1 #include "jni.h"
2 #include <assert.h>
3 #include "cubeb-jni-instances.h"
4
5 #define AUDIO_STREAM_TYPE_MUSIC 3
6
7 struct cubeb_jni {
8 jobject s_audio_manager_obj = nullptr;
9 jclass s_audio_manager_class = nullptr;
10 jmethodID s_get_output_latency_id = nullptr;
11 };
12
13 extern "C"
14 cubeb_jni *
cubeb_jni_init()15 cubeb_jni_init()
16 {
17 jobject ctx_obj = cubeb_jni_get_context_instance();
18 JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
19 if (!jni_env || !ctx_obj) {
20 return nullptr;
21 }
22
23 cubeb_jni * cubeb_jni_ptr = new cubeb_jni;
24 assert(cubeb_jni_ptr);
25
26 // Find the audio manager object and make it global to call it from another method
27 jclass context_class = jni_env->FindClass("android/content/Context");
28 jfieldID audio_service_field = jni_env->GetStaticFieldID(context_class, "AUDIO_SERVICE", "Ljava/lang/String;");
29 jstring jstr = (jstring)jni_env->GetStaticObjectField(context_class, audio_service_field);
30 jmethodID get_system_service_id = jni_env->GetMethodID(context_class, "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;");
31 jobject audio_manager_obj = jni_env->CallObjectMethod(ctx_obj, get_system_service_id, jstr);
32 cubeb_jni_ptr->s_audio_manager_obj = reinterpret_cast<jobject>(jni_env->NewGlobalRef(audio_manager_obj));
33
34 // Make the audio manager class a global reference in order to preserve method id
35 jclass audio_manager_class = jni_env->FindClass("android/media/AudioManager");
36 cubeb_jni_ptr->s_audio_manager_class = reinterpret_cast<jclass>(jni_env->NewGlobalRef(audio_manager_class));
37 cubeb_jni_ptr->s_get_output_latency_id = jni_env->GetMethodID (audio_manager_class, "getOutputLatency", "(I)I");
38
39 jni_env->DeleteLocalRef(ctx_obj);
40 jni_env->DeleteLocalRef(context_class);
41 jni_env->DeleteLocalRef(jstr);
42 jni_env->DeleteLocalRef(audio_manager_obj);
43 jni_env->DeleteLocalRef(audio_manager_class);
44
45 return cubeb_jni_ptr;
46 }
47
48 extern "C"
cubeb_get_output_latency_from_jni(cubeb_jni * cubeb_jni_ptr)49 int cubeb_get_output_latency_from_jni(cubeb_jni * cubeb_jni_ptr)
50 {
51 assert(cubeb_jni_ptr);
52 JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
53 return jni_env->CallIntMethod(cubeb_jni_ptr->s_audio_manager_obj, cubeb_jni_ptr->s_get_output_latency_id, AUDIO_STREAM_TYPE_MUSIC); //param: AudioManager.STREAM_MUSIC
54 }
55
56 extern "C"
cubeb_jni_destroy(cubeb_jni * cubeb_jni_ptr)57 void cubeb_jni_destroy(cubeb_jni * cubeb_jni_ptr)
58 {
59 assert(cubeb_jni_ptr);
60
61 JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
62 assert(jni_env);
63
64 jni_env->DeleteGlobalRef(cubeb_jni_ptr->s_audio_manager_obj);
65 jni_env->DeleteGlobalRef(cubeb_jni_ptr->s_audio_manager_class);
66
67 delete cubeb_jni_ptr;
68 }
69