org.mvel2.asm.FieldWriter Maven / Gradle / Ivy
// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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package org.mvel2.asm;
/**
* A {@link FieldVisitor} that generates a corresponding 'field_info' structure, as defined in the
* Java Virtual Machine Specification (JVMS).
*
* @see JVMS
* 4.5
* @author Eric Bruneton
*/
final class FieldWriter extends FieldVisitor {
/** Where the constants used in this FieldWriter must be stored. */
private final SymbolTable symbolTable;
// Note: fields are ordered as in the field_info structure, and those related to attributes are
// ordered as in Section 4.7 of the JVMS.
/**
* The access_flags field of the field_info JVMS structure. This field can contain ASM specific
* access flags, such as {@link Opcodes#ACC_DEPRECATED}, which are removed when generating the
* ClassFile structure.
*/
private final int accessFlags;
/** The name_index field of the field_info JVMS structure. */
private final int nameIndex;
/** The descriptor_index field of the field_info JVMS structure. */
private final int descriptorIndex;
/**
* The signature_index field of the Signature attribute of this field_info, or 0 if there is no
* Signature attribute.
*/
private int signatureIndex;
/**
* The constantvalue_index field of the ConstantValue attribute of this field_info, or 0 if there
* is no ConstantValue attribute.
*/
private int constantValueIndex;
/**
* The last runtime visible annotation of this field. The previous ones can be accessed with the
* {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeVisibleAnnotation;
/**
* The last runtime invisible annotation of this field. The previous ones can be accessed with the
* {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeInvisibleAnnotation;
/**
* The last runtime visible type annotation of this field. The previous ones can be accessed with
* the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeVisibleTypeAnnotation;
/**
* The last runtime invisible type annotation of this field. The previous ones can be accessed
* with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeInvisibleTypeAnnotation;
/**
* The first non standard attribute of this field. The next ones can be accessed with the {@link
* Attribute#nextAttribute} field. May be {@literal null}.
*
* WARNING: this list stores the attributes in the reverse order of their visit.
* firstAttribute is actually the last attribute visited in {@link #visitAttribute}. The {@link
* #putFieldInfo} method writes the attributes in the order defined by this list, i.e. in the
* reverse order specified by the user.
*/
private Attribute firstAttribute;
// -----------------------------------------------------------------------------------------------
// Constructor
// -----------------------------------------------------------------------------------------------
/**
* Constructs a new {@link FieldWriter}.
*
* @param symbolTable where the constants used in this FieldWriter must be stored.
* @param access the field's access flags (see {@link Opcodes}).
* @param name the field's name.
* @param descriptor the field's descriptor (see {@link Type}).
* @param signature the field's signature. May be {@literal null}.
* @param constantValue the field's constant value. May be {@literal null}.
*/
FieldWriter(final SymbolTable symbolTable, final int access, final String name, final String descriptor, final String signature,
final Object constantValue) {
super(Opcodes.ASM7);
this.symbolTable = symbolTable;
this.accessFlags = access;
this.nameIndex = symbolTable.addConstantUtf8(name);
this.descriptorIndex = symbolTable.addConstantUtf8(descriptor);
if (signature != null) {
this.signatureIndex = symbolTable.addConstantUtf8(signature);
}
if (constantValue != null) {
this.constantValueIndex = symbolTable.addConstant(constantValue).index;
}
}
// -----------------------------------------------------------------------------------------------
// Implementation of the FieldVisitor abstract class
// -----------------------------------------------------------------------------------------------
@Override
public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
// Create a ByteVector to hold an 'annotation' JVMS structure.
// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.
ByteVector annotation = new ByteVector();
// Write type_index and reserve space for num_element_value_pairs.
annotation.putShort(symbolTable.addConstantUtf8(descriptor)).putShort(0);
if (visible) {
return lastRuntimeVisibleAnnotation = new AnnotationWriter(symbolTable, annotation, lastRuntimeVisibleAnnotation);
} else {
return lastRuntimeInvisibleAnnotation = new AnnotationWriter(symbolTable, annotation, lastRuntimeInvisibleAnnotation);
}
}
@Override
public AnnotationVisitor visitTypeAnnotation(final int typeRef, final TypePath typePath, final String descriptor,
final boolean visible) {
// Create a ByteVector to hold a 'type_annotation' JVMS structure.
// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20.
ByteVector typeAnnotation = new ByteVector();
// Write target_type, target_info, and target_path.
TypeReference.putTarget(typeRef, typeAnnotation);
TypePath.put(typePath, typeAnnotation);
// Write type_index and reserve space for num_element_value_pairs.
typeAnnotation.putShort(symbolTable.addConstantUtf8(descriptor)).putShort(0);
if (visible) {
return lastRuntimeVisibleTypeAnnotation = new AnnotationWriter(symbolTable, typeAnnotation, lastRuntimeVisibleTypeAnnotation);
} else {
return lastRuntimeInvisibleTypeAnnotation = new AnnotationWriter(symbolTable, typeAnnotation,
lastRuntimeInvisibleTypeAnnotation);
}
}
@Override
public void visitAttribute(final Attribute attribute) {
// Store the attributes in the reverse order of their visit by this method.
attribute.nextAttribute = firstAttribute;
firstAttribute = attribute;
}
@Override
public void visitEnd() {
// Nothing to do.
}
// -----------------------------------------------------------------------------------------------
// Utility methods
// -----------------------------------------------------------------------------------------------
/**
* Returns the size of the field_info JVMS structure generated by this FieldWriter. Also adds the
* names of the attributes of this field in the constant pool.
*
* @return the size in bytes of the field_info JVMS structure.
*/
int computeFieldInfoSize() {
// The access_flags, name_index, descriptor_index and attributes_count fields use 8 bytes.
int size = 8;
// For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
if (constantValueIndex != 0) {
// ConstantValue attributes always use 8 bytes.
symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE);
size += 8;
}
// Before Java 1.5, synthetic fields are represented with a Synthetic attribute.
if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && symbolTable.getMajorVersion() < Opcodes.V1_5) {
// Synthetic attributes always use 6 bytes.
symbolTable.addConstantUtf8(Constants.SYNTHETIC);
size += 6;
}
if (signatureIndex != 0) {
// Signature attributes always use 8 bytes.
symbolTable.addConstantUtf8(Constants.SIGNATURE);
size += 8;
}
// ACC_DEPRECATED is ASM specific, the ClassFile format uses a Deprecated attribute instead.
if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
// Deprecated attributes always use 6 bytes.
symbolTable.addConstantUtf8(Constants.DEPRECATED);
size += 6;
}
if (lastRuntimeVisibleAnnotation != null) {
size += lastRuntimeVisibleAnnotation.computeAnnotationsSize(Constants.RUNTIME_VISIBLE_ANNOTATIONS);
}
if (lastRuntimeInvisibleAnnotation != null) {
size += lastRuntimeInvisibleAnnotation.computeAnnotationsSize(Constants.RUNTIME_INVISIBLE_ANNOTATIONS);
}
if (lastRuntimeVisibleTypeAnnotation != null) {
size += lastRuntimeVisibleTypeAnnotation.computeAnnotationsSize(Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS);
}
if (lastRuntimeInvisibleTypeAnnotation != null) {
size += lastRuntimeInvisibleTypeAnnotation.computeAnnotationsSize(Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS);
}
if (firstAttribute != null) {
size += firstAttribute.computeAttributesSize(symbolTable);
}
return size;
}
/**
* Puts the content of the field_info JVMS structure generated by this FieldWriter into the given
* ByteVector.
*
* @param output where the field_info structure must be put.
*/
void putFieldInfo(final ByteVector output) {
boolean useSyntheticAttribute = symbolTable.getMajorVersion() < Opcodes.V1_5;
// Put the access_flags, name_index and descriptor_index fields.
int mask = useSyntheticAttribute ? Opcodes.ACC_SYNTHETIC : 0;
output.putShort(accessFlags & ~mask).putShort(nameIndex).putShort(descriptorIndex);
// Compute and put the attributes_count field.
// For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
int attributesCount = 0;
if (constantValueIndex != 0) {
++attributesCount;
}
if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) {
++attributesCount;
}
if (signatureIndex != 0) {
++attributesCount;
}
if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
++attributesCount;
}
if (lastRuntimeVisibleAnnotation != null) {
++attributesCount;
}
if (lastRuntimeInvisibleAnnotation != null) {
++attributesCount;
}
if (lastRuntimeVisibleTypeAnnotation != null) {
++attributesCount;
}
if (lastRuntimeInvisibleTypeAnnotation != null) {
++attributesCount;
}
if (firstAttribute != null) {
attributesCount += firstAttribute.getAttributeCount();
}
output.putShort(attributesCount);
// Put the field_info attributes.
// For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
if (constantValueIndex != 0) {
output.putShort(symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE)).putInt(2).putShort(constantValueIndex);
}
if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) {
output.putShort(symbolTable.addConstantUtf8(Constants.SYNTHETIC)).putInt(0);
}
if (signatureIndex != 0) {
output.putShort(symbolTable.addConstantUtf8(Constants.SIGNATURE)).putInt(2).putShort(signatureIndex);
}
if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
output.putShort(symbolTable.addConstantUtf8(Constants.DEPRECATED)).putInt(0);
}
if (lastRuntimeVisibleAnnotation != null) {
lastRuntimeVisibleAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_ANNOTATIONS), output);
}
if (lastRuntimeInvisibleAnnotation != null) {
lastRuntimeInvisibleAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_ANNOTATIONS), output);
}
if (lastRuntimeVisibleTypeAnnotation != null) {
lastRuntimeVisibleTypeAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS),
output);
}
if (lastRuntimeInvisibleTypeAnnotation != null) {
lastRuntimeInvisibleTypeAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS),
output);
}
if (firstAttribute != null) {
firstAttribute.putAttributes(symbolTable, output);
}
}
/**
* Collects the attributes of this field into the given set of attribute prototypes.
*
* @param attributePrototypes a set of attribute prototypes.
*/
final void collectAttributePrototypes(final Attribute.Set attributePrototypes) {
attributePrototypes.addAttributes(firstAttribute);
}
}