[FFmpeg-devel] [PATCH v2 1/6] avcodec: add av_jni_{get, set}_android_app_ctx helper

[Matthieu Bouron]

On Mon, Mar 04, 2024 at 05:35:36PM +0100, Matthieu Bouron wrote:
> On Mon, Mar 4, 2024 at 4:11 PM Matthieu Bouron
> <matthieu.bouron at gmail.com> wrote:
> >
> > On Mon, Mar 4, 2024 at 12:29 PM Andreas Rheinhardt
> > <andreas.rheinhardt at outlook.com> wrote:

[...]

> > >
> > > I am against adding stub functions on platforms where they are known to
> > > be useless, i.e. everything except android.
> >
> > Ok. Will update the patch introducing a new header "jni_android.h".
> > Unless we want to also scope avcodec/jni.h to Android only ?
> 
> Or maybe you mean adding a ifdef guard to it ?
> 

New patch attached. The functions are now only built for Android.

[...]
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>From 1b674e78c6a86090f5c9ed6fef5f47ae83ba98be Mon Sep 17 00:00:00 2001
From: Matthieu Bouron <matthieu.bouron at gmail.com>
Date: Mon, 12 Feb 2024 23:13:09 +0100
Subject: [PATCH v3 1/6] avcodec: add av_jni_{get,set}_android_app_ctx helper

This will allow users to pass the Android ApplicationContext which is mandatory
to retrieve the ContentResolver responsible to resolve/open Android content-uri.
---
 libavcodec/jni.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 libavcodec/jni.h | 17 +++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/libavcodec/jni.c b/libavcodec/jni.c
index ae6490de9d..cfe95bd1ec 100644
--- a/libavcodec/jni.c
+++ b/libavcodec/jni.c
@@ -77,3 +77,45 @@ void *av_jni_get_java_vm(void *log_ctx)
 }
 
 #endif
+
+#if defined(__ANDROID__)
+
+int av_jni_set_android_app_ctx(void *app_ctx, void *log_ctx)
+{
+#if CONFIG_JNI
+    JNIEnv *env = ff_jni_get_env(log_ctx);
+    if (!env)
+        return AVERROR(EINVAL);
+
+    jobjectRefType type = (*env)->GetObjectRefType(env, app_ctx);
+    if (type != JNIGlobalRefType) {
+        av_log(log_ctx, AV_LOG_ERROR, "Application context must be passed as a global reference");
+        return AVERROR(EINVAL);
+    }
+
+    pthread_mutex_lock(&lock);
+    android_app_ctx = app_ctx;
+    pthread_mutex_unlock(&lock);
+
+    return 0;
+#else
+    return AVERROR(ENOSYS);
+#endif
+}
+
+void *av_jni_get_android_app_ctx(void)
+{
+#if CONFIG_JNI
+    void *ctx;
+
+    pthread_mutex_lock(&lock);
+    ctx = android_app_ctx;
+    pthread_mutex_unlock(&lock);
+
+    return ctx;
+#else
+    return NULL;
+#endif
+}
+
+#endif
diff --git a/libavcodec/jni.h b/libavcodec/jni.h
index dd99e92611..da8025f830 100644
--- a/libavcodec/jni.h
+++ b/libavcodec/jni.h
@@ -43,4 +43,21 @@ int av_jni_set_java_vm(void *vm, void *log_ctx);
  */
 void *av_jni_get_java_vm(void *log_ctx);
 
+/*
+ * Set the Android application context which will be used to retrieve the Android
+ * content resolver to resolve content uris.
+ *
+ * @param app_ctx global JNI reference to the Android application context
+ * @return 0 on success, < 0 otherwise
+ */
+int av_jni_set_android_app_ctx(void *app_ctx, void *log_ctx);
+
+/*
+ * Get the Android application context that has been set with
+ * av_jni_set_android_app_ctx.
+ *
+ * @return a pointer the the Android application context
+ */
+void *av_jni_get_android_app_ctx(void);
+
 #endif /* AVCODEC_JNI_H */
-- 
2.44.0