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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.mockups;
import javax.annotation.*;
import static java.lang.reflect.Modifier.*;
import mockit.*;
import mockit.external.asm.*;
import mockit.internal.*;
import mockit.internal.mockups.MockMethods.*;
import mockit.internal.state.*;
import static mockit.external.asm.Opcodes.*;
import static mockit.internal.util.GeneratedClasses.*;
/**
* 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 "mock" 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 mock methods are unaffected.
*
* Any fields (static or not) in the real class remain untouched.
*/
final class MockupsModifier extends BaseClassModifier
{
private static final int ABSTRACT_OR_SYNTHETIC = ACC_ABSTRACT + ACC_SYNTHETIC;
@Nonnull private final MockMethods mockMethods;
private final boolean useMockingBridgeForUpdatingMockState;
@Nonnull private final Class mockedClass;
private MockMethod mockMethod;
private boolean isConstructor;
/**
* Initializes the modifier for a given real/mock class pair.
*
* The mock instance provided will receive calls for any instance methods defined in the mock class.
* Therefore, it needs to be later recovered by the modified bytecode inside the real method.
* To enable this, the mock instance is added to a global data structure made available through the
* {@link TestRun#getMock(String, Object)} method.
*
* @param cr the class file reader for the real class
* @param realClass the class to be mocked-up, or a base type of an implementation class to be mocked-up
* @param mockUp an instance of the mockup class
* @param mockMethods contains the set of mock methods collected from the mock class; each mock 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
*/
MockupsModifier(
@Nonnull ClassReader cr, @Nonnull Class realClass, @Nonnull MockUp mockUp, @Nonnull MockMethods mockMethods)
{
super(cr);
mockedClass = realClass;
this.mockMethods = mockMethods;
ClassLoader classLoaderOfRealClass = realClass.getClassLoader();
useMockingBridgeForUpdatingMockState = isClassLoaderWithNoDirectAccess(classLoaderOfRealClass);
inferUseOfMockingBridge(classLoaderOfRealClass, mockUp);
}
private void inferUseOfMockingBridge(@Nullable ClassLoader classLoaderOfRealClass, @Nonnull Object mock)
{
setUseMockingBridge(classLoaderOfRealClass);
if (!useMockingBridge && !isPublic(mock.getClass().getModifiers())) {
useMockingBridge = true;
}
}
@Override
public void visit(
int version, int access, @Nonnull String name, @Nullable String signature, @Nullable String superName,
@Nullable String[] interfaces)
{
super.visit(version, access, name, signature, superName, interfaces);
if (isGeneratedImplementationClass(name)) {
classDesc = name.substring(IMPLCLASS_PREFIX.length());
}
}
/**
* If the specified method has a mock definition, then generates bytecode to redirect calls made to it to the mock
* method. If it has no mock, does nothing.
*
* @param access not relevant
* @param name together with desc, used to identity the method in given set of mock methods
* @param signature not relevant
* @param exceptions not relevant
*
* @return {@code null} if the method was redefined, otherwise a {@code MethodWriter} that writes out the visited
* method code without changes
*/
@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 mock method (if any) as having the corresponding mocked method.
mockMethods.findMethod(access, name, desc, signature);
}
return cw.visitMethod(access, name, desc, signature, exceptions);
}
isConstructor = "".equals(name);
if (isConstructor && isMockedSuperclass() || !hasMock(access, name, desc, signature)) {
return cw.visitMethod(access, name, desc, signature, exceptions);
}
startModifiedMethodVersion(access, name, desc, signature, exceptions);
if (isConstructor) {
generateCallToSuperConstructor();
}
else if (isNative(methodAccess)) {
generateCallToUpdateMockState();
generateCallToMockMethod();
generateMethodReturn();
mw.visitMaxs(1, 0); // dummy values, real ones are calculated by ASM
return methodAnnotationsVisitor;
}
generateDynamicCallToMock();
return copyOriginalImplementationCode(isConstructor);
}
private boolean hasMock(int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature)
{
String mockName = getCorrespondingMockName(name);
mockMethod = mockMethods.findMethod(access, mockName, desc, signature);
return mockMethod != null;
}
@Nonnull
private static String getCorrespondingMockName(@Nonnull String name)
{
if ("".equals(name)) {
return "$init";
}
if ("".equals(name)) {
return "$clinit";
}
return name;
}
private boolean isMockedSuperclass() { return mockedClass != mockMethods.getRealClass(); }
private void generateDynamicCallToMock()
{
Label startOfRealImplementation = null;
if (!isStatic(methodAccess) && !isConstructor && isMockedSuperclass()) {
startOfRealImplementation = new Label();
mw.visitVarInsn(ALOAD, 0);
mw.visitTypeInsn(INSTANCEOF, Type.getInternalName(mockMethods.getRealClass()));
mw.visitJumpInsn(IFEQ, startOfRealImplementation);
}
generateCallToUpdateMockState();
if (isConstructor) {
generateConditionalCallForMockedConstructor();
}
else {
generateConditionalCallForMockedMethod(startOfRealImplementation);
}
}
private void generateCallToUpdateMockState()
{
if (useMockingBridgeForUpdatingMockState) {
generateCallToControlMethodThroughMockingBridge();
mw.visitTypeInsn(CHECKCAST, "java/lang/Boolean");
mw.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Boolean", "booleanValue", "()Z", false);
}
else {
mw.visitLdcInsn(mockMethods.getMockClassInternalName());
generateCodeToPassThisOrNullIfStaticMethod();
mw.visitIntInsn(SIPUSH, mockMethod.getIndexForMockState());
mw.visitMethodInsn(
INVOKESTATIC, "mockit/internal/state/TestRun", "updateMockState",
"(Ljava/lang/String;Ljava/lang/Object;I)Z", false);
}
}
private void generateCallToControlMethodThroughMockingBridge()
{
generateCodeToObtainInstanceOfMockingBridge(MockupBridge.MB);
// First and second "invoke" arguments:
generateCodeToPassThisOrNullIfStaticMethod();
mw.visitInsn(ACONST_NULL);
// Create array for call arguments (third "invoke" argument):
generateCodeToCreateArrayOfObject(mw, 2);
int i = 0;
generateCodeToFillArrayElement(i++, mockMethods.getMockClassInternalName());
generateCodeToFillArrayElement(i, mockMethod.getIndexForMockState());
generateCallToInvocationHandler();
}
private void generateConditionalCallForMockedMethod(@Nullable Label startOfRealImplementation)
{
if (startOfRealImplementation == null) {
//noinspection AssignmentToMethodParameter
startOfRealImplementation = new Label();
}
mw.visitJumpInsn(IFEQ, startOfRealImplementation);
generateCallToMockMethod();
generateMethodReturn();
mw.visitLabel(startOfRealImplementation);
}
private void generateConditionalCallForMockedConstructor()
{
generateCallToMockMethod();
int jumpInsnOpcode;
if (shouldUseMockingBridge()) {
mw.visitLdcInsn(VOID_TYPE);
jumpInsnOpcode = IF_ACMPEQ;
}
else {
jumpInsnOpcode = mockMethod.hasInvocationParameter ? IFNE : IFEQ;
}
Label startOfRealImplementation = new Label();
mw.visitJumpInsn(jumpInsnOpcode, startOfRealImplementation);
mw.visitInsn(RETURN);
mw.visitLabel(startOfRealImplementation);
}
private void generateCallToMockMethod()
{
if (shouldUseMockingBridge()) {
generateCallToMockMethodThroughMockingBridge();
}
else {
generateDirectCallToMockMethod();
}
}
private boolean shouldUseMockingBridge() { return useMockingBridge || !mockMethod.isPublic(); }
private void generateCallToMockMethodThroughMockingBridge()
{
generateCodeToObtainInstanceOfMockingBridge(MockMethodBridge.MB);
// First and second "invoke" arguments:
boolean isStatic = generateCodeToPassThisOrNullIfStaticMethod();
mw.visitInsn(ACONST_NULL);
// Create array for call arguments (third "invoke" argument):
Type[] argTypes = Type.getArgumentTypes(methodDesc);
generateCodeToCreateArrayOfObject(mw, 6 + argTypes.length);
int i = 0;
generateCodeToFillArrayElement(i++, mockMethods.getMockClassInternalName());
generateCodeToFillArrayElement(i++, classDesc);
generateCodeToFillArrayElement(i++, methodAccess);
if (mockMethod.isAdvice) {
generateCodeToFillArrayElement(i++, methodName);
generateCodeToFillArrayElement(i++, methodDesc);
}
else {
generateCodeToFillArrayElement(i++, mockMethod.name);
generateCodeToFillArrayElement(i++, mockMethod.desc);
}
generateCodeToFillArrayElement(i++, mockMethod.getIndexForMockState());
generateCodeToFillArrayWithParameterValues(mw, argTypes, i, isStatic ? 0 : 1);
generateCallToInvocationHandler();
}
private void generateDirectCallToMockMethod()
{
String mockClassDesc = mockMethods.getMockClassInternalName();
int invokeOpcode;
if (mockMethod.isStatic()) {
invokeOpcode = INVOKESTATIC;
}
else {
generateCodeToObtainMockUpInstance(mockClassDesc);
invokeOpcode = INVOKEVIRTUAL;
}
boolean canProceedIntoConstructor = generateArgumentsForMockMethodInvocation();
mw.visitMethodInsn(invokeOpcode, mockClassDesc, mockMethod.name, mockMethod.desc, false);
if (canProceedIntoConstructor) {
mw.visitMethodInsn(
INVOKEVIRTUAL, "mockit/internal/mockups/MockInvocation", "shouldProceedIntoConstructor", "()Z", false);
}
}
private void generateCodeToObtainMockUpInstance(@Nonnull String mockClassDesc)
{
mw.visitLdcInsn(mockClassDesc);
generateCodeToPassThisOrNullIfStaticMethod();
mw.visitMethodInsn(
INVOKESTATIC, "mockit/internal/state/TestRun", "getMock",
"(Ljava/lang/String;Ljava/lang/Object;)Ljava/lang/Object;", false);
mw.visitTypeInsn(CHECKCAST, mockClassDesc);
}
private boolean generateArgumentsForMockMethodInvocation()
{
Type[] argTypes = Type.getArgumentTypes(mockMethod.mockDescWithoutInvocationParameter);
int varIndex = isStatic(methodAccess) ? 0 : 1;
boolean canProceedIntoConstructor = false;
if (mockMethod.hasInvocationParameter) {
generateCallToCreateNewMockInvocation(argTypes, varIndex);
// When invoking a constructor, the invocation object will need to be consulted for proceeding:
if (isConstructor) {
mw.visitInsn(mockMethod.isStatic() ? DUP : DUP_X1);
canProceedIntoConstructor = true;
}
}
boolean forGenericMethod = mockMethod.isForGenericMethod();
for (Type argType : argTypes) {
int opcode = argType.getOpcode(ILOAD);
mw.visitVarInsn(opcode, varIndex);
if (forGenericMethod && argType.getSort() >= Type.ARRAY) {
mw.visitTypeInsn(CHECKCAST, argType.getInternalName());
}
varIndex += argType.getSize();
}
return canProceedIntoConstructor;
}
private void generateCallToCreateNewMockInvocation(@Nonnull Type[] argTypes, int initialParameterIndex)
{
generateCodeToPassThisOrNullIfStaticMethod();
int argCount = argTypes.length;
if (argCount == 0) {
mw.visitInsn(ACONST_NULL);
}
else {
generateCodeToCreateArrayOfObject(mw, argCount);
generateCodeToFillArrayWithParameterValues(mw, argTypes, 0, initialParameterIndex);
}
mw.visitLdcInsn(mockMethods.getMockClassInternalName());
mw.visitIntInsn(SIPUSH, mockMethod.getIndexForMockState());
mw.visitLdcInsn(classDesc);
mw.visitLdcInsn(methodName);
mw.visitLdcInsn(methodDesc);
mw.visitMethodInsn(
INVOKESTATIC, "mockit/internal/mockups/MockInvocation", "create",
"(Ljava/lang/Object;[Ljava/lang/Object;Ljava/lang/String;I" +
"Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lmockit/internal/mockups/MockInvocation;", false);
}
private void generateMethodReturn()
{
if (shouldUseMockingBridge()) {
generateReturnWithObjectAtTopOfTheStack(methodDesc);
}
else {
Type returnType = Type.getReturnType(methodDesc);
mw.visitInsn(returnType.getOpcode(IRETURN));
}
}
}