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JMockit is a Java toolkit for automated developer testing.
It contains mocking/faking APIs and a code coverage tool, supporting both JUnit and TestNG.
The mocking APIs allow all kinds of Java code, without testability restrictions, to be tested
in isolation from selected dependencies.
/*
* Copyright (c) 2006 Rogério Liesenfeld
* This file is subject to the terms of the MIT license (see LICENSE.txt).
*/
package mockit.internal;
import javax.annotation.*;
import static java.lang.reflect.Modifier.*;
import mockit.external.asm.*;
import mockit.internal.state.*;
import mockit.internal.util.*;
import static mockit.external.asm.Opcodes.*;
public class BaseClassModifier extends ClassVisitor
{
private static final int METHOD_ACCESS_MASK = 0xFFFF - ACC_ABSTRACT - ACC_NATIVE;
protected static final Type VOID_TYPE = Type.getType("Ljava/lang/Void;");
@Nonnull
protected final MethodVisitor methodAnnotationsVisitor = new MethodVisitor() {
@Override
public AnnotationVisitor visitAnnotation(String desc, boolean visible)
{
return mw.visitAnnotation(desc, visible);
}
@Override
public void visitLocalVariable(
@Nonnull String name, @Nonnull String desc, String signature, @Nonnull Label start, @Nonnull Label end,
int index)
{}
@Override
public AnnotationVisitor visitParameterAnnotation(int parameter, String desc, boolean visible) { return null; }
};
@Nonnull protected final ClassWriter cw;
protected MethodWriter mw;
protected boolean useMockingBridge;
protected String superClassName;
protected String classDesc;
protected int methodAccess;
protected String methodName;
protected String methodDesc;
protected BaseClassModifier(@Nonnull ClassReader classReader)
{
super(new ClassWriter(classReader));
//noinspection ConstantConditions
cw = (ClassWriter) cv;
}
protected final void setUseMockingBridge(@Nullable ClassLoader classLoader)
{
useMockingBridge = ClassLoad.isClassLoaderWithNoDirectAccess(classLoader);
}
@Override
public void visit(
int version, int access, @Nonnull String name, @Nullable String signature, @Nullable String superName,
@Nullable String[] interfaces)
{
int modifiedVersion = version;
int originalVersion = version & 0xFFFF;
if (originalVersion < V1_5) {
// LDC instructions (see MethodVisitor#visitLdcInsn) are more capable in JVMs with support for class files of
// version 49 (Java 5) or newer, so we "upgrade" it to avoid a VerifyError:
modifiedVersion = V1_5;
}
cw.visit(modifiedVersion, access, name, signature, superName, interfaces);
superClassName = superName;
classDesc = name;
}
/**
* Just creates a new MethodWriter which will write out the method bytecode when visited.
*
* Removes any "abstract" or "native" modifiers for the modified version.
*/
protected final void startModifiedMethodVersion(
int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature, @Nullable String[] exceptions)
{
mw = cw.visitMethod(access & METHOD_ACCESS_MASK, name, desc, signature, exceptions);
methodAccess = access;
methodName = name;
methodDesc = desc;
if (isNative(access)) {
TestRun.mockFixture().addRedefinedClassWithNativeMethods(classDesc);
}
}
public final boolean wasModified() { return methodName != null; }
protected final void generateCallToSuperConstructor()
{
if (superClassName != null) {
mw.visitVarInsn(ALOAD, 0);
String constructorDesc;
if ("java/lang/Object".equals(superClassName)) {
constructorDesc = "()V";
}
else {
constructorDesc = SuperConstructorCollector.INSTANCE.findConstructor(classDesc, superClassName);
for (Type paramType : Type.getArgumentTypes(constructorDesc)) {
pushDefaultValueForType(paramType);
}
}
mw.visitMethodInsn(INVOKESPECIAL, superClassName, "", constructorDesc, false);
}
}
protected final void generateReturnWithObjectAtTopOfTheStack(@Nonnull String mockedMethodDesc)
{
Type returnType = Type.getReturnType(mockedMethodDesc);
TypeConversion.generateCastFromObject(mw, returnType);
mw.visitInsn(returnType.getOpcode(IRETURN));
}
protected final boolean generateCodeToPassThisOrNullIfStaticMethod()
{
return generateCodeToPassThisOrNullIfStaticMethod(mw, methodAccess);
}
public static boolean generateCodeToPassThisOrNullIfStaticMethod(@Nonnull MethodWriter mw, int access)
{
boolean isStatic = isStatic(access);
if (isStatic) {
mw.visitInsn(ACONST_NULL);
}
else {
mw.visitVarInsn(ALOAD, 0);
}
return isStatic;
}
public static void generateCodeToCreateArrayOfObject(@Nonnull MethodWriter mw, int arrayLength)
{
mw.visitIntInsn(BIPUSH, arrayLength);
mw.visitTypeInsn(ANEWARRAY, "java/lang/Object");
}
public static void generateCodeToFillArrayWithParameterValues(
@Nonnull MethodWriter mw, @Nonnull Type[] parameterTypes, int initialArrayIndex, int initialParameterIndex)
{
int i = initialArrayIndex;
int j = initialParameterIndex;
for (Type parameterType : parameterTypes) {
mw.visitInsn(DUP);
mw.visitIntInsn(BIPUSH, i++);
mw.visitVarInsn(parameterType.getOpcode(ILOAD), j);
TypeConversion.generateCastToObject(mw, parameterType);
mw.visitInsn(AASTORE);
j += parameterType.getSize();
}
}
protected final void generateCodeToObtainInstanceOfMockingBridge(@Nonnull MockingBridge mockingBridge)
{
String hostClassName = MockingBridge.getHostClassName();
mw.visitFieldInsn(GETSTATIC, hostClassName, mockingBridge.id, "Ljava/lang/reflect/InvocationHandler;");
}
protected final void generateCodeToFillArrayElement(int arrayIndex, @Nullable Object value)
{
mw.visitInsn(DUP);
mw.visitIntInsn(BIPUSH, arrayIndex);
if (value == null) {
mw.visitInsn(ACONST_NULL);
}
else if (value instanceof Integer) {
mw.visitIntInsn(SIPUSH, (Integer) value);
mw.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;", false);
}
else if (value instanceof Boolean) {
mw.visitInsn((Boolean) value ? ICONST_1 : ICONST_0);
mw.visitMethodInsn(INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;", false);
}
else {
mw.visitLdcInsn(value);
}
mw.visitInsn(AASTORE);
}
private void pushDefaultValueForType(@Nonnull Type type)
{
switch (type.getSort()) {
case Type.VOID: break;
case Type.BOOLEAN:
case Type.CHAR:
case Type.BYTE:
case Type.SHORT:
case Type.INT: mw.visitInsn(ICONST_0); break;
case Type.LONG: mw.visitInsn(LCONST_0); break;
case Type.FLOAT: mw.visitInsn(FCONST_0); break;
case Type.DOUBLE: mw.visitInsn(DCONST_0); break;
case Type.ARRAY: generateCreationOfEmptyArray(type); break;
default: mw.visitInsn(ACONST_NULL);
}
}
private void generateCreationOfEmptyArray(@Nonnull Type arrayType)
{
int dimensions = arrayType.getDimensions();
for (int dimension = 0; dimension < dimensions; dimension++) {
mw.visitInsn(ICONST_0);
}
if (dimensions > 1) {
mw.visitMultiANewArrayInsn(arrayType.getDescriptor(), dimensions);
return;
}
Type elementType = arrayType.getElementType();
int elementSort = elementType.getSort();
if (elementSort == Type.OBJECT) {
mw.visitTypeInsn(ANEWARRAY, elementType.getInternalName());
}
else {
int typ = getArrayElementTypeCode(elementSort);
mw.visitIntInsn(NEWARRAY, typ);
}
}
private static int getArrayElementTypeCode(int elementSort)
{
switch (elementSort) {
case Type.BOOLEAN: return T_BOOLEAN;
case Type.CHAR: return T_CHAR;
case Type.BYTE: return T_BYTE;
case Type.SHORT: return T_SHORT;
case Type.INT: return T_INT;
case Type.FLOAT: return T_FLOAT;
case Type.LONG: return T_LONG;
default: return T_DOUBLE;
}
}
protected final void generateCallToInvocationHandler()
{
mw.visitMethodInsn(
INVOKEINTERFACE, "java/lang/reflect/InvocationHandler", "invoke",
"(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;", true);
}
protected final void generateEmptyImplementation(@Nonnull String desc)
{
Type returnType = Type.getReturnType(desc);
pushDefaultValueForType(returnType);
mw.visitInsn(returnType.getOpcode(IRETURN));
mw.visitMaxs(1, 0);
}
protected final void generateEmptyImplementation()
{
mw.visitInsn(RETURN);
mw.visitMaxs(1, 0);
}
@Nonnull
protected final MethodVisitor copyOriginalImplementationCode(boolean disregardCallToSuper)
{
if (disregardCallToSuper) {
return new DynamicConstructorModifier();
}
if (isNative(methodAccess)) {
generateEmptyImplementation(methodDesc);
return methodAnnotationsVisitor;
}
return new DynamicModifier();
}
private class DynamicModifier extends MethodVisitor
{
DynamicModifier() { super(mw); }
@Override
public final void visitLocalVariable(
@Nonnull String name, @Nonnull String desc, @Nullable String signature,
@Nonnull Label start, @Nonnull Label end, int index)
{
// For some reason, the start position for "this" gets displaced by bytecode inserted at the beginning,
// in a method modified by the EMMA tool. If not treated, this causes a ClassFormatError.
if (end.position > 0 && start.position > end.position) {
start.position = end.position;
}
// Ignores any local variable with required information missing, to avoid a VerifyError/ClassFormatError.
if (start.position > 0 && end.position > 0) {
mw.visitLocalVariable(name, desc, signature, start, end, index);
}
}
}
private final class DynamicConstructorModifier extends DynamicModifier
{
private boolean pendingCallToConstructorOfSameClass;
private boolean callToAnotherConstructorAlreadyDisregarded;
@Override
public void visitTypeInsn(int opcode, @Nonnull String type)
{
if (!callToAnotherConstructorAlreadyDisregarded && opcode == NEW && type.equals(classDesc)) {
pendingCallToConstructorOfSameClass = true;
}
mw.visitTypeInsn(opcode, type);
}
@Override
public void visitMethodInsn(
int opcode, @Nonnull String owner, @Nonnull String name, @Nonnull String desc, boolean itf)
{
if (pendingCallToConstructorOfSameClass) {
if (opcode == INVOKESPECIAL && "".equals(name) && owner.equals(classDesc)) {
mw.visitMethodInsn(INVOKESPECIAL, owner, name, desc, itf);
pendingCallToConstructorOfSameClass = false;
}
}
else if (
callToAnotherConstructorAlreadyDisregarded ||
opcode != INVOKESPECIAL || !"".equals(name) ||
!owner.equals(superClassName) && !owner.equals(classDesc)
) {
mw.visitMethodInsn(opcode, owner, name, desc, itf);
}
else {
callToAnotherConstructorAlreadyDisregarded = true;
}
}
@Override
public void visitTryCatchBlock(Label start, Label end, Label handler, String type)
{
if (callToAnotherConstructorAlreadyDisregarded) {
mw.visitTryCatchBlock(start, end, handler, type);
}
}
}
}