toString()Ljava/lang/String; * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * L11 * LINENUMBER 189 L11 * ALOAD 2 * ATHROW * L9 * LINENUMBER 186 L9 * ALOAD 1 * IFNULL L13 * L14 * LINENUMBER 187 L14 * GETSTATIC java/lang/System.out : Ljava/io/PrintStream; * NEW java/lang/StringBuilder * DUP * LDC "Finish with: f=" * INVOKESPECIAL java/lang/StringBuilder.<init>(Ljava/lang/String;)V * ALOAD 1 * INVOKEVIRTUAL java/lang/StringBuilder.append(Ljava/lang/Object;)Ljava/lang/StringBuilder; * INVOKEVIRTUAL java/lang/StringBuilder.toString()Ljava/lang/String; * INVOKEVIRTUAL java/io/PrintStream.println(Ljava/lang/String;)V * L13 * LINENUMBER 190 L13 * RETURN * L15 * LOCALVARIABLE this Ltest/performance/Test1; L0 L15 0 * LOCALVARIABLE f Ltest/performance/Test1$FinishReturnTypeEnum; L0 L15 1 * MAXSTACK = 4 * MAXLOCALS = 3 * </pre> * <p/> * <p>Note that 'LINENUMBER 186' instruction occurs many times and code after that instruction is nearly identical * (see {@link CodeFootstamp} criteria of 'identity').</p> * <p/> * <p>On the other hand duplicated 'LINENUMBER 186' instruction could happened for for example for 'for' loop. In this * case the code after this instruction is different.</p> * <p/> * <p>The goal of this class is to provide {@link #duplicatedLinesCollector} that is map of: * (line number -> (duplicated lineId -> origin lineId)).</p> */ public class DetectDuplicatedCodeClassVisitor extends ClassVisitor { /** * map of (line number -> (duplicated lineId -> origin lineId)) */ private Map<Integer, Map<Integer, Integer>> duplicatedLinesCollector = new HashMap<Integer, Map<Integer, Integer>>(); /** * Name (internal asm) of currently processed class */ private String className; /** * Every LINENUMBER instruction will have generated it's lineId. * <p/> * The generated ids must be the same as those generated by * ( {@link AbstractFindTouchPointsClassInstrumenter#lineIdGenerator} ) */ private final AtomicInteger lineIdGenerator = new AtomicInteger(0); public DetectDuplicatedCodeClassVisitor(ClassVisitor cv) { super(Opcodes.ASM4, new CheckClassAdapter(cv, false)); } @Override public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { super.visit(version, access, name, signature, superName, interfaces); this.className = name; } @Override public MethodVisitor visitMethod(int access, String methodName, String description, String signature, String[] exceptions) { MethodVisitor nestedVisitor = super.visitMethod(access, methodName, description, signature, exceptions); return new DetectDuplicatedCodeMethodVisitor(nestedVisitor, duplicatedLinesCollector, className, methodName, description, lineIdGenerator); } /** * Returns map of (line number -> (duplicated lineId -> origin lineId)) */ public Map<Integer, Map<Integer, Integer>> getDuplicatesLinesCollector() { return duplicatedLinesCollector; } }