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
17package android.hardware.automotive.audiocontrol@2.0;
18
19import android.hardware.audio.common@6.0::AudioUsage;
20
21/**
22 * Callback interface for audio focus listener.
23 *
24 * For typical configuration, the listener the car audio service.
25 */
26interface IFocusListener {
27    /**
28     * Called whenever HAL is requesting focus as it is starting to play audio of a given usage in a
29     * specified zone.
30     *
31     * In response, IAudioControl#onAudioFocusChange will be called with focusChange status. This
32     * interaction is oneway to avoid blocking HAL so that it is not required to wait for a response
33     * before playing audio.
34     *
35     * @param usage The audio usage associated with the focus request {@code AttributeUsage}
36     * @param zoneId The identifier for the audio zone where the HAL is requesting focus
37     * @param focusGain The AudioFocusChange associated with this request. Should be one of the
38     * following: GAIN, GAIN_TRANSIENT, GAIN_TRANSIENT_MAY_DUCK, GAIN_TRANSIENT_EXCLUSIVE.
39     */
40    oneway requestAudioFocus(bitfield<AudioUsage> usage, int32_t zoneId,
41        bitfield<AudioFocusChange> focusGain);
42
43    /**
44     * Called whenever HAL is abandoning focus as it is finished playing audio of a given usage in a
45     * specific zone.
46     *
47     * In response, IAudioControl#onAudioFocusChange will be called with focusChange status. This
48     * interaction is oneway to avoid blocking HAL so that it is not required to wait for a response
49     * before stopping audio playback.
50     *
51     * @param usage The audio usage for which the HAL is abandoning focus {@code AttributeUsage}
52     * @param zoneId The identifier for the audio zone that the HAL abandoning focus
53     */
54    oneway abandonAudioFocus(bitfield<AudioUsage> usage, int32_t zoneId);
55};
56