path: root/libavcodec/ffjni.h (plain)
blob: 6027bac0ab12dcd2af1e85f842d968a6f6100a08

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	*/
88	enum FFJniFieldType {
89
90	FF_JNI_CLASS,
91	FF_JNI_FIELD,
92	FF_JNI_STATIC_FIELD,
93	FF_JNI_METHOD,
94	FF_JNI_STATIC_METHOD
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;
107	enum FFJniFieldType type;
108	int offset;
109	int mandatory;
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 */
146