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JMockit is a Java toolkit for automated developer testing.
It contains APIs for the creation of the objects to be tested, for mocking dependencies, and for faking external
APIs; JUnit (4 & 5) and TestNG test runners are supported.
It also contains an advanced code coverage tool.
/*
* 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 mockit.external.asm;
import java.util.*;
import javax.annotation.*;
import mockit.internal.util.*;
/**
* A {@link ClassVisitor} that generates classes in bytecode form. More precisely this visitor generates a byte array
* conforming to the Java class file format. It can be used alone, to generate a Java class "from scratch", or with one
* or more {@link ClassReader} and adapter class visitor to generate a modified class from one or more existing Java
* classes.
*/
public final class ClassWriter extends ClassVisitor
{
/**
* The class reader from which this class writer was constructed.
*/
@Nonnull final ClassReader cr;
/**
* Minor and major version numbers of the class to be generated.
*/
private int version;
/**
* The access flags of this class.
*/
private int access;
/**
* The constant pool item that contains the internal name of this class.
*/
private int name;
/**
* The internal name of this class.
*/
String thisName;
/**
* The constant pool item that contains the signature of this class.
*/
private int signature;
/**
* The constant pool item that contains the internal name of the super class of this class.
*/
private int superName;
@Nullable private Interfaces interfaces;
@Nonnull private final SourceInfo sourceInfo;
@Nullable private OuterClass outerClass;
@Nullable private InnerClasses innerClasses;
@Nonnull final BootstrapMethods bootstrapMethods;
/**
* The fields of this class.
*/
@Nonnull private final List fields;
/**
* The methods of this class.
*/
@Nonnull private final List methods;
/**
* true if the stack map frames must be recomputed from scratch.
*
* If this flag is set, then the stack map frames are recomputed from the methods bytecode. The arguments of the
* {@link MethodVisitor#visitMaxStack} method are also ignored and recomputed from the bytecode. In other words,
* computeFrames implies computeMaxs.
*/
private final boolean computeFrames;
/**
* Constructs a new {@link ClassWriter} object and enables optimizations for "mostly add" bytecode transformations.
* These optimizations are the following:
*
* - The constant pool from the original class is copied as is in the new class, which saves time.
* New constant pool entries will be added at the end if necessary, but unused constant pool entries won't be
* removed.
* - Methods that are not transformed are copied as is in the new class, directly from the original class bytecode
* (i.e. without emitting visit events for all the method instructions), which saves a lot of time.
* Untransformed methods are detected by the fact that the {@link ClassReader} receives {@link MethodVisitor}
* objects that come from a {@link ClassWriter} (and not from any other {@link ClassVisitor} instance).
*
*
* @param classReader the {@link ClassReader} used to read the original class. It will be used to copy the entire
* constant pool from the original class and also to copy other fragments of original bytecode
* where applicable.
*/
public ClassWriter(@Nonnull ClassReader classReader) {
cp = new ConstantPoolGeneration();
sourceInfo = new SourceInfo(cp);
bootstrapMethods = new BootstrapMethods(cp);
version = classReader.getVersion();
computeFrames = version >= ClassVersion.V1_7;
cr = classReader;
classReader.copyPool(this);
fields = new ArrayList();
methods = new ArrayList();
}
// ------------------------------------------------------------------------
// Implementation of the ClassVisitor base class
// ------------------------------------------------------------------------
@Override
public void visit(
int version, int access, @Nonnull String name, @Nullable String signature, @Nullable String superName,
@Nullable String[] interfaces
) {
this.version = version;
this.access = access;
this.name = cp.newClass(name);
thisName = name;
if (signature != null) {
this.signature = cp.newUTF8(signature);
}
this.superName = superName == null ? 0 : cp.newClass(superName);
if (interfaces != null && interfaces.length > 0) {
this.interfaces = new Interfaces(cp, interfaces);
}
if (superName != null) {
ClassLoad.addSuperClass(name, superName);
}
}
@Override
public void visitSource(@Nullable String file, @Nullable String debug) {
sourceInfo.add(file, debug);
}
@Override
public void visitOuterClass(@Nonnull String owner, @Nullable String name, @Nullable String desc) {
outerClass = new OuterClass(cp, owner, name, desc);
}
@Nonnull @Override
public AnnotationVisitor visitAnnotation(@Nonnull String desc) {
return addAnnotation(desc);
}
@Override
public void visitInnerClass(
@Nonnull String name, @Nullable String outerName, @Nullable String innerName, int access
) {
if (innerClasses == null) {
innerClasses = new InnerClasses(cp);
}
innerClasses.add(name, outerName, innerName, access);
}
@Nonnull @Override
public FieldVisitor visitField(
int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature, @Nullable Object value
) {
FieldWriter field = new FieldWriter(this, access, name, desc, signature, value);
fields.add(field);
return field;
}
@Nonnull @Override
public MethodWriter visitMethod(
int access, @Nonnull String name, @Nonnull String desc, @Nullable String signature, @Nullable String[] exceptions
) {
MethodWriter method = new MethodWriter(this, access, name, desc, signature, exceptions, computeFrames);
methods.add(method);
return method;
}
// ------------------------------------------------------------------------
// Other public methods
// ------------------------------------------------------------------------
/**
* Returns the bytecode of the class that was build with this class writer.
*/
@Nonnull @Override
public byte[] toByteArray() {
cp.checkConstantPoolMaxSize();
// Computes the real size of the bytecode of this class.
int interfaceCount = interfaces == null ? 0 : interfaces.getCount();
int size = 24 + 2 * interfaceCount;
size += getFieldsSize();
size += getMethodsSize();
int attributeCount = 0;
if (bootstrapMethods.hasMethods()) {
// We put it as first attribute in order to improve a bit the performance of copyBootstrapMethods.
attributeCount++;
size += bootstrapMethods.getSize();
}
if (signature != 0) {
attributeCount++;
size += 8;
cp.newUTF8("Signature");
}
attributeCount += sourceInfo.getAttributeCount();
size += sourceInfo.getSize();
if (outerClass != null) {
attributeCount++;
size += outerClass.getSize();
}
boolean deprecated = Access.isDeprecated(access);
if (deprecated) {
attributeCount++;
size += 6;
cp.newUTF8("Deprecated");
}
if (isSynthetic()) {
attributeCount++;
size += 6;
cp.newUTF8("Synthetic");
}
if (innerClasses != null) {
attributeCount++;
size += innerClasses.getSize();
}
if (annotations != null) {
attributeCount++;
size += getAnnotationsSize();
}
size += cp.getSize();
// Allocates a byte vector of this size, in order to avoid unnecessary arraycopy operations in the
// ByteVector.enlarge() method.
ByteVector out = new ByteVector(size);
out.putInt(0xCAFEBABE).putInt(version);
cp.put(out);
int accessFlag = Access.computeFlag(access, 0);
out.putShort(accessFlag);
out.putShort(name);
out.putShort(superName);
out.putShort(interfaceCount);
if (interfaceCount > 0) {
interfaces.put(out);
}
putFields(out);
putMethods(out);
out.putShort(attributeCount);
bootstrapMethods.put(out);
putSignature(out);
sourceInfo.put(out);
if (outerClass != null) {
outerClass.put(out);
}
if (deprecated) {
out.putShort(cp.newUTF8("Deprecated")).putInt(0);
}
if (isSynthetic()) {
out.putShort(cp.newUTF8("Synthetic")).putInt(0);
}
if (innerClasses != null) {
innerClasses.put(out);
}
putAnnotations(out);
return out.data;
}
@Nonnegative
private int getMethodsSize() {
int size = 0;
for (MethodWriter mb : methods) {
size += mb.getSize();
}
return size;
}
@Nonnegative
private int getFieldsSize() {
int size = 0;
for (FieldWriter fb : fields) {
size += fb.getSize();
}
return size;
}
private void putFields(@Nonnull ByteVector out) {
out.putShort(fields.size());
for (FieldWriter fb : fields) {
fb.put(out);
}
}
private void putMethods(@Nonnull ByteVector out) {
out.putShort(methods.size());
for (MethodWriter mb : methods) {
mb.put(out);
}
}
private void putSignature(@Nonnull ByteVector out) {
if (signature != 0) {
out.putShort(cp.newUTF8("Signature")).putInt(2).putShort(signature);
}
}
// ------------------------------------------------------------------------
// Utility methods: version, synthetic
// ------------------------------------------------------------------------
int getClassVersion() { return version & 0xFFFF; }
private boolean isSynthetic() { return isSynthetic(access); }
boolean isSynthetic(int access) {
return
Access.isSynthetic(access) &&
((access & Access.SYNTHETIC_ATTRIBUTE) != 0 || getClassVersion() < ClassVersion.V1_5);
}
}