TaskSnapshotLoader.java revision f3e412e5021c43491ed3ced61f02c2fd436e064e 
1/*
2 * Copyright (C) 2017 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.server.wm;
18
19import static com.android.server.wm.TaskSnapshotPersister.*;
20import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;
21import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
22
23import android.app.ActivityManager.TaskSnapshot;
24import android.graphics.Bitmap;
25import android.graphics.Bitmap.Config;
26import android.graphics.BitmapFactory;
27import android.graphics.BitmapFactory.Options;
28import android.graphics.GraphicBuffer;
29import android.graphics.Rect;
30import android.util.Slog;
31
32import com.android.server.wm.nano.WindowManagerProtos.TaskSnapshotProto;
33
34import java.io.File;
35import java.io.IOException;
36import java.nio.file.Files;
37
38/**
39 * Loads a persisted {@link TaskSnapshot} from disk.
40 * <p>
41 * Do not hold the window manager lock when accessing this class.
42 * <p>
43 * Test class: {@link TaskSnapshotPersisterLoaderTest}
44 */
45class TaskSnapshotLoader {
46
47    private static final String TAG = TAG_WITH_CLASS_NAME ? "TaskSnapshotLoader" : TAG_WM;
48
49    private final TaskSnapshotPersister mPersister;
50
51    TaskSnapshotLoader(TaskSnapshotPersister persister) {
52        mPersister = persister;
53    }
54
55    /**
56     * Loads a task from the disk.
57     * <p>
58     * Do not hold the window manager lock when calling this method, as we directly read data from
59     * disk here, which might be slow.
60     *
61     * @param taskId The id of the task to load.
62     * @param userId The id of the user the task belonged to.
63     * @param reducedResolution Whether to load a reduced resolution version of the snapshot.
64     * @return The loaded {@link TaskSnapshot} or {@code null} if it couldn't be loaded.
65     */
66    TaskSnapshot loadTask(int taskId, int userId, boolean reducedResolution) {
67        final File protoFile = mPersister.getProtoFile(taskId, userId);
68        final File bitmapFile = reducedResolution
69                ? mPersister.getReducedResolutionBitmapFile(taskId, userId)
70                : mPersister.getBitmapFile(taskId, userId);
71        if (bitmapFile == null || !protoFile.exists() || !bitmapFile.exists()) {
72            return null;
73        }
74        try {
75            final byte[] bytes = Files.readAllBytes(protoFile.toPath());
76            final TaskSnapshotProto proto = TaskSnapshotProto.parseFrom(bytes);
77            final Options options = new Options();
78            options.inPreferredConfig = Config.HARDWARE;
79            final Bitmap bitmap = BitmapFactory.decodeFile(bitmapFile.getPath(), options);
80            if (bitmap == null) {
81                Slog.w(TAG, "Failed to load bitmap: " + bitmapFile.getPath());
82                return null;
83            }
84            final GraphicBuffer buffer = bitmap.createGraphicBufferHandle();
85            if (buffer == null) {
86                Slog.w(TAG, "Failed to retrieve gralloc buffer for bitmap: "
87                        + bitmapFile.getPath());
88                return null;
89            }
90            return new TaskSnapshot(buffer, proto.orientation,
91                    new Rect(proto.insetLeft, proto.insetTop, proto.insetRight, proto.insetBottom),
92                    reducedResolution, reducedResolution ? REDUCED_SCALE : 1f,
93                    proto.isRealSnapshot);
94        } catch (IOException e) {
95            Slog.w(TAG, "Unable to load task snapshot data for taskId=" + taskId);
96            return null;
97        }
98    }
99}
100