net.bytebuddy.implementation.bytecode.member.FieldAccess Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of byte-buddy-dep Show documentation
Show all versions of byte-buddy-dep Show documentation
Byte Buddy is a Java library for creating Java classes at run time.
This artifact is a build of Byte Buddy with a remaining dependency onto ASM.
You should never depend on this module without repackaging Byte Buddy and ASM into your own namespace.
/*
* Copyright 2014 - Present Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.bytebuddy.implementation.bytecode.member;
import net.bytebuddy.build.HashCodeAndEqualsPlugin;
import net.bytebuddy.description.enumeration.EnumerationDescription;
import net.bytebuddy.description.field.FieldDescription;
import net.bytebuddy.description.field.FieldList;
import net.bytebuddy.description.type.TypeDefinition;
import net.bytebuddy.implementation.Implementation;
import net.bytebuddy.implementation.bytecode.StackManipulation;
import net.bytebuddy.implementation.bytecode.StackSize;
import net.bytebuddy.implementation.bytecode.assign.TypeCasting;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import static net.bytebuddy.matcher.ElementMatchers.named;
/**
* An access representation to a given field.
*/
public enum FieldAccess {
/**
* The representation of field access to a static field.
*/
STATIC(Opcodes.PUTSTATIC, Opcodes.GETSTATIC, StackSize.ZERO),
/**
* The representation of field access to an instance field.
*/
INSTANCE(Opcodes.PUTFIELD, Opcodes.GETFIELD, StackSize.SINGLE);
/**
* The opcode for setting a field value.
*/
private final int putterOpcode;
/**
* The opcode for getting a field value.
*/
private final int getterOpcode;
/**
* The amount of operand slots this field access operation consumes when it is applied before eventually
* adding new values onto the operand stack.
*/
private final int targetSizeChange;
/**
* Creates a new field access.
*
* @param putterOpcode The opcode for setting a field value.
* @param getterOpcode The opcode for getting a field value.
* @param targetSizeChange The amount of operand slots this field access operation consumes when it is applied
* before eventually adding new values onto the operand stack.
*/
FieldAccess(int putterOpcode, int getterOpcode, StackSize targetSizeChange) {
this.putterOpcode = putterOpcode;
this.getterOpcode = getterOpcode;
this.targetSizeChange = targetSizeChange.getSize();
}
/**
* Creates an accessor to read an enumeration value.
*
* @param enumerationDescription The description of the enumeration.
* @return A stack manipulation for reading the enumeration.
*/
public static StackManipulation forEnumeration(EnumerationDescription enumerationDescription) {
FieldList fieldList = enumerationDescription.getEnumerationType()
.getDeclaredFields()
.filter(named(enumerationDescription.getValue()));
return fieldList.size() != 1 || !fieldList.getOnly().isStatic() || !fieldList.getOnly().isPublic() || !fieldList.getOnly().isEnum()
? StackManipulation.Illegal.INSTANCE
: STATIC.new AccessDispatcher(fieldList.getOnly()).read();
}
/**
* Creates a field access representation for a given field.
*
* @param fieldDescription The field to be accessed.
* @return A field access definition for the given field.
*/
public static Defined forField(FieldDescription.InDefinedShape fieldDescription) {
return fieldDescription.isStatic()
? STATIC.new AccessDispatcher(fieldDescription)
: INSTANCE.new AccessDispatcher(fieldDescription);
}
/**
* Creates a field access representation for a given field. If the field's return type derives from its declared shape, the value
* is additionally casted to the generically resolved field.
*
* @param fieldDescription The field to be accessed.
* @return A field access definition for the given field.
*/
public static Defined forField(FieldDescription fieldDescription) {
FieldDescription.InDefinedShape declaredField = fieldDescription.asDefined();
return fieldDescription.getType().asErasure().equals(declaredField.getType().asErasure())
? forField(declaredField)
: OfGenericField.of(fieldDescription, forField(declaredField));
}
/**
* Representation of a field access for which a getter and a setter can be created.
*/
public interface Defined {
/**
* Creates a getter representation for a given field.
*
* @return A stack manipulation representing the retrieval of a field value.
*/
StackManipulation read();
/**
* Creates a setter representation for a given field.
*
* @return A stack manipulation representing the setting of a field value.
*/
StackManipulation write();
}
/**
* A dispatcher for implementing a generic read or write access on a field.
*/
@HashCodeAndEqualsPlugin.Enhance
protected static class OfGenericField implements Defined {
/**
* The resolved generic field type.
*/
private final TypeDefinition targetType;
/**
* An accessor for the field in its defined shape.
*/
private final Defined defined;
/**
* Creates a new dispatcher for a generic field.
*
* @param targetType The resolved generic field type.
* @param defined An accessor for the field in its defined shape.
*/
protected OfGenericField(TypeDefinition targetType, Defined defined) {
this.targetType = targetType;
this.defined = defined;
}
/**
* Creates a generic access dispatcher for a given field.
*
* @param fieldDescription The field that is being accessed.
* @param fieldAccess A field accessor for the field in its defined shape.
* @return A field access dispatcher for the given field.
*/
protected static Defined of(FieldDescription fieldDescription, Defined fieldAccess) {
return new OfGenericField(fieldDescription.getType(), fieldAccess);
}
/**
* {@inheritDoc}
*/
public StackManipulation read() {
return new StackManipulation.Compound(defined.read(), TypeCasting.to(targetType));
}
/**
* {@inheritDoc}
*/
public StackManipulation write() {
return defined.write();
}
}
/**
* A dispatcher for implementing a non-generic read or write access on a field.
*/
@HashCodeAndEqualsPlugin.Enhance(includeSyntheticFields = true)
protected class AccessDispatcher implements Defined {
/**
* A description of the accessed field.
*/
private final FieldDescription.InDefinedShape fieldDescription;
/**
* Creates a new access dispatcher.
*
* @param fieldDescription A description of the accessed field.
*/
protected AccessDispatcher(FieldDescription.InDefinedShape fieldDescription) {
this.fieldDescription = fieldDescription;
}
/**
* {@inheritDoc}
*/
public StackManipulation read() {
return new FieldGetInstruction();
}
/**
* {@inheritDoc}
*/
public StackManipulation write() {
return new FieldPutInstruction();
}
/**
* An abstract base implementation for accessing a field value.
*/
private abstract class AbstractFieldInstruction extends StackManipulation.AbstractBase {
/**
* {@inheritDoc}
*/
public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext) {
methodVisitor.visitFieldInsn(getOpcode(),
fieldDescription.getDeclaringType().getInternalName(),
fieldDescription.getInternalName(),
fieldDescription.getDescriptor());
return resolveSize(fieldDescription.getType().getStackSize());
}
/**
* Returns the opcode for implementing the field access.
*
* @return The opcode for implementing the field access.
*/
protected abstract int getOpcode();
/**
* Resolves the actual size of this field access operation.
*
* @param fieldSize The size of the accessed field.
* @return The size of the field access operation based on the field's size.
*/
protected abstract Size resolveSize(StackSize fieldSize);
}
/**
* A reading field access operation.
*/
@HashCodeAndEqualsPlugin.Enhance(includeSyntheticFields = true)
protected class FieldGetInstruction extends AbstractFieldInstruction {
@Override
protected int getOpcode() {
return getterOpcode;
}
@Override
protected Size resolveSize(StackSize fieldSize) {
int sizeChange = fieldSize.getSize() - targetSizeChange;
return new Size(sizeChange, sizeChange);
}
}
/**
* A writing field access operation.
*/
@HashCodeAndEqualsPlugin.Enhance(includeSyntheticFields = true)
protected class FieldPutInstruction extends AbstractFieldInstruction {
@Override
protected int getOpcode() {
return putterOpcode;
}
@Override
protected Size resolveSize(StackSize fieldSize) {
return new Size(-1 * (fieldSize.getSize() + targetSizeChange), 0);
}
}
}
}