1 /*
2  * Copyright 2018 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 package androidx.media;
18 
19 import android.content.Context;
20 import android.os.Build;
21 import android.support.v4.media.session.MediaControllerCompat;
22 import android.support.v4.media.session.MediaSessionCompat;
23 import android.util.Log;
24 
25 import androidx.annotation.NonNull;
26 import androidx.annotation.Nullable;
27 import androidx.core.os.BuildCompat;
28 
29 /**
30  * Provides support for interacting with {@link MediaSessionCompat media sessions} that
31  * applications have published to express their ongoing media playback state.
32  *
33  * @see MediaSessionCompat
34  * @see MediaControllerCompat
35  */
36 public final class MediaSessionManager {
37     static final String TAG = "MediaSessionManager";
38     static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
39 
40     private static final Object sLock = new Object();
41     private static volatile MediaSessionManager sSessionManager;
42 
43     MediaSessionManagerImpl mImpl;
44 
45     /**
46      * Gets an instance of the media session manager associated with the context.
47      *
48      * @return The MediaSessionManager instance for this context.
49      */
getSessionManager(@onNull Context context)50     public static @NonNull MediaSessionManager getSessionManager(@NonNull Context context) {
51         MediaSessionManager manager = sSessionManager;
52         if (manager == null) {
53             synchronized (sLock) {
54                 manager = sSessionManager;
55                 if (manager == null) {
56                     sSessionManager = new MediaSessionManager(context.getApplicationContext());
57                     manager = sSessionManager;
58                 }
59             }
60         }
61         return manager;
62     }
63 
MediaSessionManager(Context context)64     private MediaSessionManager(Context context) {
65         if (BuildCompat.isAtLeastP()) {
66             mImpl = new MediaSessionManagerImplApi28(context);
67         } else if (Build.VERSION.SDK_INT >= 21) {
68             mImpl = new MediaSessionManagerImplApi21(context);
69         } else {
70             mImpl = new MediaSessionManagerImplBase(context);
71         }
72     }
73 
74     /**
75      * Checks whether the remote user is a trusted app.
76      * <p>
77      * An app is trusted if the app holds the android.Manifest.permission.MEDIA_CONTENT_CONTROL
78      * permission or has an enabled notification listener.
79      *
80      * @param userInfo The remote user info from either
81      *            {@link MediaSessionCompat#getCurrentControllerInfo()} and
82      *            {@link MediaBrowserServiceCompat#getCurrentBrowserInfo()}.
83      * @return {@code true} if the remote user is trusted and its package name matches with the UID.
84      *            {@code false} otherwise.
85      */
isTrustedForMediaControl(@onNull RemoteUserInfo userInfo)86     public boolean isTrustedForMediaControl(@NonNull RemoteUserInfo userInfo) {
87         if (userInfo == null) {
88             throw new IllegalArgumentException("userInfo should not be null");
89         }
90         return mImpl.isTrustedForMediaControl(userInfo.mImpl);
91     }
92 
getContext()93     Context getContext() {
94         return mImpl.getContext();
95     }
96 
97     interface MediaSessionManagerImpl {
getContext()98         Context getContext();
isTrustedForMediaControl(RemoteUserInfoImpl userInfo)99         boolean isTrustedForMediaControl(RemoteUserInfoImpl userInfo);
100     }
101 
102     interface RemoteUserInfoImpl {
getPackageName()103         String getPackageName();
getPid()104         int getPid();
getUid()105         int getUid();
106     }
107 
108     /**
109      * Information of a remote user of {@link android.support.v4.media.session.MediaSessionCompat}
110      * or {@link MediaBrowserServiceCompat}.
111      * This can be used to decide whether the remote user is trusted app.
112      *
113      * @see #isTrustedForMediaControl(RemoteUserInfo)
114      */
115     public static final class RemoteUserInfo {
116         /**
117          * Used by {@link #getPackageName()} when the session is connected to the legacy controller
118          * whose exact package name cannot be obtained.
119          */
120         public static String LEGACY_CONTROLLER = "android.media.session.MediaController";
121 
122         RemoteUserInfoImpl mImpl;
123 
RemoteUserInfo(@onNull String packageName, int pid, int uid)124         public RemoteUserInfo(@NonNull String packageName, int pid, int uid) {
125             if (BuildCompat.isAtLeastP()) {
126                 mImpl = new MediaSessionManagerImplApi28.RemoteUserInfo(packageName, pid, uid);
127             } else {
128                 mImpl = new MediaSessionManagerImplBase.RemoteUserInfo(packageName, pid, uid);
129             }
130         }
131 
132         /**
133          * @return package name of the controller. Can be {@link #LEGACY_CONTROLLER} if the package
134          *         name cannot be obtained.
135          */
getPackageName()136         public @NonNull String getPackageName() {
137             return mImpl.getPackageName();
138         }
139 
140         /**
141          * @return pid of the controller
142          */
getPid()143         public int getPid() {
144             return mImpl.getPid();
145         }
146 
147         /**
148          * @return uid of the controller
149          */
getUid()150         public int getUid() {
151             return mImpl.getUid();
152         }
153 
154         @Override
equals(@ullable Object obj)155         public boolean equals(@Nullable Object obj) {
156             return mImpl.equals(obj);
157         }
158 
159         @Override
hashCode()160         public int hashCode() {
161             return mImpl.hashCode();
162         }
163     }
164 }
165