1/*
2 * Copyright (C) 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
17package com.android.systemui.statusbar.policy;
18
19import android.content.Context;
20import android.hardware.camera2.CameraAccessException;
21import android.hardware.camera2.CameraCharacteristics;
22import android.hardware.camera2.CameraManager;
23import android.os.Handler;
24import android.os.HandlerThread;
25import android.os.Process;
26import android.text.TextUtils;
27import android.util.Log;
28
29import java.lang.ref.WeakReference;
30import java.util.ArrayList;
31
32/**
33 * Manages the flashlight.
34 */
35public class FlashlightController {
36
37    private static final String TAG = "FlashlightController";
38    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
39
40    private static final int DISPATCH_ERROR = 0;
41    private static final int DISPATCH_CHANGED = 1;
42    private static final int DISPATCH_AVAILABILITY_CHANGED = 2;
43
44    private final CameraManager mCameraManager;
45    /** Call {@link #ensureHandler()} before using */
46    private Handler mHandler;
47
48    /** Lock on mListeners when accessing */
49    private final ArrayList<WeakReference<FlashlightListener>> mListeners = new ArrayList<>(1);
50
51    /** Lock on {@code this} when accessing */
52    private boolean mFlashlightEnabled;
53
54    private final String mCameraId;
55    private boolean mTorchAvailable;
56
57    public FlashlightController(Context mContext) {
58        mCameraManager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
59
60        String cameraId = null;
61        try {
62            cameraId = getCameraId();
63        } catch (Throwable e) {
64            Log.e(TAG, "Couldn't initialize.", e);
65            return;
66        } finally {
67            mCameraId = cameraId;
68        }
69
70        if (mCameraId != null) {
71            ensureHandler();
72            mCameraManager.registerTorchCallback(mTorchCallback, mHandler);
73        }
74    }
75
76    public void setFlashlight(boolean enabled) {
77        boolean pendingError = false;
78        synchronized (this) {
79            if (mFlashlightEnabled != enabled) {
80                mFlashlightEnabled = enabled;
81                try {
82                    mCameraManager.setTorchMode(mCameraId, enabled);
83                } catch (CameraAccessException e) {
84                    Log.e(TAG, "Couldn't set torch mode", e);
85                    mFlashlightEnabled = false;
86                    pendingError = true;
87                }
88            }
89        }
90        dispatchModeChanged(mFlashlightEnabled);
91        if (pendingError) {
92            dispatchError();
93        }
94    }
95
96    public boolean hasFlashlight() {
97        return mCameraId != null;
98    }
99
100    public synchronized boolean isEnabled() {
101        return mFlashlightEnabled;
102    }
103
104    public synchronized boolean isAvailable() {
105        return mTorchAvailable;
106    }
107
108    public void addListener(FlashlightListener l) {
109        synchronized (mListeners) {
110            cleanUpListenersLocked(l);
111            mListeners.add(new WeakReference<>(l));
112        }
113    }
114
115    public void removeListener(FlashlightListener l) {
116        synchronized (mListeners) {
117            cleanUpListenersLocked(l);
118        }
119    }
120
121    private synchronized void ensureHandler() {
122        if (mHandler == null) {
123            HandlerThread thread = new HandlerThread(TAG, Process.THREAD_PRIORITY_BACKGROUND);
124            thread.start();
125            mHandler = new Handler(thread.getLooper());
126        }
127    }
128
129    private String getCameraId() throws CameraAccessException {
130        String[] ids = mCameraManager.getCameraIdList();
131        for (String id : ids) {
132            CameraCharacteristics c = mCameraManager.getCameraCharacteristics(id);
133            Boolean flashAvailable = c.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
134            Integer lensFacing = c.get(CameraCharacteristics.LENS_FACING);
135            if (flashAvailable != null && flashAvailable
136                    && lensFacing != null && lensFacing == CameraCharacteristics.LENS_FACING_BACK) {
137                return id;
138            }
139        }
140        return null;
141    }
142
143    private void dispatchModeChanged(boolean enabled) {
144        dispatchListeners(DISPATCH_CHANGED, enabled);
145    }
146
147    private void dispatchError() {
148        dispatchListeners(DISPATCH_CHANGED, false /* argument (ignored) */);
149    }
150
151    private void dispatchAvailabilityChanged(boolean available) {
152        dispatchListeners(DISPATCH_AVAILABILITY_CHANGED, available);
153    }
154
155    private void dispatchListeners(int message, boolean argument) {
156        synchronized (mListeners) {
157            final int N = mListeners.size();
158            boolean cleanup = false;
159            for (int i = 0; i < N; i++) {
160                FlashlightListener l = mListeners.get(i).get();
161                if (l != null) {
162                    if (message == DISPATCH_ERROR) {
163                        l.onFlashlightError();
164                    } else if (message == DISPATCH_CHANGED) {
165                        l.onFlashlightChanged(argument);
166                    } else if (message == DISPATCH_AVAILABILITY_CHANGED) {
167                        l.onFlashlightAvailabilityChanged(argument);
168                    }
169                } else {
170                    cleanup = true;
171                }
172            }
173            if (cleanup) {
174                cleanUpListenersLocked(null);
175            }
176        }
177    }
178
179    private void cleanUpListenersLocked(FlashlightListener listener) {
180        for (int i = mListeners.size() - 1; i >= 0; i--) {
181            FlashlightListener found = mListeners.get(i).get();
182            if (found == null || found == listener) {
183                mListeners.remove(i);
184            }
185        }
186    }
187
188    private final CameraManager.TorchCallback mTorchCallback =
189            new CameraManager.TorchCallback() {
190
191        @Override
192        public void onTorchModeUnavailable(String cameraId) {
193            if (TextUtils.equals(cameraId, mCameraId)) {
194                setCameraAvailable(false);
195            }
196        }
197
198        @Override
199        public void onTorchModeChanged(String cameraId, boolean enabled) {
200            if (TextUtils.equals(cameraId, mCameraId)) {
201                setCameraAvailable(true);
202                setTorchMode(enabled);
203            }
204        }
205
206        private void setCameraAvailable(boolean available) {
207            boolean changed;
208            synchronized (FlashlightController.this) {
209                changed = mTorchAvailable != available;
210                mTorchAvailable = available;
211            }
212            if (changed) {
213                if (DEBUG) Log.d(TAG, "dispatchAvailabilityChanged(" + available + ")");
214                dispatchAvailabilityChanged(available);
215            }
216        }
217
218        private void setTorchMode(boolean enabled) {
219            boolean changed;
220            synchronized (FlashlightController.this) {
221                changed = mFlashlightEnabled != enabled;
222                mFlashlightEnabled = enabled;
223            }
224            if (changed) {
225                if (DEBUG) Log.d(TAG, "dispatchModeChanged(" + enabled + ")");
226                dispatchModeChanged(enabled);
227            }
228        }
229    };
230
231    public interface FlashlightListener {
232
233        /**
234         * Called when the flashlight was turned off or on.
235         * @param enabled true if the flashlight is currently turned on.
236         */
237        void onFlashlightChanged(boolean enabled);
238
239
240        /**
241         * Called when there is an error that turns the flashlight off.
242         */
243        void onFlashlightError();
244
245        /**
246         * Called when there is a change in availability of the flashlight functionality
247         * @param available true if the flashlight is currently available.
248         */
249        void onFlashlightAvailabilityChanged(boolean available);
250    }
251}
252