J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2001-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.reflect; |
| 27 | |
| 28 | import java.lang.reflect.*; |
| 29 | import java.util.Collections; |
| 30 | import java.util.HashMap; |
| 31 | import java.util.Map; |
| 32 | |
| 33 | /** Common utility routines used by both java.lang and |
| 34 | java.lang.reflect */ |
| 35 | |
| 36 | public class Reflection { |
| 37 | |
| 38 | /** Used to filter out fields and methods from certain classes from public |
| 39 | view, where they are sensitive or they may contain VM-internal objects. |
| 40 | These Maps are updated very rarely. Rather than synchronize on |
| 41 | each access, we use copy-on-write */ |
| 42 | private static volatile Map<Class,String[]> fieldFilterMap; |
| 43 | private static volatile Map<Class,String[]> methodFilterMap; |
| 44 | |
| 45 | static { |
| 46 | Map<Class,String[]> map = new HashMap<Class,String[]>(); |
| 47 | map.put(Reflection.class, |
| 48 | new String[] {"fieldFilterMap", "methodFilterMap"}); |
| 49 | map.put(System.class, new String[] {"security"}); |
| 50 | fieldFilterMap = map; |
| 51 | |
| 52 | methodFilterMap = new HashMap<Class,String[]>(); |
| 53 | } |
| 54 | |
| 55 | /** Returns the class of the method <code>realFramesToSkip</code> |
| 56 | frames up the stack (zero-based), ignoring frames associated |
| 57 | with java.lang.reflect.Method.invoke() and its implementation. |
| 58 | The first frame is that associated with this method, so |
| 59 | <code>getCallerClass(0)</code> returns the Class object for |
| 60 | sun.reflect.Reflection. Frames associated with |
| 61 | java.lang.reflect.Method.invoke() and its implementation are |
| 62 | completely ignored and do not count toward the number of "real" |
| 63 | frames skipped. */ |
| 64 | public static native Class getCallerClass(int realFramesToSkip); |
| 65 | |
| 66 | /** Retrieves the access flags written to the class file. For |
| 67 | inner classes these flags may differ from those returned by |
| 68 | Class.getModifiers(), which searches the InnerClasses |
| 69 | attribute to find the source-level access flags. This is used |
| 70 | instead of Class.getModifiers() for run-time access checks due |
| 71 | to compatibility reasons; see 4471811. Only the values of the |
| 72 | low 13 bits (i.e., a mask of 0x1FFF) are guaranteed to be |
| 73 | valid. */ |
| 74 | private static native int getClassAccessFlags(Class c); |
| 75 | |
| 76 | /** A quick "fast-path" check to try to avoid getCallerClass() |
| 77 | calls. */ |
| 78 | public static boolean quickCheckMemberAccess(Class memberClass, |
| 79 | int modifiers) |
| 80 | { |
| 81 | return Modifier.isPublic(getClassAccessFlags(memberClass) & modifiers); |
| 82 | } |
| 83 | |
| 84 | public static void ensureMemberAccess(Class currentClass, |
| 85 | Class memberClass, |
| 86 | Object target, |
| 87 | int modifiers) |
| 88 | throws IllegalAccessException |
| 89 | { |
| 90 | if (currentClass == null || memberClass == null) { |
| 91 | throw new InternalError(); |
| 92 | } |
| 93 | |
| 94 | if (!verifyMemberAccess(currentClass, memberClass, target, modifiers)) { |
| 95 | throw new IllegalAccessException("Class " + currentClass.getName() + |
| 96 | " can not access a member of class " + |
| 97 | memberClass.getName() + |
| 98 | " with modifiers \"" + |
| 99 | Modifier.toString(modifiers) + |
| 100 | "\""); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | public static boolean verifyMemberAccess(Class currentClass, |
| 105 | // Declaring class of field |
| 106 | // or method |
| 107 | Class memberClass, |
| 108 | // May be NULL in case of statics |
| 109 | Object target, |
| 110 | int modifiers) |
| 111 | { |
| 112 | // Verify that currentClass can access a field, method, or |
| 113 | // constructor of memberClass, where that member's access bits are |
| 114 | // "modifiers". |
| 115 | |
| 116 | boolean gotIsSameClassPackage = false; |
| 117 | boolean isSameClassPackage = false; |
| 118 | |
| 119 | if (currentClass == memberClass) { |
| 120 | // Always succeeds |
| 121 | return true; |
| 122 | } |
| 123 | |
| 124 | if (!Modifier.isPublic(getClassAccessFlags(memberClass))) { |
| 125 | isSameClassPackage = isSameClassPackage(currentClass, memberClass); |
| 126 | gotIsSameClassPackage = true; |
| 127 | if (!isSameClassPackage) { |
| 128 | return false; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // At this point we know that currentClass can access memberClass. |
| 133 | |
| 134 | if (Modifier.isPublic(modifiers)) { |
| 135 | return true; |
| 136 | } |
| 137 | |
| 138 | boolean successSoFar = false; |
| 139 | |
| 140 | if (Modifier.isProtected(modifiers)) { |
| 141 | // See if currentClass is a subclass of memberClass |
| 142 | if (isSubclassOf(currentClass, memberClass)) { |
| 143 | successSoFar = true; |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | if (!successSoFar && !Modifier.isPrivate(modifiers)) { |
| 148 | if (!gotIsSameClassPackage) { |
| 149 | isSameClassPackage = isSameClassPackage(currentClass, |
| 150 | memberClass); |
| 151 | gotIsSameClassPackage = true; |
| 152 | } |
| 153 | |
| 154 | if (isSameClassPackage) { |
| 155 | successSoFar = true; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | if (!successSoFar) { |
| 160 | return false; |
| 161 | } |
| 162 | |
| 163 | if (Modifier.isProtected(modifiers)) { |
| 164 | // Additional test for protected members: JLS 6.6.2 |
| 165 | Class targetClass = (target == null ? memberClass : target.getClass()); |
| 166 | if (targetClass != currentClass) { |
| 167 | if (!gotIsSameClassPackage) { |
| 168 | isSameClassPackage = isSameClassPackage(currentClass, memberClass); |
| 169 | gotIsSameClassPackage = true; |
| 170 | } |
| 171 | if (!isSameClassPackage) { |
| 172 | if (!isSubclassOf(targetClass, currentClass)) { |
| 173 | return false; |
| 174 | } |
| 175 | } |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | return true; |
| 180 | } |
| 181 | |
| 182 | private static boolean isSameClassPackage(Class c1, Class c2) { |
| 183 | return isSameClassPackage(c1.getClassLoader(), c1.getName(), |
| 184 | c2.getClassLoader(), c2.getName()); |
| 185 | } |
| 186 | |
| 187 | /** Returns true if two classes are in the same package; classloader |
| 188 | and classname information is enough to determine a class's package */ |
| 189 | private static boolean isSameClassPackage(ClassLoader loader1, String name1, |
| 190 | ClassLoader loader2, String name2) |
| 191 | { |
| 192 | if (loader1 != loader2) { |
| 193 | return false; |
| 194 | } else { |
| 195 | int lastDot1 = name1.lastIndexOf('.'); |
| 196 | int lastDot2 = name2.lastIndexOf('.'); |
| 197 | if ((lastDot1 == -1) || (lastDot2 == -1)) { |
| 198 | // One of the two doesn't have a package. Only return true |
| 199 | // if the other one also doesn't have a package. |
| 200 | return (lastDot1 == lastDot2); |
| 201 | } else { |
| 202 | int idx1 = 0; |
| 203 | int idx2 = 0; |
| 204 | |
| 205 | // Skip over '['s |
| 206 | if (name1.charAt(idx1) == '[') { |
| 207 | do { |
| 208 | idx1++; |
| 209 | } while (name1.charAt(idx1) == '['); |
| 210 | if (name1.charAt(idx1) != 'L') { |
| 211 | // Something is terribly wrong. Shouldn't be here. |
| 212 | throw new InternalError("Illegal class name " + name1); |
| 213 | } |
| 214 | } |
| 215 | if (name2.charAt(idx2) == '[') { |
| 216 | do { |
| 217 | idx2++; |
| 218 | } while (name2.charAt(idx2) == '['); |
| 219 | if (name2.charAt(idx2) != 'L') { |
| 220 | // Something is terribly wrong. Shouldn't be here. |
| 221 | throw new InternalError("Illegal class name " + name2); |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | // Check that package part is identical |
| 226 | int length1 = lastDot1 - idx1; |
| 227 | int length2 = lastDot2 - idx2; |
| 228 | |
| 229 | if (length1 != length2) { |
| 230 | return false; |
| 231 | } |
| 232 | return name1.regionMatches(false, idx1, name2, idx2, length1); |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | static boolean isSubclassOf(Class queryClass, |
| 238 | Class ofClass) |
| 239 | { |
| 240 | while (queryClass != null) { |
| 241 | if (queryClass == ofClass) { |
| 242 | return true; |
| 243 | } |
| 244 | queryClass = queryClass.getSuperclass(); |
| 245 | } |
| 246 | return false; |
| 247 | } |
| 248 | |
| 249 | // fieldNames must contain only interned Strings |
| 250 | public static synchronized void registerFieldsToFilter(Class containingClass, |
| 251 | String ... fieldNames) { |
| 252 | fieldFilterMap = |
| 253 | registerFilter(fieldFilterMap, containingClass, fieldNames); |
| 254 | } |
| 255 | |
| 256 | // methodNames must contain only interned Strings |
| 257 | public static synchronized void registerMethodsToFilter(Class containingClass, |
| 258 | String ... methodNames) { |
| 259 | methodFilterMap = |
| 260 | registerFilter(methodFilterMap, containingClass, methodNames); |
| 261 | } |
| 262 | |
| 263 | private static Map<Class,String[]> registerFilter(Map<Class,String[]> map, |
| 264 | Class containingClass, String ... names) { |
| 265 | if (map.get(containingClass) != null) { |
| 266 | throw new IllegalArgumentException |
| 267 | ("Filter already registered: " + containingClass); |
| 268 | } |
| 269 | map = new HashMap<Class,String[]>(map); |
| 270 | map.put(containingClass, names); |
| 271 | return map; |
| 272 | } |
| 273 | |
| 274 | public static Field[] filterFields(Class containingClass, |
| 275 | Field[] fields) { |
| 276 | if (fieldFilterMap == null) { |
| 277 | // Bootstrapping |
| 278 | return fields; |
| 279 | } |
| 280 | return (Field[])filter(fields, fieldFilterMap.get(containingClass)); |
| 281 | } |
| 282 | |
| 283 | public static Method[] filterMethods(Class containingClass, Method[] methods) { |
| 284 | if (methodFilterMap == null) { |
| 285 | // Bootstrapping |
| 286 | return methods; |
| 287 | } |
| 288 | return (Method[])filter(methods, methodFilterMap.get(containingClass)); |
| 289 | } |
| 290 | |
| 291 | private static Member[] filter(Member[] members, String[] filteredNames) { |
| 292 | if ((filteredNames == null) || (members.length == 0)) { |
| 293 | return members; |
| 294 | } |
| 295 | int numNewMembers = 0; |
| 296 | for (Member member : members) { |
| 297 | boolean shouldSkip = false; |
| 298 | for (String filteredName : filteredNames) { |
| 299 | if (member.getName() == filteredName) { |
| 300 | shouldSkip = true; |
| 301 | break; |
| 302 | } |
| 303 | } |
| 304 | if (!shouldSkip) { |
| 305 | ++numNewMembers; |
| 306 | } |
| 307 | } |
| 308 | Member[] newMembers = |
| 309 | (Member[])Array.newInstance(members[0].getClass(), numNewMembers); |
| 310 | int destIdx = 0; |
| 311 | for (Member member : members) { |
| 312 | boolean shouldSkip = false; |
| 313 | for (String filteredName : filteredNames) { |
| 314 | if (member.getName() == filteredName) { |
| 315 | shouldSkip = true; |
| 316 | break; |
| 317 | } |
| 318 | } |
| 319 | if (!shouldSkip) { |
| 320 | newMembers[destIdx++] = member; |
| 321 | } |
| 322 | } |
| 323 | return newMembers; |
| 324 | } |
| 325 | } |