FFmpeg
ffjni.h
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1 /*
2  * JNI utility functions
3  *
4  * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #ifndef AVCODEC_FFJNI_H
24 #define AVCODEC_FFJNI_H
25 
26 #include <jni.h>
27 
28 /*
29  * Attach permanently a JNI environment to the current thread and retrieve it.
30  *
31  * If successfully attached, the JNI environment will automatically be detached
32  * at thread destruction.
33  *
34  * @param attached pointer to an integer that will be set to 1 if the
35  * environment has been attached to the current thread or 0 if it is
36  * already attached.
37  * @param log_ctx context used for logging, can be NULL
38  * @return the JNI environment on success, NULL otherwise
39  */
40 JNIEnv *ff_jni_get_env(void *log_ctx);
41 
42 /*
43  * Convert a jstring to its utf characters equivalent.
44  *
45  * @param env JNI environment
46  * @param string Java string to convert
47  * @param log_ctx context used for logging, can be NULL
48  * @return a pointer to an array of unicode characters on success, NULL
49  * otherwise
50  */
51 char *ff_jni_jstring_to_utf_chars(JNIEnv *env, jstring string, void *log_ctx);
52 
53 /*
54  * Convert utf chars to its jstring equivalent.
55  *
56  * @param env JNI environment
57  * @param utf_chars a pointer to an array of unicode characters
58  * @param log_ctx context used for logging, can be NULL
59  * @return a Java string object on success, NULL otherwise
60  */
61 jstring ff_jni_utf_chars_to_jstring(JNIEnv *env, const char *utf_chars, void *log_ctx);
62 
63 /*
64  * Extract the error summary from a jthrowable in the form of "className: errorMessage"
65  *
66  * @param env JNI environment
67  * @param exception exception to get the summary from
68  * @param error address pointing to the error, the value is updated if a
69  * summary can be extracted
70  * @param log_ctx context used for logging, can be NULL
71  * @return 0 on success, < 0 otherwise
72  */
73 int ff_jni_exception_get_summary(JNIEnv *env, jthrowable exception, char **error, void *log_ctx);
74 
75 /*
76  * Check if an exception has occurred,log it using av_log and clear it.
77  *
78  * @param env JNI environment
79  * @param log value used to enable logging if an exception has occurred,
80  * 0 disables logging, != 0 enables logging
81  * @param log_ctx context used for logging, can be NULL
82  */
83 int ff_jni_exception_check(JNIEnv *env, int log, void *log_ctx);
84 
85 /*
86  * Jni field type.
87  */
89 
95 
96 };
97 
98 /*
99  * Jni field describing a class, a field or a method to be retrieved using
100  * the ff_jni_init_jfields method.
101  */
102 struct FFJniField {
103 
104  const char *name;
105  const char *method;
106  const char *signature;
108  int offset;
110 
111 };
112 
113 /*
114  * Retrieve class references, field ids and method ids to an arbitrary structure.
115  *
116  * @param env JNI environment
117  * @param jfields a pointer to an arbitrary structure where the different
118  * fields are declared and where the FFJNIField mapping table offsets are
119  * pointing to
120  * @param jfields_mapping null terminated array of FFJNIFields describing
121  * the class/field/method to be retrieved
122  * @param global make the classes references global. It is the caller
123  * responsibility to properly release global references.
124  * @param log_ctx context used for logging, can be NULL
125  * @return 0 on success, < 0 otherwise
126  */
127 int ff_jni_init_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx);
128 
129 /*
130  * Delete class references, field ids and method ids of an arbitrary structure.
131  *
132  * @param env JNI environment
133  * @param jfields a pointer to an arbitrary structure where the different
134  * fields are declared and where the FFJNIField mapping table offsets are
135  * pointing to
136  * @param jfields_mapping null terminated array of FFJNIFields describing
137  * the class/field/method to be deleted
138  * @param global threat the classes references as global and delete them
139  * accordingly
140  * @param log_ctx context used for logging, can be NULL
141  * @return 0 on success, < 0 otherwise
142  */
143 int ff_jni_reset_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx);
144 
145 #endif /* AVCODEC_FFJNI_H */
int ff_jni_reset_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx)
Definition: ffjni.c:374
jstring ff_jni_utf_chars_to_jstring(JNIEnv *env, const char *utf_chars, void *log_ctx)
Definition: ffjni.c:127
int offset
Definition: ffjni.h:108
enum FFJniFieldType type
Definition: ffjni.h:107
const char * method
Definition: ffjni.h:105
char * ff_jni_jstring_to_utf_chars(JNIEnv *env, jstring string, void *log_ctx)
Definition: ffjni.c:97
int ff_jni_exception_get_summary(JNIEnv *env, jthrowable exception, char **error, void *log_ctx)
Definition: ffjni.c:141
static void error(const char *err)
int ff_jni_exception_check(JNIEnv *env, int log, void *log_ctx)
Definition: ffjni.c:252
const char * name
Definition: ffjni.h:104
FFJniFieldType
Definition: ffjni.h:88
JNIEnv * ff_jni_get_env(void *log_ctx)
Definition: ffjni.c:51
int mandatory
Definition: ffjni.h:109
const char * signature
Definition: ffjni.h:106
int ff_jni_init_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx)
Definition: ffjni.c:285