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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 JMockit developers
* This file is subject to the terms of the MIT license (see LICENSE.txt).
*/
package mockit.internal.faking;
import javax.annotation.*;
import static java.lang.reflect.Modifier.*;
import mockit.*;
import mockit.asm.classes.*;
import mockit.asm.controlFlow.*;
import mockit.asm.jvmConstants.*;
import mockit.asm.methods.*;
import mockit.asm.types.*;
import mockit.internal.*;
import mockit.internal.faking.FakeMethods.*;
import mockit.internal.state.*;
import mockit.internal.util.*;
import static mockit.asm.jvmConstants.Opcodes.*;
/**
* Responsible for generating all necessary bytecode in the redefined (real) class.
* Such code will redirect calls made on "real" methods to equivalent calls on the corresponding "fake" methods.
* The original code won't be executed by the running JVM until the class redefinition is undone.
*
* Methods in the real class with no corresponding fake methods are unaffected.
*
* Any fields (static or not) in the real class remain untouched.
*/
final class FakedClassModifier extends BaseClassModifier
{
private static final int ABSTRACT_OR_SYNTHETIC = Access.ABSTRACT + Access.SYNTHETIC;
@Nonnull private final FakeMethods fakeMethods;
private final boolean useClassLoadingBridgeForUpdatingFakeState;
@Nonnull private final Class fakedClass;
private FakeMethod fakeMethod;
private boolean isConstructor;
/**
* Initializes the modifier for a given real/fake class pair.
*
* The fake instance provided will receive calls for any instance methods defined in the fake class.
* Therefore, it needs to be later recovered by the modified bytecode inside the real method.
* To enable this, the fake instance is added to a global data structure made available through the {@link TestRun#getFake(String)}
* method.
*
* @param cr the class file reader for the real class
* @param realClass the class to be faked, or a base type of an implementation class to be faked
* @param fake an instance of the fake class
* @param fakeMethods contains the set of fake methods collected from the fake class; each fake method is identified by a pair composed
* of "name" and "desc", where "name" is the method name, and "desc" is the JVM internal description of the parameters; once the real
* class modification is complete this set will be empty, unless no corresponding real method was found for any of its method identifiers
*/
FakedClassModifier(@Nonnull ClassReader cr, @Nonnull Class realClass, @Nonnull MockUp fake, @Nonnull FakeMethods fakeMethods) {
super(cr);
fakedClass = realClass;
this.fakeMethods = fakeMethods;
ClassLoader classLoaderOfRealClass = realClass.getClassLoader();
useClassLoadingBridgeForUpdatingFakeState = ClassLoad.isClassLoaderWithNoDirectAccess(classLoaderOfRealClass);
inferUseOfClassLoadingBridge(classLoaderOfRealClass, fake);
}
private void inferUseOfClassLoadingBridge(@Nullable ClassLoader classLoaderOfRealClass, @Nonnull Object fake) {
setUseClassLoadingBridge(classLoaderOfRealClass);
if (!useClassLoadingBridge && !isPublic(fake.getClass().getModifiers())) {
useClassLoadingBridge = true;
}
}
@Override
public MethodVisitor visitMethod(
int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature, @Nullable String[] exceptions
) {
if ((access & ABSTRACT_OR_SYNTHETIC) != 0) {
if (isAbstract(access)) {
// Marks a matching fake method (if any) as having the corresponding faked method.
fakeMethods.findMethod(access, name, desc, signature);
}
return cw.visitMethod(access, name, desc, signature, exceptions);
}
isConstructor = "".equals(name);
if (isConstructor && isFakedSuperclass() || !hasFake(access, name, desc, signature)) {
return cw.visitMethod(access, name, desc, signature, exceptions);
}
if (isPrivate(access)) {
String kindOfMember = isConstructor ? "constructor " : "method ";
String privateMemberDesc = fakedClass.getSimpleName() + '#' + name + desc;
throw new IllegalArgumentException("Unsupported fake for private " + kindOfMember + privateMemberDesc + " found");
}
startModifiedMethodVersion(access, name, desc, signature, exceptions);
if (isNative(methodAccess)) {
generateCodeForInterceptedNativeMethod();
return methodAnnotationsVisitor;
}
return copyOriginalImplementationWithInjectedInterceptionCode();
}
private boolean hasFake(int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature) {
String fakeName = getCorrespondingFakeName(name);
fakeMethod = fakeMethods.findMethod(access, fakeName, desc, signature);
return fakeMethod != null;
}
@Nonnull
private static String getCorrespondingFakeName(@Nonnull String name) {
if ("".equals(name)) {
return "$init";
}
if ("".equals(name)) {
return "$clinit";
}
return name;
}
private boolean isFakedSuperclass() { return fakedClass != fakeMethods.getRealClass(); }
private void generateCodeForInterceptedNativeMethod() {
generateCallToUpdateFakeState();
generateCallToFakeMethod();
generateMethodReturn();
mw.visitMaxStack(1); // dummy value, real one is calculated by ASM
}
@Override
protected void generateInterceptionCode() {
Label startOfRealImplementation = null;
if (!isStatic(methodAccess) && !isConstructor && isFakedSuperclass()) {
Class targetClass = fakeMethods.getRealClass();
if (fakedClass.getClassLoader() == targetClass.getClassLoader()) {
startOfRealImplementation = new Label();
mw.visitVarInsn(ALOAD, 0);
mw.visitTypeInsn(INSTANCEOF, JavaType.getInternalName(targetClass));
mw.visitJumpInsn(IFEQ, startOfRealImplementation);
}
}
generateCallToUpdateFakeState();
if (isConstructor) {
generateConditionalCallForFakedConstructor();
}
else {
generateConditionalCallForFakedMethod(startOfRealImplementation);
}
}
private void generateCallToUpdateFakeState() {
if (useClassLoadingBridgeForUpdatingFakeState) {
generateCallToControlMethodThroughClassLoadingBridge();
mw.visitTypeInsn(CHECKCAST, "java/lang/Boolean");
mw.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Boolean", "booleanValue", "()Z", false);
}
else {
mw.visitLdcInsn(fakeMethods.getFakeClassInternalName());
mw.visitIntInsn(SIPUSH, fakeMethod.getIndexForFakeState());
mw.visitMethodInsn(INVOKESTATIC, "mockit/internal/state/TestRun", "updateFakeState", "(Ljava/lang/String;I)Z", false);
}
}
private void generateCallToControlMethodThroughClassLoadingBridge() {
generateCodeToObtainInstanceOfClassLoadingBridge(FakeBridge.MB);
// First and second "invoke" arguments:
generateCodeToPassThisOrNullIfStaticMethod();
mw.visitInsn(ACONST_NULL);
// Create array for call arguments (third "invoke" argument):
generateCodeToCreateArrayOfObject(2);
int i = 0;
generateCodeToFillArrayElement(i++, fakeMethods.getFakeClassInternalName());
generateCodeToFillArrayElement(i, fakeMethod.getIndexForFakeState());
generateCallToInvocationHandler();
}
private void generateConditionalCallForFakedMethod(@Nullable Label startOfRealImplementation) {
if (startOfRealImplementation == null) {
//noinspection AssignmentToMethodParameter
startOfRealImplementation = new Label();
}
mw.visitJumpInsn(IFEQ, startOfRealImplementation);
generateCallToFakeMethod();
generateMethodReturn();
mw.visitLabel(startOfRealImplementation);
}
private void generateConditionalCallForFakedConstructor() {
generateCallToFakeMethod();
int jumpInsnOpcode;
if (shouldUseClassLoadingBridge()) {
mw.visitLdcInsn(VOID_TYPE);
jumpInsnOpcode = IF_ACMPEQ;
}
else {
jumpInsnOpcode = fakeMethod.hasInvocationParameter() ? IFNE : IFEQ;
}
Label startOfRealImplementation = new Label();
mw.visitJumpInsn(jumpInsnOpcode, startOfRealImplementation);
mw.visitInsn(RETURN);
mw.visitLabel(startOfRealImplementation);
}
private void generateCallToFakeMethod() {
if (shouldUseClassLoadingBridge()) {
generateCallToFakeMethodThroughClassLoadingBridge();
}
else {
generateDirectCallToFakeMethod();
}
}
private boolean shouldUseClassLoadingBridge() { return useClassLoadingBridge || !fakeMethod.isPublic(); }
private void generateCallToFakeMethodThroughClassLoadingBridge() {
generateCodeToObtainInstanceOfClassLoadingBridge(FakeMethodBridge.MB);
// First and second "invoke" arguments:
boolean isStatic = generateCodeToPassThisOrNullIfStaticMethod();
mw.visitInsn(ACONST_NULL);
// Create array for call arguments (third "invoke" argument):
JavaType[] argTypes = JavaType.getArgumentTypes(methodDesc);
generateCodeToCreateArrayOfObject(6 + argTypes.length);
int i = 0;
generateCodeToFillArrayElement(i++, fakeMethods.getFakeClassInternalName());
generateCodeToFillArrayElement(i++, classDesc);
generateCodeToFillArrayElement(i++, methodAccess);
if (fakeMethod.hasInvocationParameterOnly()) {
generateCodeToFillArrayElement(i++, methodName);
generateCodeToFillArrayElement(i++, methodDesc);
}
else {
generateCodeToFillArrayElement(i++, fakeMethod.name);
generateCodeToFillArrayElement(i++, fakeMethod.desc);
}
generateCodeToFillArrayElement(i++, fakeMethod.getIndexForFakeState());
generateCodeToFillArrayWithParameterValues(argTypes, i, isStatic ? 0 : 1);
generateCallToInvocationHandler();
}
private void generateDirectCallToFakeMethod() {
String fakeClassDesc = fakeMethods.getFakeClassInternalName();
int invokeOpcode;
if (fakeMethod.isStatic()) {
invokeOpcode = INVOKESTATIC;
}
else {
generateCodeToObtainFakeInstance(fakeClassDesc);
invokeOpcode = INVOKEVIRTUAL;
}
boolean canProceedIntoConstructor = generateArgumentsForFakeMethodInvocation();
mw.visitMethodInsn(invokeOpcode, fakeClassDesc, fakeMethod.name, fakeMethod.desc, false);
if (canProceedIntoConstructor) {
mw.visitMethodInsn(INVOKEVIRTUAL, "mockit/internal/faking/FakeInvocation", "shouldProceedIntoConstructor", "()Z", false);
}
}
private void generateCodeToObtainFakeInstance(@Nonnull String fakeClassDesc) {
mw.visitLdcInsn(fakeClassDesc);
mw.visitMethodInsn(INVOKESTATIC, "mockit/internal/state/TestRun", "getFake", "(Ljava/lang/String;)Ljava/lang/Object;", false);
mw.visitTypeInsn(CHECKCAST, fakeClassDesc);
}
private boolean generateArgumentsForFakeMethodInvocation() {
String fakedDesc = fakeMethod.hasInvocationParameterOnly() ? methodDesc : fakeMethod.fakeDescWithoutInvocationParameter;
JavaType[] argTypes = JavaType.getArgumentTypes(fakedDesc);
int varIndex = isStatic(methodAccess) ? 0 : 1;
boolean canProceedIntoConstructor = false;
if (fakeMethod.hasInvocationParameter()) {
generateCallToCreateNewFakeInvocation(argTypes, varIndex);
// When invoking a constructor, the invocation object will need to be consulted for proceeding:
if (isConstructor) {
mw.visitInsn(fakeMethod.isStatic() ? DUP : DUP_X1);
canProceedIntoConstructor = true;
}
}
if (!fakeMethod.hasInvocationParameterOnly()) {
passArgumentsForFakeMethodCall(argTypes, varIndex);
}
return canProceedIntoConstructor;
}
private void generateCallToCreateNewFakeInvocation(@Nonnull JavaType[] argTypes, @Nonnegative int initialParameterIndex) {
generateCodeToPassThisOrNullIfStaticMethod();
int argCount = argTypes.length;
if (argCount == 0) {
mw.visitInsn(ACONST_NULL);
}
else {
generateCodeToCreateArrayOfObject(argCount);
generateCodeToFillArrayWithParameterValues(argTypes, 0, initialParameterIndex);
}
mw.visitLdcInsn(fakeMethods.getFakeClassInternalName());
mw.visitIntInsn(SIPUSH, fakeMethod.getIndexForFakeState());
mw.visitLdcInsn(classDesc);
mw.visitLdcInsn(methodName);
mw.visitLdcInsn(methodDesc);
mw.visitMethodInsn(
INVOKESTATIC, "mockit/internal/faking/FakeInvocation", "create",
"(Ljava/lang/Object;[Ljava/lang/Object;Ljava/lang/String;ILjava/lang/String;Ljava/lang/String;Ljava/lang/String;)" +
"Lmockit/internal/faking/FakeInvocation;", false);
}
private void passArgumentsForFakeMethodCall(@Nonnull JavaType[] argTypes, @Nonnegative int varIndex) {
boolean forGenericMethod = fakeMethod.isForGenericMethod();
for (JavaType argType : argTypes) {
int opcode = argType.getOpcode(ILOAD);
mw.visitVarInsn(opcode, varIndex);
if (forGenericMethod && argType instanceof ReferenceType) {
String typeDesc = ((ReferenceType) argType).getInternalName();
mw.visitTypeInsn(CHECKCAST, typeDesc);
}
varIndex += argType.getSize();
}
}
private void generateMethodReturn() {
if (shouldUseClassLoadingBridge() || fakeMethod.isAdvice) {
generateReturnWithObjectAtTopOfTheStack(methodDesc);
}
else {
JavaType returnType = JavaType.getReturnType(methodDesc);
mw.visitInsn(returnType.getOpcode(IRETURN));
}
}
}