ObjectStreamClass.c revision fd17eabf30cec65a5cfb4df1a298fcf515ef7c93 
1/*
2 * Copyright (c) 2001, 2003, 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#include "jni.h"
27#include "jvm.h"
28
29#include "JNIHelp.h"
30
31#define NATIVE_METHOD(className, functionName, signature) \
32{ #functionName, signature, (void*)(className ## _ ## functionName) }
33
34static jclass noSuchMethodErrCl;
35
36static void ObjectStreamClass_initNative(JNIEnv *env)
37{
38    jclass cl = (*env)->FindClass(env, "java/lang/NoSuchMethodError");
39    if (cl == NULL) {           /* exception thrown */
40        return;
41    }
42    noSuchMethodErrCl = (*env)->NewGlobalRef(env, cl);
43}
44
45/*
46 * Class:     java_io_ObjectStreamClass
47 * Method:    hasStaticInitializer
48 * Signature: (Ljava/lang/Class;Z)Z
49 *
50 * Returns true if the given class defines a <clinit>()V method; returns false
51 * otherwise.
52 */
53JNIEXPORT jboolean JNICALL
54ObjectStreamClass_hasStaticInitializer(JNIEnv *env, jclass this,
55                                       jclass clazz,
56                                       jboolean checkSuperclass)
57{
58    jclass superCl = NULL;
59    jmethodID superClinitId = NULL;
60    jmethodID clinitId =
61        (*env)->GetStaticMethodID(env, clazz, "<clinit>", "()V");
62    if (clinitId == NULL) {     /* error thrown */
63        jthrowable th = (*env)->ExceptionOccurred(env);
64        (*env)->ExceptionClear(env);    /* normal return */
65        if (!(*env)->IsInstanceOf(env, th, noSuchMethodErrCl)) {
66            (*env)->Throw(env, th);
67        }
68        return JNI_FALSE;
69    }
70
71    // Android-changed, if checkSuperclass == true, remove check for
72    // superclass clinitId != child clinitId.
73    // We're returning true to enable deserializing classes without explicit serialVersionID
74    // that would fail in this check (b/29064453).
75    if (checkSuperclass == JNI_FALSE) {
76        return JNI_TRUE;
77    }
78
79    /*
80     * Check superclass for static initializer as well--if the same method ID
81     * is returned, then the static initializer is from a superclass.
82     * Empirically, this step appears to be unnecessary in 1.4; however, the
83     * JNI spec makes no guarantee that GetStaticMethodID will not return the
84     * ID for a superclass initializer.
85     */
86    if ((superCl = (*env)->GetSuperclass(env, clazz)) == NULL) {
87        return JNI_TRUE;
88    }
89    superClinitId =
90        (*env)->GetStaticMethodID(env, superCl, "<clinit>", "()V");
91    if (superClinitId == NULL) {        /* error thrown */
92        jthrowable th = (*env)->ExceptionOccurred(env);
93        (*env)->ExceptionClear(env);    /* normal return */
94        if (!(*env)->IsInstanceOf(env, th, noSuchMethodErrCl)) {
95            (*env)->Throw(env, th);
96        }
97        return JNI_TRUE;
98    }
99
100    return (clinitId != superClinitId);
101}
102
103static JNINativeMethod gMethods[] = {
104  NATIVE_METHOD(ObjectStreamClass, hasStaticInitializer, "(Ljava/lang/Class;Z)Z"),
105};
106
107void register_java_io_ObjectStreamClass(JNIEnv* env) {
108  jniRegisterNativeMethods(env, "java/io/ObjectStreamClass", gMethods, NELEM(gMethods));
109  ObjectStreamClass_initNative(env);
110}
111