1/*
2 * Copyright (C) 2014 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 com.android.camera.one.v2.core;
18
19import android.view.Surface;
20
21import com.android.camera.async.BufferQueue;
22
23/**
24 * A generic Surface-holding object which can be attached to a {@link Request},
25 * when build via {@link RequestBuilder}. The simplest implementation may simply
26 * provide a {@link Surface} on which to send frames from the camera. However,
27 * other implementations may wish to filter images sent to the {@link Surface}
28 * in response to different {@link Request}s. To enable this, {@link #bind} is
29 * called for each Request with a queue which will contain the timestamps of
30 * every image captured for that request.
31 * <p>
32 * Implementations must provide a {@link Surface} and (optionally) implement
33 * logic to filter images added to the surface according to a stream of image
34 * timestamps.
35 * </p>
36 * <p>
37 * Implementations should use the {@link CaptureStream#bind} method to kick off
38 * a process of taking, as input, a {@link com.android.camera.async.BufferQueue}
39 * of image timestamps as well as the images added to the {@link Surface}, and
40 * producing, as output, a stream of useful handles to the image data.
41 * </p>
42 */
43public interface CaptureStream {
44
45    /**
46     * Implementations should use this method to allocate all resources
47     * necessary to ensure that the requested images can be saved.
48     *
49     * @param timestamps A stream of monotonically-increasing timestamps of
50     *            images which correspond to the request to which the surface
51     *            will be bound Images with timestamps not present in the queue
52     *            should typically be ignored/discarded by the implementation.
53     *            Note that for non-repeating requests, this will only be a
54     *            single timestamp.
55     * @return The stream which clients may use to interact with the returned
56     *         images.
57     * @throws InterruptedException if interrupted while waiting to allocate
58     *             resources necessary to begin accepting new images.
59     */
60    public Surface bind(BufferQueue<Long> timestamps)
61            throws InterruptedException, ResourceAcquisitionFailedException;
62}
63