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.provider.Settings;
23 
24 // TODO: Needed for move to system service: import com.android.internal.R;
25 
26 /**
27  * Plays DTMF tones locally for the caller to hear. In order to reduce (1) the amount of times we
28  * check the "play local tones" setting and (2) the length of time we keep the tone generator, this
29  * class employs a concept of a call "session" that starts and stops when the foreground call
30  * changes.
31  */
32 class DtmfLocalTonePlayer extends CallsManagerListenerBase {
33     /** Generator used to actually play the tone. */
34     private ToneGenerator mToneGenerator;
35 
36     /** The current call associated with an existing dtmf session. */
37     private Call mCall;
38 
39     /** The context. */
40     private final Context mContext;
41 
DtmfLocalTonePlayer(Context context)42     public DtmfLocalTonePlayer(Context context) {
43         mContext = context;
44     }
45 
46     /** {@inheritDoc} */
47     @Override
onForegroundCallChanged(Call oldForegroundCall, Call newForegroundCall)48     public void onForegroundCallChanged(Call oldForegroundCall, Call newForegroundCall) {
49         endDtmfSession(oldForegroundCall);
50         startDtmfSession(newForegroundCall);
51     }
52 
53     /**
54      * Starts playing the dtmf tone specified by c.
55      *
56      * @param call The associated call.
57      * @param c The digit to play.
58      */
playTone(Call call, char c)59     void playTone(Call call, char c) {
60         // Do nothing if it is not the right call.
61         if (mCall != call) {
62             return;
63         }
64 
65         if (mToneGenerator == null) {
66             Log.d(this, "playTone: mToneGenerator == null, %c.", c);
67         } else {
68             Log.d(this, "starting local tone: %c.", c);
69             int tone = getMappedTone(c);
70             if (tone != ToneGenerator.TONE_UNKNOWN) {
71                 mToneGenerator.startTone(tone, -1 /* toneDuration */);
72             }
73         }
74     }
75 
76     /**
77      * Stops any currently playing dtmf tone.
78      *
79      * @param call The associated call.
80      */
stopTone(Call call)81     void stopTone(Call call) {
82         // Do nothing if it's not the right call.
83         if (mCall != call) {
84             return;
85         }
86 
87         if (mToneGenerator == null) {
88             Log.d(this, "stopTone: mToneGenerator == null.");
89         } else {
90             Log.d(this, "stopping local tone.");
91             mToneGenerator.stopTone();
92         }
93     }
94 
95     /**
96      * Runs initialization requires to play local tones during a call.
97      *
98      * @param call The call associated with this dtmf session.
99      */
startDtmfSession(Call call)100     private void startDtmfSession(Call call) {
101         if (call == null) {
102             return;
103         }
104         final Context context = call.getContext();
105         final boolean areLocalTonesEnabled;
106         if (context.getResources().getBoolean(R.bool.allow_local_dtmf_tones)) {
107             areLocalTonesEnabled = Settings.System.getInt(
108                     context.getContentResolver(), Settings.System.DTMF_TONE_WHEN_DIALING, 1) == 1;
109         } else {
110             areLocalTonesEnabled = false;
111         }
112 
113         mCall = call;
114 
115         if (areLocalTonesEnabled) {
116             if (mToneGenerator == null) {
117                 try {
118                     mToneGenerator = new ToneGenerator(AudioManager.STREAM_DTMF, 80);
119                 } catch (RuntimeException e) {
120                     Log.e(this, e, "Error creating local tone generator.");
121                     mToneGenerator = null;
122                 }
123             }
124         }
125     }
126 
127     /**
128      * Releases resources needed for playing local dtmf tones.
129      *
130      * @param call The call associated with the session to end.
131      */
endDtmfSession(Call call)132     private void endDtmfSession(Call call) {
133         if (call != null && mCall == call) {
134             // Do a stopTone() in case the sessions ends before we are told to stop the tone.
135             stopTone(call);
136 
137             mCall = null;
138 
139             if (mToneGenerator != null) {
140                 mToneGenerator.release();
141                 mToneGenerator = null;
142             }
143         }
144     }
145 
getMappedTone(char digit)146     private static final int getMappedTone(char digit) {
147         if (digit >= '0' && digit <= '9') {
148             return ToneGenerator.TONE_DTMF_0 + digit - '0';
149         } else if (digit == '#') {
150             return ToneGenerator.TONE_DTMF_P;
151         } else if (digit == '*') {
152             return ToneGenerator.TONE_DTMF_S;
153         }
154         return ToneGenerator.TONE_UNKNOWN;
155     }
156 }
157