1 /*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * JNI helper functions.
19 *
20 * This file may be included by C or C++ code, which is trouble because jni.h
21 * uses different typedefs for JNIEnv in each language.
22 *
23 * TODO: remove C support.
24 */
25 #ifndef NATIVEHELPER_JNIHELP_H_
26 #define NATIVEHELPER_JNIHELP_H_
27
28 #include "jni.h"
29 #include <errno.h>
30 #include <unistd.h>
31
32 #ifndef NELEM
33 # define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0])))
34 #endif
35
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39
40 /*
41 * Register one or more native methods with a particular class.
42 * "className" looks like "java/lang/String". Aborts on failure.
43 * TODO: fix all callers and change the return type to void.
44 */
45 int jniRegisterNativeMethods(C_JNIEnv* env, const char* className, const JNINativeMethod* gMethods, int numMethods);
46
47 /*
48 * Throw an exception with the specified class and an optional message.
49 *
50 * The "className" argument will be passed directly to FindClass, which
51 * takes strings with slashes (e.g. "java/lang/Object").
52 *
53 * If an exception is currently pending, we log a warning message and
54 * clear it.
55 *
56 * Returns 0 on success, nonzero if something failed (e.g. the exception
57 * class couldn't be found, so *an* exception will still be pending).
58 *
59 * Currently aborts the VM if it can't throw the exception.
60 */
61 int jniThrowException(C_JNIEnv* env, const char* className, const char* msg);
62
63 /*
64 * Throw a java.lang.NullPointerException, with an optional message.
65 */
66 int jniThrowNullPointerException(C_JNIEnv* env, const char* msg);
67
68 /*
69 * Throw a java.lang.RuntimeException, with an optional message.
70 */
71 int jniThrowRuntimeException(C_JNIEnv* env, const char* msg);
72
73 /*
74 * Throw a java.io.IOException, generating the message from errno.
75 */
76 int jniThrowIOException(C_JNIEnv* env, int errnum);
77
78 /*
79 * Return a pointer to a locale-dependent error string explaining errno
80 * value 'errnum'. The returned pointer may or may not be equal to 'buf'.
81 * This function is thread-safe (unlike strerror) and portable (unlike
82 * strerror_r).
83 */
84 const char* jniStrError(int errnum, char* buf, size_t buflen);
85
86 /*
87 * Returns a new java.io.FileDescriptor for the given int fd.
88 */
89 jobject jniCreateFileDescriptor(C_JNIEnv* env, int fd);
90
91 /*
92 * Returns the int fd from a java.io.FileDescriptor.
93 */
94 int jniGetFDFromFileDescriptor(C_JNIEnv* env, jobject fileDescriptor);
95
96 /*
97 * Sets the int fd in a java.io.FileDescriptor.
98 */
99 void jniSetFileDescriptorOfFD(C_JNIEnv* env, jobject fileDescriptor, int value);
100
101 /*
102 * Returns the reference from a java.lang.ref.Reference.
103 */
104 jobject jniGetReferent(C_JNIEnv* env, jobject ref);
105
106 /*
107 * Log a message and an exception.
108 * If exception is NULL, logs the current exception in the JNI environment.
109 */
110 void jniLogException(C_JNIEnv* env, int priority, const char* tag, jthrowable exception);
111
112 #ifdef __cplusplus
113 }
114 #endif
115
116
117 /*
118 * For C++ code, we provide inlines that map to the C functions. g++ always
119 * inlines these, even on non-optimized builds.
120 */
121 #if defined(__cplusplus)
jniRegisterNativeMethods(JNIEnv * env,const char * className,const JNINativeMethod * gMethods,int numMethods)122 inline int jniRegisterNativeMethods(JNIEnv* env, const char* className, const JNINativeMethod* gMethods, int numMethods) {
123 return jniRegisterNativeMethods(&env->functions, className, gMethods, numMethods);
124 }
125
jniThrowException(JNIEnv * env,const char * className,const char * msg)126 inline int jniThrowException(JNIEnv* env, const char* className, const char* msg) {
127 return jniThrowException(&env->functions, className, msg);
128 }
129
130 extern "C" int jniThrowExceptionFmt(C_JNIEnv* env, const char* className, const char* fmt, va_list args);
131
132 /*
133 * Equivalent to jniThrowException but with a printf-like format string and
134 * variable-length argument list. This is only available in C++.
135 */
jniThrowExceptionFmt(JNIEnv * env,const char * className,const char * fmt,...)136 inline int jniThrowExceptionFmt(JNIEnv* env, const char* className, const char* fmt, ...) {
137 va_list args;
138 va_start(args, fmt);
139 return jniThrowExceptionFmt(&env->functions, className, fmt, args);
140 va_end(args);
141 }
142
jniThrowNullPointerException(JNIEnv * env,const char * msg)143 inline int jniThrowNullPointerException(JNIEnv* env, const char* msg) {
144 return jniThrowNullPointerException(&env->functions, msg);
145 }
146
jniThrowRuntimeException(JNIEnv * env,const char * msg)147 inline int jniThrowRuntimeException(JNIEnv* env, const char* msg) {
148 return jniThrowRuntimeException(&env->functions, msg);
149 }
150
jniThrowIOException(JNIEnv * env,int errnum)151 inline int jniThrowIOException(JNIEnv* env, int errnum) {
152 return jniThrowIOException(&env->functions, errnum);
153 }
154
jniCreateFileDescriptor(JNIEnv * env,int fd)155 inline jobject jniCreateFileDescriptor(JNIEnv* env, int fd) {
156 return jniCreateFileDescriptor(&env->functions, fd);
157 }
158
jniGetFDFromFileDescriptor(JNIEnv * env,jobject fileDescriptor)159 inline int jniGetFDFromFileDescriptor(JNIEnv* env, jobject fileDescriptor) {
160 return jniGetFDFromFileDescriptor(&env->functions, fileDescriptor);
161 }
162
jniSetFileDescriptorOfFD(JNIEnv * env,jobject fileDescriptor,int value)163 inline void jniSetFileDescriptorOfFD(JNIEnv* env, jobject fileDescriptor, int value) {
164 jniSetFileDescriptorOfFD(&env->functions, fileDescriptor, value);
165 }
166
jniGetReferent(JNIEnv * env,jobject ref)167 inline jobject jniGetReferent(JNIEnv* env, jobject ref) {
168 return jniGetReferent(&env->functions, ref);
169 }
170
171 inline void jniLogException(JNIEnv* env, int priority, const char* tag, jthrowable exception = NULL) {
172 jniLogException(&env->functions, priority, tag, exception);
173 }
174
175 #if !defined(DISALLOW_COPY_AND_ASSIGN)
176 // DISALLOW_COPY_AND_ASSIGN disallows the copy and operator= functions. It goes in the private:
177 // declarations in a class.
178 #if __cplusplus >= 201103L
179 #define DISALLOW_COPY_AND_ASSIGN(TypeName) \
180 TypeName(const TypeName&) = delete; \
181 void operator=(const TypeName&) = delete
182 #else
183 #define DISALLOW_COPY_AND_ASSIGN(TypeName) \
184 TypeName(const TypeName&); \
185 void operator=(const TypeName&)
186 #endif // __has_feature(cxx_deleted_functions)
187 #endif // !defined(DISALLOW_COPY_AND_ASSIGN)
188
189 #endif
190
191 /*
192 * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
193 * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
194 * not already defined, then define it here.
195 */
196 #ifndef TEMP_FAILURE_RETRY
197 /* Used to retry syscalls that can return EINTR. */
198 #define TEMP_FAILURE_RETRY(exp) ({ \
199 typeof (exp) _rc; \
200 do { \
201 _rc = (exp); \
202 } while (_rc == -1 && errno == EINTR); \
203 _rc; })
204 #endif
205
206 #endif /* NATIVEHELPER_JNIHELP_H_ */
207