org.mvel2.asm.AnnotationWriter Maven / Gradle / Ivy
// ASM: a very small and fast Java bytecode manipulation framework
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package org.mvel2.asm;
/**
* An {@link AnnotationVisitor} that generates a corresponding 'annotation' or 'type_annotation'
* structure, as defined in the Java Virtual Machine Specification (JVMS). AnnotationWriter
* instances can be chained in a doubly linked list, from which Runtime[In]Visible[Type]Annotations
* attributes can be generated with the {@link #putAnnotations} method. Similarly, arrays of such
* lists can be used to generate Runtime[In]VisibleParameterAnnotations attributes.
*
* @see JVMS
* 4.7.16
* @see JVMS
* 4.7.20
* @author Eric Bruneton
* @author Eugene Kuleshov
*/
final class AnnotationWriter extends AnnotationVisitor {
/** Where the constants used in this AnnotationWriter must be stored. */
private final SymbolTable symbolTable;
/**
* Whether values are named or not. AnnotationWriter instances used for annotation default and
* annotation arrays use unnamed values (i.e. they generate an 'element_value' structure for each
* value, instead of an element_name_index followed by an element_value).
*/
private final boolean useNamedValues;
/**
* The 'annotation' or 'type_annotation' JVMS structure corresponding to the annotation values
* visited so far. All the fields of these structures, except the last one - the
* element_value_pairs array, must be set before this ByteVector is passed to the constructor
* (num_element_value_pairs can be set to 0, it is reset to the correct value in {@link
* #visitEnd()}). The element_value_pairs array is filled incrementally in the various visit()
* methods.
*
* Note: as an exception to the above rules, for AnnotationDefault attributes (which contain a
* single element_value by definition), this ByteVector is initially empty when passed to the
* constructor, and {@link #numElementValuePairsOffset} is set to -1.
*/
private final ByteVector annotation;
/**
* The offset in {@link #annotation} where {@link #numElementValuePairs} must be stored (or -1 for
* the case of AnnotationDefault attributes).
*/
private final int numElementValuePairsOffset;
/**
* The previous AnnotationWriter. This field is used to store the list of annotations of a
* Runtime[In]Visible[Type]Annotations attribute. It is unused for nested or array annotations
* (annotation values of annotation type), or for AnnotationDefault attributes.
*/
private final AnnotationWriter previousAnnotation;
/** The number of element value pairs visited so far. */
private int numElementValuePairs;
/**
* The next AnnotationWriter. This field is used to store the list of annotations of a
* Runtime[In]Visible[Type]Annotations attribute. It is unused for nested or array annotations
* (annotation values of annotation type), or for AnnotationDefault attributes.
*/
private AnnotationWriter nextAnnotation;
// -----------------------------------------------------------------------------------------------
// Constructors
// -----------------------------------------------------------------------------------------------
/**
* Constructs a new {@link AnnotationWriter}.
*
* @param symbolTable where the constants used in this AnnotationWriter must be stored.
* @param useNamedValues whether values are named or not. AnnotationDefault and annotation arrays
* use unnamed values.
* @param annotation where the 'annotation' or 'type_annotation' JVMS structure corresponding to
* the visited content must be stored. This ByteVector must already contain all the fields of
* the structure except the last one (the element_value_pairs array).
* @param previousAnnotation the previously visited annotation of the
* Runtime[In]Visible[Type]Annotations attribute to which this annotation belongs, or null in
* other cases (e.g. nested or array annotations).
*/
AnnotationWriter(final SymbolTable symbolTable, final boolean useNamedValues, final ByteVector annotation,
final AnnotationWriter previousAnnotation) {
super(Opcodes.ASM7);
this.symbolTable = symbolTable;
this.useNamedValues = useNamedValues;
this.annotation = annotation;
// By hypothesis, num_element_value_pairs is stored in the last unsigned short of 'annotation'.
this.numElementValuePairsOffset = annotation.length == 0 ? -1 : annotation.length - 2;
this.previousAnnotation = previousAnnotation;
if (previousAnnotation != null) {
previousAnnotation.nextAnnotation = this;
}
}
/**
* Constructs a new {@link AnnotationWriter} using named values.
*
* @param symbolTable where the constants used in this AnnotationWriter must be stored.
* @param annotation where the 'annotation' or 'type_annotation' JVMS structure corresponding to
* the visited content must be stored. This ByteVector must already contain all the fields of
* the structure except the last one (the element_value_pairs array).
* @param previousAnnotation the previously visited annotation of the
* Runtime[In]Visible[Type]Annotations attribute to which this annotation belongs, or null in
* other cases (e.g. nested or array annotations).
*/
AnnotationWriter(final SymbolTable symbolTable, final ByteVector annotation, final AnnotationWriter previousAnnotation) {
this(symbolTable, /* useNamedValues = */ true, annotation, previousAnnotation);
}
// -----------------------------------------------------------------------------------------------
// Implementation of the AnnotationVisitor abstract class
// -----------------------------------------------------------------------------------------------
/**
* Returns the size of a Runtime[In]VisibleParameterAnnotations attribute containing all the
* annotation lists from the given AnnotationWriter sub-array. Also adds the attribute name to the
* constant pool of the class.
*
* @param attributeName one of "Runtime[In]VisibleParameterAnnotations".
* @param annotationWriters an array of AnnotationWriter lists (designated by their last
* element).
* @param annotableParameterCount the number of elements in annotationWriters to take into account
* (elements [0..annotableParameterCount[ are taken into account).
* @return the size in bytes of a Runtime[In]VisibleParameterAnnotations attribute corresponding
* to the given sub-array of AnnotationWriter lists. This includes the size of the
* attribute_name_index and attribute_length fields.
*/
static int computeParameterAnnotationsSize(final String attributeName, final AnnotationWriter[] annotationWriters,
final int annotableParameterCount) {
// Note: attributeName is added to the constant pool by the call to computeAnnotationsSize
// below. This assumes that there is at least one non-null element in the annotationWriters
// sub-array (which is ensured by the lazy instantiation of this array in MethodWriter).
// The attribute_name_index, attribute_length and num_parameters fields use 7 bytes, and each
// element of the parameter_annotations array uses 2 bytes for its num_annotations field.
int attributeSize = 7 + 2 * annotableParameterCount;
for (int i = 0; i < annotableParameterCount; ++i) {
AnnotationWriter annotationWriter = annotationWriters[i];
attributeSize += annotationWriter == null ? 0 : annotationWriter.computeAnnotationsSize(attributeName) - 8;
}
return attributeSize;
}
/**
* Puts a Runtime[In]VisibleParameterAnnotations attribute containing all the annotation lists
* from the given AnnotationWriter sub-array in the given ByteVector.
*
* @param attributeNameIndex constant pool index of the attribute name (one of
* Runtime[In]VisibleParameterAnnotations).
* @param annotationWriters an array of AnnotationWriter lists (designated by their last
* element).
* @param annotableParameterCount the number of elements in annotationWriters to put (elements
* [0..annotableParameterCount[ are put).
* @param output where the attribute must be put.
*/
static void putParameterAnnotations(final int attributeNameIndex, final AnnotationWriter[] annotationWriters,
final int annotableParameterCount, final ByteVector output) {
// The num_parameters field uses 1 byte, and each element of the parameter_annotations array
// uses 2 bytes for its num_annotations field.
int attributeLength = 1 + 2 * annotableParameterCount;
for (int i = 0; i < annotableParameterCount; ++i) {
AnnotationWriter annotationWriter = annotationWriters[i];
attributeLength += annotationWriter == null ? 0 : annotationWriter.computeAnnotationsSize(null) - 8;
}
output.putShort(attributeNameIndex);
output.putInt(attributeLength);
output.putByte(annotableParameterCount);
for (int i = 0; i < annotableParameterCount; ++i) {
AnnotationWriter annotationWriter = annotationWriters[i];
AnnotationWriter firstAnnotation = null;
int numAnnotations = 0;
while (annotationWriter != null) {
// In case user the forgot to call visitEnd().
annotationWriter.visitEnd();
numAnnotations++;
firstAnnotation = annotationWriter;
annotationWriter = annotationWriter.previousAnnotation;
}
output.putShort(numAnnotations);
annotationWriter = firstAnnotation;
while (annotationWriter != null) {
output.putByteArray(annotationWriter.annotation.data, 0, annotationWriter.annotation.length);
annotationWriter = annotationWriter.nextAnnotation;
}
}
}
@Override
public void visit(final String name, final Object value) {
// Case of an element_value with a const_value_index, class_info_index or array_index field.
// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.1.
++numElementValuePairs;
if (useNamedValues) {
annotation.putShort(symbolTable.addConstantUtf8(name));
}
if (value instanceof String) {
annotation.put12('s', symbolTable.addConstantUtf8((String) value));
} else if (value instanceof Byte) {
annotation.put12('B', symbolTable.addConstantInteger(((Byte) value).byteValue()).index);
} else if (value instanceof Boolean) {
int booleanValue = ((Boolean) value).booleanValue() ? 1 : 0;
annotation.put12('Z', symbolTable.addConstantInteger(booleanValue).index);
} else if (value instanceof Character) {
annotation.put12('C', symbolTable.addConstantInteger(((Character) value).charValue()).index);
} else if (value instanceof Short) {
annotation.put12('S', symbolTable.addConstantInteger(((Short) value).shortValue()).index);
} else if (value instanceof Type) {
annotation.put12('c', symbolTable.addConstantUtf8(((Type) value).getDescriptor()));
} else if (value instanceof byte[]) {
byte[] byteArray = (byte[]) value;
annotation.put12('[', byteArray.length);
for (byte byteValue : byteArray) {
annotation.put12('B', symbolTable.addConstantInteger(byteValue).index);
}
} else if (value instanceof boolean[]) {
boolean[] booleanArray = (boolean[]) value;
annotation.put12('[', booleanArray.length);
for (boolean booleanValue : booleanArray) {
annotation.put12('Z', symbolTable.addConstantInteger(booleanValue ? 1 : 0).index);
}
} else if (value instanceof short[]) {
short[] shortArray = (short[]) value;
annotation.put12('[', shortArray.length);
for (short shortValue : shortArray) {
annotation.put12('S', symbolTable.addConstantInteger(shortValue).index);
}
} else if (value instanceof char[]) {
char[] charArray = (char[]) value;
annotation.put12('[', charArray.length);
for (char charValue : charArray) {
annotation.put12('C', symbolTable.addConstantInteger(charValue).index);
}
} else if (value instanceof int[]) {
int[] intArray = (int[]) value;
annotation.put12('[', intArray.length);
for (int intValue : intArray) {
annotation.put12('I', symbolTable.addConstantInteger(intValue).index);
}
} else if (value instanceof long[]) {
long[] longArray = (long[]) value;
annotation.put12('[', longArray.length);
for (long longValue : longArray) {
annotation.put12('J', symbolTable.addConstantLong(longValue).index);
}
} else if (value instanceof float[]) {
float[] floatArray = (float[]) value;
annotation.put12('[', floatArray.length);
for (float floatValue : floatArray) {
annotation.put12('F', symbolTable.addConstantFloat(floatValue).index);
}
} else if (value instanceof double[]) {
double[] doubleArray = (double[]) value;
annotation.put12('[', doubleArray.length);
for (double doubleValue : doubleArray) {
annotation.put12('D', symbolTable.addConstantDouble(doubleValue).index);
}
} else {
Symbol symbol = symbolTable.addConstant(value);
annotation.put12(".s.IFJDCS".charAt(symbol.tag), symbol.index);
}
}
@Override
public void visitEnum(final String name, final String descriptor, final String value) {
// Case of an element_value with an enum_const_value field.
// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.1.
++numElementValuePairs;
if (useNamedValues) {
annotation.putShort(symbolTable.addConstantUtf8(name));
}
annotation.put12('e', symbolTable.addConstantUtf8(descriptor)).putShort(symbolTable.addConstantUtf8(value));
}
@Override
public AnnotationVisitor visitAnnotation(final String name, final String descriptor) {
// Case of an element_value with an annotation_value field.
// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.1.
++numElementValuePairs;
if (useNamedValues) {
annotation.putShort(symbolTable.addConstantUtf8(name));
}
// Write tag and type_index, and reserve 2 bytes for num_element_value_pairs.
annotation.put12('@', symbolTable.addConstantUtf8(descriptor)).putShort(0);
return new AnnotationWriter(symbolTable, annotation, null);
}
// -----------------------------------------------------------------------------------------------
// Utility methods
// -----------------------------------------------------------------------------------------------
@Override
public AnnotationVisitor visitArray(final String name) {
// Case of an element_value with an array_value field.
// https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.1
++numElementValuePairs;
if (useNamedValues) {
annotation.putShort(symbolTable.addConstantUtf8(name));
}
// Write tag, and reserve 2 bytes for num_values. Here we take advantage of the fact that the
// end of an element_value of array type is similar to the end of an 'annotation' structure: an
// unsigned short num_values followed by num_values element_value, versus an unsigned short
// num_element_value_pairs, followed by num_element_value_pairs { element_name_index,
// element_value } tuples. This allows us to use an AnnotationWriter with unnamed values to
// visit the array elements. Its num_element_value_pairs will correspond to the number of array
// elements and will be stored in what is in fact num_values.
annotation.put12('[', 0);
return new AnnotationWriter(symbolTable, /* useNamedValues = */ false, annotation, null);
}
@Override
public void visitEnd() {
if (numElementValuePairsOffset != -1) {
byte[] data = annotation.data;
data[numElementValuePairsOffset] = (byte) (numElementValuePairs >>> 8);
data[numElementValuePairsOffset + 1] = (byte) numElementValuePairs;
}
}
/**
* Returns the size of a Runtime[In]Visible[Type]Annotations attribute containing this annotation
* and all its predecessors (see {@link #previousAnnotation}. Also adds the attribute name
* to the constant pool of the class (if not null).
*
* @param attributeName one of "Runtime[In]Visible[Type]Annotations", or null.
* @return the size in bytes of a Runtime[In]Visible[Type]Annotations attribute containing this
* annotation and all its predecessors. This includes the size of the attribute_name_index and
* attribute_length fields.
*/
int computeAnnotationsSize(final String attributeName) {
if (attributeName != null) {
symbolTable.addConstantUtf8(attributeName);
}
// The attribute_name_index, attribute_length and num_annotations fields use 8 bytes.
int attributeSize = 8;
AnnotationWriter annotationWriter = this;
while (annotationWriter != null) {
attributeSize += annotationWriter.annotation.length;
annotationWriter = annotationWriter.previousAnnotation;
}
return attributeSize;
}
/**
* Puts a Runtime[In]Visible[Type]Annotations attribute containing this annotations and all its
* predecessors (see {@link #previousAnnotation} in the given ByteVector. Annotations are
* put in the same order they have been visited.
*
* @param attributeNameIndex the constant pool index of the attribute name (one of
* "Runtime[In]Visible[Type]Annotations").
* @param output where the attribute must be put.
*/
void putAnnotations(final int attributeNameIndex, final ByteVector output) {
int attributeLength = 2; // For num_annotations.
int numAnnotations = 0;
AnnotationWriter annotationWriter = this;
AnnotationWriter firstAnnotation = null;
while (annotationWriter != null) {
// In case the user forgot to call visitEnd().
annotationWriter.visitEnd();
attributeLength += annotationWriter.annotation.length;
numAnnotations++;
firstAnnotation = annotationWriter;
annotationWriter = annotationWriter.previousAnnotation;
}
output.putShort(attributeNameIndex);
output.putInt(attributeLength);
output.putShort(numAnnotations);
annotationWriter = firstAnnotation;
while (annotationWriter != null) {
output.putByteArray(annotationWriter.annotation.data, 0, annotationWriter.annotation.length);
annotationWriter = annotationWriter.nextAnnotation;
}
}
}