1 files changed, 82 insertions, 0 deletions
diff --git a/media/libcubeb/src/cubeb-jni.cpp b/media/libcubeb/src/cubeb-jni.cpp
new file mode 100644
index 0000000000..8e7345b8aa
--- /dev/null
+++ b/media/libcubeb/src/cubeb-jni.cpp
@@ -0,0 +1,82 @@
+/* clang-format off */
+#include "jni.h"
+#include <assert.h>
+#include "cubeb-jni-instances.h"
+/* clang-format on */
+
+#define AUDIO_STREAM_TYPE_MUSIC 3
+
+struct cubeb_jni {
+  jobject s_audio_manager_obj = nullptr;
+  jclass s_audio_manager_class = nullptr;
+  jmethodID s_get_output_latency_id = nullptr;
+};
+
+extern "C" cubeb_jni *
+cubeb_jni_init()
+{
+  jobject ctx_obj = cubeb_jni_get_context_instance();
+  JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
+  if (!jni_env || !ctx_obj) {
+    return nullptr;
+  }
+
+  cubeb_jni * cubeb_jni_ptr = new cubeb_jni;
+  assert(cubeb_jni_ptr);
+
+  // Find the audio manager object and make it global to call it from another
+  // method
+  jclass context_class = jni_env->FindClass("android/content/Context");
+  jfieldID audio_service_field = jni_env->GetStaticFieldID(
+      context_class, "AUDIO_SERVICE", "Ljava/lang/String;");
+  jstring jstr = (jstring)jni_env->GetStaticObjectField(context_class,
+                                                        audio_service_field);
+  jmethodID get_system_service_id =
+      jni_env->GetMethodID(context_class, "getSystemService",
+                           "(Ljava/lang/String;)Ljava/lang/Object;");
+  jobject audio_manager_obj =
+      jni_env->CallObjectMethod(ctx_obj, get_system_service_id, jstr);
+  cubeb_jni_ptr->s_audio_manager_obj =
+      reinterpret_cast<jobject>(jni_env->NewGlobalRef(audio_manager_obj));
+
+  // Make the audio manager class a global reference in order to preserve method
+  // id
+  jclass audio_manager_class = jni_env->FindClass("android/media/AudioManager");
+  cubeb_jni_ptr->s_audio_manager_class =
+      reinterpret_cast<jclass>(jni_env->NewGlobalRef(audio_manager_class));
+  cubeb_jni_ptr->s_get_output_latency_id =
+      jni_env->GetMethodID(audio_manager_class, "getOutputLatency", "(I)I");
+
+  jni_env->DeleteLocalRef(ctx_obj);
+  jni_env->DeleteLocalRef(context_class);
+  jni_env->DeleteLocalRef(jstr);
+  jni_env->DeleteLocalRef(audio_manager_obj);
+  jni_env->DeleteLocalRef(audio_manager_class);
+
+  return cubeb_jni_ptr;
+}
+
+extern "C" int
+cubeb_get_output_latency_from_jni(cubeb_jni * cubeb_jni_ptr)
+{
+  assert(cubeb_jni_ptr);
+  JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
+  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
+}
+
+extern "C" void
+cubeb_jni_destroy(cubeb_jni * cubeb_jni_ptr)
+{
+  assert(cubeb_jni_ptr);
+
+  JNIEnv * jni_env = cubeb_get_jni_env_for_thread();
+  assert(jni_env);
+
+  jni_env->DeleteGlobalRef(cubeb_jni_ptr->s_audio_manager_obj);
+  jni_env->DeleteGlobalRef(cubeb_jni_ptr->s_audio_manager_class);
+
+  delete cubeb_jni_ptr;
+}