1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
|
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.media;
import android.media.session.MediaController.PlaybackInfo;
import android.media.session.PlaybackState;
import android.media.session.MediaSession;
import android.os.UserHandle;
import java.io.PrintWriter;
import java.util.ArrayList;
/**
* Keeps track of media sessions and their priority for notifications, media
* button dispatch, etc.
*/
public class MediaSessionStack {
/**
* These are states that usually indicate the user took an action and should
* bump priority regardless of the old state.
*/
private static final int[] ALWAYS_PRIORITY_STATES = {
PlaybackState.STATE_FAST_FORWARDING,
PlaybackState.STATE_REWINDING,
PlaybackState.STATE_SKIPPING_TO_PREVIOUS,
PlaybackState.STATE_SKIPPING_TO_NEXT };
/**
* These are states that usually indicate the user took an action if they
* were entered from a non-priority state.
*/
private static final int[] TRANSITION_PRIORITY_STATES = {
PlaybackState.STATE_BUFFERING,
PlaybackState.STATE_CONNECTING,
PlaybackState.STATE_PLAYING };
private final ArrayList<MediaSessionRecord> mSessions = new ArrayList<MediaSessionRecord>();
private MediaSessionRecord mGlobalPrioritySession;
// The last record that either entered one of the playing states or was
// added.
private MediaSessionRecord mLastInterestingRecord;
private MediaSessionRecord mCachedButtonReceiver;
private MediaSessionRecord mCachedDefault;
private MediaSessionRecord mCachedVolumeDefault;
private ArrayList<MediaSessionRecord> mCachedActiveList;
private ArrayList<MediaSessionRecord> mCachedTransportControlList;
/**
* Add a record to the priority tracker.
*
* @param record The record to add.
*/
public void addSession(MediaSessionRecord record) {
mSessions.add(record);
clearCache();
mLastInterestingRecord = record;
}
/**
* Remove a record from the priority tracker.
*
* @param record The record to remove.
*/
public void removeSession(MediaSessionRecord record) {
mSessions.remove(record);
if (record == mGlobalPrioritySession) {
mGlobalPrioritySession = null;
}
clearCache();
}
/**
* Notify the priority tracker that a session's state changed.
*
* @param record The record that changed.
* @param oldState Its old playback state.
* @param newState Its new playback state.
* @return true if the priority order was updated, false otherwise.
*/
public boolean onPlaystateChange(MediaSessionRecord record, int oldState, int newState) {
if (shouldUpdatePriority(oldState, newState)) {
mSessions.remove(record);
mSessions.add(0, record);
clearCache();
// This becomes the last interesting record since it entered a
// playing state
mLastInterestingRecord = record;
return true;
} else if (!MediaSession.isActiveState(newState)) {
// Just clear the volume cache when a state goes inactive
mCachedVolumeDefault = null;
}
return false;
}
/**
* Handle any stack changes that need to occur in response to a session
* state change. TODO add the old and new session state as params
*
* @param record The record that changed.
*/
public void onSessionStateChange(MediaSessionRecord record) {
if ((record.getFlags() & MediaSession.FLAG_EXCLUSIVE_GLOBAL_PRIORITY) != 0) {
mGlobalPrioritySession = record;
}
// For now just clear the cache. Eventually we'll selectively clear
// depending on what changed.
clearCache();
}
/**
* Get the current priority sorted list of active sessions. The most
* important session is at index 0 and the least important at size - 1.
*
* @param userId The user to check.
* @return All the active sessions in priority order.
*/
public ArrayList<MediaSessionRecord> getActiveSessions(int userId) {
if (mCachedActiveList == null) {
mCachedActiveList = getPriorityListLocked(true, 0, userId);
}
return mCachedActiveList;
}
/**
* Get the current priority sorted list of active sessions that use
* transport controls. The most important session is at index 0 and the
* least important at size -1.
*
* @param userId The user to check.
* @return All the active sessions that handle transport controls in
* priority order.
*/
public ArrayList<MediaSessionRecord> getTransportControlSessions(int userId) {
if (mCachedTransportControlList == null) {
mCachedTransportControlList = getPriorityListLocked(true,
MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS, userId);
}
return mCachedTransportControlList;
}
/**
* Get the highest priority active session.
*
* @param userId The user to check.
* @return The current highest priority session or null.
*/
public MediaSessionRecord getDefaultSession(int userId) {
if (mCachedDefault != null) {
return mCachedDefault;
}
ArrayList<MediaSessionRecord> records = getPriorityListLocked(true, 0, userId);
if (records.size() > 0) {
return records.get(0);
}
return null;
}
/**
* Get the highest priority session that can handle media buttons.
*
* @param userId The user to check.
* @param includeNotPlaying Return a non-playing session if nothing else is
* available
* @return The default media button session or null.
*/
public MediaSessionRecord getDefaultMediaButtonSession(int userId, boolean includeNotPlaying) {
if (mGlobalPrioritySession != null && mGlobalPrioritySession.isActive()) {
return mGlobalPrioritySession;
}
if (mCachedButtonReceiver != null) {
return mCachedButtonReceiver;
}
ArrayList<MediaSessionRecord> records = getPriorityListLocked(true,
MediaSession.FLAG_HANDLES_MEDIA_BUTTONS, userId);
if (records.size() > 0) {
MediaSessionRecord record = records.get(0);
if (record.isPlaybackActive(false)) {
// Since we're going to send a button event to this record make
// it the last interesting one.
mLastInterestingRecord = record;
mCachedButtonReceiver = record;
} else if (mLastInterestingRecord != null) {
if (records.contains(mLastInterestingRecord)) {
mCachedButtonReceiver = mLastInterestingRecord;
} else {
// That record is no longer used. Clear its reference.
mLastInterestingRecord = null;
}
}
if (includeNotPlaying && mCachedButtonReceiver == null) {
// If we really want a record and we didn't find one yet use the
// highest priority session even if it's not playing.
mCachedButtonReceiver = record;
}
}
return mCachedButtonReceiver;
}
public MediaSessionRecord getDefaultVolumeSession(int userId) {
if (mGlobalPrioritySession != null && mGlobalPrioritySession.isActive()) {
return mGlobalPrioritySession;
}
if (mCachedVolumeDefault != null) {
return mCachedVolumeDefault;
}
ArrayList<MediaSessionRecord> records = getPriorityListLocked(true, 0, userId);
int size = records.size();
for (int i = 0; i < size; i++) {
MediaSessionRecord record = records.get(i);
if (record.isPlaybackActive(false)) {
mCachedVolumeDefault = record;
return record;
}
}
return null;
}
public MediaSessionRecord getDefaultRemoteSession(int userId) {
ArrayList<MediaSessionRecord> records = getPriorityListLocked(true, 0, userId);
int size = records.size();
for (int i = 0; i < size; i++) {
MediaSessionRecord record = records.get(i);
if (record.getPlaybackType() == PlaybackInfo.PLAYBACK_TYPE_REMOTE) {
return record;
}
}
return null;
}
public boolean isGlobalPriorityActive() {
return mGlobalPrioritySession == null ? false : mGlobalPrioritySession.isActive();
}
public void dump(PrintWriter pw, String prefix) {
ArrayList<MediaSessionRecord> sortedSessions = getPriorityListLocked(false, 0,
UserHandle.USER_ALL);
int count = sortedSessions.size();
pw.println(prefix + "Global priority session is " + mGlobalPrioritySession);
pw.println(prefix + "Sessions Stack - have " + count + " sessions:");
String indent = prefix + " ";
for (int i = 0; i < count; i++) {
MediaSessionRecord record = sortedSessions.get(i);
record.dump(pw, indent);
pw.println();
}
}
/**
* Get a priority sorted list of sessions. Can filter to only return active
* sessions or sessions with specific flags.
*
* @param activeOnly True to only return active sessions, false to return
* all sessions.
* @param withFlags Only return sessions with all the specified flags set. 0
* returns all sessions.
* @param userId The user to get sessions for. {@link UserHandle#USER_ALL}
* will return sessions for all users.
* @return The priority sorted list of sessions.
*/
private ArrayList<MediaSessionRecord> getPriorityListLocked(boolean activeOnly, int withFlags,
int userId) {
ArrayList<MediaSessionRecord> result = new ArrayList<MediaSessionRecord>();
int lastLocalIndex = 0;
int lastActiveIndex = 0;
int lastPublishedIndex = 0;
int size = mSessions.size();
for (int i = 0; i < size; i++) {
final MediaSessionRecord session = mSessions.get(i);
if (userId != UserHandle.USER_ALL && userId != session.getUserId()) {
// Filter out sessions for the wrong user
continue;
}
if ((session.getFlags() & withFlags) != withFlags) {
// Filter out sessions with the wrong flags
continue;
}
if (!session.isActive()) {
if (!activeOnly) {
// If we're getting unpublished as well always put them at
// the end
result.add(session);
}
continue;
}
if (session.isSystemPriority()) {
// System priority sessions are special and always go at the
// front. We expect there to only be one of these at a time.
result.add(0, session);
lastLocalIndex++;
lastActiveIndex++;
lastPublishedIndex++;
} else if (session.isPlaybackActive(true)) {
// TODO this with real local route check
if (true) {
// Active local sessions get top priority
result.add(lastLocalIndex, session);
lastLocalIndex++;
lastActiveIndex++;
lastPublishedIndex++;
} else {
// Then active remote sessions
result.add(lastActiveIndex, session);
lastActiveIndex++;
lastPublishedIndex++;
}
} else {
// inactive sessions go at the end in order of whoever last did
// something.
result.add(lastPublishedIndex, session);
lastPublishedIndex++;
}
}
return result;
}
private boolean shouldUpdatePriority(int oldState, int newState) {
if (containsState(newState, ALWAYS_PRIORITY_STATES)) {
return true;
}
if (!containsState(oldState, TRANSITION_PRIORITY_STATES)
&& containsState(newState, TRANSITION_PRIORITY_STATES)) {
return true;
}
return false;
}
private boolean containsState(int state, int[] states) {
for (int i = 0; i < states.length; i++) {
if (states[i] == state) {
return true;
}
}
return false;
}
private void clearCache() {
mCachedDefault = null;
mCachedVolumeDefault = null;
mCachedButtonReceiver = null;
mCachedActiveList = null;
mCachedTransportControlList = null;
}
}
|