CameraManager.java revision 70c2207c34cf0e6b3b383b1b1500ff5385aa51a6
1/* 2 * Copyright (C) 2013 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 android.hardware.camera2; 18 19import android.content.Context; 20import android.hardware.ICameraService; 21import android.hardware.ICameraServiceListener; 22import android.hardware.IProCameraUser; 23import android.hardware.camera2.impl.CameraMetadataNative; 24import android.hardware.camera2.utils.CameraBinderDecorator; 25import android.hardware.camera2.utils.CameraRuntimeException; 26import android.hardware.camera2.utils.BinderHolder; 27import android.os.IBinder; 28import android.os.Handler; 29import android.os.Looper; 30import android.os.RemoteException; 31import android.os.ServiceManager; 32import android.util.Log; 33import android.util.ArrayMap; 34 35import java.util.ArrayList; 36 37/** 38 * <p>An interface for iterating, listing, and connecting to 39 * {@link CameraDevice CameraDevices}.</p> 40 * 41 * <p>You can get an instance of this class by calling 42 * {@link android.content.Context#getSystemService(String) Context.getSystemService()}.</p> 43 * 44 * <pre>CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);</pre> 45 * 46 * <p>For more details about communicating with camera devices, read the Camera 47 * developer guide or the {@link android.hardware.camera2 camera2} 48 * package documentation.</p> 49 */ 50public final class CameraManager { 51 52 /** 53 * This should match the ICameraService definition 54 */ 55 private static final String CAMERA_SERVICE_BINDER_NAME = "media.camera"; 56 private static final int USE_CALLING_UID = -1; 57 58 private final ICameraService mCameraService; 59 private ArrayList<String> mDeviceIdList; 60 61 private ArrayMap<AvailabilityListener, Handler> mListenerMap = 62 new ArrayMap<AvailabilityListener, Handler>(); 63 64 private final Context mContext; 65 private final Object mLock = new Object(); 66 67 /** 68 * @hide 69 */ 70 public CameraManager(Context context) { 71 mContext = context; 72 73 IBinder cameraServiceBinder = ServiceManager.getService(CAMERA_SERVICE_BINDER_NAME); 74 ICameraService cameraServiceRaw = ICameraService.Stub.asInterface(cameraServiceBinder); 75 76 /** 77 * Wrap the camera service in a decorator which automatically translates return codes 78 * into exceptions, and RemoteExceptions into other exceptions. 79 */ 80 mCameraService = CameraBinderDecorator.newInstance(cameraServiceRaw); 81 82 try { 83 mCameraService.addListener(new CameraServiceListener()); 84 } catch(CameraRuntimeException e) { 85 throw new IllegalStateException("Failed to register a camera service listener", 86 e.asChecked()); 87 } catch (RemoteException e) { 88 // impossible 89 } 90 } 91 92 /** 93 * Return the list of currently connected camera devices by 94 * identifier. 95 * 96 * <p>Non-removable cameras use integers starting at 0 for their 97 * identifiers, while removable cameras have a unique identifier for each 98 * individual device, even if they are the same model.</p> 99 * 100 * @return The list of currently connected camera devices. 101 */ 102 public String[] getCameraIdList() throws CameraAccessException { 103 synchronized (mLock) { 104 try { 105 return getOrCreateDeviceIdListLocked().toArray(new String[0]); 106 } catch(CameraAccessException e) { 107 // this should almost never happen, except if mediaserver crashes 108 throw new IllegalStateException( 109 "Failed to query camera service for device ID list", e); 110 } 111 } 112 } 113 114 /** 115 * Register a listener to be notified about camera device availability. 116 * 117 * <p>Registering the same listener again will replace the handler with the 118 * new one provided.</p> 119 * 120 * @param listener The new listener to send camera availability notices to 121 * @param handler The handler on which the listener should be invoked, or 122 * {@code null} to use the current thread's {@link android.os.Looper looper}. 123 */ 124 public void addAvailabilityListener(AvailabilityListener listener, Handler handler) { 125 if (handler == null) { 126 Looper looper = Looper.myLooper(); 127 if (looper == null) { 128 throw new IllegalArgumentException( 129 "No handler given, and current thread has no looper!"); 130 } 131 handler = new Handler(looper); 132 } 133 134 synchronized (mLock) { 135 mListenerMap.put(listener, handler); 136 } 137 } 138 139 /** 140 * Remove a previously-added listener; the listener will no longer receive 141 * connection and disconnection callbacks. 142 * 143 * <p>Removing a listener that isn't registered has no effect.</p> 144 * 145 * @param listener The listener to remove from the notification list 146 */ 147 public void removeAvailabilityListener(AvailabilityListener listener) { 148 synchronized (mLock) { 149 mListenerMap.remove(listener); 150 } 151 } 152 153 /** 154 * <p>Query the capabilities of a camera device. These capabilities are 155 * immutable for a given camera.</p> 156 * 157 * @param cameraId The id of the camera device to query 158 * @return The properties of the given camera 159 * 160 * @throws IllegalArgumentException if the cameraId does not match any 161 * currently connected camera device. 162 * @throws CameraAccessException if the camera is disabled by device policy. 163 * @throws SecurityException if the application does not have permission to 164 * access the camera 165 * 166 * @see #getCameraIdList 167 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 168 */ 169 public CameraProperties getCameraProperties(String cameraId) 170 throws CameraAccessException { 171 172 synchronized (mLock) { 173 if (!getOrCreateDeviceIdListLocked().contains(cameraId)) { 174 throw new IllegalArgumentException(String.format("Camera id %s does not match any" + 175 " currently connected camera device", cameraId)); 176 } 177 } 178 179 // TODO: implement and call a service function to get the capabilities on C++ side 180 181 // TODO: get properties from service 182 return new CameraProperties(new CameraMetadataNative()); 183 } 184 185 /** 186 * Open a connection to a camera with the given ID. Use 187 * {@link #getCameraIdList} to get the list of available camera 188 * devices. Note that even if an id is listed, open may fail if the device 189 * is disconnected between the calls to {@link #getCameraIdList} and 190 * {@link #openCamera}. 191 * 192 * @param cameraId The unique identifier of the camera device to open 193 * 194 * @throws CameraAccessException if the camera is disabled by device policy, 195 * or too many camera devices are already open, or the cameraId does not match 196 * any currently available camera device. 197 * 198 * @throws SecurityException if the application does not have permission to 199 * access the camera 200 * 201 * @see #getCameraIdList 202 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 203 */ 204 public CameraDevice openCamera(String cameraId) throws CameraAccessException { 205 206 try { 207 208 synchronized (mLock) { 209 210 ICameraDeviceUser cameraUser; 211 212 android.hardware.camera2.impl.CameraDevice device = 213 new android.hardware.camera2.impl.CameraDevice(cameraId); 214 215 BinderHolder holder = new BinderHolder(); 216 mCameraService.connectDevice(device.getCallbacks(), 217 Integer.parseInt(cameraId), 218 mContext.getPackageName(), USE_CALLING_UID, holder); 219 cameraUser = ICameraDeviceUser.Stub.asInterface(holder.getBinder()); 220 221 // TODO: factor out listener to be non-nested, then move setter to constructor 222 device.setRemoteDevice(cameraUser); 223 224 return device; 225 226 } 227 228 } catch (NumberFormatException e) { 229 throw new IllegalArgumentException("Expected cameraId to be numeric, but it was: " 230 + cameraId); 231 } catch (CameraRuntimeException e) { 232 throw e.asChecked(); 233 } catch (RemoteException e) { 234 // impossible 235 return null; 236 } 237 } 238 239 /** 240 * Interface for listening to camera devices becoming available or 241 * unavailable. 242 * 243 * <p>Cameras become available when they are no longer in use, or when a new 244 * removable camera is connected. They become unavailable when some 245 * application or service starts using a camera, or when a removable camera 246 * is disconnected.</p> 247 * 248 * @see addAvailabilityListener 249 */ 250 public static abstract class AvailabilityListener { 251 252 /** 253 * A new camera has become available to use. 254 * 255 * <p>The default implementation of this method does nothing.</p> 256 * 257 * @param cameraId The unique identifier of the new camera. 258 */ 259 public void onCameraAvailable(String cameraId) { 260 // default empty implementation 261 } 262 263 /** 264 * A previously-available camera has become unavailable for use. 265 * 266 * <p>If an application had an active CameraDevice instance for the 267 * now-disconnected camera, that application will receive a 268 * {@link CameraDevice.CameraDeviceListener#onCameraDisconnected disconnection error}.</p> 269 * 270 * <p>The default implementation of this method does nothing.</p> 271 * 272 * @param cameraId The unique identifier of the disconnected camera. 273 */ 274 public void onCameraUnavailable(String cameraId) { 275 // default empty implementation 276 } 277 } 278 279 private ArrayList<String> getOrCreateDeviceIdListLocked() throws CameraAccessException { 280 if (mDeviceIdList == null) { 281 int numCameras = 0; 282 283 try { 284 numCameras = mCameraService.getNumberOfCameras(); 285 } catch(CameraRuntimeException e) { 286 throw e.asChecked(); 287 } catch (RemoteException e) { 288 // impossible 289 return null; 290 } 291 292 mDeviceIdList = new ArrayList<String>(); 293 for (int i = 0; i < numCameras; ++i) { 294 // Non-removable cameras use integers starting at 0 for their 295 // identifiers 296 mDeviceIdList.add(String.valueOf(i)); 297 } 298 299 } 300 return mDeviceIdList; 301 } 302 303 // TODO: this class needs unit tests 304 // TODO: extract class into top level 305 private class CameraServiceListener extends ICameraServiceListener.Stub { 306 307 // Keep up-to-date with ICameraServiceListener.h 308 309 // Device physically unplugged 310 public static final int STATUS_NOT_PRESENT = 0; 311 // Device physically has been plugged in 312 // and the camera can be used exclusively 313 public static final int STATUS_PRESENT = 1; 314 // Device physically has been plugged in 315 // but it will not be connect-able until enumeration is complete 316 public static final int STATUS_ENUMERATING = 2; 317 // Camera is in use by another app and cannot be used exclusively 318 public static final int STATUS_NOT_AVAILABLE = 0x80000000; 319 320 // Camera ID -> Status map 321 private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>(); 322 323 private static final String TAG = "CameraServiceListener"; 324 325 @Override 326 public IBinder asBinder() { 327 return this; 328 } 329 330 private boolean isAvailable(int status) { 331 switch (status) { 332 case STATUS_PRESENT: 333 return true; 334 default: 335 return false; 336 } 337 } 338 339 private boolean validStatus(int status) { 340 switch (status) { 341 case STATUS_NOT_PRESENT: 342 case STATUS_PRESENT: 343 case STATUS_ENUMERATING: 344 case STATUS_NOT_AVAILABLE: 345 return true; 346 default: 347 return false; 348 } 349 } 350 351 @Override 352 public void onStatusChanged(int status, int cameraId) throws RemoteException { 353 synchronized(CameraManager.this.mLock) { 354 355 Log.v(TAG, 356 String.format("Camera id %d has status changed to 0x%x", cameraId, status)); 357 358 final String id = String.valueOf(cameraId); 359 360 if (!validStatus(status)) { 361 Log.e(TAG, String.format("Ignoring invalid device %d status 0x%x", cameraId, 362 status)); 363 return; 364 } 365 366 Integer oldStatus = mDeviceStatus.put(id, status); 367 368 if (oldStatus != null && oldStatus == status) { 369 Log.v(TAG, String.format( 370 "Device status changed to 0x%x, which is what it already was", 371 status)); 372 return; 373 } 374 375 // TODO: consider abstracting out this state minimization + transition 376 // into a separate 377 // more easily testable class 378 // i.e. (new State()).addState(STATE_AVAILABLE) 379 // .addState(STATE_NOT_AVAILABLE) 380 // .addTransition(STATUS_PRESENT, STATE_AVAILABLE), 381 // .addTransition(STATUS_NOT_PRESENT, STATE_NOT_AVAILABLE) 382 // .addTransition(STATUS_ENUMERATING, STATE_NOT_AVAILABLE); 383 // .addTransition(STATUS_NOT_AVAILABLE, STATE_NOT_AVAILABLE); 384 385 // Translate all the statuses to either 'available' or 'not available' 386 // available -> available => no new update 387 // not available -> not available => no new update 388 if (oldStatus != null && isAvailable(status) == isAvailable(oldStatus)) { 389 390 Log.v(TAG, 391 String.format( 392 "Device status was previously available (%d), " + 393 " and is now again available (%d)" + 394 "so no new client visible update will be sent", 395 isAvailable(status), isAvailable(status))); 396 return; 397 } 398 399 final int listenerCount = mListenerMap.size(); 400 for (int i = 0; i < listenerCount; i++) { 401 Handler handler = mListenerMap.valueAt(i); 402 final AvailabilityListener listener = mListenerMap.keyAt(i); 403 if (isAvailable(status)) { 404 handler.post( 405 new Runnable() { 406 public void run() { 407 listener.onCameraAvailable(id); 408 } 409 }); 410 } else { 411 handler.post( 412 new Runnable() { 413 public void run() { 414 listener.onCameraUnavailable(id); 415 } 416 }); 417 } 418 } // for 419 } // synchronized 420 } // onStatusChanged 421 } // CameraServiceListener 422} // CameraManager 423