| ClassReader.java |
/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 2002-2003 The Apache Software Foundation. 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. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Axis" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.jboss.axis.utils.bytecode;
import org.jboss.axis.utils.Messages;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
/**
* This is the class file reader for obtaining the parameter names
* for declared methods in a class. The class must have debugging
* attributes for us to obtain this information. <p>
* <p/>
* This does not work for inherited methods. To obtain parameter
* names for inherited methods, you must use a paramReader for the
* class that originally declared the method. <p>
* <p/>
* don't get tricky, it's the bare minimum. Instances of this class
* are not threadsafe -- don't share them. <p>
*
* @author Edwin Smith, Macromedia
*/
public class ClassReader extends ByteArrayInputStream
{
// constants values that appear in java class files,
// from jvm spec 2nd ed, section 4.4, pp 103
private static final int CONSTANT_Class = 7;
private static final int CONSTANT_Fieldref = 9;
private static final int CONSTANT_Methodref = 10;
private static final int CONSTANT_InterfaceMethodref = 11;
private static final int CONSTANT_String = 8;
private static final int CONSTANT_Integer = 3;
private static final int CONSTANT_Float = 4;
private static final int CONSTANT_Long = 5;
private static final int CONSTANT_Double = 6;
private static final int CONSTANT_NameAndType = 12;
private static final int CONSTANT_Utf8 = 1;
/**
* the constant pool. constant pool indices in the class file
* directly index into this array. The value stored in this array
* is the position in the class file where that constant begins.
*/
private int[] cpoolIndex;
private Object[] cpool;
private Map attrMethods;
/**
* load the bytecode for a given class, by using the class's defining
* classloader and assuming that for a class named P.C, the bytecodes are
* in a resource named /P/C.class.
*
* @param c the class of interest
* @return a byte array containing the bytecode
* @throws IOException
*/
protected static byte[] getBytes(Class c) throws IOException
{
InputStream fin = c.getResourceAsStream('/' + c.getName().replace('.', '/') + ".class");
if (fin == null)
{
throw new IOException(Messages.getMessage("cantLoadByecode", c.getName()));
}
try
{
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int actual;
do
{
actual = fin.read(buf);
if (actual > 0)
{
out.write(buf, 0, actual);
}
}
while (actual > 0);
return out.toByteArray();
}
finally
{
fin.close();
}
}
static String classDescriptorToName(String desc)
{
return desc.replace('/', '.');
}
protected static Map findAttributeReaders(Class c)
{
HashMap map = new HashMap();
Method[] methods = c.getMethods();
for (int i = 0; i < methods.length; i++)
{
String name = methods[i].getName();
if (name.startsWith("read") && methods[i].getReturnType() == void.class)
{
map.put(name.substring(4), methods[i]);
}
}
return map;
}
protected static String getSignature(Member method, Class[] paramTypes)
{
// compute the method descriptor
StringBuffer b = new StringBuffer((method instanceof Method) ? method.getName() : "<init>");
b.append('(');
for (int i = 0; i < paramTypes.length; i++)
{
addDescriptor(b, paramTypes[i]);
}
b.append(')');
if (method instanceof Method)
{
addDescriptor(b, ((Method)method).getReturnType());
}
else if (method instanceof Constructor)
{
addDescriptor(b, void.class);
}
return b.toString();
}
private static void addDescriptor(StringBuffer b, Class c)
{
if (c.isPrimitive())
{
if (c == void.class)
b.append('V');
else if (c == int.class)
b.append('I');
else if (c == boolean.class)
b.append('Z');
else if (c == byte.class)
b.append('B');
else if (c == short.class)
b.append('S');
else if (c == long.class)
b.append('J');
else if (c == char.class)
b.append('C');
else if (c == float.class)
b.append('F');
else if (c == double.class) b.append('D');
}
else if (c.isArray())
{
b.append('[');
addDescriptor(b, c.getComponentType());
}
else
{
b.append('L').append(c.getName().replace('.', '/')).append(';');
}
}
/**
* @return the next unsigned 16 bit value
*/
protected final int readShort()
{
return (read() << 8) | read();
}
/**
* @return the next signed 32 bit value
*/
protected final int readInt()
{
return (read() << 24) | (read() << 16) | (read() << 8) | read();
}
/**
* skip n bytes in the input stream.
*/
protected void skipFully(int n) throws IOException
{
while (n > 0)
{
int c = (int)skip(n);
if (c <= 0)
throw new EOFException(Messages.getMessage("unexpectedEOF00"));
n -= c;
}
}
protected final Member resolveMethod(int index) throws IOException, ClassNotFoundException, NoSuchMethodException
{
int oldPos = pos;
try
{
Member m = (Member)cpool[index];
if (m == null)
{
pos = cpoolIndex[index];
Class owner = resolveClass(readShort());
NameAndType nt = resolveNameAndType(readShort());
String signature = nt.name + nt.type;
if (nt.name.equals("<init>"))
{
Constructor[] ctors = owner.getConstructors();
for (int i = 0; i < ctors.length; i++)
{
String sig = getSignature(ctors[i], ctors[i].getParameterTypes());
if (sig.equals(signature))
{
cpool[index] = m = ctors[i];
return m;
}
}
}
else
{
Method[] methods = owner.getDeclaredMethods();
for (int i = 0; i < methods.length; i++)
{
String sig = getSignature(methods[i], methods[i].getParameterTypes());
if (sig.equals(signature))
{
cpool[index] = m = methods[i];
return m;
}
}
}
throw new NoSuchMethodException(signature);
}
return m;
}
finally
{
pos = oldPos;
}
}
protected final Field resolveField(int i) throws IOException, ClassNotFoundException, NoSuchFieldException
{
int oldPos = pos;
try
{
Field f = (Field)cpool[i];
if (f == null)
{
pos = cpoolIndex[i];
Class owner = resolveClass(readShort());
NameAndType nt = resolveNameAndType(readShort());
cpool[i] = f = owner.getDeclaredField(nt.name);
}
return f;
}
finally
{
pos = oldPos;
}
}
private static class NameAndType
{
String name;
String type;
public NameAndType(String name, String type)
{
this.name = name;
this.type = type;
}
}
protected final NameAndType resolveNameAndType(int i) throws IOException
{
int oldPos = pos;
try
{
NameAndType nt = (NameAndType)cpool[i];
if (nt == null)
{
pos = cpoolIndex[i];
String name = resolveUtf8(readShort());
String type = resolveUtf8(readShort());
cpool[i] = nt = new NameAndType(name, type);
}
return nt;
}
finally
{
pos = oldPos;
}
}
protected final Class resolveClass(int i) throws IOException, ClassNotFoundException
{
int oldPos = pos;
try
{
Class c = (Class)cpool[i];
if (c == null)
{
pos = cpoolIndex[i];
String name = resolveUtf8(readShort());
cpool[i] = c = Class.forName(classDescriptorToName(name));
}
return c;
}
finally
{
pos = oldPos;
}
}
protected final String resolveUtf8(int i) throws IOException
{
int oldPos = pos;
try
{
String s = (String)cpool[i];
if (s == null)
{
pos = cpoolIndex[i];
int len = readShort();
skipFully(len);
cpool[i] = s = new String(buf, pos - len, len, "utf-8");
}
return s;
}
finally
{
pos = oldPos;
}
}
protected final void readCpool() throws IOException
{
int count = readShort(); // cpool count
cpoolIndex = new int[count];
cpool = new Object[count];
for (int i = 1; i < count; i++)
{
int c = read();
cpoolIndex[i] = super.pos;
switch (c) // constant pool tag
{
case CONSTANT_Fieldref:
case CONSTANT_Methodref:
case CONSTANT_InterfaceMethodref:
case CONSTANT_NameAndType:
readShort(); // class index or (12) name index
// fall through
case CONSTANT_Class:
case CONSTANT_String:
readShort(); // string index or class index
break;
case CONSTANT_Long:
case CONSTANT_Double:
readInt(); // hi-value
// see jvm spec section 4.4.5 - double and long cpool
// entries occupy two "slots" in the cpool table.
i++;
// fall through
case CONSTANT_Integer:
case CONSTANT_Float:
readInt(); // value
break;
case CONSTANT_Utf8:
int len = readShort();
skipFully(len);
break;
default:
// corrupt class file
throw new IllegalStateException(Messages.getMessage("unexpectedBytes00"));
}
}
}
protected final void skipAttributes() throws IOException
{
int count = readShort();
for (int i = 0; i < count; i++)
{
readShort(); // name index
skipFully(readInt());
}
}
/**
* read an attributes array. the elements of a class file that
* can contain attributes are: fields, methods, the class itself,
* and some other types of attributes.
*/
protected final void readAttributes() throws IOException
{
int count = readShort();
for (int i = 0; i < count; i++)
{
int nameIndex = readShort(); // name index
int attrLen = readInt();
int curPos = pos;
String attrName = resolveUtf8(nameIndex);
Method m = (Method)attrMethods.get(attrName);
if (m != null)
{
try
{
m.invoke(this, new Object[]{});
}
catch (IllegalAccessException e)
{
pos = curPos;
skipFully(attrLen);
}
catch (InvocationTargetException e)
{
try
{
throw e.getTargetException();
}
catch (Error ex)
{
throw ex;
}
catch (RuntimeException ex)
{
throw ex;
}
catch (IOException ex)
{
throw ex;
}
catch (Throwable ex)
{
pos = curPos;
skipFully(attrLen);
}
}
}
else
{
// don't care what attribute this is
skipFully(attrLen);
}
}
}
/**
* read a code attribute
*
* @throws IOException
*/
public void readCode() throws IOException
{
readShort(); // max stack
readShort(); // max locals
skipFully(readInt()); // code
skipFully(8 * readShort()); // exception table
// read the code attributes (recursive). This is where
// we will find the LocalVariableTable attribute.
readAttributes();
}
protected ClassReader(byte buf[], Map attrMethods)
{
super(buf);
this.attrMethods = attrMethods;
}
}
| ClassReader.java |