CameraManager.java revision 68f40066c914aefc1f88819dd46dd1135fb9f5bc
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 final 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 CameraCharacteristics getCameraCharacteristics(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 CameraCharacteristics(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 private CameraDevice openCamera(String cameraId) throws CameraAccessException { 205 try { 206 207 synchronized (mLock) { 208 209 ICameraDeviceUser cameraUser; 210 211 android.hardware.camera2.impl.CameraDevice device = 212 new android.hardware.camera2.impl.CameraDevice(cameraId); 213 214 BinderHolder holder = new BinderHolder(); 215 mCameraService.connectDevice(device.getCallbacks(), 216 Integer.parseInt(cameraId), 217 mContext.getPackageName(), USE_CALLING_UID, holder); 218 cameraUser = ICameraDeviceUser.Stub.asInterface(holder.getBinder()); 219 220 // TODO: factor out listener to be non-nested, then move setter to constructor 221 device.setRemoteDevice(cameraUser); 222 223 return device; 224 225 } 226 227 } catch (NumberFormatException e) { 228 throw new IllegalArgumentException("Expected cameraId to be numeric, but it was: " 229 + cameraId); 230 } catch (CameraRuntimeException e) { 231 throw e.asChecked(); 232 } catch (RemoteException e) { 233 // impossible 234 return null; 235 } 236 } 237 238 /** 239 * Open a connection to a camera with the given ID. 240 * 241 * <p>Use {@link #getCameraIdList} to get the list of available camera 242 * devices. Note that even if an id is listed, open may fail if the device 243 * is disconnected between the calls to {@link #getCameraIdList} and 244 * {@link #openCamera}.</p> 245 * 246 * <p>If the camera successfully opens after this function call returns, 247 * {@link CameraDevice.StateListener#onOpened} will be invoked with the 248 * newly opened {@link CameraDevice} in the unconfigured state.</p> 249 * 250 * <p>If the camera becomes disconnected during initialization 251 * after this function call returns, 252 * {@link CameraDevice.StateListener#onDisconnected} with a 253 * {@link CameraDevice} in the disconnected state (and 254 * {@link CameraDevice.StateListener#onOpened} will be skipped).</p> 255 * 256 * <p>If the camera fails to initialize after this function call returns, 257 * {@link CameraDevice.StateListener#onError} will be invoked with a 258 * {@link CameraDevice} in the error state (and 259 * {@link CameraDevice.StateListener#onOpened} will be skipped).</p> 260 * 261 * @param cameraId 262 * The unique identifier of the camera device to open 263 * @param listener 264 * The listener which is invoked once the camera is opened 265 * @param handler 266 * The handler on which the listener should be invoked, or 267 * {@code null} to use the current thread's {@link android.os.Looper looper}. 268 * 269 * @throws CameraAccessException if the camera is disabled by device policy, 270 * or the camera has become or was disconnected. 271 * 272 * @throws IllegalArgumentException if cameraId or the listener was null, 273 * or the cameraId does not match any currently or previously available 274 * camera device. 275 * 276 * @throws SecurityException if the application does not have permission to 277 * access the camera 278 * 279 * @see #getCameraIdList 280 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 281 */ 282 public void openCamera(String cameraId, final CameraDevice.StateListener listener, 283 Handler handler) 284 throws CameraAccessException { 285 286 if (cameraId == null) { 287 throw new IllegalArgumentException("cameraId was null"); 288 } else if (listener == null) { 289 throw new IllegalArgumentException("listener was null"); 290 } else if (handler == null) { 291 if (Looper.myLooper() != null) { 292 handler = new Handler(); 293 } else { 294 throw new IllegalArgumentException( 295 "Looper doesn't exist in the calling thread"); 296 } 297 } 298 299 final CameraDevice camera = openCamera(cameraId); 300 camera.setDeviceListener(listener, handler); 301 302 // TODO: make truly async in the camera service 303 handler.post(new Runnable() { 304 @Override 305 public void run() { 306 listener.onOpened(camera); 307 } 308 }); 309 } 310 311 /** 312 * Interface for listening to camera devices becoming available or 313 * unavailable. 314 * 315 * <p>Cameras become available when they are no longer in use, or when a new 316 * removable camera is connected. They become unavailable when some 317 * application or service starts using a camera, or when a removable camera 318 * is disconnected.</p> 319 * 320 * @see addAvailabilityListener 321 */ 322 public static abstract class AvailabilityListener { 323 324 /** 325 * A new camera has become available to use. 326 * 327 * <p>The default implementation of this method does nothing.</p> 328 * 329 * @param cameraId The unique identifier of the new camera. 330 */ 331 public void onCameraAvailable(String cameraId) { 332 // default empty implementation 333 } 334 335 /** 336 * A previously-available camera has become unavailable for use. 337 * 338 * <p>If an application had an active CameraDevice instance for the 339 * now-disconnected camera, that application will receive a 340 * {@link CameraDevice.StateListener#onDisconnected disconnection error}.</p> 341 * 342 * <p>The default implementation of this method does nothing.</p> 343 * 344 * @param cameraId The unique identifier of the disconnected camera. 345 */ 346 public void onCameraUnavailable(String cameraId) { 347 // default empty implementation 348 } 349 } 350 351 private ArrayList<String> getOrCreateDeviceIdListLocked() throws CameraAccessException { 352 if (mDeviceIdList == null) { 353 int numCameras = 0; 354 355 try { 356 numCameras = mCameraService.getNumberOfCameras(); 357 } catch(CameraRuntimeException e) { 358 throw e.asChecked(); 359 } catch (RemoteException e) { 360 // impossible 361 return null; 362 } 363 364 mDeviceIdList = new ArrayList<String>(); 365 for (int i = 0; i < numCameras; ++i) { 366 // Non-removable cameras use integers starting at 0 for their 367 // identifiers 368 mDeviceIdList.add(String.valueOf(i)); 369 } 370 371 } 372 return mDeviceIdList; 373 } 374 375 // TODO: this class needs unit tests 376 // TODO: extract class into top level 377 private class CameraServiceListener extends ICameraServiceListener.Stub { 378 379 // Keep up-to-date with ICameraServiceListener.h 380 381 // Device physically unplugged 382 public static final int STATUS_NOT_PRESENT = 0; 383 // Device physically has been plugged in 384 // and the camera can be used exclusively 385 public static final int STATUS_PRESENT = 1; 386 // Device physically has been plugged in 387 // but it will not be connect-able until enumeration is complete 388 public static final int STATUS_ENUMERATING = 2; 389 // Camera is in use by another app and cannot be used exclusively 390 public static final int STATUS_NOT_AVAILABLE = 0x80000000; 391 392 // Camera ID -> Status map 393 private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>(); 394 395 private static final String TAG = "CameraServiceListener"; 396 397 @Override 398 public IBinder asBinder() { 399 return this; 400 } 401 402 private boolean isAvailable(int status) { 403 switch (status) { 404 case STATUS_PRESENT: 405 return true; 406 default: 407 return false; 408 } 409 } 410 411 private boolean validStatus(int status) { 412 switch (status) { 413 case STATUS_NOT_PRESENT: 414 case STATUS_PRESENT: 415 case STATUS_ENUMERATING: 416 case STATUS_NOT_AVAILABLE: 417 return true; 418 default: 419 return false; 420 } 421 } 422 423 @Override 424 public void onStatusChanged(int status, int cameraId) throws RemoteException { 425 synchronized(CameraManager.this.mLock) { 426 427 Log.v(TAG, 428 String.format("Camera id %d has status changed to 0x%x", cameraId, status)); 429 430 final String id = String.valueOf(cameraId); 431 432 if (!validStatus(status)) { 433 Log.e(TAG, String.format("Ignoring invalid device %d status 0x%x", cameraId, 434 status)); 435 return; 436 } 437 438 Integer oldStatus = mDeviceStatus.put(id, status); 439 440 if (oldStatus != null && oldStatus == status) { 441 Log.v(TAG, String.format( 442 "Device status changed to 0x%x, which is what it already was", 443 status)); 444 return; 445 } 446 447 // TODO: consider abstracting out this state minimization + transition 448 // into a separate 449 // more easily testable class 450 // i.e. (new State()).addState(STATE_AVAILABLE) 451 // .addState(STATE_NOT_AVAILABLE) 452 // .addTransition(STATUS_PRESENT, STATE_AVAILABLE), 453 // .addTransition(STATUS_NOT_PRESENT, STATE_NOT_AVAILABLE) 454 // .addTransition(STATUS_ENUMERATING, STATE_NOT_AVAILABLE); 455 // .addTransition(STATUS_NOT_AVAILABLE, STATE_NOT_AVAILABLE); 456 457 // Translate all the statuses to either 'available' or 'not available' 458 // available -> available => no new update 459 // not available -> not available => no new update 460 if (oldStatus != null && isAvailable(status) == isAvailable(oldStatus)) { 461 462 Log.v(TAG, 463 String.format( 464 "Device status was previously available (%d), " + 465 " and is now again available (%d)" + 466 "so no new client visible update will be sent", 467 isAvailable(status), isAvailable(status))); 468 return; 469 } 470 471 final int listenerCount = mListenerMap.size(); 472 for (int i = 0; i < listenerCount; i++) { 473 Handler handler = mListenerMap.valueAt(i); 474 final AvailabilityListener listener = mListenerMap.keyAt(i); 475 if (isAvailable(status)) { 476 handler.post( 477 new Runnable() { 478 @Override 479 public void run() { 480 listener.onCameraAvailable(id); 481 } 482 }); 483 } else { 484 handler.post( 485 new Runnable() { 486 @Override 487 public void run() { 488 listener.onCameraUnavailable(id); 489 } 490 }); 491 } 492 } // for 493 } // synchronized 494 } // onStatusChanged 495 } // CameraServiceListener 496} // CameraManager 497