/*
* Copyright (c) 2001, 2006, 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 sun.reflect;
import java.lang.reflect.*;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/** Common utility routines used by both java.lang and
java.lang.reflect */
public class Reflection {
/** Used to filter out fields and methods from certain classes from public
view, where they are sensitive or they may contain VM-internal objects.
These Maps are updated very rarely. Rather than synchronize on
each access, we use copy-on-write */
private static volatile Map<Class,String[]> fieldFilterMap;
private static volatile Map<Class,String[]> methodFilterMap;
static {
Map<Class,String[]> map = new HashMap<Class,String[]>();
map.put(Reflection.class,
new String[] {"fieldFilterMap", "methodFilterMap"});
map.put(System.class, new String[] {"security"});
fieldFilterMap = map;
methodFilterMap = new HashMap<Class,String[]>();
}
/** Returns the class of the method <code>realFramesToSkip</code>
frames up the stack (zero-based), ignoring frames associated
with java.lang.reflect.Method.invoke() and its implementation.
The first frame is that associated with this method, so
<code>getCallerClass(0)</code> returns the Class object for
sun.reflect.Reflection. Frames associated with
java.lang.reflect.Method.invoke() and its implementation are
completely ignored and do not count toward the number of "real"
frames skipped. */
public static native Class getCallerClass(int realFramesToSkip);
/** Retrieves the access flags written to the class file. For
inner classes these flags may differ from those returned by
Class.getModifiers(), which searches the InnerClasses
attribute to find the source-level access flags. This is used
instead of Class.getModifiers() for run-time access checks due
to compatibility reasons; see 4471811. Only the values of the
low 13 bits (i.e., a mask of 0x1FFF) are guaranteed to be
valid. */
private static native int getClassAccessFlags(Class c);
/** A quick "fast-path" check to try to avoid getCallerClass()
calls. */
public static boolean quickCheckMemberAccess(Class memberClass,
int modifiers)
{
return Modifier.isPublic(getClassAccessFlags(memberClass) & modifiers);
}
public static void ensureMemberAccess(Class currentClass,
Class memberClass,
Object target,
int modifiers)
throws IllegalAccessException
{
if (currentClass == null || memberClass == null) {
throw new InternalError();
}
if (!verifyMemberAccess(currentClass, memberClass, target, modifiers)) {
throw new IllegalAccessException("Class " + currentClass.getName() +
" can not access a member of class " +
memberClass.getName() +
" with modifiers \"" +
Modifier.toString(modifiers) +
"\"");
}
}
public static boolean verifyMemberAccess(Class currentClass,
// Declaring class of field
// or method
Class memberClass,
// May be NULL in case of statics
Object target,
int modifiers)
{
// Verify that currentClass can access a field, method, or
// constructor of memberClass, where that member's access bits are
// "modifiers".
boolean gotIsSameClassPackage = false;
boolean isSameClassPackage = false;
if (currentClass == memberClass) {
// Always succeeds
return true;
}
if (!Modifier.isPublic(getClassAccessFlags(memberClass))) {
isSameClassPackage = isSameClassPackage(currentClass, memberClass);
gotIsSameClassPackage = true;
if (!isSameClassPackage) {
return false;
}
}
// At this point we know that currentClass can access memberClass.
if (Modifier.isPublic(modifiers)) {
return true;
}
boolean successSoFar = false;
if (Modifier.isProtected(modifiers)) {
// See if currentClass is a subclass of memberClass
if (isSubclassOf(currentClass, memberClass)) {
successSoFar = true;
}
}
if (!successSoFar && !Modifier.isPrivate(modifiers)) {
if (!gotIsSameClassPackage) {
isSameClassPackage = isSameClassPackage(currentClass,
memberClass);
gotIsSameClassPackage = true;
}
if (isSameClassPackage) {
successSoFar = true;
}
}
if (!successSoFar) {
return false;
}
if (Modifier.isProtected(modifiers)) {
// Additional test for protected members: JLS 6.6.2
Class targetClass = (target == null ? memberClass : target.getClass());
if (targetClass != currentClass) {
if (!gotIsSameClassPackage) {
isSameClassPackage = isSameClassPackage(currentClass, memberClass);
gotIsSameClassPackage = true;
}
if (!isSameClassPackage) {
if (!isSubclassOf(targetClass, currentClass)) {
return false;
}
}
}
}
return true;
}
private static boolean isSameClassPackage(Class c1, Class c2) {
return isSameClassPackage(c1.getClassLoader(), c1.getName(),
c2.getClassLoader(), c2.getName());
}
/** Returns true if two classes are in the same package; classloader
and classname information is enough to determine a class's package */
private static boolean isSameClassPackage(ClassLoader loader1, String name1,
ClassLoader loader2, String name2)
{
if (loader1 != loader2) {
return false;
} else {
int lastDot1 = name1.lastIndexOf('.');
int lastDot2 = name2.lastIndexOf('.');
if ((lastDot1 == -1) || (lastDot2 == -1)) {
// One of the two doesn't have a package. Only return true
// if the other one also doesn't have a package.
return (lastDot1 == lastDot2);
} else {
int idx1 = 0;
int idx2 = 0;
// Skip over '['s
if (name1.charAt(idx1) == '[') {
do {
idx1++;
} while (name1.charAt(idx1) == '[');
if (name1.charAt(idx1) != 'L') {
// Something is terribly wrong. Shouldn't be here.
throw new InternalError("Illegal class name " + name1);
}
}
if (name2.charAt(idx2) == '[') {
do {
idx2++;
} while (name2.charAt(idx2) == '[');
if (name2.charAt(idx2) != 'L') {
// Something is terribly wrong. Shouldn't be here.
throw new InternalError("Illegal class name " + name2);
}
}
// Check that package part is identical
int length1 = lastDot1 - idx1;
int length2 = lastDot2 - idx2;
if (length1 != length2) {
return false;
}
return name1.regionMatches(false, idx1, name2, idx2, length1);
}
}
}
static boolean isSubclassOf(Class queryClass,
Class ofClass)
{
while (queryClass != null) {
if (queryClass == ofClass) {
return true;
}
queryClass = queryClass.getSuperclass();
}
return false;
}
// fieldNames must contain only interned Strings
public static synchronized void registerFieldsToFilter(Class containingClass,
String ... fieldNames) {
fieldFilterMap =
registerFilter(fieldFilterMap, containingClass, fieldNames);
}
// methodNames must contain only interned Strings
public static synchronized void registerMethodsToFilter(Class containingClass,
String ... methodNames) {
methodFilterMap =
registerFilter(methodFilterMap, containingClass, methodNames);
}
private static Map<Class,String[]> registerFilter(Map<Class,String[]> map,
Class containingClass, String ... names) {
if (map.get(containingClass) != null) {
throw new IllegalArgumentException
("Filter already registered: " + containingClass);
}
map = new HashMap<Class,String[]>(map);
map.put(containingClass, names);
return map;
}
public static Field[] filterFields(Class containingClass,
Field[] fields) {
if (fieldFilterMap == null) {
// Bootstrapping
return fields;
}
return (Field[])filter(fields, fieldFilterMap.get(containingClass));
}
public static Method[] filterMethods(Class containingClass, Method[] methods) {
if (methodFilterMap == null) {
// Bootstrapping
return methods;
}
return (Method[])filter(methods, methodFilterMap.get(containingClass));
}
private static Member[] filter(Member[] members, String[] filteredNames) {
if ((filteredNames == null) || (members.length == 0)) {
return members;
}
int numNewMembers = 0;
for (Member member : members) {
boolean shouldSkip = false;
for (String filteredName : filteredNames) {
if (member.getName() == filteredName) {
shouldSkip = true;
break;
}
}
if (!shouldSkip) {
++numNewMembers;
}
}
Member[] newMembers =
(Member[])Array.newInstance(members[0].getClass(), numNewMembers);
int destIdx = 0;
for (Member member : members) {
boolean shouldSkip = false;
for (String filteredName : filteredNames) {
if (member.getName() == filteredName) {
shouldSkip = true;
break;
}
}
if (!shouldSkip) {
newMembers[destIdx++] = member;
}
}
return newMembers;
}
}