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Utilities for ASM, a very small and fast Java bytecode manipulation framework
/***
* 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 org.objectweb.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 org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.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.
* @throws IllegalStateException
* If a subclass calls this constructor.
*/
public SerialVersionUIDAdder(final ClassVisitor cv) {
this(Opcodes.ASM5, cv);
if (getClass() != SerialVersionUIDAdder.class) {
throw new IllegalStateException();
}
}
/**
* Creates a new {@link SerialVersionUIDAdder}.
*
* @param api
* the ASM API version implemented by this visitor. Must be one
* of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
* @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
- ();
}
// ------------------------------------------------------------------------
// Overridden 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_ENUM) == 0;
if (computeSVUID) {
this.name = name;
this.access = access;
this.interfaces = new String[interfaces.length];
System.arraycopy(interfaces, 0, this.interfaces, 0,
interfaces.length);
}
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, 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.
*/
int access = this.access;
if ((access & Opcodes.ACC_INTERFACE) != 0) {
access = (svuidMethods.size() > 0) ? (access | Opcodes.ACC_ABSTRACT)
: (access & ~Opcodes.ACC_ABSTRACT);
}
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();
}
}
}