[FFmpeg-devel] [PATCH v4 1/6] avcodec: add av_jni_{get, set}_android_app_ctx helper

[Andreas Rheinhardt]

Matthieu Bouron:
> This will allow users to pass the Android ApplicationContext which is mandatory
> to retrieve the ContentResolver responsible to resolve/open Android content-uri.
> ---
>  doc/APIchanges   |  3 +++
>  libavcodec/jni.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  libavcodec/jni.h | 17 +++++++++++++++++
>  3 files changed, 62 insertions(+)
> 
> diff --git a/doc/APIchanges b/doc/APIchanges
> index a44c8e4f10..ae1868047e 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
>  
>  API changes, most recent first:
>  
> +2024-03-xx - xxxxxxxxxx - lavc 61.2.100 - jni.h
> +  Add av_jni_set_android_app_ctx() and av_jni_get_android_app_ctx().
> +
>  2024-03-xx - xxxxxxxxxx - lavu 59.2.100 - channel_layout.h
>    Add AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL.
>  
> 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);

This should mention that these functions are only available on android.

> +
>  #endif /* AVCODEC_JNI_H */