1 /*
2  * Copyright 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 
17 package com.android.server.telecom;
18 
19 import android.content.Context;
20 import android.media.AudioManager;
21 import android.media.ToneGenerator;
22 import android.os.Handler;
23 import android.os.HandlerThread;
24 import android.os.Message;
25 import android.provider.Settings;
26 
27 import com.android.internal.util.Preconditions;
28 
29 // TODO: Needed for move to system service: import com.android.internal.R;
30 
31 /**
32  * Plays DTMF tones locally for the caller to hear. In order to reduce (1) the amount of times we
33  * check the "play local tones" setting and (2) the length of time we keep the tone generator, this
34  * class employs a concept of a call "session" that starts and stops when the foreground call
35  * changes.
36  */
37 public class DtmfLocalTonePlayer {
38     /** Generator used to actually play the tone. */
39     private ToneGenerator mToneGenerator;
40 
41     /** The current call associated with an existing dtmf session. */
42     private Call mCall;
43 
44     /**
45      * Message codes to be used for creating and deleting ToneGenerator object in the tonegenerator
46      * thread.
47      */
48     private static final int EVENT_CREATE_OBJECT = 1;
49     private static final int EVENT_DELETE_OBJECT = 2;
50 
51     /** Handler running on the tonegenerator thread. */
52     private Handler mHandler;
53 
DtmfLocalTonePlayer()54     public DtmfLocalTonePlayer() { }
55 
onForegroundCallChanged(Call oldForegroundCall, Call newForegroundCall)56     public void onForegroundCallChanged(Call oldForegroundCall, Call newForegroundCall) {
57         endDtmfSession(oldForegroundCall);
58         startDtmfSession(newForegroundCall);
59     }
60 
61     /**
62      * Starts playing the dtmf tone specified by c.
63      *
64      * @param call The associated call.
65      * @param c The digit to play.
66      */
playTone(Call call, char c)67     void playTone(Call call, char c) {
68         // Do nothing if it is not the right call.
69         if (mCall != call) {
70             return;
71         }
72         synchronized(this) {
73             if (mToneGenerator == null) {
74                 Log.d(this, "playTone: mToneGenerator == null, %c.", c);
75             } else {
76                 Log.d(this, "starting local tone: %c.", c);
77                 int tone = getMappedTone(c);
78                 if (tone != ToneGenerator.TONE_UNKNOWN) {
79                     mToneGenerator.startTone(tone, -1 /* toneDuration */);
80                 }
81             }
82         }
83     }
84 
85     /**
86      * Stops any currently playing dtmf tone.
87      *
88      * @param call The associated call.
89      */
stopTone(Call call)90     void stopTone(Call call) {
91         // Do nothing if it's not the right call.
92         if (mCall != call) {
93             return;
94         }
95         synchronized(this) {
96             if (mToneGenerator == null) {
97                 Log.d(this, "stopTone: mToneGenerator == null.");
98             } else {
99                 Log.d(this, "stopping local tone.");
100                 mToneGenerator.stopTone();
101             }
102         }
103     }
104 
105     /**
106      * Runs initialization requires to play local tones during a call.
107      *
108      * @param call The call associated with this dtmf session.
109      */
startDtmfSession(Call call)110     private void startDtmfSession(Call call) {
111         if (call == null) {
112             return;
113         }
114         final Context context = call.getContext();
115         final boolean areLocalTonesEnabled;
116         if (context.getResources().getBoolean(R.bool.allow_local_dtmf_tones)) {
117             areLocalTonesEnabled = Settings.System.getInt(
118                     context.getContentResolver(), Settings.System.DTMF_TONE_WHEN_DIALING, 1) == 1;
119         } else {
120             areLocalTonesEnabled = false;
121         }
122 
123         mCall = call;
124 
125         if (areLocalTonesEnabled) {
126             Log.d(this, "Posting create.");
127             postMessage(EVENT_CREATE_OBJECT);
128         }
129     }
130 
131     /**
132      * Releases resources needed for playing local dtmf tones.
133      *
134      * @param call The call associated with the session to end.
135      */
endDtmfSession(Call call)136     private void endDtmfSession(Call call) {
137         if (call != null && mCall == call) {
138             // Do a stopTone() in case the sessions ends before we are told to stop the tone.
139             stopTone(call);
140 
141             mCall = null;
142             Log.d(this, "Posting delete.");
143             postMessage(EVENT_DELETE_OBJECT);
144         }
145     }
146 
147     /**
148      * Posts a message to the tonegenerator-thread handler. Creates the handler if the handler
149      * has not been instantiated.
150      *
151      * @param messageCode The message to post.
152      */
postMessage(int messageCode)153     private void postMessage(int messageCode) {
154         synchronized(this) {
155             if (mHandler == null) {
156                 mHandler = getNewHandler();
157             }
158 
159             if (mHandler == null) {
160                 Log.d(this, "Message %d skipped because there is no handler.", messageCode);
161             } else {
162                 mHandler.obtainMessage(messageCode, null).sendToTarget();
163             }
164         }
165     }
166 
167     /**
168      * Creates a new tonegenerator Handler running in its own thread.
169      */
getNewHandler()170     private Handler getNewHandler() {
171         Preconditions.checkState(mHandler == null);
172 
173         HandlerThread thread = new HandlerThread("tonegenerator-dtmf");
174         thread.start();
175 
176         return new Handler(thread.getLooper()) {
177             @Override
178             public void handleMessage(Message msg) {
179                 switch(msg.what) {
180                     case EVENT_CREATE_OBJECT:
181                         synchronized(DtmfLocalTonePlayer.this) {
182                             if (mToneGenerator == null) {
183                                 try {
184                                     mToneGenerator = new ToneGenerator(
185                                             AudioManager.STREAM_DTMF, 80);
186                                 } catch (RuntimeException e) {
187                                     Log.e(this, e, "Error creating local tone generator.");
188                                     mToneGenerator = null;
189                                 }
190                             }
191                         }
192                         break;
193                     case EVENT_DELETE_OBJECT:
194                         synchronized(DtmfLocalTonePlayer.this) {
195                             if (mToneGenerator != null) {
196                                 mToneGenerator.release();
197                                 mToneGenerator = null;
198                             }
199                             // Delete the handler after the tone generator object is deleted by
200                             // the tonegenerator thread.
201                             if (mHandler != null && !mHandler.hasMessages(EVENT_CREATE_OBJECT)) {
202                                 // Stop the handler only if there are no pending CREATE messages.
203                                 mHandler.removeMessages(EVENT_DELETE_OBJECT);
204                                 mHandler.getLooper().quitSafely();
205                                 mHandler = null;
206                             }
207                         }
208                         break;
209                 }
210             }
211         };
212     }
213 
214     private static int getMappedTone(char digit) {
215         if (digit >= '0' && digit <= '9') {
216             return ToneGenerator.TONE_DTMF_0 + digit - '0';
217         } else if (digit == '#') {
218             return ToneGenerator.TONE_DTMF_P;
219         } else if (digit == '*') {
220             return ToneGenerator.TONE_DTMF_S;
221         }
222         return ToneGenerator.TONE_UNKNOWN;
223     }
224 }
225