42 import sun.reflect.ReflectionFactory;
43
44 /** This class provides the methods for fundamental JVM operations
45 * needed in the ORB that are not part of the public Java API. This includes:
46 * <ul>
47 * <li>throwException, which can throw undeclared checked exceptions.
48 * This is needed to handle throwing arbitrary exceptions across a standardized
49 * OMG interface that (incorrectly) does not specify appropriate exceptions.</li>
50 * <li>putXXX/getXXX methods that allow unchecked access to fields of objects.
51 * This is used for setting uninitialzed non-static final fields (which is
52 * impossible with reflection) and for speed.</li>
53 * <li>objectFieldOffset to obtain the field offsets for use in the putXXX/getXXX methods</li>
54 * <li>newConstructorForSerialization to get the special constructor required for a
55 * Serializable class</li>
56 * <li>latestUserDefinedLoader to get the latest user defined class loader from
57 * the call stack as required by the RMI-IIOP specification (really from the
58 * JDK 1.1 days)</li>
59 * </ul>
60 * The code that calls Bridge.get() must have the following Permissions:
61 * <ul>
62 * <li>RuntimePermission "reflectionFactoryAccess"</li>
63 * <li>BridgePermission "getBridge"</li>
64 * <li>ReflectPermission "suppressAccessChecks"</li>
65 * <li>StackFramePermission "retainClassReference"</li>
66 * </ul>
67 * <p>
68 * All of these permissions are required to obtain and correctly initialize
69 * the instance of Bridge. No security checks are performed on calls
70 * made to Bridge instance methods, so access to the Bridge instance
71 * must be protected.
72 * <p>
73 * This class is a singleton (per ClassLoader of course). Access to the
74 * instance is obtained through the Bridge.get() method.
75 */
76 public final class Bridge
77 {
78 private static final Permission getBridgePermission =
79 new BridgePermission("getBridge");
80 private static Bridge bridge = null ;
81
82 /** Access to Unsafe to read/write fields. */
83 private static final Unsafe unsafe = AccessController.doPrivileged(
84 (PrivilegedAction<Unsafe>)() -> {
85 try {
88 return (Unsafe)field.get(null);
89
90 } catch (NoSuchFieldException |IllegalAccessException ex) {
91 throw new InternalError("Unsafe.theUnsafe field not available", ex);
92 }
93 }
94 ) ;
95
96 private final ReflectionFactory reflectionFactory ;
97 private final StackWalker stackWalker;
98
99 private Bridge() {
100 reflectionFactory = ReflectionFactory.getReflectionFactory();
101 stackWalker = StackWalker.getInstance(
102 StackWalker.Option.RETAIN_CLASS_REFERENCE);
103 }
104
105 /** Fetch the Bridge singleton. This requires the following
106 * permissions:
107 * <ul>
108 * <li>RuntimePermission "reflectionFactoryAccess"</li>
109 * <li>BridgePermission "getBridge"</li>
110 * <li>ReflectPermission "suppressAccessChecks"</li>
111 * <li>StackFramePermission "retainClassReference"</li>
112 * </ul>
113 * @return The singleton instance of the Bridge class
114 * @throws SecurityException if the caller does not have the
115 * required permissions and the caller has a non-null security manager.
116 */
117 public static final synchronized Bridge get()
118 {
119 SecurityManager sman = System.getSecurityManager() ;
120 if (sman != null)
121 sman.checkPermission( getBridgePermission ) ;
122
123 if (bridge == null) {
124 bridge = new Bridge() ;
125 }
126
127 return bridge ;
128 }
129
130 /** Returns true if the loader that loaded the frame's declaring class
131 * is a user loader (if it is not the platform class loader or one of
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42 import sun.reflect.ReflectionFactory;
43
44 /** This class provides the methods for fundamental JVM operations
45 * needed in the ORB that are not part of the public Java API. This includes:
46 * <ul>
47 * <li>throwException, which can throw undeclared checked exceptions.
48 * This is needed to handle throwing arbitrary exceptions across a standardized
49 * OMG interface that (incorrectly) does not specify appropriate exceptions.</li>
50 * <li>putXXX/getXXX methods that allow unchecked access to fields of objects.
51 * This is used for setting uninitialzed non-static final fields (which is
52 * impossible with reflection) and for speed.</li>
53 * <li>objectFieldOffset to obtain the field offsets for use in the putXXX/getXXX methods</li>
54 * <li>newConstructorForSerialization to get the special constructor required for a
55 * Serializable class</li>
56 * <li>latestUserDefinedLoader to get the latest user defined class loader from
57 * the call stack as required by the RMI-IIOP specification (really from the
58 * JDK 1.1 days)</li>
59 * </ul>
60 * The code that calls Bridge.get() must have the following Permissions:
61 * <ul>
62 * <li>BridgePermission "getBridge"</li>
63 * <li>ReflectPermission "suppressAccessChecks"</li>
64 * <li>RuntimePermission "getStackWalkerWithClassReference"</li>
65 * <li>RuntimePermission "reflectionFactoryAccess"</li>
66 * </ul>
67 * <p>
68 * All of these permissions are required to obtain and correctly initialize
69 * the instance of Bridge. No security checks are performed on calls
70 * made to Bridge instance methods, so access to the Bridge instance
71 * must be protected.
72 * <p>
73 * This class is a singleton (per ClassLoader of course). Access to the
74 * instance is obtained through the Bridge.get() method.
75 */
76 public final class Bridge
77 {
78 private static final Permission getBridgePermission =
79 new BridgePermission("getBridge");
80 private static Bridge bridge = null ;
81
82 /** Access to Unsafe to read/write fields. */
83 private static final Unsafe unsafe = AccessController.doPrivileged(
84 (PrivilegedAction<Unsafe>)() -> {
85 try {
88 return (Unsafe)field.get(null);
89
90 } catch (NoSuchFieldException |IllegalAccessException ex) {
91 throw new InternalError("Unsafe.theUnsafe field not available", ex);
92 }
93 }
94 ) ;
95
96 private final ReflectionFactory reflectionFactory ;
97 private final StackWalker stackWalker;
98
99 private Bridge() {
100 reflectionFactory = ReflectionFactory.getReflectionFactory();
101 stackWalker = StackWalker.getInstance(
102 StackWalker.Option.RETAIN_CLASS_REFERENCE);
103 }
104
105 /** Fetch the Bridge singleton. This requires the following
106 * permissions:
107 * <ul>
108 * <li>BridgePermission "getBridge"</li>
109 * <li>ReflectPermission "suppressAccessChecks"</li>
110 * <li>RuntimePermission "getStackWalkerWithClassReference"</li>
111 * <li>RuntimePermission "reflectionFactoryAccess"</li>
112 * </ul>
113 * @return The singleton instance of the Bridge class
114 * @throws SecurityException if the caller does not have the
115 * required permissions and the caller has a non-null security manager.
116 */
117 public static final synchronized Bridge get()
118 {
119 SecurityManager sman = System.getSecurityManager() ;
120 if (sman != null)
121 sman.checkPermission( getBridgePermission ) ;
122
123 if (bridge == null) {
124 bridge = new Bridge() ;
125 }
126
127 return bridge ;
128 }
129
130 /** Returns true if the loader that loaded the frame's declaring class
131 * is a user loader (if it is not the platform class loader or one of
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