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/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    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
 * 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 com.google.gwt.dev.asm.commons;

import java.io.ByteArrayOutputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;

import com.google.gwt.dev.asm.ClassVisitor;
import com.google.gwt.dev.asm.FieldVisitor;
import com.google.gwt.dev.asm.MethodVisitor;
import com.google.gwt.dev.asm.Opcodes;

/**
 * A {@link ClassVisitor} that adds a serial version unique identifier to a
 * class if missing. Here is typical usage of this class:
 * 
 * 
 *   ClassWriter cw = new ClassWriter(...);
 *   ClassVisitor sv = new SerialVersionUIDAdder(cw);
 *   ClassVisitor ca = new MyClassAdapter(sv);
 *   new ClassReader(orginalClass).accept(ca, false);
 * 
* * The SVUID algorithm can be found http://java.sun.com/j2se/1.4.2/docs/guide/serialization/spec/class.html: * *
 * The serialVersionUID is computed using the signature of a stream of bytes
 * that reflect the class definition. The National Institute of Standards and
 * Technology (NIST) Secure Hash Algorithm (SHA-1) is used to compute a
 * signature for the stream. The first two 32-bit quantities are used to form a
 * 64-bit hash. A java.lang.DataOutputStream is used to convert primitive data
 * types to a sequence of bytes. The values input to the stream are defined by
 * the Java Virtual Machine (VM) specification for classes.
 * 
 * The sequence of items in the stream is as follows:
 * 
 * 1. The class name written using UTF encoding.
 * 2. The class modifiers written as a 32-bit integer.
 * 3. The name of each interface sorted by name written using UTF encoding.
 * 4. For each field of the class sorted by field name (except private static
 * and private transient fields):
 * 1. The name of the field in UTF encoding.
 * 2. The modifiers of the field written as a 32-bit integer.
 * 3. The descriptor of the field in UTF encoding
 * 5. If a class initializer exists, write out the following:
 * 1. The name of the method, <clinit>, in UTF encoding.
 * 2. The modifier of the method, java.lang.reflect.Modifier.STATIC,
 * written as a 32-bit integer.
 * 3. The descriptor of the method, ()V, in UTF encoding.
 * 6. For each non-private constructor sorted by method name and signature:
 * 1. The name of the method, <init>, in UTF encoding.
 * 2. The modifiers of the method written as a 32-bit integer.
 * 3. The descriptor of the method in UTF encoding.
 * 7. For each non-private method sorted by method name and signature:
 * 1. The name of the method in UTF encoding.
 * 2. The modifiers of the method written as a 32-bit integer.
 * 3. The descriptor of the method in UTF encoding.
 * 8. The SHA-1 algorithm is executed on the stream of bytes produced by
 * DataOutputStream and produces five 32-bit values sha[0..4].
 * 
 * 9. The hash value is assembled from the first and second 32-bit values of
 * the SHA-1 message digest. If the result of the message digest, the five
 * 32-bit words H0 H1 H2 H3 H4, is in an array of five int values named
 * sha, the hash value would be computed as follows:
 * 
 * long hash = ((sha[0] >>> 24) & 0xFF) |
 * ((sha[0] >>> 16) & 0xFF) << 8 |
 * ((sha[0] >>> 8) & 0xFF) << 16 |
 * ((sha[0] >>> 0) & 0xFF) << 24 |
 * ((sha[1] >>> 24) & 0xFF) << 32 |
 * ((sha[1] >>> 16) & 0xFF) << 40 |
 * ((sha[1] >>> 8) & 0xFF) << 48 |
 * ((sha[1] >>> 0) & 0xFF) << 56;
 * 
* * @author Rajendra Inamdar, Vishal Vishnoi */ public class SerialVersionUIDAdder extends ClassVisitor { /** * Flag that indicates if we need to compute SVUID. */ private boolean computeSVUID; /** * Set to true if the class already has SVUID. */ private boolean hasSVUID; /** * Classes access flags. */ private int access; /** * Internal name of the class */ private String name; /** * Interfaces implemented by the class. */ private String[] interfaces; /** * Collection of fields. (except private static and private transient * fields) */ private Collection svuidFields; /** * Set to true if the class has static initializer. */ private boolean hasStaticInitializer; /** * Collection of non-private constructors. */ private Collection svuidConstructors; /** * Collection of non-private methods. */ private Collection svuidMethods; /** * Creates a new {@link SerialVersionUIDAdder}. Subclasses must not use * this constructor. Instead, they must use the * {@link #SerialVersionUIDAdder(int, ClassVisitor)} version. * * @param cv * a {@link ClassVisitor} to which this visitor will delegate * calls. */ public SerialVersionUIDAdder(final ClassVisitor cv) { this(Opcodes.ASM4, cv); } /** * Creates a new {@link SerialVersionUIDAdder}. * * @param api * the ASM API version implemented by this visitor. Must be one * of {@link Opcodes#ASM4}. * @param cv * a {@link ClassVisitor} to which this visitor will delegate * calls. */ protected SerialVersionUIDAdder(final int api, final ClassVisitor cv) { super(api, cv); svuidFields = new ArrayList(); svuidConstructors = new ArrayList(); svuidMethods = new ArrayList(); } // ------------------------------------------------------------------------ // Overriden methods // ------------------------------------------------------------------------ /* * Visit class header and get class name, access , and interfaces * information (step 1,2, and 3) for SVUID computation. */ @Override public void visit(final int version, final int access, final String name, final String signature, final String superName, final String[] interfaces) { computeSVUID = (access & Opcodes.ACC_INTERFACE) == 0; if (computeSVUID) { this.name = name; this.access = access; this.interfaces = interfaces; } super.visit(version, access, name, signature, superName, interfaces); } /* * Visit the methods and get constructor and method information (step 5 and * 7). Also determine if there is a class initializer (step 6). */ @Override public MethodVisitor visitMethod(final int access, final String name, final String desc, final String signature, final String[] exceptions) { if (computeSVUID) { if ("".equals(name)) { hasStaticInitializer = true; } /* * Remembers non private constructors and methods for SVUID * computation For constructor and method modifiers, only the * ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL, * ACC_SYNCHRONIZED, ACC_NATIVE, ACC_ABSTRACT and ACC_STRICT flags * are used. */ int mods = access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PRIVATE | Opcodes.ACC_PROTECTED | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL | Opcodes.ACC_SYNCHRONIZED | Opcodes.ACC_NATIVE | Opcodes.ACC_ABSTRACT | Opcodes.ACC_STRICT); // all non private methods if ((access & Opcodes.ACC_PRIVATE) == 0) { if ("".equals(name)) { svuidConstructors.add(new Item(name, mods, desc)); } else if (!"".equals(name)) { svuidMethods.add(new Item(name, mods, desc)); } } } return super.visitMethod(access, name, desc, signature, exceptions); } /* * Gets class field information for step 4 of the algorithm. Also determines * if the class already has a SVUID. */ @Override public FieldVisitor visitField(final int access, final String name, final String desc, final String signature, final Object value) { if (computeSVUID) { if ("serialVersionUID".equals(name)) { // since the class already has SVUID, we won't be computing it. computeSVUID = false; hasSVUID = true; } /* * Remember field for SVUID computation For field modifiers, only * the ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, * ACC_FINAL, ACC_VOLATILE, and ACC_TRANSIENT flags are used when * computing serialVersionUID values. */ if ((access & Opcodes.ACC_PRIVATE) == 0 || (access & (Opcodes.ACC_STATIC | Opcodes.ACC_TRANSIENT)) == 0) { int mods = access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PRIVATE | Opcodes.ACC_PROTECTED | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL | Opcodes.ACC_VOLATILE | Opcodes.ACC_TRANSIENT); svuidFields.add(new Item(name, mods, desc)); } } return super.visitField(access, name, desc, signature, value); } /** * Handle a bizarre special case. Nested classes (static classes declared * inside another class) that are protected have their access bit set to * public in their class files to deal with some odd reflection situation. * Our SVUID computation must do as the JVM does and ignore access bits in * the class file in favor of the access bits InnerClass attribute. */ @Override public void visitInnerClass(final String aname, final String outerName, final String innerName, final int attr_access) { if ((name != null) && name.equals(aname)) { this.access = attr_access; } super.visitInnerClass(aname, outerName, innerName, attr_access); } /* * Add the SVUID if class doesn't have one */ @Override public void visitEnd() { // compute SVUID and add it to the class if (computeSVUID && !hasSVUID) { try { addSVUID(computeSVUID()); } catch (Throwable e) { throw new RuntimeException("Error while computing SVUID for " + name, e); } } super.visitEnd(); } // ------------------------------------------------------------------------ // Utility methods // ------------------------------------------------------------------------ /** * Returns true if the class already has a SVUID field. The result of this * method is only valid when visitEnd is or has been called. * * @return true if the class already has a SVUID field. */ public boolean hasSVUID() { return hasSVUID; } protected void addSVUID(long svuid) { FieldVisitor fv = super.visitField(Opcodes.ACC_FINAL + Opcodes.ACC_STATIC, "serialVersionUID", "J", null, new Long( svuid)); if (fv != null) { fv.visitEnd(); } } /** * Computes and returns the value of SVUID. * * @return Returns the serial version UID * @throws IOException * if an I/O error occurs */ protected long computeSVUID() throws IOException { ByteArrayOutputStream bos; DataOutputStream dos = null; long svuid = 0; try { bos = new ByteArrayOutputStream(); dos = new DataOutputStream(bos); /* * 1. The class name written using UTF encoding. */ dos.writeUTF(name.replace('/', '.')); /* * 2. The class modifiers written as a 32-bit integer. */ dos.writeInt(access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_FINAL | Opcodes.ACC_INTERFACE | Opcodes.ACC_ABSTRACT)); /* * 3. The name of each interface sorted by name written using UTF * encoding. */ Arrays.sort(interfaces); for (int i = 0; i < interfaces.length; i++) { dos.writeUTF(interfaces[i].replace('/', '.')); } /* * 4. For each field of the class sorted by field name (except * private static and private transient fields): * * 1. The name of the field in UTF encoding. 2. The modifiers of the * field written as a 32-bit integer. 3. The descriptor of the field * in UTF encoding * * Note that field signatures are not dot separated. Method and * constructor signatures are dot separated. Go figure... */ writeItems(svuidFields, dos, false); /* * 5. If a class initializer exists, write out the following: 1. The * name of the method, , in UTF encoding. 2. The modifier of * the method, java.lang.reflect.Modifier.STATIC, written as a * 32-bit integer. 3. The descriptor of the method, ()V, in UTF * encoding. */ if (hasStaticInitializer) { dos.writeUTF(""); dos.writeInt(Opcodes.ACC_STATIC); dos.writeUTF("()V"); } // if.. /* * 6. For each non-private constructor sorted by method name and * signature: 1. The name of the method, , in UTF encoding. 2. * The modifiers of the method written as a 32-bit integer. 3. The * descriptor of the method in UTF encoding. */ writeItems(svuidConstructors, dos, true); /* * 7. For each non-private method sorted by method name and * signature: 1. The name of the method in UTF encoding. 2. The * modifiers of the method written as a 32-bit integer. 3. The * descriptor of the method in UTF encoding. */ writeItems(svuidMethods, dos, true); dos.flush(); /* * 8. The SHA-1 algorithm is executed on the stream of bytes * produced by DataOutputStream and produces five 32-bit values * sha[0..4]. */ byte[] hashBytes = computeSHAdigest(bos.toByteArray()); /* * 9. The hash value is assembled from the first and second 32-bit * values of the SHA-1 message digest. If the result of the message * digest, the five 32-bit words H0 H1 H2 H3 H4, is in an array of * five int values named sha, the hash value would be computed as * follows: * * long hash = ((sha[0] >>> 24) & 0xFF) | ((sha[0] >>> 16) & 0xFF) * << 8 | ((sha[0] >>> 8) & 0xFF) << 16 | ((sha[0] >>> 0) & 0xFF) << * 24 | ((sha[1] >>> 24) & 0xFF) << 32 | ((sha[1] >>> 16) & 0xFF) << * 40 | ((sha[1] >>> 8) & 0xFF) << 48 | ((sha[1] >>> 0) & 0xFF) << * 56; */ for (int i = Math.min(hashBytes.length, 8) - 1; i >= 0; i--) { svuid = (svuid << 8) | (hashBytes[i] & 0xFF); } } finally { // close the stream (if open) if (dos != null) { dos.close(); } } return svuid; } /** * Returns the SHA-1 message digest of the given value. * * @param value * the value whose SHA message digest must be computed. * @return the SHA-1 message digest of the given value. */ protected byte[] computeSHAdigest(final byte[] value) { try { return MessageDigest.getInstance("SHA").digest(value); } catch (Exception e) { throw new UnsupportedOperationException(e.toString()); } } /** * Sorts the items in the collection and writes it to the data output stream * * @param itemCollection * collection of items * @param dos * a DataOutputStream value * @param dotted * a boolean value * @exception IOException * if an error occurs */ private static void writeItems(final Collection itemCollection, final DataOutput dos, final boolean dotted) throws IOException { int size = itemCollection.size(); Item[] items = itemCollection.toArray(new Item[size]); Arrays.sort(items); for (int i = 0; i < size; i++) { dos.writeUTF(items[i].name); dos.writeInt(items[i].access); dos.writeUTF(dotted ? items[i].desc.replace('/', '.') : items[i].desc); } } // ------------------------------------------------------------------------ // Inner classes // ------------------------------------------------------------------------ private static class Item implements Comparable { final String name; final int access; final String desc; Item(final String name, final int access, final String desc) { this.name = name; this.access = access; this.desc = desc; } public int compareTo(final Item other) { int retVal = name.compareTo(other.name); if (retVal == 0) { retVal = desc.compareTo(other.desc); } return retVal; } @Override public boolean equals(final Object o) { if (o instanceof Item) { return compareTo((Item) o) == 0; } return false; } @Override public int hashCode() { return (name + desc).hashCode(); } } }




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