proguard.classfile.editor.SimplifiedClassEditor Maven / Gradle / Ivy
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2018 GuardSquare NV
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.classfile.editor;
import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.Constant;
import proguard.classfile.instruction.*;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;
import proguard.obfuscate.*;
import java.util.*;
import static proguard.classfile.ClassConstants.*;
/**
* This editor allows to build and/or edit classes (ProgramClass instances).
* It provides methods to easily add fields and methods to classes.
*
* @author Johan Leys
*/
public class SimplifiedClassEditor
extends SimplifiedVisitor
implements
// Implementation interfaces.
AttributeVisitor
{
private static final String EXTRA_INIT_METHOD_NAME = "init$";
private static final String EXTRA_INIT_METHOD_DESCRIPTOR = "()V";
private final ProgramClass programClass;
private final ClassEditor classEditor;
private final ConstantPoolEditor constantPoolEditor;
private final NameFactory nameFactory;
private String superClassName;
private final List methodComposers = new ArrayList();
private Instruction[] instructions;
/**
* Creates a new SimplifiedClassEditor for the Java class with the given
* name.
*
* @param u2accessFlags access flags for the new class.
* @param className the fully qualified name of the new class.
*
* @see ClassConstants
*/
public SimplifiedClassEditor(int u2accessFlags, String className)
{
this(u2accessFlags, className, null);
}
/**
* Creates a new SimplifiedClassEditor for the Java class with the given
* name and super class.
*
* @param u2accessFlags access flags for the new class.
* @param className the fully qualified name of the new class.
* @param superclassName the fully qualified name of the super class.
*
* @see ClassConstants
*/
public SimplifiedClassEditor(int u2accessFlags,
String className,
String superclassName)
{
this(new ProgramClass(ClassConstants.CLASS_VERSION_1_2,
1,
new Constant[10],
u2accessFlags,
0,
0));
programClass.u2thisClass =
constantPoolEditor.addClassConstant(className, programClass);
if (superclassName != null)
{
programClass.u2superClass =
constantPoolEditor.addClassConstant(superclassName, null);
this.superClassName = superclassName;
}
}
/**
* Creates a new SimplifiedClassEditor for the given class.
*
* @param programClass the class to be edited.
*/
public SimplifiedClassEditor(ProgramClass programClass)
{
this.programClass = programClass;
classEditor = new ClassEditor(programClass);
constantPoolEditor = new ConstantPoolEditor(programClass);
nameFactory = UniqueMemberNameFactory.newInjectedMemberNameFactory(programClass);
}
/**
* Finalizes the editing of the class. This method does not initialize
* references to/from related classes.
* At least one of the finishEditing methods should be called before
* calling {@link #getProgramClass}.
*
* @see #finishEditing(ClassPool, ClassPool)
*/
public void finishEditing() {
for (CodeComposer composer : methodComposers) {
composer.finishEditing();
}
}
/**
* Finalizes the editing of the class, and initializes all references
* of the edited class w.r.t. the given program and library class pool.
* At least one of the finishEditing methods should be called before
* calling {@link #getProgramClass}.
*
* @param programClassPool the program class pool
* @param libraryClassPool the library class pool
*/
public void finishEditing(ClassPool programClassPool,
ClassPool libraryClassPool) {
for (CodeComposer composer : methodComposers) {
composer.finishEditing();
}
// Initialize all references to/from the edited class.
if (superClassName != null)
{
new ClassSuperHierarchyInitializer(programClassPool, libraryClassPool, null, null).visitProgramClass(programClass);
new ClassSubHierarchyInitializer().visitProgramClass(programClass);
}
new ClassReferenceInitializer(programClassPool, libraryClassPool).visitProgramClass(programClass);
}
/**
* Returns the edited ProgramClass instance.
* Make sure to call one of the finishEditing methods after finishing editing,
* before calling this method.
*
* @return the edited ProgramClass instance.
*
* @see #finishEditing()
* @see #finishEditing(ClassPool, ClassPool)
*/
public ProgramClass getProgramClass()
{
return programClass;
}
/**
* Adds the given class constant to the edited class.
*
* @param name the class name to be added.
* @param referencedClass the corresponding referenced class.
*
* @return the constant pool index of the ClassConstant.
*/
public int addClassConstant(String name,
Clazz referencedClass) {
return constantPoolEditor.addClassConstant(name, referencedClass);
}
/**
* Adds a new field to the edited class.
*
* @param u2accessFlags acces flags for the new field.
* @param fieldName name of the new field.
* @param fieldDescriptor descriptor of the new field.
*
* @return this SimpleClassEditor.
*/
public SimplifiedClassEditor addField(int u2accessFlags,
String fieldName,
String fieldDescriptor)
{
Field field = new ProgramField(u2accessFlags,
constantPoolEditor.addUtf8Constant(fieldName),
constantPoolEditor.addUtf8Constant(fieldDescriptor),
null);
classEditor.addField(field);
return this;
}
/**
* Adds a new method to the edited class. The returned composer can be used
* to attach code to the method.
*
* @param u2accessFlags acces flags for the new method.
* @param methodName name of the new method.
* @param methodDescriptor descriptor of the new method.
* @param maxCodeFragmentLength maximum length for the code fragment of the
* new method.
*
* @return the composer for adding code to the created method.
*/
public CompactCodeAttributeComposer addMethod(int u2accessFlags,
String methodName,
String methodDescriptor,
int maxCodeFragmentLength)
{
return addMethod(u2accessFlags, methodName, methodDescriptor, null, maxCodeFragmentLength);
}
/**
* Adds a new method to the edited class. The returned composer can be used
* to attach code to the method.
*
* @param u2accessFlags acces flags for the new method.
* @param methodName name of the new method.
* @param methodDescriptor descriptor of the new method.
* @param referencedClasses the classes referenced by the method descriptor.
* @param maxCodeFragmentLength maximum length for the code fragment of the
* new method.
*
* @return the composer for adding code to the created method.
*/
public CompactCodeAttributeComposer addMethod(int u2accessFlags,
String methodName,
String methodDescriptor,
Clazz[] referencedClasses,
int maxCodeFragmentLength)
{
ProgramMethod method = new ProgramMethod(u2accessFlags,
constantPoolEditor.addUtf8Constant(methodName),
constantPoolEditor.addUtf8Constant(methodDescriptor),
referencedClasses);
CodeComposer composer = new CodeComposer(method, maxCodeFragmentLength);
methodComposers.add(composer);
return composer;
}
/**
* Adds a new method to the edited class, with the given instructions array.
*
* @param u2accessFlags acces flags for the new method.
* @param methodName name of the new method.
* @param methodDescriptor descriptor of the new method.
* @param instructions the instructions of the new method.
*/
public ProgramMethod addMethod(int u2accessFlags,
String methodName,
String methodDescriptor,
Instruction[] instructions)
{
return addMethod(u2accessFlags, methodName, methodDescriptor, instructions, null, null);
}
/**
* Adds the given static initializer instructions to the edited class.
* If the class already contains a static initializer, the new instructions
* will be appended to the existing initializer.
*
* @param instructions the instructions to be added.
* @param mergeIntoExistingInitializer indicates whether the instructions should
* be added to the existing static initializer
* (if it exists), or if a new method should
* be created, which is then called from the
* existing initializer.
*/
public void addStaticInitializerInstructions(Instruction[] instructions,
boolean mergeIntoExistingInitializer)
{
Method method = programClass.findMethod(METHOD_NAME_CLINIT, METHOD_TYPE_CLINIT);
if (method == null) {
addMethod(ACC_STATIC, METHOD_NAME_CLINIT, METHOD_TYPE_CLINIT,
instructions, null,
new SimpleInstruction(InstructionConstants.OP_RETURN));
}
else {
if (!mergeIntoExistingInitializer)
{
// Create a new static initializer.
ProgramMethod newMethod =
addMethod(ACC_STATIC,
nameFactory.nextName(), "()V",
instructions,
null,
new SimpleInstruction(InstructionConstants.OP_RETURN));
// Call the new initializer from the existing one.
InstructionSequenceBuilder builder = new InstructionSequenceBuilder(programClass);
builder.invokestatic(programClass.getName(),
newMethod.getName(programClass),
"()V",
programClass,
newMethod);
instructions = builder.instructions();
}
CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor();
((ProgramMethod) method).attributesAccept(programClass,
new CodeAttributeEditorResetter(codeAttributeEditor));
codeAttributeEditor.insertBeforeOffset(0, instructions);
((ProgramMethod) method).attributesAccept(programClass,
codeAttributeEditor);
}
}
/**
* Adds the given initialization instructions to the edited class.
*
* - If the class doesn't contain a constructor yet, it will be created,
* and the instructions will be added to this constructor.
* - If there is a single super-calling constructor, the instructions will
* be added at the beginning of it's code attribute.
* - If there are multiple super-calling constructors, a new private
* parameterless helper method will be created, to which the instructions
* will be added. An invocation to this new method will be added at the
* beginning of the code attribute of all super-calling constructors.
*
* @param instructions the instructions to be added.
*/
public void addInitializerInstructions(Instruction[] instructions)
{
Method method = programClass.findMethod(METHOD_NAME_INIT, null);
if (method == null) {
// First call the super constructor.
Instruction[] firstInstruction = {
new VariableInstruction(InstructionConstants.OP_ALOAD_0),
new ConstantInstruction(
InstructionConstants.OP_INVOKESPECIAL,
constantPoolEditor.addMethodrefConstant(programClass.getSuperClass().getName(), METHOD_NAME_INIT, METHOD_TYPE_INIT, null, null))
};
// End by calling return.
SimpleInstruction lastInstruction =
new SimpleInstruction(InstructionConstants.OP_RETURN);
addMethod(ACC_PUBLIC, METHOD_NAME_INIT, METHOD_TYPE_INIT,
instructions,
firstInstruction,
lastInstruction);
}
else {
// Find all super-calling constructors.
Set constructors = new HashSet();
programClass.methodsAccept(
new ConstructorMethodFilter(
new MethodCollector(constructors), null, null));
if (constructors.size() == 1)
{
// There is only one supper-calling constructor.
// Add the code to this constructor.
this.instructions = instructions;
constructors.iterator().next().accept(programClass,
new AllAttributeVisitor(
this));
}
else
{
// There are multiple super-calling constructors. Add the
// instructions to a separate, parameterless initialization
// method, and invoke this method from all super-calling
// constructors.
ProgramMethod initMethod = (ProgramMethod) programClass.findMethod(EXTRA_INIT_METHOD_NAME,
EXTRA_INIT_METHOD_DESCRIPTOR);
if (initMethod == null)
{
// There is no init$ method yet. Create it now, and add the
// given instructions to it.
initMethod = addMethod(ACC_PRIVATE,
EXTRA_INIT_METHOD_NAME,
EXTRA_INIT_METHOD_DESCRIPTOR,
instructions,
null,
new SimpleInstruction(InstructionConstants.OP_RETURN));
// Insert a call to the new init$ method in all super-calling constructors.
InstructionSequenceBuilder builder = new InstructionSequenceBuilder(programClass);
builder.aload_0();
builder.invokespecial(programClass.getName(),
EXTRA_INIT_METHOD_NAME,
EXTRA_INIT_METHOD_DESCRIPTOR,
programClass,
initMethod);
this.instructions = builder.instructions();
programClass.methodsAccept(
new ConstructorMethodFilter(
new AllAttributeVisitor(
this), null, null));
}
else {
// There is already an init$ method. Add the instructions to this method.
this.instructions = instructions;
initMethod.accept(programClass,
new AllAttributeVisitor(
this));
}
}
}
}
/**
* Adds a new method to the edited class, with the given instructions array.
*
* @param u2accessFlags acces flags for the new method.
* @param methodName name of the new method.
* @param methodDescriptor descriptor of the new method.
* @param instructions the instructions of the new method.
* @param firstInstructions extra instructions to add in front of the
* new method.
* @param lastInstruction extra instruction to add at the end of the
* new method.
*/
private ProgramMethod addMethod(int u2accessFlags,
String methodName,
String methodDescriptor,
Instruction[] instructions,
Instruction[] firstInstructions,
Instruction lastInstruction)
{
ProgramMethod method = new ProgramMethod(u2accessFlags,
constantPoolEditor.addUtf8Constant(methodName),
constantPoolEditor.addUtf8Constant(methodDescriptor),
null);
CodeAttribute codeAttribute =
new CodeAttribute(constantPoolEditor.addUtf8Constant(ClassConstants.ATTR_Code));
CodeAttributeComposer composer = new CodeAttributeComposer();
composer.reset();
composer.beginCodeFragment(0);
composer.appendInstructions(instructions);
if (firstInstructions != null) {
for (Instruction instruction : firstInstructions) {
composer.appendInstruction(instruction);
}
}
if (lastInstruction != null) {
composer.appendInstruction(lastInstruction);
}
composer.endCodeFragment();
composer.visitCodeAttribute(programClass, method, codeAttribute);
new AttributesEditor(programClass, method, false).addAttribute(codeAttribute);
classEditor.addMethod(method);
return method;
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
{
CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor();
((ProgramMethod) method).attributesAccept(programClass, new CodeAttributeEditorResetter(codeAttributeEditor));
codeAttributeEditor.insertBeforeOffset(0, instructions);
codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute);
}
private class CodeComposer extends CompactCodeAttributeComposer {
private final ProgramMethod method;
public CodeComposer(ProgramMethod method,
int maxCodeFragmentLength)
{
super(programClass);
this.method = method;
beginCodeFragment(maxCodeFragmentLength);
}
public void finishEditing() {
endCodeFragment();
CodeAttribute codeAttribute =
new CodeAttribute(constantPoolEditor.addUtf8Constant(ClassConstants.ATTR_Code));
visitCodeAttribute(programClass, method, codeAttribute);
new AttributesEditor(programClass, method, false).addAttribute(codeAttribute);
classEditor.addMethod(method);
}
}
}
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