/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file:
 *
 * 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 jdk.internal.org.objectweb.asm;

A non standard class, field, method or code attribute.
Author:Eric Bruneton, Eugene Kuleshov
/** * A non standard class, field, method or code attribute. * * @author Eric Bruneton * @author Eugene Kuleshov */
public class Attribute {
The type of this attribute.
/** * The type of this attribute. */
public final String type;
The raw value of this attribute, used only for unknown attributes.
/** * The raw value of this attribute, used only for unknown attributes. */
byte[] value;
The next attribute in this attribute list. May be null.
/** * The next attribute in this attribute list. May be <tt>null</tt>. */
Attribute next;
Constructs a new empty attribute.
Params:
  • type – the type of the attribute.
/** * Constructs a new empty attribute. * * @param type * the type of the attribute. */
protected Attribute(final String type) { this.type = type; }
Returns true if this type of attribute is unknown. The default implementation of this method always returns true.
Returns:true if this type of attribute is unknown.
/** * Returns <tt>true</tt> if this type of attribute is unknown. The default * implementation of this method always returns <tt>true</tt>. * * @return <tt>true</tt> if this type of attribute is unknown. */
public boolean isUnknown() { return true; }
Returns true if this type of attribute is a code attribute.
Returns:true if this type of attribute is a code attribute.
/** * Returns <tt>true</tt> if this type of attribute is a code attribute. * * @return <tt>true</tt> if this type of attribute is a code attribute. */
public boolean isCodeAttribute() { return false; }
Returns the labels corresponding to this attribute.
Returns:the labels corresponding to this attribute, or null if this attribute is not a code attribute that contains labels.
/** * Returns the labels corresponding to this attribute. * * @return the labels corresponding to this attribute, or <tt>null</tt> if * this attribute is not a code attribute that contains labels. */
protected Label[] getLabels() { return null; }
Reads a type attribute. This method must return a new Attribute object, of type type, corresponding to the len bytes starting at the given offset, in the given class reader.
Params:
  • cr – the class that contains the attribute to be read.
  • off – index of the first byte of the attribute's content in cr.b. The 6 attribute header bytes, containing the type and the length of the attribute, are not taken into account here.
  • len – the length of the attribute's content.
  • buf – buffer to be used to call readUTF8, readClass or readConst.
  • codeOff – index of the first byte of code's attribute content in cr.b, or -1 if the attribute to be read is not a code attribute. The 6 attribute header bytes, containing the type and the length of the attribute, are not taken into account here.
  • labels – the labels of the method's code, or null if the attribute to be read is not a code attribute.
Returns:a new Attribute object corresponding to the given bytes.
/** * Reads a {@link #type type} attribute. This method must return a * <i>new</i> {@link Attribute} object, of type {@link #type type}, * corresponding to the <tt>len</tt> bytes starting at the given offset, in * the given class reader. * * @param cr * the class that contains the attribute to be read. * @param off * index of the first byte of the attribute's content in * {@link ClassReader#b cr.b}. The 6 attribute header bytes, * containing the type and the length of the attribute, are not * taken into account here. * @param len * the length of the attribute's content. * @param buf * buffer to be used to call {@link ClassReader#readUTF8 * readUTF8}, {@link ClassReader#readClass(int,char[]) readClass} * or {@link ClassReader#readConst readConst}. * @param codeOff * index of the first byte of code's attribute content in * {@link ClassReader#b cr.b}, or -1 if the attribute to be read * is not a code attribute. The 6 attribute header bytes, * containing the type and the length of the attribute, are not * taken into account here. * @param labels * the labels of the method's code, or <tt>null</tt> if the * attribute to be read is not a code attribute. * @return a <i>new</i> {@link Attribute} object corresponding to the given * bytes. */
protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) { Attribute attr = new Attribute(type); attr.value = new byte[len]; System.arraycopy(cr.b, off, attr.value, 0, len); return attr; }
Returns the byte array form of this attribute.
Params:
  • cw – the class to which this attribute must be added. This parameter can be used to add to the constant pool of this class the items that corresponds to this attribute.
  • code – the bytecode of the method corresponding to this code attribute, or null if this attribute is not a code attributes.
  • len – the length of the bytecode of the method corresponding to this code attribute, or null if this attribute is not a code attribute.
  • maxStack – the maximum stack size of the method corresponding to this code attribute, or -1 if this attribute is not a code attribute.
  • maxLocals – the maximum number of local variables of the method corresponding to this code attribute, or -1 if this attribute is not a code attribute.
Returns:the byte array form of this attribute.
/** * Returns the byte array form of this attribute. * * @param cw * the class to which this attribute must be added. This * parameter can be used to add to the constant pool of this * class the items that corresponds to this attribute. * @param code * the bytecode of the method corresponding to this code * attribute, or <tt>null</tt> if this attribute is not a code * attributes. * @param len * the length of the bytecode of the method corresponding to this * code attribute, or <tt>null</tt> if this attribute is not a * code attribute. * @param maxStack * the maximum stack size of the method corresponding to this * code attribute, or -1 if this attribute is not a code * attribute. * @param maxLocals * the maximum number of local variables of the method * corresponding to this code attribute, or -1 if this attribute * is not a code attribute. * @return the byte array form of this attribute. */
protected ByteVector write(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals) { ByteVector v = new ByteVector(); v.data = value; v.length = value.length; return v; }
Returns the length of the attribute list that begins with this attribute.
Returns:the length of the attribute list that begins with this attribute.
/** * Returns the length of the attribute list that begins with this attribute. * * @return the length of the attribute list that begins with this attribute. */
final int getCount() { int count = 0; Attribute attr = this; while (attr != null) { count += 1; attr = attr.next; } return count; }
Returns the size of all the attributes in this attribute list.
Params:
  • cw – the class writer to be used to convert the attributes into byte arrays, with the write method.
  • code – the bytecode of the method corresponding to these code attributes, or null if these attributes are not code attributes.
  • len – the length of the bytecode of the method corresponding to these code attributes, or null if these attributes are not code attributes.
  • maxStack – the maximum stack size of the method corresponding to these code attributes, or -1 if these attributes are not code attributes.
  • maxLocals – the maximum number of local variables of the method corresponding to these code attributes, or -1 if these attributes are not code attributes.
Returns:the size of all the attributes in this attribute list. This size includes the size of the attribute headers.
/** * Returns the size of all the attributes in this attribute list. * * @param cw * the class writer to be used to convert the attributes into * byte arrays, with the {@link #write write} method. * @param code * the bytecode of the method corresponding to these code * attributes, or <tt>null</tt> if these attributes are not code * attributes. * @param len * the length of the bytecode of the method corresponding to * these code attributes, or <tt>null</tt> if these attributes * are not code attributes. * @param maxStack * the maximum stack size of the method corresponding to these * code attributes, or -1 if these attributes are not code * attributes. * @param maxLocals * the maximum number of local variables of the method * corresponding to these code attributes, or -1 if these * attributes are not code attributes. * @return the size of all the attributes in this attribute list. This size * includes the size of the attribute headers. */
final int getSize(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals) { Attribute attr = this; int size = 0; while (attr != null) { cw.newUTF8(attr.type); size += attr.write(cw, code, len, maxStack, maxLocals).length + 6; attr = attr.next; } return size; }
Writes all the attributes of this attribute list in the given byte vector.
Params:
  • cw – the class writer to be used to convert the attributes into byte arrays, with the write method.
  • code – the bytecode of the method corresponding to these code attributes, or null if these attributes are not code attributes.
  • len – the length of the bytecode of the method corresponding to these code attributes, or null if these attributes are not code attributes.
  • maxStack – the maximum stack size of the method corresponding to these code attributes, or -1 if these attributes are not code attributes.
  • maxLocals – the maximum number of local variables of the method corresponding to these code attributes, or -1 if these attributes are not code attributes.
  • out – where the attributes must be written.
/** * Writes all the attributes of this attribute list in the given byte * vector. * * @param cw * the class writer to be used to convert the attributes into * byte arrays, with the {@link #write write} method. * @param code * the bytecode of the method corresponding to these code * attributes, or <tt>null</tt> if these attributes are not code * attributes. * @param len * the length of the bytecode of the method corresponding to * these code attributes, or <tt>null</tt> if these attributes * are not code attributes. * @param maxStack * the maximum stack size of the method corresponding to these * code attributes, or -1 if these attributes are not code * attributes. * @param maxLocals * the maximum number of local variables of the method * corresponding to these code attributes, or -1 if these * attributes are not code attributes. * @param out * where the attributes must be written. */
final void put(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals, final ByteVector out) { Attribute attr = this; while (attr != null) { ByteVector b = attr.write(cw, code, len, maxStack, maxLocals); out.putShort(cw.newUTF8(attr.type)).putInt(b.length); out.putByteArray(b.data, 0, b.length); attr = attr.next; } } }