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| 1 | +/* | |
| 2 | + * Copyright (c) 2001, 2006, Oracle and/or its affiliates. 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * 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 | +} | |