Java tutorial
/* * Quasar: lightweight threads and actors for the JVM. * Copyright (c) 2013-2014, Parallel Universe Software Co. All rights reserved. * * This program and the accompanying materials are dual-licensed under * either the terms of the Eclipse Public License v1.0 as published by * the Eclipse Foundation * * or (per the licensee's choosing) * * under the terms of the GNU Lesser General Public License version 3.0 * as published by the Free Software Foundation. */ /* * Copyright (c) 2008-2013, Matthias Mann * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 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. * * Neither the name of Matthias Mann 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 co.paralleluniverse.fibers.instrument; import co.paralleluniverse.fibers.SuspendExecution; import static co.paralleluniverse.fibers.instrument.Classes.ALREADY_INSTRUMENTED_DESC; import static co.paralleluniverse.fibers.instrument.Classes.ANNOTATION_DESC; import co.paralleluniverse.fibers.instrument.MethodDatabase.ClassEntry; import co.paralleluniverse.fibers.instrument.MethodDatabase.SuspendableType; import org.objectweb.asm.AnnotationVisitor; import org.objectweb.asm.ClassVisitor; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; /** * Check if a class contains suspendable methods. * Basicly this class checks if a method is declared to throw {@link SuspendExecution}. * * @author Matthias Mann */ public class CheckInstrumentationVisitor extends ClassVisitor { private final MethodDatabase db; private final SuspendableClassifier classifier; private String className; private boolean isInterface; private boolean suspendableInterface; private ClassEntry classEntry; private boolean hasSuspendable; private boolean alreadyInstrumented; public CheckInstrumentationVisitor(MethodDatabase db) { super(Opcodes.ASM4); this.db = db; this.classifier = db.getClassifier(); } public boolean needsInstrumentation() { return hasSuspendable; } ClassEntry getClassEntry() { return classEntry; } public String getName() { return className; } public boolean isAlreadyInstrumented() { return alreadyInstrumented; } @Override public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { this.className = name; this.isInterface = (access & Opcodes.ACC_INTERFACE) != 0; this.classEntry = new ClassEntry(superName); classEntry.setInterfaces(interfaces); } @Override public AnnotationVisitor visitAnnotation(String desc, boolean visible) { if (desc.equals(ALREADY_INSTRUMENTED_DESC)) this.alreadyInstrumented = true; else if (isInterface && desc.equals(ANNOTATION_DESC)) this.suspendableInterface = true; return null; } @Override public MethodVisitor visitMethod(int access, final String name, final String desc, String signature, String[] exceptions) { SuspendableType suspendable = null; if (suspendableInterface) suspendable = SuspendableType.SUSPENDABLE_SUPER; if (suspendable == null) suspendable = classEntry.check(name, desc); if (suspendable == null) suspendable = classifier.isSuspendable(db, className, classEntry.getSuperName(), classEntry.getInterfaces(), name, desc, signature, exceptions); if (suspendable == SuspendableType.SUSPENDABLE) { hasSuspendable = true; // synchronized methods can't be made suspendable if ((access & Opcodes.ACC_SYNCHRONIZED) == Opcodes.ACC_SYNCHRONIZED) { if (!className.equals("clojure/lang/LazySeq")) throw new UnableToInstrumentException("synchronized method", className, name, desc); } } classEntry.set(name, desc, suspendable); if (suspendable == null) // look for @Suspendable annotation return new MethodVisitor(Opcodes.ASM4) { private boolean susp = false; @Override public AnnotationVisitor visitAnnotation(String adesc, boolean visible) { if (adesc.equals(ANNOTATION_DESC)) susp = true; return null; } @Override public void visitEnd() { super.visitEnd(); classEntry.set(name, desc, susp ? SuspendableType.SUSPENDABLE : SuspendableType.NON_SUSPENDABLE); hasSuspendable = hasSuspendable | susp; } }; else return null; } }