/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2006, University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.classfile.engine;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import edu.umd.cs.findbugs.annotations.CheckForNull;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.DescriptorFactory;
import edu.umd.cs.findbugs.classfile.FieldDescriptor;
import edu.umd.cs.findbugs.classfile.IClassConstants;
import edu.umd.cs.findbugs.classfile.ICodeBaseEntry;
import edu.umd.cs.findbugs.classfile.InvalidClassFileFormatException;
import edu.umd.cs.findbugs.classfile.MethodDescriptor;
import edu.umd.cs.findbugs.classfile.analysis.ClassInfo;
import edu.umd.cs.findbugs.classfile.analysis.ClassNameAndSuperclassInfo;
import edu.umd.cs.findbugs.internalAnnotations.SlashedClassName;
import edu.umd.cs.findbugs.io.IO;
import edu.umd.cs.findbugs.util.ClassName;
/**
* Parse a class to extract symbolic information. see <a
* href=http://java.sun.com
* /docs/books/vmspec/2nd-edition/html/ClassFile.doc.html">
* http://java.sun.com/docs/books/vmspec/2nd-edition/html/ClassFile.doc.html
* </a>
*
* @author David Hovemeyer
*/
public class ClassParser implements ClassParserInterface {
static class Constant {
int tag;
Object[] data;
Constant(int tag, Object[] data) {
this.tag = tag;
this.data = data;
}
}
private DataInputStream in;
private ClassDescriptor expectedClassDescriptor;
private ICodeBaseEntry codeBaseEntry;
private Constant[] constantPool;
private ClassDescriptor immediateEnclosingClass;
/**
* Constructor.
*
* @param in
* the DataInputStream to read class data from
* @param expectedClassDescriptor
* ClassDescriptor expected: null if unknown
* @param codeBaseEntry
* codebase entry class is loaded from
*/
public ClassParser(DataInputStream in, @CheckForNull ClassDescriptor expectedClassDescriptor, ICodeBaseEntry codeBaseEntry) {
this.in = in;
this.expectedClassDescriptor = expectedClassDescriptor;
this.codeBaseEntry = codeBaseEntry;
}
/*
* (non-Javadoc)
*
* @see
* edu.umd.cs.findbugs.classfile.engine.ClassParserInterface#parse(edu.umd
* .cs.findbugs.classfile.analysis.ClassNameAndSuperclassInfo.Builder)
*/
public void parse(ClassNameAndSuperclassInfo.Builder builder) throws InvalidClassFileFormatException {
try {
int magic = in.readInt();
if (magic != 0xcafebabe)
throw new InvalidClassFileFormatException("Classfile header isn't 0xCAFEBABE", expectedClassDescriptor,
codeBaseEntry);
int major_version = in.readUnsignedShort();
int minor_version = in.readUnsignedShort();
int constant_pool_count = in.readUnsignedShort();
constantPool = new Constant[constant_pool_count];
for (int i = 1; i < constantPool.length; i++) {
constantPool[i] = readConstant();
if (constantPool[i].tag == IClassConstants.CONSTANT_Double
|| constantPool[i].tag == IClassConstants.CONSTANT_Long) {
// Double and Long constants take up two constant pool
// entries
++i;
}
}
int access_flags = in.readUnsignedShort();
int this_class = in.readUnsignedShort();
ClassDescriptor thisClassDescriptor = getClassDescriptor(this_class);
int super_class = in.readUnsignedShort();
ClassDescriptor superClassDescriptor = getClassDescriptor(super_class);
int interfaces_count = in.readUnsignedShort();
if (interfaces_count < 0) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
ClassDescriptor[] interfaceDescriptorList;
if (interfaces_count == 0)
interfaceDescriptorList = ClassDescriptor.EMPTY_ARRAY;
else {
interfaceDescriptorList = new ClassDescriptor[interfaces_count];
for (int i = 0; i < interfaceDescriptorList.length; i++)
interfaceDescriptorList[i] = getClassDescriptor(in.readUnsignedShort());
}
// Extract all references to other classes,
// both CONSTANT_Class entries and also referenced method
// signatures.
Collection<ClassDescriptor> referencedClassDescriptorList = extractReferencedClasses();
builder.setClassDescriptor(thisClassDescriptor);
builder.setSuperclassDescriptor(superClassDescriptor);
builder.setInterfaceDescriptorList(interfaceDescriptorList);
builder.setCodeBaseEntry(codeBaseEntry);
builder.setAccessFlags(access_flags);
builder.setReferencedClassDescriptors(referencedClassDescriptorList);
builder.setClassfileVersion(major_version, minor_version);
} catch (IOException e) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry, e);
}
}
/*
* (non-Javadoc)
*
* @see
* edu.umd.cs.findbugs.classfile.engine.ClassParserInterface#parse(edu.umd
* .cs.findbugs.classfile.analysis.ClassInfo.Builder)
*/
public void parse(ClassInfo.Builder builder) throws InvalidClassFileFormatException {
throw new UnsupportedOperationException("Need to use a ClassParserUsingASM to build ClassInfo");
}
/**
* Extract references to other classes.
*
* @return array of ClassDescriptors of referenced classes
* @throws InvalidClassFileFormatException
*/
private Collection<ClassDescriptor> extractReferencedClasses() throws InvalidClassFileFormatException {
Set<ClassDescriptor> referencedClassSet = new HashSet<ClassDescriptor>();
for (Constant constant : constantPool) {
if (constant == null) {
continue;
}
if (constant.tag == IClassConstants.CONSTANT_Class) {
@SlashedClassName
String className = getUtf8String((Integer) constant.data[0]);
if (className.indexOf('[') >= 0) {
extractReferencedClassesFromSignature(referencedClassSet, className);
} else if (ClassName.isValidClassName(className)) {
referencedClassSet.add(DescriptorFactory.instance().getClassDescriptor(className));
}
} else if (constant.tag == IClassConstants.CONSTANT_Methodref || constant.tag == IClassConstants.CONSTANT_Fieldref
|| constant.tag == IClassConstants.CONSTANT_InterfaceMethodref) {
// Get the target class name
String className = getClassName((Integer) constant.data[0]);
extractReferencedClassesFromSignature(referencedClassSet, className);
// Parse signature to extract class names
String signature = getSignatureFromNameAndType((Integer) constant.data[1]);
extractReferencedClassesFromSignature(referencedClassSet, signature);
}
}
return referencedClassSet;
}
/**
* @param referencedClassSet
* @param signature
*/
public static void extractReferencedClassesFromSignature(Set<ClassDescriptor> referencedClassSet, String signature) {
while (signature.length() > 0) {
int start = signature.indexOf('L');
if (start < 0) {
break;
}
int end = signature.indexOf(';', start);
if (end < 0) {
break;
}
@SlashedClassName
String className = signature.substring(start + 1, end);
if (ClassName.isValidClassName(className)) {
referencedClassSet.add(DescriptorFactory.instance().getClassDescriptor(className));
}
signature = signature.substring(end + 1);
}
}
// 8: UTF-8 string
// I: int
// F: float
// L: long
// D: double
// i: 2-byte constant pool index
private static final String[] CONSTANT_FORMAT_MAP = { null, "8", // 1:
// CONSTANT_Utf8
null, "I", // 3: CONSTANT_Integer
"F", // 4: CONSTANT_Float
"L", // 5: CONSTANT_Long
"D", // 6: CONSTANT_Double
"i", // 7: CONSTANT_Class
"i", // 8: CONSTANT_String
"ii", // 9: CONSTANT_Fieldref
"ii", // 10: CONSTANT_Methodref
"ii", // 11: CONSTANT_InterfaceMethodref
"ii", // 12: CONSTANT_NameAndType
};
/**
* Read a constant from the constant pool.
*
* @return a Constant
* @throws InvalidClassFileFormatException
* @throws IOException
*/
private Constant readConstant() throws InvalidClassFileFormatException, IOException {
int tag = in.readUnsignedByte();
if (tag < 0 || tag >= CONSTANT_FORMAT_MAP.length || CONSTANT_FORMAT_MAP[tag] == null) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
String format = CONSTANT_FORMAT_MAP[tag];
Object[] data = new Object[format.length()];
for (int i = 0; i < format.length(); i++) {
char spec = format.charAt(i);
switch (spec) {
case '8':
data[i] = in.readUTF();
break;
case 'I':
data[i] = in.readInt();
break;
case 'F':
data[i] = new Float(in.readFloat());
break;
case 'L':
data[i] = in.readLong();
break;
case 'D':
data[i] = new Double(in.readDouble());
break;
case 'i':
data[i] = in.readUnsignedShort();
break;
default:
throw new IllegalStateException();
}
}
return new Constant(tag, data);
}
/**
* Get a class name from a CONSTANT_Class. Note that this may be an array
* (e.g., "[Ljava/lang/String;").
*
* @param index
* index of the constant
* @return the class name
* @throws InvalidClassFileFormatException
*/
private @SlashedClassName
String getClassName(int index) throws InvalidClassFileFormatException {
if (index == 0) {
return null;
}
checkConstantPoolIndex(index);
Constant constant = constantPool[index];
checkConstantTag(constant, IClassConstants.CONSTANT_Class);
int refIndex = ((Integer) constant.data[0]).intValue();
String stringValue = getUtf8String(refIndex);
return stringValue;
}
/**
* Get the ClassDescriptor of a class referenced in the constant pool.
*
* @param index
* index of the referenced class in the constant pool
* @return the ClassDescriptor of the referenced class
* @throws InvalidClassFileFormatException
*/
private ClassDescriptor getClassDescriptor(int index) throws InvalidClassFileFormatException {
@SlashedClassName
String className = getClassName(index);
return className != null ? DescriptorFactory.instance().getClassDescriptor(className) : null;
}
/**
* Get the UTF-8 string constant at given constant pool index.
*
* @param refIndex
* the constant pool index
* @return the String at that index
* @throws InvalidClassFileFormatException
*/
private String getUtf8String(int refIndex) throws InvalidClassFileFormatException {
checkConstantPoolIndex(refIndex);
Constant refConstant = constantPool[refIndex];
checkConstantTag(refConstant, IClassConstants.CONSTANT_Utf8);
return (String) refConstant.data[0];
}
/**
* Check that a constant pool index is valid.
*
* @param expectedClassDescriptor
* class descriptor
* @param constantPool
* the constant pool
* @param index
* the index to check
* @throws InvalidClassFileFormatException
* if the index is not valid
*/
private void checkConstantPoolIndex(int index) throws InvalidClassFileFormatException {
if (index < 0 || index >= constantPool.length || constantPool[index] == null) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
}
/**
* Check that a constant has the expected tag.
*
* @param constant
* the constant to check
* @param expectedTag
* the expected constant tag
* @throws InvalidClassFileFormatException
* if the constant's tag does not match the expected tag
*/
private void checkConstantTag(Constant constant, int expectedTag) throws InvalidClassFileFormatException {
if (constant.tag != expectedTag) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
}
interface FieldOrMethodDescriptorCreator<E> {
public E create(String className, String name, String signature, int accessFlags);
}
/**
* Read field_info, return FieldDescriptor.
*
* @param thisClassDescriptor
* the ClassDescriptor of this class (being parsed)
* @return the FieldDescriptor
* @throws IOException
* @throws InvalidClassFileFormatException
*/
private FieldDescriptor readField(ClassDescriptor thisClassDescriptor) throws IOException, InvalidClassFileFormatException {
return readFieldOrMethod(thisClassDescriptor, new FieldOrMethodDescriptorCreator<FieldDescriptor>() {
/*
* (non-Javadoc)
*
* @see edu.umd.cs.findbugs.classfile.engine.ClassParser.
* FieldOrMethodDescriptorCreator#create(java.lang.String,
* java.lang.String, java.lang.String, int)
*/
public FieldDescriptor create(String className, String name, String signature, int accessFlags) {
return DescriptorFactory.instance().getFieldDescriptor(className, name, signature,
(accessFlags & IClassConstants.ACC_STATIC) != 0);
}
});
}
/**
* Read method_info, read method descriptor.
*
* @param thisClassDescriptor
* @return
* @throws IOException
* @throws InvalidClassFileFormatException
*/
private MethodDescriptor readMethod(ClassDescriptor thisClassDescriptor) throws InvalidClassFileFormatException, IOException {
return readFieldOrMethod(thisClassDescriptor, new FieldOrMethodDescriptorCreator<MethodDescriptor>() {
/*
* (non-Javadoc)
*
* @see edu.umd.cs.findbugs.classfile.engine.ClassParser.
* FieldOrMethodDescriptorCreator#create(java.lang.String,
* java.lang.String, java.lang.String, int)
*/
public MethodDescriptor create(String className, String name, String signature, int accessFlags) {
return DescriptorFactory.instance().getMethodDescriptor(className, name, signature,
(accessFlags & IClassConstants.ACC_STATIC) != 0);
}
});
}
/**
* Read field_info or method_info. They have the same format.
*
* @param <E>
* descriptor type to return
* @param thisClassDescriptor
* class descriptor of class being parsed
* @param creator
* callback to create the FieldDescriptor or MethodDescriptor
* @return the parsed descriptor
* @throws IOException
* @throws InvalidClassFileFormatException
*/
private <E> E readFieldOrMethod(ClassDescriptor thisClassDescriptor, FieldOrMethodDescriptorCreator<E> creator)
throws IOException, InvalidClassFileFormatException {
int access_flags = in.readUnsignedShort();
int name_index = in.readUnsignedShort();
int descriptor_index = in.readUnsignedShort();
int attributes_count = in.readUnsignedShort();
String name = getUtf8String(name_index);
String signature = getUtf8String(descriptor_index);
if (attributes_count < 0) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
for (int i = 0; i < attributes_count; i++) {
readAttribute();
}
return creator.create(thisClassDescriptor.getClassName(), name, signature, access_flags);
}
/**
* Read an attribute.
*
* @throws IOException
* @throws InvalidClassFileFormatException
*/
private void readAttribute() throws IOException, InvalidClassFileFormatException {
int attribute_name_index = in.readUnsignedShort();
String attrName = getUtf8String(attribute_name_index);
int attribute_length = in.readInt();
if (attribute_length < 0) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
if (attrName.equals("InnerClasses")) {
readInnerClassesAttribute(attribute_length);
} else {
IO.skipFully(in, attribute_length);
}
}
/**
* Read an InnerClasses attribute.
*
* @param attribute_length
* length of attribute (excluding first 6 bytes)
* @throws InvalidClassFileFormatException
* @throws IOException
*/
private void readInnerClassesAttribute(int attribute_length) throws InvalidClassFileFormatException, IOException {
int number_of_classes = in.readUnsignedShort();
if (attribute_length != number_of_classes * 8) {
throw new InvalidClassFileFormatException(expectedClassDescriptor, codeBaseEntry);
}
for (int i = 0; i < number_of_classes; i++) {
int inner_class_info_index = in.readUnsignedShort();
int outer_class_info_index = in.readUnsignedShort();
int inner_name_index = in.readUnsignedShort();
int inner_class_access_flags = in.readUnsignedShort();
if (outer_class_info_index != 0) {
// Record which class this class is a member of.
this.immediateEnclosingClass = getClassDescriptor(outer_class_info_index);
}
}
}
/**
* Get the signature from a CONSTANT_NameAndType.
*
* @param index
* the index of the CONSTANT_NameAndType
* @return the signature
* @throws InvalidClassFileFormatException
*/
private String getSignatureFromNameAndType(int index) throws InvalidClassFileFormatException {
checkConstantPoolIndex(index);
Constant constant = constantPool[index];
checkConstantTag(constant, IClassConstants.CONSTANT_NameAndType);
return getUtf8String((Integer) constant.data[1]);
}
}