Copyright (c) 2005, 2016 BEA Systems, Inc.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
   tyeung@bea.com - initial API and implementation
   olivier_thomann@ca.ibm.com - add hashCode() and equals(..) methods
/*******************************************************************************
 * Copyright (c) 2005, 2016 BEA Systems, Inc.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *    tyeung@bea.com - initial API and implementation
 *    olivier_thomann@ca.ibm.com - add hashCode() and equals(..) methods
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.classfmt;

import java.util.Arrays;

import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.compiler.ast.Annotation;
import org.eclipse.jdt.internal.compiler.codegen.ConstantPool;
import org.eclipse.jdt.internal.compiler.env.*;
import org.eclipse.jdt.internal.compiler.impl.*;
import org.eclipse.jdt.internal.compiler.lookup.TagBits;
import org.eclipse.jdt.internal.compiler.util.Util;

public class AnnotationInfo extends ClassFileStruct implements IBinaryAnnotation {
	
The name of the annotation type /** The name of the annotation type */
	private char[] typename;
	
null until this annotation is initialized
See Also:
getElementValuePairs()/**
	 * null until this annotation is initialized
	 * @see #getElementValuePairs()
	 */
	private volatile ElementValuePairInfo[] pairs;

	long standardAnnotationTagBits = 0;
	int readOffset = 0;

	static Object[] EmptyValueArray = new Object[0];

	public RuntimeException exceptionDuringDecode;

AnnotationInfo(byte[] classFileBytes, int[] contantPoolOffsets, int offset) {
	super(classFileBytes, contantPoolOffsets, offset);
}
Params:
classFileBytes – 
offset – the offset into classFileBytes for the "type_index" of the annotation attribute.
populate – true to indicate to build out the annotation structure./**
 * @param classFileBytes
 * @param offset the offset into <code>classFileBytes</code> for the "type_index" of the annotation attribute.
 * @param populate <code>true</code> to indicate to build out the annotation structure.
 */
AnnotationInfo(byte[] classFileBytes, int[] contantPoolOffsets, int offset, boolean runtimeVisible, boolean populate) {
	this(classFileBytes, contantPoolOffsets, offset);
	if (populate)
		decodeAnnotation();
	else
		this.readOffset = scanAnnotation(0, runtimeVisible, true);
}
private void decodeAnnotation() {
	this.readOffset = 0;
	int utf8Offset = this.constantPoolOffsets[u2At(0)] - this.structOffset;
	this.typename = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
	int numberOfPairs = u2At(2);
	// u2 type_index + u2 num_member_value_pair
	this.readOffset += 4;
	ElementValuePairInfo[] decodedPairs = numberOfPairs == 0 ? ElementValuePairInfo.NoMembers : new ElementValuePairInfo[numberOfPairs];
	int i = 0;
	try {
		while (i < numberOfPairs) {
			// u2 member_name_index;
			utf8Offset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			char[] membername = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
			this.readOffset += 2;
			Object value = decodeDefaultValue();
			decodedPairs[i++] = new ElementValuePairInfo(membername, value);
		}
		this.pairs = decodedPairs;
	} catch (RuntimeException any) {
		sanitizePairs(decodedPairs);
		StringBuilder newMessage = new StringBuilder(any.getMessage());
		newMessage.append(" while decoding pair #").append(i).append(" of annotation @").append(this.typename); //$NON-NLS-1$ //$NON-NLS-2$
		newMessage.append(", bytes at structOffset ").append(this.structOffset).append(":"); //$NON-NLS-1$ //$NON-NLS-2$
		int offset = this.structOffset;
		while (offset <= this.structOffset+this.readOffset && offset < this.reference.length) {
			newMessage.append(' ').append(Integer.toHexString(this.reference[offset++] & 0xFF));
		}
		throw new IllegalStateException(newMessage.toString(), any);
	}
}
private void sanitizePairs(ElementValuePairInfo[] oldPairs) {
	if (oldPairs != null) {
		ElementValuePairInfo[] newPairs = new ElementValuePairInfo[oldPairs.length];
		int count = 0;
		for (int i = 0; i < oldPairs.length; i++) {
			ElementValuePairInfo evpInfo = oldPairs[i];
			if (evpInfo != null)
				newPairs[count++] = evpInfo;
		}
		if (count < oldPairs.length) {
			this.pairs = Arrays.copyOf(newPairs, count);
		} else {
			this.pairs = newPairs;
		}
	} else {
		this.pairs = ElementValuePairInfo.NoMembers;
	}
}
Object decodeDefaultValue() {
	Object value = null;
	// u1 tag;
	int tag = u1At(this.readOffset);
	this.readOffset++;
	int constValueOffset = -1;
	switch (tag) {
		case 'Z': // boolean constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = BooleanConstant.fromValue(i4At(constValueOffset + 1) == 1);
			this.readOffset += 2;
			break;
		case 'I': // integer constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = IntConstant.fromValue(i4At(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'C': // char constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = CharConstant.fromValue((char) i4At(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'B': // byte constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = ByteConstant.fromValue((byte) i4At(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'S': // short constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = ShortConstant.fromValue((short) i4At(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'D': // double constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = DoubleConstant.fromValue(doubleAt(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'F': // float constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = FloatConstant.fromValue(floatAt(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 'J': // long constant
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = LongConstant.fromValue(i8At(constValueOffset + 1));
			this.readOffset += 2;
			break;
		case 's': // String
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			value = StringConstant.fromValue(String.valueOf(utf8At(constValueOffset + 3, u2At(constValueOffset + 1))));
			this.readOffset += 2;
			break;
		case 'e':
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			char[] typeName = utf8At(constValueOffset + 3, u2At(constValueOffset + 1));
			this.readOffset += 2;
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			char[] constName = utf8At(constValueOffset + 3, u2At(constValueOffset + 1));
			this.readOffset += 2;
			value = new EnumConstantSignature(typeName, constName);
			break;
		case 'c':
			constValueOffset = this.constantPoolOffsets[u2At(this.readOffset)] - this.structOffset;
			char[] className = utf8At(constValueOffset + 3, u2At(constValueOffset + 1));
			value = new ClassSignature(className);
			this.readOffset += 2;
			break;
		case '@':
			value = new AnnotationInfo(this.reference, this.constantPoolOffsets, this.readOffset + this.structOffset, false, true);
			this.readOffset += ((AnnotationInfo) value).readOffset;
			break;
		case '[':
			int numberOfValues = u2At(this.readOffset);
			this.readOffset += 2;
			if (numberOfValues == 0) {
				value = EmptyValueArray;
			} else {
				Object[] arrayElements = new Object[numberOfValues];
				value = arrayElements;
				for (int i = 0; i < numberOfValues; i++)
					arrayElements[i] = decodeDefaultValue();
			}
			break;
		default:
			String tagDisplay = tag == 0 ? "0x00" : (char) tag + " ("+Integer.toHexString(tag&0xFF)+')';  //$NON-NLS-1$//$NON-NLS-2$
			throw new IllegalStateException("Unrecognized tag " + tagDisplay); //$NON-NLS-1$
	}
	return value;
}
@Override
public IBinaryElementValuePair[] getElementValuePairs() {
	if (this.pairs == null)
		lazyInitialize();
	return this.pairs;
}
@Override
public char[] getTypeName() {
	return this.typename;
}
@Override
public boolean isDeprecatedAnnotation() {
	return (this.standardAnnotationTagBits & (TagBits.AnnotationDeprecated | TagBits.AnnotationTerminallyDeprecated)) != 0;
}
void initialize() {
	if (this.pairs == null)
		decodeAnnotation();
}
synchronized void lazyInitialize() {
	if (this.pairs == null)
		decodeAnnotation();
}
private int readRetentionPolicy(int offset) {
	int currentOffset = offset;
	int tag = u1At(currentOffset);
	currentOffset++;
	switch (tag) {
		case 'e':
			int utf8Offset = this.constantPoolOffsets[u2At(currentOffset)] - this.structOffset;
			char[] typeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
			currentOffset += 2;
			if (typeName.length == 38 && CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_RETENTIONPOLICY)) {
				utf8Offset = this.constantPoolOffsets[u2At(currentOffset)] - this.structOffset;
				char[] constName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
				this.standardAnnotationTagBits |= Annotation.getRetentionPolicy(constName);
			}
			currentOffset += 2;
			break;
		case 'B':
		case 'C':
		case 'D':
		case 'F':
		case 'I':
		case 'J':
		case 'S':
		case 'Z':
		case 's':
		case 'c':
			currentOffset += 2;
			break;
		case '@':
			// none of the supported standard annotation are in the nested
			// level.
			currentOffset = scanAnnotation(currentOffset, false, false);
			break;
		case '[':
			int numberOfValues = u2At(currentOffset);
			currentOffset += 2;
			for (int i = 0; i < numberOfValues; i++)
				currentOffset = scanElementValue(currentOffset);
			break;
		default:
			throw new IllegalStateException();
	}
	return currentOffset;
}
private int readTargetValue(int offset) {
	int currentOffset = offset;
	int tag = u1At(currentOffset);
	currentOffset++;
	switch (tag) {
		case 'e':
			int utf8Offset = this.constantPoolOffsets[u2At(currentOffset)] - this.structOffset;
			char[] typeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
			currentOffset += 2;
			if (typeName.length == 34 && CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_ELEMENTTYPE)) {
				utf8Offset = this.constantPoolOffsets[u2At(currentOffset)] - this.structOffset;
				char[] constName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
				this.standardAnnotationTagBits |= Annotation.getTargetElementType(constName);
			}
			currentOffset += 2;
			break;
		case 'B':
		case 'C':
		case 'D':
		case 'F':
		case 'I':
		case 'J':
		case 'S':
		case 'Z':
		case 's':
		case 'c':
			currentOffset += 2;
			break;
		case '@':
			// none of the supported standard annotation are in the nested
			// level.
			currentOffset = scanAnnotation(currentOffset, false, false);
			break;
		case '[':
			int numberOfValues = u2At(currentOffset);
			currentOffset += 2;
			if (numberOfValues == 0) {
				this.standardAnnotationTagBits |= TagBits.AnnotationTarget;
			} else {
				for (int i = 0; i < numberOfValues; i++)
					currentOffset = readTargetValue(currentOffset);
			}
			break;
		default:
			throw new IllegalStateException();
	}
	return currentOffset;
}
Read through this annotation in order to figure out the necessary tag
bits and the length of this annotation. The data structure will not be
flushed out.
The tag bits are derived from the following (supported) standard
annotation. java.lang.annotation.Documented,
java.lang.annotation.Retention, java.lang.annotation.Target, and
java.lang.Deprecated
Params:
expectRuntimeVisibleAnno – 
           true to indicate that this is a runtime-visible annotation
toplevel – false to indicate that an nested annotation is read.
		true otherwise
Returns:
the next offset to read./**
 * Read through this annotation in order to figure out the necessary tag
 * bits and the length of this annotation. The data structure will not be
 * flushed out.
 *
 * The tag bits are derived from the following (supported) standard
 * annotation. java.lang.annotation.Documented,
 * java.lang.annotation.Retention, java.lang.annotation.Target, and
 * java.lang.Deprecated
 *
 * @param expectRuntimeVisibleAnno
 *            <code>true</cod> to indicate that this is a runtime-visible annotation
 * @param toplevel <code>false</code> to indicate that an nested annotation is read.
 * 		<code>true</code> otherwise
 * @return the next offset to read.
 */
private int scanAnnotation(int offset, boolean expectRuntimeVisibleAnno, boolean toplevel) {
	int currentOffset = offset;
	int utf8Offset = this.constantPoolOffsets[u2At(offset)] - this.structOffset;
	char[] typeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
	if (toplevel)
		this.typename = typeName;
	int numberOfPairs = u2At(offset + 2);
	// u2 type_index + u2 number_member_value_pair
	currentOffset += 4;
	if (expectRuntimeVisibleAnno && toplevel) {
		switch (typeName.length) {
			case 22:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_DEPRECATED)) {
					this.standardAnnotationTagBits |= TagBits.AnnotationDeprecated;
				}
				break;
			case 23:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_SAFEVARARGS)) {
					this.standardAnnotationTagBits |= TagBits.AnnotationSafeVarargs;
					return currentOffset;
				}
				break;
			case 29:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_TARGET)) {
					currentOffset += 2;
					return readTargetValue(currentOffset);
				}
				break;
			case 32:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_RETENTION)) {
					currentOffset += 2;
					return readRetentionPolicy(currentOffset);
				}
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_INHERITED)) {
					this.standardAnnotationTagBits |= TagBits.AnnotationInherited;
					return currentOffset;
				}
				break;
			case 33:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_ANNOTATION_DOCUMENTED)) {
					this.standardAnnotationTagBits |= TagBits.AnnotationDocumented;
					return currentOffset;
				}
				break;
			case 52:
				if (CharOperation.equals(typeName, ConstantPool.JAVA_LANG_INVOKE_METHODHANDLE_POLYMORPHICSIGNATURE)) {
					this.standardAnnotationTagBits |= TagBits.AnnotationPolymorphicSignature;
					return currentOffset;
				}
				break;
		}
	}
	for (int i = 0; i < numberOfPairs; i++) {
		// u2 member_name_index
		currentOffset += 2;
		currentOffset = scanElementValue(currentOffset);
	}
	return currentOffset;
}
Params:
offset – 
           the offset to start reading.
Returns:
the next offset to read./**
 * @param offset
 *            the offset to start reading.
 * @return the next offset to read.
 */
private int scanElementValue(int offset) {
	int currentOffset = offset;
	int tag = u1At(currentOffset);
	currentOffset++;
	switch (tag) {
		case 'Z':
			if ((this.standardAnnotationTagBits & TagBits.AnnotationDeprecated) != 0) {
				// assume member_name is 'since', because @Deprecated has only one boolean member
				int constantOffset = this.constantPoolOffsets[u2At(currentOffset)] - this.structOffset + 1;
				if (i4At(constantOffset) == 1) {
					this.standardAnnotationTagBits |= TagBits.AnnotationTerminallyDeprecated;
				}
			}
			currentOffset += 2;
			break;
		case 'B':
		case 'C':
		case 'D':
		case 'F':
		case 'I':
		case 'J':
		case 'S':
		case 's':
		case 'c':
			currentOffset += 2;
			break;
		case 'e':
			currentOffset += 4;
			break;
		case '@':
			// none of the supported standard annotation are in the nested
			// level.
			currentOffset = scanAnnotation(currentOffset, false, false);
			break;
		case '[':
			int numberOfValues = u2At(currentOffset);
			currentOffset += 2;
			for (int i = 0; i < numberOfValues; i++)
				currentOffset = scanElementValue(currentOffset);
			break;
		default:
			throw new IllegalStateException();
	}
	return currentOffset;
}
@Override
public String toString() {
	return BinaryTypeFormatter.annotationToString(this);
}
@Override
public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + Util.hashCode(this.pairs);
	result = prime * result + CharOperation.hashCode(this.typename);
	return result;
}
@Override
public boolean equals(Object obj) {
	if (this == obj) {
		return true;
	}
	if (obj == null) {
		return false;
	}
	if (getClass() != obj.getClass()) {
		return false;
	}
	AnnotationInfo other = (AnnotationInfo) obj;
	if (!Arrays.equals(this.pairs, other.pairs)) {
		return false;
	}
	if (!Arrays.equals(this.typename, other.typename)) {
		return false;
	}
	return true;
}
}