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1 /*
<lambda>null2  * 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 package com.android.systemui.media.controls.domain.pipeline
18 
19 import android.content.ComponentName
20 import android.content.Context
21 import android.media.session.MediaController
22 import android.media.session.MediaController.PlaybackInfo
23 import android.media.session.MediaSession
24 import android.media.session.MediaSessionManager
25 import android.util.Log
26 import com.android.systemui.dagger.qualifiers.Background
27 import com.android.systemui.dagger.qualifiers.Main
28 import com.android.systemui.media.controls.shared.model.MediaData
29 import com.android.systemui.statusbar.phone.NotificationListenerWithPlugins
30 import java.util.concurrent.Executor
31 import javax.inject.Inject
32 
33 private const val TAG = "MediaSessionBasedFilter"
34 
35 /**
36  * Filters media loaded events for local media sessions while an app is casting.
37  *
38  * When an app is casting there can be one remote media sessions and potentially more local media
39  * sessions. In this situation, there should only be a media object for the remote session. To
40  * achieve this, update events for the local session need to be filtered.
41  */
42 class MediaSessionBasedFilter
43 @Inject
44 constructor(
45     context: Context,
46     private val sessionManager: MediaSessionManager,
47     @Main private val foregroundExecutor: Executor,
48     @Background private val backgroundExecutor: Executor,
49 ) : MediaDataManager.Listener {
50 
51     private val listeners: MutableSet<MediaDataManager.Listener> = mutableSetOf()
52 
53     // Keep track of MediaControllers for a given package to check if an app is casting and it
54     // filter loaded events for local sessions.
55     private val packageControllers: LinkedHashMap<String, MutableList<MediaController>> =
56         LinkedHashMap()
57 
58     // Keep track of the key used for the session tokens. This information is used to know when to
59     // dispatch a removed event so that a media object for a local session will be removed.
60     private val keyedTokens: MutableMap<String, MutableSet<TokenId>> = mutableMapOf()
61 
62     // Keep track of which media session tokens have associated notifications.
63     private val tokensWithNotifications: MutableSet<TokenId> = mutableSetOf()
64 
65     private val sessionListener =
66         object : MediaSessionManager.OnActiveSessionsChangedListener {
67             override fun onActiveSessionsChanged(controllers: List<MediaController>?) {
68                 handleControllersChanged(controllers)
69             }
70         }
71 
72     init {
73         backgroundExecutor.execute {
74             val name = ComponentName(context, NotificationListenerWithPlugins::class.java)
75             sessionManager.addOnActiveSessionsChangedListener(sessionListener, name)
76             handleControllersChanged(sessionManager.getActiveSessions(name))
77         }
78     }
79 
80     /** Add a listener for filtered [MediaData] changes */
81     fun addListener(listener: MediaDataManager.Listener) = listeners.add(listener)
82 
83     /** Remove a listener that was registered with addListener */
84     fun removeListener(listener: MediaDataManager.Listener) = listeners.remove(listener)
85 
86     /**
87      * May filter loaded events by not passing them along to listeners.
88      *
89      * If an app has only one session with playback type PLAYBACK_TYPE_REMOTE, then assuming that
90      * the app is casting. Sometimes apps will send redundant updates to a local session with
91      * playback type PLAYBACK_TYPE_LOCAL. These updates should be filtered to improve the usability
92      * of the media controls.
93      */
94     override fun onMediaDataLoaded(
95         key: String,
96         oldKey: String?,
97         data: MediaData,
98         immediately: Boolean,
99         receivedSmartspaceCardLatency: Int,
100         isSsReactivated: Boolean,
101     ) {
102         backgroundExecutor.execute {
103             data.token?.let { tokensWithNotifications.add(TokenId(it)) }
104             val isMigration = oldKey != null && key != oldKey
105             if (isMigration) {
106                 keyedTokens.remove(oldKey)?.let { removed -> keyedTokens.put(key, removed) }
107             }
108             if (data.token != null) {
109                 keyedTokens.get(key)?.let { tokens -> tokens.add(TokenId(data.token)) }
110                     ?: run {
111                         val tokens = mutableSetOf(TokenId(data.token))
112                         keyedTokens.put(key, tokens)
113                     }
114             }
115             // Determine if an app is casting by checking if it has a session with playback type
116             // PLAYBACK_TYPE_REMOTE.
117             val remoteControllers =
118                 packageControllers.get(data.packageName)?.filter {
119                     it.playbackInfo?.playbackType == PlaybackInfo.PLAYBACK_TYPE_REMOTE
120                 }
121             // Limiting search to only apps with a single remote session.
122             val remote = if (remoteControllers?.size == 1) remoteControllers.firstOrNull() else null
123             if (
124                 isMigration ||
125                     remote == null ||
126                     remote.sessionToken == data.token ||
127                     !tokensWithNotifications.contains(TokenId(remote.sessionToken))
128             ) {
129                 // Not filtering in this case. Passing the event along to listeners.
130                 dispatchMediaDataLoaded(key, oldKey, data, immediately)
131             } else {
132                 // Filtering this event because the app is casting and the loaded events is for a
133                 // local session.
134                 Log.d(TAG, "filtering key=$key local=${data.token} remote=${remote?.sessionToken}")
135                 // If the local session uses a different notification key, then lets go a step
136                 // farther and dismiss the media data so that media controls for the local session
137                 // don't hang around while casting.
138                 if (!keyedTokens.get(key)!!.contains(TokenId(remote.sessionToken))) {
139                     dispatchMediaDataRemoved(key, userInitiated = false)
140                 }
141             }
142         }
143     }
144 
145     override fun onMediaDataRemoved(key: String, userInitiated: Boolean) {
146         // Queue on background thread to ensure ordering of loaded and removed events is maintained.
147         backgroundExecutor.execute {
148             keyedTokens.remove(key)
149             dispatchMediaDataRemoved(key, userInitiated)
150         }
151     }
152 
153     private fun dispatchMediaDataLoaded(
154         key: String,
155         oldKey: String?,
156         info: MediaData,
157         immediately: Boolean,
158     ) {
159         foregroundExecutor.execute {
160             listeners.toSet().forEach { it.onMediaDataLoaded(key, oldKey, info, immediately) }
161         }
162     }
163 
164     private fun dispatchMediaDataRemoved(key: String, userInitiated: Boolean) {
165         foregroundExecutor.execute {
166             listeners.toSet().forEach { it.onMediaDataRemoved(key, userInitiated) }
167         }
168     }
169 
170     private fun handleControllersChanged(controllers: List<MediaController>?) {
171         packageControllers.clear()
172         controllers?.forEach { controller ->
173             packageControllers.get(controller.packageName)?.let { tokens -> tokens.add(controller) }
174                 ?: run {
175                     val tokens = mutableListOf(controller)
176                     packageControllers.put(controller.packageName, tokens)
177                 }
178         }
179         controllers?.map { TokenId(it.sessionToken) }?.let { tokensWithNotifications.retainAll(it) }
180     }
181 
182     /**
183      * Represents a unique identifier for a [MediaSession.Token].
184      *
185      * It's used to avoid storing strong binders for media session tokens.
186      */
187     private data class TokenId(val id: Int) {
188         constructor(token: MediaSession.Token) : this(token.hashCode())
189     }
190 }
191