On Tue, Mar 01, 2016 at 09:06:35PM +0100, wm4 wrote:
> On Tue, 1 Mar 2016 20:57:12 +0100
> Matthieu Bouron <matthieu.bou...@gmail.com> wrote:
>
> > On Tue, Mar 01, 2016 at 08:55:23PM +0100, Matthieu Bouron wrote:
> > > On Tue, Mar 01, 2016 at 08:38:04PM +0100, wm4 wrote:
> > > > On Tue, 1 Mar 2016 20:33:14 +0100
> > > > Matthieu Bouron <matthieu.bou...@gmail.com> wrote:
> > > >
> > > > > On Tue, Mar 01, 2016 at 08:24:27PM +0100, Matthieu Bouron wrote:
> > > > > > On Tue, Mar 01, 2016 at 08:13:48PM +0100, wm4 wrote:
> > > > > > > On Tue, 1 Mar 2016 20:10:50 +0100
> > > > > > > Matthieu Bouron <matthieu.bou...@gmail.com> wrote:
> > > > > > >
> > > > > > > > On Tue, Mar 01, 2016 at 07:56:30PM +0100, wm4 wrote:
> > > > > > > > > On Tue, 1 Mar 2016 19:52:08 +0100
> > > > > > > > > Matthieu Bouron <matthieu.bou...@gmail.com> wrote:
> > > > > > > > >
> > > > > > > > > > On Fri, Feb 26, 2016 at 05:36:40PM +0100, Matthieu Bouron
> > > > > > > > > > wrote:
> > > > > > > > > > > On Fri, Feb 26, 2016 at 4:41 PM, Matthieu Bouron
> > > > > > > > > > > <matthieu.bou...@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > On Mon, Feb 22, 2016 at 12:20:35PM +0100, Matthieu
> > > > > > > > > > > > Bouron wrote:
> > > > > > > > > > > > > From: Matthieu Bouron <matthieu.bou...@stupeflix.com>
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > [...]
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Patch updated with the following differences:
> > > > > > > > > > > > * fix of switch/case code style
> > > > > > > > > > > > * removal of a miss declaration of FFJNIField enum as
> > > > > > > > > > > > a global variable
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > Patch updated with the following differences:
> > > > > > > > > > > * fixes a few typo in comments
> > > > > > > > > > > * fixes a if statement in ff_jni_init_jfields
> > > > > > > > > >
> > > > > > > > > > Patch updated with the following differences:
> > > > > > > > > > * fixes a few typo in comments and message logs
> > > > > > > > > > * add missing .so at end of library names when trying to
> > > > > > > > > > find
> > > > > > > > > > JNI_GetCreatedVMs symbol (also add libart.so)
> > > > > > > > > > * reintroduce public functions that allow the user to set
> > > > > > > > > > the Java
> > > > > > > > > > virtual machine (av_jni_(set,get)_java_vm) as the private
> > > > > > > > > > C++
> > > > > > > > > > JniInvocation wrapper is not available on all devices
> > > > > > > > > > (android >= 4.4)
> > > > > > > > >
> > > > > > > > > I'm wondering if the VM should be stored per AVCodecContext.
> > > > > > > > > (Since it
> > > > > > > > > has to be set explicitly again by the user.)
> > > > > > > >
> > > > > > > > I think it is fine to store one VM for all the AVCodecContext
> > > > > > > > as it will
> > > > > > > > be the same during all the lifetime of the application. I
> > > > > > > > should also
> > > > > > > > enforce that the VM cannot be changed afterwards.
> > > > > > > >
> > > > > > > > av_jni_set_java_vm stores the Java VM pointer locally in jni.c
> > > > > > > > and not in
> > > > > > > > ffjni.c and it is retrieved in jni.c using av_jni_get_java_vm.
> > > > > > > > I've done
> > > > > > > > it that way because if at some point we are to include ffjni.c
> > > > > > > > from
> > > > > > > > libavformat it won't work (it will only set the java vm in the
> > > > > > > > libavcodec
> > > > > > > > memory space).
> > > > > > >
> > > > > > > The problem is that this is not library-safe. What if two libs
> > > > > > > within
> > > > > > > the process (which both are using libavcodec) are setting a
> > > > > > > different
> > > > > > > VM?
> > > > > >
> > > > > > In the Android application context, you only have, AFAIK, one VM
> > > > > > running
> > > > > > during the lifetime of the application. The code does handle the
> > > > > > general
> > > > >
> > > > > does *not* (sorry)
> > > > >
> > > > > > JNI case (even outside Android) but do we really want to do that
> > > > > > anyway ?
> > > >
> > > > If there's guaranteed to be exactly one, I don't get why we can't get
> > > > it into existence ourselves?
> > > >
> > > > Where exactly would an application get the VM handle from?
> > >
> > > You get the Java VM pointer when JNI_onLoad(JavaVM *vm, void *reserved) is
> > > executed at library load. This is where you can pass the pointer to lavc.
> > >
> > > IMHO, av_jni_set_java_vm should set the VM once and then warn (or return
> > > an error)
> > > if the user is providing a different Java VM pointer.
> > >
> > > In theory, on some version of Android, you can spawn your own VM using
> > > their
> > > private C++ JniInvocation wrapper.
> > > On a regular desktop, you can create Java VMs (using JNI_createJavaVM).
> >
> > Also note that the JniInvocation wrapper is still used if the user hasn't
> > provided a JavaVM using av_jni_set_java_vm but that will only work on
> > android >= 4.4.2
>
> I still don't quite understand the implications, so no resistance from
> me anymore, I guess.
New patch attached with the following differences:
* only one Java VM can be set using av_jni_set_java_vm. If the user try
to set another Java VM at some point the function will error out and log
an error message.
* fixes some typo
>From 8430e591c647c1f455618cc0375e509542be5196 Mon Sep 17 00:00:00 2001
From: Matthieu Bouron <matthieu.bou...@stupeflix.com>
Date: Mon, 28 Sep 2015 15:18:56 +0200
Subject: [PATCH 1/2] lavc: add JNI support
---
configure | 5 +
libavcodec/Makefile | 4 +
libavcodec/ffjni.c | 483 ++++++++++++++++++++++++++++++++++++++++++++++++++++
libavcodec/ffjni.h | 148 ++++++++++++++++
libavcodec/jni.c | 77 +++++++++
libavcodec/jni.h | 44 +++++
6 files changed, 761 insertions(+)
create mode 100644 libavcodec/ffjni.c
create mode 100644 libavcodec/ffjni.h
create mode 100644 libavcodec/jni.c
create mode 100644 libavcodec/jni.h
diff --git a/configure b/configure
index 8491fa1..fe94f84 100755
--- a/configure
+++ b/configure
@@ -208,6 +208,7 @@ External library support:
--enable-gnutls enable gnutls, needed for https support
if openssl is not used [no]
--disable-iconv disable iconv [autodetect]
+ --enable-jni enable JNI support [no]
--enable-ladspa enable LADSPA audio filtering [no]
--enable-libass enable libass subtitles rendering,
needed for subtitles and ass filter [no]
@@ -1436,6 +1437,7 @@ EXTERNAL_LIBRARY_LIST="
gmp
gnutls
iconv
+ jni
ladspa
libass
libbluray
@@ -5544,6 +5546,8 @@ enabled decklink && { check_header DeckLinkAPI.h || die "ERROR: DeckLin
enabled frei0r && { check_header frei0r.h || die "ERROR: frei0r.h header not found"; }
enabled gmp && require2 gmp gmp.h mpz_export -lgmp
enabled gnutls && require_pkg_config gnutls gnutls/gnutls.h gnutls_global_init
+enabled jni && { [ $target_os = "android" ] && check_header jni.h && enabled pthreads &&
+ check_lib2 "dlfcn.h" dlopen -ldl; }
enabled ladspa && { check_header ladspa.h || die "ERROR: ladspa.h header not found"; }
enabled libiec61883 && require libiec61883 libiec61883/iec61883.h iec61883_cmp_connect -lraw1394 -lavc1394 -lrom1394 -liec61883
enabled libass && require_pkg_config libass ass/ass.h ass_library_init
@@ -6312,6 +6316,7 @@ echo "threading support ${thread_type-no}"
echo "safe bitstream reader ${safe_bitstream_reader-no}"
echo "SDL support ${sdl-no}"
echo "opencl enabled ${opencl-no}"
+echo "JNI support ${jni-no}"
echo "texi2html enabled ${texi2html-no}"
echo "perl enabled ${perl-no}"
echo "pod2man enabled ${pod2man-no}"
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 667e257..c7a0ede 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -9,6 +9,7 @@ HEADERS = avcodec.h \
d3d11va.h \
dirac.h \
dxva2.h \
+ jni.h \
qsv.h \
vaapi.h \
vda.h \
@@ -30,6 +31,7 @@ OBJS = allcodecs.o \
dirac.o \
dv_profile.o \
imgconvert.o \
+ jni.o \
mathtables.o \
options.o \
parser.o \
@@ -78,6 +80,7 @@ OBJS-$(CONFIG_IIRFILTER) += iirfilter.o
OBJS-$(CONFIG_IMDCT15) += imdct15.o
OBJS-$(CONFIG_INTRAX8) += intrax8.o intrax8dsp.o
OBJS-$(CONFIG_IVIDSP) += ivi_dsp.o
+OBJS-$(CONFIG_JNI) += ffjni.o jni.o
OBJS-$(CONFIG_JPEGTABLES) += jpegtables.o
OBJS-$(CONFIG_LIBXVID) += libxvid_rc.o
OBJS-$(CONFIG_LLAUDDSP) += lossless_audiodsp.o
@@ -935,6 +938,7 @@ SKIPHEADERS += %_tablegen.h \
SKIPHEADERS-$(CONFIG_D3D11VA) += d3d11va.h dxva2_internal.h
SKIPHEADERS-$(CONFIG_DXVA2) += dxva2.h dxva2_internal.h
+SKIPHEADERS-$(CONFIG_JNI) += ffjni.h
SKIPHEADERS-$(CONFIG_LIBSCHROEDINGER) += libschroedinger.h
SKIPHEADERS-$(CONFIG_LIBUTVIDEO) += libutvideo.h
SKIPHEADERS-$(CONFIG_LIBVPX) += libvpx.h
diff --git a/libavcodec/ffjni.c b/libavcodec/ffjni.c
new file mode 100644
index 0000000..c37c8c3
--- /dev/null
+++ b/libavcodec/ffjni.c
@@ -0,0 +1,483 @@
+/*
+ * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <dlfcn.h>
+#include <jni.h>
+#include <pthread.h>
+#include <stdlib.h>
+
+#include "libavutil/bprint.h"
+#include "libavutil/log.h"
+
+#include "config.h"
+#include "jni.h"
+#include "ffjni.h"
+
+static JavaVM *java_vm = NULL;
+static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+
+/**
+ * Check if JniInvocation has been initialized. Only available on
+ * Android >= 4.4.
+ *
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+static int check_jni_invocation(void *log_ctx)
+{
+ int ret = AVERROR_EXTERNAL;
+ void *handle = NULL;
+ void **jni_invocation = NULL;
+
+ handle = dlopen(NULL, RTLD_LOCAL);
+ if (!handle) {
+ goto done;
+ }
+
+ jni_invocation = (void **)dlsym(handle, "_ZN13JniInvocation15jni_invocation_E");
+ if (!jni_invocation) {
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find JniInvocation::jni_invocation_ symbol\n");
+ goto done;
+ }
+
+ ret = !(jni_invocation != NULL && *jni_invocation != NULL);
+
+done:
+ if (handle) {
+ dlclose(handle);
+ }
+
+ return ret;
+}
+
+/**
+ * Return created Java virtual machine using private JNI_GetCreatedJavaVMs
+ * function from the specified library name.
+ *
+ * @param name library name used for symbol lookups, can be NULL
+ * @param log_ctx context used for logging, can be NULL
+ * @return the current Java virtual machine in use
+ */
+static JavaVM *get_java_vm(const char *name, void *log_ctx)
+{
+ JavaVM *vm = NULL;
+ jsize nb_vm = 0;
+
+ void *handle = NULL;
+ jint (*get_created_java_vms) (JavaVM ** vmBuf, jsize bufLen, jsize *nVMs) = NULL;
+
+ handle = dlopen(name, RTLD_LOCAL);
+ if (!handle) {
+ return NULL;
+ }
+
+ get_created_java_vms = (jint (*)(JavaVM **, jsize, jsize *)) dlsym(handle, "JNI_GetCreatedJavaVMs");
+ if (!get_created_java_vms) {
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find JNI_GetCreatedJavaVMs symbol in library '%s'\n", name);
+ goto done;
+ }
+
+ if (get_created_java_vms(&vm, 1, &nb_vm) != JNI_OK) {
+ av_log(log_ctx, AV_LOG_ERROR, "Could not get created Java virtual machines\n");
+ goto done;
+ }
+
+done:
+ if (handle) {
+ dlclose(handle);
+ }
+
+ return vm;
+}
+
+JNIEnv *ff_jni_attach_env(int *attached, void *log_ctx)
+{
+ int ret = 0;
+ JNIEnv *env = NULL;
+
+ *attached = 0;
+
+ pthread_mutex_lock(&lock);
+ if (java_vm == NULL && (java_vm = av_jni_get_java_vm(log_ctx)) == NULL) {
+
+ av_log(log_ctx, AV_LOG_INFO, "Retrieving current Java virtual machine using Android JniInvocation wrapper\n");
+ if (check_jni_invocation(log_ctx) == 0) {
+ if ((java_vm = get_java_vm(NULL, log_ctx)) != NULL ||
+ (java_vm = get_java_vm("libdvm.so", log_ctx)) != NULL ||
+ (java_vm = get_java_vm("libart.so", log_ctx)) != NULL) {
+ av_log(log_ctx, AV_LOG_INFO, "Found Java virtual machine using Android JniInvocation wrapper\n");
+ }
+ }
+ }
+ pthread_mutex_unlock(&lock);
+
+ if (!java_vm) {
+ av_log(log_ctx, AV_LOG_ERROR, "Could not retrieve a Java virtual machine\n");
+ return NULL;
+ }
+
+ ret = (*java_vm)->GetEnv(java_vm, (void **)&env, JNI_VERSION_1_6);
+ switch(ret) {
+ case JNI_EDETACHED:
+ if ((*java_vm)->AttachCurrentThread(java_vm, &env, NULL) != 0) {
+ av_log(log_ctx, AV_LOG_ERROR, "Failed to attach the JNI environment to the current thread\n");
+ env = NULL;
+ } else {
+ *attached = 1;
+ }
+ break;
+ case JNI_OK:
+ break;
+ case JNI_EVERSION:
+ av_log(log_ctx, AV_LOG_ERROR, "The specified JNI version is not supported\n");
+ break;
+ default:
+ av_log(log_ctx, AV_LOG_ERROR, "Failed to get the JNI environment attached to this thread");
+ break;
+ }
+
+ return env;
+}
+
+int ff_jni_detach_env(void *log_ctx)
+{
+ if (java_vm == NULL) {
+ av_log(log_ctx, AV_LOG_ERROR, "No Java virtual machine has been registered\n");
+ return AVERROR(EINVAL);
+ }
+
+ return (*java_vm)->DetachCurrentThread(java_vm);
+}
+
+char *ff_jni_jstring_to_utf_chars(JNIEnv *env, jstring string, void *log_ctx)
+{
+ char *ret = NULL;
+ const char *utf_chars = NULL;
+
+ jboolean copy = 0;
+
+ if (!string) {
+ return NULL;
+ }
+
+ utf_chars = (*env)->GetStringUTFChars(env, string, ©);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "String.getStringUTFChars() threw an exception\n");
+ return NULL;
+ }
+
+ ret = av_strdup(utf_chars);
+
+ (*env)->ReleaseStringUTFChars(env, string, utf_chars);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "String.releaseStringUTFChars() threw an exception\n");
+ return NULL;;
+ }
+
+ return ret;
+}
+
+jstring ff_jni_utf_chars_to_jstring(JNIEnv *env, const char *utf_chars, void *log_ctx)
+{
+ jstring ret;
+
+ ret = (*env)->NewStringUTF(env, utf_chars);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "NewStringUTF() threw an exception\n");
+ return NULL;
+ }
+
+ return ret;
+}
+
+int ff_jni_exception_get_summary(JNIEnv *env, jthrowable exception, char **error, void *log_ctx)
+{
+ int ret = 0;
+
+ AVBPrint bp;
+
+ char *name = NULL;
+ char *message = NULL;
+
+ jclass class_class = NULL;
+ jmethodID get_name_id = NULL;
+
+ jclass exception_class = NULL;
+ jmethodID get_message_id = NULL;
+
+ jstring string;
+
+ av_bprint_init(&bp, 0, AV_BPRINT_SIZE_AUTOMATIC);
+
+ exception_class = (*env)->GetObjectClass(env, exception);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find Throwable class\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ class_class = (*env)->GetObjectClass(env, exception_class);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find Throwable class's class\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ get_name_id = (*env)->GetMethodID(env, class_class, "getName", "()Ljava/lang/String;");
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find method Class.getName()\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ string = (*env)->CallObjectMethod(env, exception_class, get_name_id);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Class.getName() threw an exception\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ if (string) {
+ name = ff_jni_jstring_to_utf_chars(env, string, log_ctx);
+ (*env)->DeleteLocalRef(env, string);
+ string = NULL;
+ }
+
+ get_message_id = (*env)->GetMethodID(env, exception_class, "getMessage", "()Ljava/lang/String;");
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Could not find method java/lang/Throwable.getMessage()\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ string = (*env)->CallObjectMethod(env, exception, get_message_id);
+ if ((*env)->ExceptionCheck(env)) {
+ (*env)->ExceptionClear(env);
+ av_log(log_ctx, AV_LOG_ERROR, "Throwable.getMessage() threw an exception\n");
+ ret = AVERROR_EXTERNAL;
+ goto done;
+ }
+
+ if (string) {
+ message = ff_jni_jstring_to_utf_chars(env, string, log_ctx);
+ (*env)->DeleteLocalRef(env, string);
+ string = NULL;
+ }
+
+ if (name && message) {
+ av_bprintf(&bp, "%s: %s", name, message);
+ } else if (name && !message) {
+ av_bprintf(&bp, "%s occured", name);
+ } else if (!name && message) {
+ av_bprintf(&bp, "Exception: %s", message);
+ } else {
+ av_log(log_ctx, AV_LOG_WARNING, "Could not retreive exception name and message\n");
+ av_bprintf(&bp, "Exception occured");
+ }
+
+ ret = av_bprint_finalize(&bp, error);
+done:
+
+ av_free(name);
+ av_free(message);
+
+ if (class_class) {
+ (*env)->DeleteLocalRef(env, class_class);
+ }
+
+ if (exception_class) {
+ (*env)->DeleteLocalRef(env, exception_class);
+ }
+
+ if (string) {
+ (*env)->DeleteLocalRef(env, string);
+ }
+
+ return ret;
+}
+
+int ff_jni_exception_check(JNIEnv *env, int log, void *log_ctx)
+{
+ int ret;
+
+ jthrowable exception;
+
+ char *message = NULL;
+
+ if (!(*(env))->ExceptionCheck((env))) {
+ return 0;
+ }
+
+ if (!log) {
+ (*(env))->ExceptionClear((env));
+ return -1;
+ }
+
+ exception = (*env)->ExceptionOccurred(env);
+ (*(env))->ExceptionClear((env));
+
+ if ((ret = ff_jni_exception_get_summary(env, exception, &message, log_ctx)) < 0) {
+ (*env)->DeleteLocalRef(env, exception);
+ return ret;
+ }
+
+ (*env)->DeleteLocalRef(env, exception);
+
+ av_log(log_ctx, AV_LOG_ERROR, "%s\n", message);
+ av_free(message);
+
+ return -1;
+}
+
+int ff_jni_init_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx)
+{
+ int i, ret = 0;
+ jclass last_clazz = NULL;
+
+ for (i = 0; jfields_mapping[i].name; i++) {
+ int mandatory = jfields_mapping[i].mandatory;
+ enum FFJniFieldType type = jfields_mapping[i].type;
+
+ if (type == FF_JNI_CLASS) {
+ jclass clazz;
+
+ last_clazz = NULL;
+
+ clazz = (*env)->FindClass(env, jfields_mapping[i].name);
+ if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) {
+ goto done;
+ }
+
+ last_clazz = *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset) =
+ global ? (*env)->NewGlobalRef(env, clazz) : clazz;
+ } else {
+
+ if (!last_clazz) {
+ ret = AVERROR_EXTERNAL;
+ break;
+ }
+
+ switch(type) {
+ case FF_JNI_FIELD: {
+ jfieldID field_id = (*env)->GetFieldID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature);
+ if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) {
+ goto done;
+ }
+
+ *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = field_id;
+ break;
+ }
+ case FF_JNI_STATIC_FIELD: {
+ jfieldID field_id = (*env)->GetStaticFieldID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature);
+ if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) {
+ goto done;
+ }
+
+ *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = field_id;
+ break;
+ }
+ case FF_JNI_METHOD: {
+ jmethodID method_id = (*env)->GetMethodID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature);
+ if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) {
+ goto done;
+ }
+
+ *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = method_id;
+ break;
+ }
+ case FF_JNI_STATIC_METHOD: {
+ jmethodID method_id = (*env)->GetStaticMethodID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature);
+ if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) {
+ goto done;
+ }
+
+ *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = method_id;
+ break;
+ }
+ default:
+ av_log(log_ctx, AV_LOG_ERROR, "Unknown JNI field type\n");
+ ret = AVERROR(EINVAL);
+ goto done;
+ }
+ }
+ }
+
+done:
+ if (ret < 0) {
+ /* reset jfields in case of failure so it does not leak references */
+ ff_jni_reset_jfields(env, jfields, jfields_mapping, global, log_ctx);
+ }
+
+ return ret;
+}
+
+int ff_jni_reset_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx)
+{
+ int i;
+
+ for (i = 0; jfields_mapping[i].name; i++) {
+ enum FFJniFieldType type = jfields_mapping[i].type;
+
+ switch(type) {
+ case FF_JNI_CLASS: {
+ jclass clazz = *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset);
+ if (!clazz)
+ continue;
+
+ if (global) {
+ (*env)->DeleteGlobalRef(env, clazz);
+ } else {
+ (*env)->DeleteLocalRef(env, clazz);
+ }
+
+ *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL;
+ break;
+ }
+ case FF_JNI_FIELD: {
+ *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL;
+ break;
+ }
+ case FF_JNI_STATIC_FIELD: {
+ *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL;
+ break;
+ }
+ case FF_JNI_METHOD: {
+ *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL;
+ break;
+ }
+ case FF_JNI_STATIC_METHOD: {
+ *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL;
+ break;
+ }
+ default:
+ av_log(log_ctx, AV_LOG_ERROR, "Unknown JNI field type\n");
+ }
+ }
+
+ return 0;
+}
diff --git a/libavcodec/ffjni.h b/libavcodec/ffjni.h
new file mode 100644
index 0000000..6a2a887
--- /dev/null
+++ b/libavcodec/ffjni.h
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_FFJNI_H
+#define AVCODEC_FFJNI_H
+
+#include <jni.h>
+
+/*
+ * Attach a JNI environment to the current thread.
+ *
+ * @param attached pointer to an integer that will be set to 1 if the
+ * environment has been attached to the current thread or 0 if it is
+ * already attached.
+ * @param log_ctx context used for logging, can be NULL
+ * @return the JNI environment on success, NULL otherwise
+ */
+JNIEnv *ff_jni_attach_env(int *attached, void *log_ctx);
+
+/*
+ * Detach the JNI environment from the current thread.
+ *
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+int ff_jni_detach_env(void *log_ctx);
+
+/*
+ * Convert a jstring to its utf characters equivalent.
+ *
+ * @param env JNI environment
+ * @param string Java string to convert
+ * @param log_ctx context used for logging, can be NULL
+ * @return a pointer to an array of unicode characters on success, NULL
+ * otherwise
+ */
+char *ff_jni_jstring_to_utf_chars(JNIEnv *env, jstring string, void *log_ctx);
+
+/*
+ * Convert utf chars to its jstring equivalent.
+ *
+ * @param env JNI environment
+ * @param utf_chars a pointer to an array of unicode characters
+ * @param log_ctx context used for logging, can be NULL
+ * @return a Java string object on success, NULL otherwise
+ */
+jstring ff_jni_utf_chars_to_jstring(JNIEnv *env, const char *utf_chars, void *log_ctx);
+
+/*
+ * Extract the error summary from a jthrowable in the form of "className: errorMessage"
+ *
+ * @param env JNI environment
+ * @param exception exception to get the summary from
+ * @param error address pointing to the error, the value is updated if a
+ * summary can be extracted
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+int ff_jni_exception_get_summary(JNIEnv *env, jthrowable exception, char **error, void *log_ctx);
+
+/*
+ * Check if an exception has occurred,log it using av_log and clear it.
+ *
+ * @param env JNI environment
+ * @param log value used to enable logging if an exception has occurred,
+ * 0 disables logging, != 0 enables logging
+ * @param log_ctx context used for logging, can be NULL
+ */
+int ff_jni_exception_check(JNIEnv *env, int log, void *log_ctx);
+
+/*
+ * Jni field type.
+ */
+enum FFJniFieldType {
+
+ FF_JNI_CLASS,
+ FF_JNI_FIELD,
+ FF_JNI_STATIC_FIELD,
+ FF_JNI_METHOD,
+ FF_JNI_STATIC_METHOD
+
+};
+
+/*
+ * Jni field describing a class, a field or a method to be retrieved using
+ * the ff_jni_init_jfields method.
+ */
+struct FFJniField {
+
+ const char *name;
+ const char *method;
+ const char *signature;
+ enum FFJniFieldType type;
+ int offset;
+ int mandatory;
+
+};
+
+/*
+ * Retrieve class references, field ids and method ids to an arbitrary structure.
+ *
+ * @param env JNI environment
+ * @param jfields a pointer to an arbitrary structure where the different
+ * fields are declared and where the FFJNIField mapping table offsets are
+ * pointing to
+ * @param jfields_mapping null terminated array of FFJNIFields describing
+ * the class/field/method to be retrieved
+ * @param global make the classes references global. It is the caller
+ * responsibility to properly release global references.
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+int ff_jni_init_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx);
+
+/*
+ * Delete class references, field ids and method ids of an arbitrary structure.
+ *
+ * @param env JNI environment
+ * @param jfields a pointer to an arbitrary structure where the different
+ * fields are declared and where the FFJNIField mapping table offsets are
+ * pointing to
+ * @param jfields_mapping null terminated array of FFJNIFields describing
+ * the class/field/method to be deleted
+ * @param global threat the classes references as global and delete them
+ * accordingly
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+int ff_jni_reset_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx);
+
+#endif /* AVCODEC_FFJNI_H */
diff --git a/libavcodec/jni.c b/libavcodec/jni.c
new file mode 100644
index 0000000..bf1e9a1
--- /dev/null
+++ b/libavcodec/jni.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdlib.h>
+
+#include "config.h"
+#include "jni.h"
+
+#if CONFIG_JNI
+
+#include <errno.h>
+#include <jni.h>
+#include <pthread.h>
+
+#include "libavutil/log.h"
+#include "libavutil/error.h"
+#include "ffjni.h"
+
+void *java_vm;
+pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+
+int av_jni_set_java_vm(void *vm, void *log_ctx)
+{
+ int ret = 0;
+
+ pthread_mutex_lock(&lock);
+ if (java_vm == NULL) {
+ java_vm = vm;
+ } else if (java_vm != vm) {
+ ret = AVERROR(EINVAL);
+ av_log(log_ctx, AV_LOG_ERROR, "A Java virtual machine has already been set");
+ }
+ pthread_mutex_unlock(&lock);
+
+ return ret;
+}
+
+void *av_jni_get_java_vm(void *log_ctx)
+{
+ void *vm;
+
+ pthread_mutex_lock(&lock);
+ vm = java_vm;
+ pthread_mutex_unlock(&lock);
+
+ return vm;
+}
+
+#else
+
+void av_jni_set_java_vm(void *vm, void *log_ctx)
+{
+}
+
+void *av_jni_get_java_vm(void *log_ctx)
+{
+ return NULL;
+}
+
+#endif
diff --git a/libavcodec/jni.h b/libavcodec/jni.h
new file mode 100644
index 0000000..b3c5bfc
--- /dev/null
+++ b/libavcodec/jni.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_JNI_H
+#define AVCODEC_JNI_H
+
+/*
+ * Manually set a Java virtual machine which will be used to retrieve the JNI
+ * environment. Once a Java VM is set it cannot be changed afterwards, meaning
+ * you can call multiple times av_jni_set_java_vm with the same Java VM pointer
+ * however it will error out if you try to set a different Java VM.
+ *
+ * @param vm Java virtual machine
+ * @param log_ctx context used for logging, can be NULL
+ * @return 0 on success, < 0 otherwise
+ */
+int av_jni_set_java_vm(void *vm, void *log_ctx);
+
+/*
+ * Get the Java virtual machine which has been set with av_jni_set_java_vm.
+ *
+ * @param vm Java virtual machine
+ * @return a pointer to the Java virtual machine
+ */
+void *av_jni_get_java_vm(void *log_ctx);
+
+#endif /* AVCODEC_JNI_H */
--
2.7.2
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