/*
* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
* 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
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*/
package com.sun.tools.classfile;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import com.sun.tools.classfile.Instruction.TypeKind;
import static com.sun.tools.classfile.ConstantPool.*;
/**
* A utility class to find where in a ClassFile references
* a {@link CONSTANT_Methodref_info method},
* a {@link CONSTANT_InterfaceMethodref_info interface method},
* or a {@link CONSTANT_Fieldref_info field}.
*/
public final class ReferenceFinder {
/**
* Filter for ReferenceFinder of what constant pool entries for reference lookup.
*/
public interface Filter {
/**
* Decides if the given CPRefInfo entry should be accepted or filtered.
*
* @param cpool ConstantPool of the ClassFile being parsed
* @param cpref constant pool entry representing a reference to
* a fields method, and interface method.
* @return {@code true} if accepted; otherwise {@code false}
*/
boolean accept(ConstantPool cpool, CPRefInfo cpref);
}
/**
* Visitor of individual method of a ClassFile that references the
* accepted field, method, or interface method references.
*/
public interface Visitor {
/**
* Invoked for a method containing one or more accepted CPRefInfo entries
*
* @param cf ClassFile
* @param method Method that does the references the accepted references
* @param refs Accepted constant pool method/field reference
*/
void visit(ClassFile cf, Method method, List<CPRefInfo> refConstantPool);
}
private final Filter filter;
private final Visitor visitor;
/**
* Constructor.
*/
public ReferenceFinder(Filter filter, Visitor visitor) {
this.filter = Objects.requireNonNull(filter);
this.visitor = Objects.requireNonNull(visitor);
}
/**
* Parses a given ClassFile and invoke the visitor if there is any reference
* to the constant pool entries referencing field, method, or
* interface method that are accepted. This method will return
* {@code true} if there is one or more accepted constant pool entries
* to lookup; otherwise, it will return {@code false}.
*
* @param cf ClassFile
* @return {@code true} if the given class file is processed to lookup
* references
* @throws ConstantPoolException if an error of the constant pool
*/
public boolean parse(ClassFile cf) throws ConstantPoolException {
List<Integer> cprefs = new ArrayList<>();
int index = 1;
for (ConstantPool.CPInfo cpInfo : cf.constant_pool.entries()) {
if (cpInfo.accept(cpVisitor, cf.constant_pool)) {
cprefs.add(index);
}
index += cpInfo.size();
}
if (cprefs.isEmpty()) {
return false;
}
for (Method m : cf.methods) {
Set<Integer> ids = new HashSet<>();
Code_attribute c_attr = (Code_attribute) m.attributes.get(Attribute.Code);
if (c_attr != null) {
for (Instruction instr : c_attr.getInstructions()) {
int idx = instr.accept(codeVisitor, cprefs);
if (idx > 0) {
ids.add(idx);
}
}
}
if (ids.size() > 0) {
List<CPRefInfo> refInfos = new ArrayList<>(ids.size());
for (int id : ids) {
refInfos.add(CPRefInfo.class.cast(cf.constant_pool.get(id)));
}
visitor.visit(cf, m, refInfos);
}
}
return true;
}
private ConstantPool.Visitor<Boolean,ConstantPool> cpVisitor =
new ConstantPool.Visitor<Boolean,ConstantPool>()
{
public Boolean visitClass(CONSTANT_Class_info info, ConstantPool cpool) {
return false;
}
public Boolean visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, ConstantPool cpool) {
return filter.accept(cpool, info);
}
public Boolean visitMethodref(CONSTANT_Methodref_info info, ConstantPool cpool) {
return filter.accept(cpool, info);
}
public Boolean visitFieldref(CONSTANT_Fieldref_info info, ConstantPool cpool) {
return filter.accept(cpool, info);
}
public Boolean visitDouble(CONSTANT_Double_info info, ConstantPool cpool) {
return false;
}
public Boolean visitFloat(CONSTANT_Float_info info, ConstantPool cpool) {
return false;
}
public Boolean visitInteger(CONSTANT_Integer_info info, ConstantPool cpool) {
return false;
}
public Boolean visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, ConstantPool cpool) {
return false;
}
public Boolean visitLong(CONSTANT_Long_info info, ConstantPool cpool) {
return false;
}
public Boolean visitNameAndType(CONSTANT_NameAndType_info info, ConstantPool cpool) {
return false;
}
public Boolean visitMethodHandle(CONSTANT_MethodHandle_info info, ConstantPool cpool) {
return false;
}
public Boolean visitMethodType(CONSTANT_MethodType_info info, ConstantPool cpool) {
return false;
}
public Boolean visitString(CONSTANT_String_info info, ConstantPool cpool) {
return false;
}
public Boolean visitUtf8(CONSTANT_Utf8_info info, ConstantPool cpool) {
return false;
}
};
private Instruction.KindVisitor<Integer, List<Integer>> codeVisitor =
new Instruction.KindVisitor<Integer, List<Integer>>()
{
public Integer visitNoOperands(Instruction instr, List<Integer> p) {
return 0;
}
public Integer visitArrayType(Instruction instr, TypeKind kind, List<Integer> p) {
return 0;
}
public Integer visitBranch(Instruction instr, int offset, List<Integer> p) {
return 0;
}
public Integer visitConstantPoolRef(Instruction instr, int index, List<Integer> p) {
return p.contains(index) ? index : 0;
}
public Integer visitConstantPoolRefAndValue(Instruction instr, int index, int value, List<Integer> p) {
return p.contains(index) ? index : 0;
}
public Integer visitLocal(Instruction instr, int index, List<Integer> p) {
return 0;
}
public Integer visitLocalAndValue(Instruction instr, int index, int value, List<Integer> p) {
return 0;
}
public Integer visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, List<Integer> p) {
return 0;
}
public Integer visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, List<Integer> p) {
return 0;
}
public Integer visitValue(Instruction instr, int value, List<Integer> p) {
return 0;
}
public Integer visitUnknown(Instruction instr, List<Integer> p) {
return 0;
}
};
}