1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 //#define LOG_NDEBUG 0
18 
19 #define LOG_TAG "AudioTrackCallback-JNI"
20 
21 #include <algorithm>
22 
23 #include <nativehelper/JNIHelp.h>
24 #include <utils/Errors.h>
25 #include <utils/Log.h>
26 
27 #include "android_media_AudioTrackCallback.h"
28 #include "core_jni_helpers.h"
29 
30 using namespace android;
31 
32 #define BYTE_BUFFER_NAME "java/nio/ByteBuffer"
33 #define BYTE_BUFFER_ALLOCATE_DIRECT_NAME "allocateDirect"
34 
35 JNIAudioTrackCallback::JNIAudioTrackCallback(JNIEnv* env, jobject thiz, jobject weak_thiz,
36                                              jmethodID postEventFromNative) {
37     // Hold onto the AudioTrack class for use in calling the static method
38     // that posts events to the application thread.
39     jclass clazz = env->GetObjectClass(thiz);
40     if (clazz == nullptr) {
41         return;
42     }
43     mClass = (jclass)env->NewGlobalRef(clazz);
44 
45     // We use a weak reference so the AudioTrack object can be garbage collected.
46     // The reference is only used as a proxy for callbacks.
47     mObject = env->NewGlobalRef(weak_thiz);
48 
49     mPostEventFromNative = postEventFromNative;
50 
51     jclass byteBufferClass = FindClassOrDie(env, BYTE_BUFFER_NAME);
52     mByteBufferClass = (jclass)env->NewGlobalRef(byteBufferClass);
53     mAllocateDirectMethod =
54             GetStaticMethodIDOrDie(env, mByteBufferClass, BYTE_BUFFER_ALLOCATE_DIRECT_NAME,
55                                    "(I)Ljava/nio/ByteBuffer;");
56 }
57 
58 JNIAudioTrackCallback::~JNIAudioTrackCallback() {
59     // remove global references
60     JNIEnv* env = AndroidRuntime::getJNIEnv();
61     if (env == nullptr) {
62         return;
63     }
64     env->DeleteGlobalRef(mObject);
65     env->DeleteGlobalRef(mClass);
66     env->DeleteGlobalRef(mByteBufferClass);
67 }
68 
69 binder::Status JNIAudioTrackCallback::onCodecFormatChanged(
70         const std::vector<uint8_t>& audioMetadata) {
71     JNIEnv* env = AndroidRuntime::getJNIEnv();
72     if (env == nullptr) {
73         return binder::Status::ok();
74     }
75 
76     jobject byteBuffer = env->CallStaticObjectMethod(mByteBufferClass, mAllocateDirectMethod,
77                                                      (jint)audioMetadata.size());
78     if (env->ExceptionCheck()) {
79         ALOGW("An exception occurred while allocating direct buffer");
80         env->ExceptionDescribe();
81         env->ExceptionClear();
82     }
83     if (byteBuffer == nullptr) {
84         ALOGE("Failed allocating a direct ByteBuffer");
85         return binder::Status::fromStatusT(NO_MEMORY);
86     }
87 
88     uint8_t* byteBufferAddr = (uint8_t*)env->GetDirectBufferAddress(byteBuffer);
89     std::copy(audioMetadata.begin(), audioMetadata.end(), byteBufferAddr);
90     env->CallStaticVoidMethod(mClass, mPostEventFromNative, mObject,
91                               AUDIO_NATIVE_EVENT_CODEC_FORMAT_CHANGE, 0, 0, byteBuffer);
92     if (env->ExceptionCheck()) {
93         ALOGW("An exception occurred while notifying codec format changed.");
94         env->ExceptionDescribe();
95         env->ExceptionClear();
96     }
97 
98     return binder::Status::ok();
99 }
100