/***
* 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 org.springframework.asm;
/**
* A non standard class, field, method or code attribute.
*
* @author Eric Bruneton
* @author Eugene Kuleshov
*/
public class
Attribute {
/**
* The type of this attribute.
*/
public final
String type;
/**
* The raw value of this attribute, used only for unknown attributes.
*/
byte[]
value;
/**
* The next attribute in this attribute list. May be <tt>null</tt>.
*/
Attribute next;
/**
* Constructs a new empty attribute.
*
* @param type
* the type of the attribute.
*/
protected
Attribute(final
String type) {
this.
type =
type;
}
/**
* 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 <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.
*
* @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 {@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.
*
* @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.
*
* @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.
*
* @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.
*
* @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;
}
}
}