Java tutorial
/** * * Copyright 2010-2011 (C) The original author or authors * * Licensed 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 com.toolazydogs.maiden.agent.asm; import java.util.logging.Logger; import static com.toolazydogs.maiden.agent.asm.AsmUtils.push; import org.objectweb.asm.AnnotationVisitor; import org.objectweb.asm.Attribute; import org.objectweb.asm.ClassVisitor; import org.objectweb.asm.FieldVisitor; import org.objectweb.asm.MethodAdapter; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; import org.objectweb.asm.Type; import com.toolazydogs.maiden.agent.IronAgent; /** * An ASM class visitor. */ public class IronClassVisitor implements ClassVisitor, Opcodes { private final static String CLASS_NAME = IronClassVisitor.class.getName(); private final static Logger LOGGER = Logger.getLogger(CLASS_NAME); private final String clazz; private final boolean nativeMethodPrefixSupported; private final ClassVisitor delegate; public IronClassVisitor(String clazz, boolean nativeMethodPrefixSupported, ClassVisitor delegate) { assert clazz != null; assert delegate != null; this.clazz = clazz; this.nativeMethodPrefixSupported = nativeMethodPrefixSupported; this.delegate = delegate; } public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { delegate.visit(version, access, name, signature, superName, interfaces); } public void visitSource(String source, String debug) { delegate.visitSource(source, debug); } public void visitOuterClass(String owner, String name, String desc) { delegate.visitOuterClass(owner, name, desc); } public AnnotationVisitor visitAnnotation(String desc, boolean visible) { return delegate.visitAnnotation(desc, visible); } public void visitAttribute(Attribute attr) { delegate.visitAttribute(attr); } public void visitInnerClass(String name, String outerName, String innerName, int access) { delegate.visitInnerClass(name, outerName, innerName, access); } public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) { return delegate.visitField(access, name, desc, signature, value); } public MethodVisitor visitMethod(int access, final String name, final String desc, String signature, String[] exceptions) { LOGGER.entering(CLASS_NAME, "visitMethod", new Object[] { access, name, desc, signature, exceptions }); boolean isNative = (access & ACC_NATIVE) != 0; boolean isSynchronized = (access & ACC_SYNCHRONIZED) != 0; boolean isStatic = (access & ACC_STATIC) != 0; MethodVisitor mv; /** * If native method prefix is supported we inject our own wrapper method. */ if (nativeMethodPrefixSupported && isNative) { delegate.visitMethod(access, IronAgent.NATIVE_METHOD_PREFIX + name, desc, signature, exceptions); mv = delegate.visitMethod(access ^ (ACC_NATIVE | ACC_SYNCHRONIZED), name, desc, signature, exceptions); } else { mv = delegate.visitMethod((isSynchronized ? access ^ ACC_SYNCHRONIZED : access), name, desc, signature, exceptions); } mv = new WaitNotifyMethodVisitor(mv); BeginEndMethodVisitor bemv = new BeginEndMethodVisitor(mv, access, name, desc, signature, exceptions); if (isSynchronized) { LOGGER.finest("Method is synchronized"); final Type classType = Type.getType("L" + clazz.replaceAll("\\.", "/") + ";.class"); if (isStatic) { LOGGER.finest("Method is static"); bemv.getListeners().add(new BeginEndMethodListener() { @Override public void begin(MethodVisitor visitor) { push(visitor, line); visitor.visitLdcInsn(classType); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "lockObject", "(ILjava/lang/Object;)V"); } @Override public void end(MethodVisitor visitor) { push(visitor, line); visitor.visitLdcInsn(classType); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "unlockObject", "(ILjava/lang/Object;)V"); } }); } else { LOGGER.finest("Method is not static"); bemv.getListeners().add(new BeginEndMethodListener() { @Override public void begin(MethodVisitor visitor) { push(visitor, line); visitor.visitVarInsn(ALOAD, 0); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "lockObject", "(ILjava/lang/Object;)V"); } @Override public void end(MethodVisitor visitor) { push(visitor, line); visitor.visitVarInsn(ALOAD, 0); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "unlockObject", "(ILjava/lang/Object;)V"); } }); } } bemv.getListeners().add(new BeginEndMethodListener() { @Override public void begin(MethodVisitor visitor) { visitor.visitLdcInsn(clazz); visitor.visitLdcInsn(name); visitor.visitLdcInsn(desc); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "push", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V"); } @Override public void end(MethodVisitor visitor) { push(visitor, line); visitor.visitMethodInsn(INVOKESTATIC, "com/toolazydogs/maiden/IronMaiden", "pop", "(I)V"); } }); MethodVisitor result = new MonitorMethodVisitor(bemv); if (nativeMethodPrefixSupported && isNative) { MethodAdapter adapter = new MethodAdapter(result); adapter.visitCode(); int args = 0; if (!isStatic) adapter.visitVarInsn(ALOAD, args++); for (Type param : Type.getArgumentTypes(desc)) { adapter.visitVarInsn(param.getOpcode(ILOAD), args); args += param.getSize(); } adapter.visitMethodInsn((isStatic ? INVOKESTATIC : INVOKEVIRTUAL), clazz.replaceAll("\\.", "/"), IronAgent.NATIVE_METHOD_PREFIX + name, desc); Type returnType = Type.getReturnType(desc); adapter.visitInsn(returnType.getOpcode(Opcodes.IRETURN)); adapter.visitMaxs(0, 0); adapter.visitEnd(); result = null; } LOGGER.exiting(CLASS_NAME, "visitMethod", result); return result; } public void visitEnd() { delegate.visitEnd(); } }