Java tutorial
/* * Copyright (c) 2015 Gargoyle Software Inc. * * 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. * * 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 (http://www.gnu.org/licenses/). */ /* * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. * 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 * or visit www.oracle.com if you need additional information or have any * questions. */ package com.gargoylesoftware.js.nashorn.internal.tools.nasgen; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.$CLINIT$; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.CLINIT; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.DEFAULT_INIT_DESC; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.INIT; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.OBJECT_DESC; import static com.gargoylesoftware.js.nashorn.internal.tools.nasgen.StringConstants.SCRIPTOBJECT_TYPE; import static org.objectweb.asm.Opcodes.ALOAD; import static org.objectweb.asm.Opcodes.DUP; import static org.objectweb.asm.Opcodes.INVOKESPECIAL; import static org.objectweb.asm.Opcodes.INVOKESTATIC; import static org.objectweb.asm.Opcodes.NEW; import static org.objectweb.asm.Opcodes.PUTFIELD; import static org.objectweb.asm.Opcodes.RETURN; import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import org.objectweb.asm.AnnotationVisitor; import org.objectweb.asm.Attribute; import org.objectweb.asm.ClassReader; import org.objectweb.asm.ClassVisitor; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.FieldVisitor; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.util.CheckClassAdapter; import com.gargoylesoftware.js.nashorn.internal.objects.annotations.Where; import com.gargoylesoftware.js.nashorn.internal.tools.nasgen.MemberInfo.Kind; /** * This class instruments the java class annotated with @ScriptClass. * * Changes done are: * * 1) remove all com.gargoylesoftware.js.nashorn.internal.objects.annotations.* annotations. * 2) static final @Property fields stay here. Other @Property fields moved to * respective classes depending on 'where' value of annotation. * 2) add "Map" type static field named "$map". * 3) add static initializer block to initialize map. */ public class ScriptClassInstrumentor extends ClassVisitor { private final ScriptClassInfo scriptClassInfo; private final int memberCount; private boolean staticInitFound; ScriptClassInstrumentor(final ClassVisitor visitor, final ScriptClassInfo sci) { super(Main.ASM_VERSION, visitor); if (sci == null) { throw new IllegalArgumentException("Null ScriptClassInfo, is the class annotated?"); } this.scriptClassInfo = sci; this.memberCount = scriptClassInfo.getInstancePropertyCount(); } @Override public AnnotationVisitor visitAnnotation(final String desc, final boolean visible) { if (ScriptClassInfo.annotations.containsKey(desc)) { // ignore @ScriptClass return null; } return super.visitAnnotation(desc, visible); } @Override public FieldVisitor visitField(final int fieldAccess, final String fieldName, final String fieldDesc, final String signature, final Object value) { final MemberInfo memInfo = scriptClassInfo.find(fieldName, fieldDesc, fieldAccess); if (memInfo != null && memInfo.getKind() == Kind.PROPERTY && memInfo.getWhere() != Where.INSTANCE && !memInfo.isStaticFinal()) { // non-instance @Property fields - these have to go elsewhere unless 'static final' return null; } final FieldVisitor delegateFV = super.visitField(fieldAccess, fieldName, fieldDesc, signature, value); return new FieldVisitor(Main.ASM_VERSION, delegateFV) { @Override public AnnotationVisitor visitAnnotation(final String desc, final boolean visible) { if (ScriptClassInfo.annotations.containsKey(desc)) { // ignore script field annotations return null; } return fv.visitAnnotation(desc, visible); } @Override public void visitAttribute(final Attribute attr) { fv.visitAttribute(attr); } @Override public void visitEnd() { fv.visitEnd(); } }; } @Override public MethodVisitor visitMethod(final int methodAccess, final String methodName, final String methodDesc, final String signature, final String[] exceptions) { final boolean isConstructor = INIT.equals(methodName); final boolean isStaticInit = CLINIT.equals(methodName); if (isStaticInit) { staticInitFound = true; } final MethodGenerator delegateMV = new MethodGenerator( super.visitMethod(methodAccess, methodName, methodDesc, signature, exceptions), methodAccess, methodName, methodDesc); return new MethodVisitor(Main.ASM_VERSION, delegateMV) { @Override public void visitInsn(final int opcode) { // call $clinit$ just before return from <clinit> if (isStaticInit && opcode == RETURN) { super.visitMethodInsn(INVOKESTATIC, scriptClassInfo.getJavaName(), $CLINIT$, DEFAULT_INIT_DESC, false); } super.visitInsn(opcode); } @Override public void visitMethodInsn(final int opcode, final String owner, final String name, final String desc, final boolean itf) { if (isConstructor && opcode == INVOKESPECIAL && INIT.equals(name) && SCRIPTOBJECT_TYPE.equals(owner)) { super.visitMethodInsn(opcode, owner, name, desc, false); if (memberCount > 0) { // initialize @Property fields if needed for (final MemberInfo memInfo : scriptClassInfo.getMembers()) { if (memInfo.isInstanceProperty() && !memInfo.getInitClass().isEmpty()) { final String clazz = memInfo.getInitClass(); super.visitVarInsn(ALOAD, 0); super.visitTypeInsn(NEW, clazz); super.visitInsn(DUP); super.visitMethodInsn(INVOKESPECIAL, clazz, INIT, DEFAULT_INIT_DESC, false); super.visitFieldInsn(PUTFIELD, scriptClassInfo.getJavaName(), memInfo.getJavaName(), memInfo.getJavaDesc()); } if (memInfo.isInstanceFunction()) { super.visitVarInsn(ALOAD, 0); ClassGenerator.newFunction(delegateMV, scriptClassInfo.getJavaName(), memInfo, scriptClassInfo.findSpecializations(memInfo.getJavaName())); super.visitFieldInsn(PUTFIELD, scriptClassInfo.getJavaName(), memInfo.getJavaName(), OBJECT_DESC); } } } } else { super.visitMethodInsn(opcode, owner, name, desc, itf); } } @Override public AnnotationVisitor visitAnnotation(final String desc, final boolean visible) { if (ScriptClassInfo.annotations.containsKey(desc)) { // ignore script method annotations return null; } return super.visitAnnotation(desc, visible); } }; } @Override public void visitEnd() { emitFields(); emitStaticInitializer(); emitGettersSetters(); super.visitEnd(); } private void emitFields() { // introduce "Function" type instance fields for each // instance @Function in script class info final String className = scriptClassInfo.getJavaName(); for (MemberInfo memInfo : scriptClassInfo.getMembers()) { if (memInfo.isInstanceFunction()) { ClassGenerator.addFunctionField(cv, memInfo.getJavaName()); memInfo = (MemberInfo) memInfo.clone(); memInfo.setJavaDesc(OBJECT_DESC); ClassGenerator.addGetter(cv, className, memInfo); ClassGenerator.addSetter(cv, className, memInfo); } } // omit addMapField() since instance classes already define a static PropertyMap field } void emitGettersSetters() { if (memberCount > 0) { for (final MemberInfo memInfo : scriptClassInfo.getMembers()) { final String className = scriptClassInfo.getJavaName(); if (memInfo.isInstanceProperty()) { ClassGenerator.addGetter(cv, className, memInfo); if (!memInfo.isFinal()) { ClassGenerator.addSetter(cv, className, memInfo); } } } } } private void emitStaticInitializer() { final String className = scriptClassInfo.getJavaName(); if (!staticInitFound) { // no user written <clinit> and so create one final MethodVisitor mv = ClassGenerator.makeStaticInitializer(this); mv.visitCode(); mv.visitInsn(RETURN); mv.visitMaxs(Short.MAX_VALUE, 0); mv.visitEnd(); } // Now generate $clinit$ final MethodGenerator mi = ClassGenerator.makeStaticInitializer(this, $CLINIT$); ClassGenerator.emitStaticInitPrefix(mi, className, memberCount); if (memberCount > 0) { for (final MemberInfo memInfo : scriptClassInfo.getMembers()) { if (memInfo.isInstanceProperty() || memInfo.isInstanceFunction()) { ClassGenerator.linkerAddGetterSetter(mi, className, memInfo); } else if (memInfo.isInstanceGetter()) { final MemberInfo setter = scriptClassInfo.findSetter(memInfo); ClassGenerator.linkerAddGetterSetter(mi, className, memInfo, setter); } } } ClassGenerator.emitStaticInitSuffix(mi, className); } /** * External entry point for ScriptClassInfoCollector if run from the command line * * @param args arguments - one argument is needed, the name of the class to collect info from * * @throws IOException if there are problems reading class */ public static void main(final String[] args) throws IOException { if (args.length != 1) { System.err.println("Usage: " + ScriptClassInstrumentor.class.getName() + " <class>"); System.exit(1); } final String fileName = args[0].replace('.', '/') + ".class"; final ScriptClassInfo sci = ClassGenerator.getScriptClassInfo(fileName); if (sci == null) { System.err.println("No @ScriptClass in " + fileName); System.exit(2); throw new AssertionError(); //guard against warning that sci is null below } try { sci.verify(); } catch (final Exception e) { System.err.println(e.getMessage()); System.exit(3); } final ClassWriter writer = ClassGenerator.makeClassWriter(); try (final BufferedInputStream bis = new BufferedInputStream(new FileInputStream(fileName))) { final ClassReader reader = new ClassReader(bis); final CheckClassAdapter checker = new CheckClassAdapter(writer); final ScriptClassInstrumentor instr = new ScriptClassInstrumentor(checker, sci); reader.accept(instr, 0); } try (FileOutputStream fos = new FileOutputStream(fileName)) { fos.write(writer.toByteArray()); } } }