CameraManager.java revision 2001188be30649198972a3199a4322d6f7f5f93d
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 CameraMetadataNative info = new CameraMetadataNative(); 180 try { 181 mCameraService.getCameraCharacteristics(Integer.valueOf(cameraId), info); 182 } catch(CameraRuntimeException e) { 183 throw e.asChecked(); 184 } catch(RemoteException e) { 185 // impossible 186 return null; 187 } 188 189 return new CameraCharacteristics(info); 190 } 191 192 /** 193 * Open a connection to a camera with the given ID. Use 194 * {@link #getCameraIdList} to get the list of available camera 195 * devices. Note that even if an id is listed, open may fail if the device 196 * is disconnected between the calls to {@link #getCameraIdList} and 197 * {@link #openCamera}. 198 * 199 * @param cameraId The unique identifier of the camera device to open 200 * 201 * @throws CameraAccessException if the camera is disabled by device policy, 202 * or too many camera devices are already open, or the cameraId does not match 203 * any currently available camera device. 204 * 205 * @throws SecurityException if the application does not have permission to 206 * access the camera 207 * 208 * @see #getCameraIdList 209 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 210 */ 211 private CameraDevice openCamera(String cameraId) throws CameraAccessException { 212 try { 213 214 synchronized (mLock) { 215 216 ICameraDeviceUser cameraUser; 217 218 android.hardware.camera2.impl.CameraDevice device = 219 new android.hardware.camera2.impl.CameraDevice(cameraId); 220 221 BinderHolder holder = new BinderHolder(); 222 mCameraService.connectDevice(device.getCallbacks(), 223 Integer.parseInt(cameraId), 224 mContext.getPackageName(), USE_CALLING_UID, holder); 225 cameraUser = ICameraDeviceUser.Stub.asInterface(holder.getBinder()); 226 227 // TODO: factor out listener to be non-nested, then move setter to constructor 228 device.setRemoteDevice(cameraUser); 229 230 return device; 231 232 } 233 234 } catch (NumberFormatException e) { 235 throw new IllegalArgumentException("Expected cameraId to be numeric, but it was: " 236 + cameraId); 237 } catch (CameraRuntimeException e) { 238 throw e.asChecked(); 239 } catch (RemoteException e) { 240 // impossible 241 return null; 242 } 243 } 244 245 /** 246 * Open a connection to a camera with the given ID. 247 * 248 * <p>Use {@link #getCameraIdList} to get the list of available camera 249 * devices. Note that even if an id is listed, open may fail if the device 250 * is disconnected between the calls to {@link #getCameraIdList} and 251 * {@link #openCamera}.</p> 252 * 253 * <p>If the camera successfully opens after this function call returns, 254 * {@link CameraDevice.StateListener#onOpened} will be invoked with the 255 * newly opened {@link CameraDevice} in the unconfigured state.</p> 256 * 257 * <p>If the camera becomes disconnected during initialization 258 * after this function call returns, 259 * {@link CameraDevice.StateListener#onDisconnected} with a 260 * {@link CameraDevice} in the disconnected state (and 261 * {@link CameraDevice.StateListener#onOpened} will be skipped).</p> 262 * 263 * <p>If the camera fails to initialize after this function call returns, 264 * {@link CameraDevice.StateListener#onError} will be invoked with a 265 * {@link CameraDevice} in the error state (and 266 * {@link CameraDevice.StateListener#onOpened} will be skipped).</p> 267 * 268 * @param cameraId 269 * The unique identifier of the camera device to open 270 * @param listener 271 * The listener which is invoked once the camera is opened 272 * @param handler 273 * The handler on which the listener should be invoked, or 274 * {@code null} to use the current thread's {@link android.os.Looper looper}. 275 * 276 * @throws CameraAccessException if the camera is disabled by device policy, 277 * or the camera has become or was disconnected. 278 * 279 * @throws IllegalArgumentException if cameraId or the listener was null, 280 * or the cameraId does not match any currently or previously available 281 * camera device. 282 * 283 * @throws SecurityException if the application does not have permission to 284 * access the camera 285 * 286 * @see #getCameraIdList 287 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 288 */ 289 public void openCamera(String cameraId, final CameraDevice.StateListener listener, 290 Handler handler) 291 throws CameraAccessException { 292 293 if (cameraId == null) { 294 throw new IllegalArgumentException("cameraId was null"); 295 } else if (listener == null) { 296 throw new IllegalArgumentException("listener was null"); 297 } else if (handler == null) { 298 if (Looper.myLooper() != null) { 299 handler = new Handler(); 300 } else { 301 throw new IllegalArgumentException( 302 "Looper doesn't exist in the calling thread"); 303 } 304 } 305 306 final CameraDevice camera = openCamera(cameraId); 307 camera.setDeviceListener(listener, handler); 308 309 // TODO: make truly async in the camera service 310 handler.post(new Runnable() { 311 @Override 312 public void run() { 313 listener.onOpened(camera); 314 } 315 }); 316 } 317 318 /** 319 * Interface for listening to camera devices becoming available or 320 * unavailable. 321 * 322 * <p>Cameras become available when they are no longer in use, or when a new 323 * removable camera is connected. They become unavailable when some 324 * application or service starts using a camera, or when a removable camera 325 * is disconnected.</p> 326 * 327 * @see addAvailabilityListener 328 */ 329 public static abstract class AvailabilityListener { 330 331 /** 332 * A new camera has become available to use. 333 * 334 * <p>The default implementation of this method does nothing.</p> 335 * 336 * @param cameraId The unique identifier of the new camera. 337 */ 338 public void onCameraAvailable(String cameraId) { 339 // default empty implementation 340 } 341 342 /** 343 * A previously-available camera has become unavailable for use. 344 * 345 * <p>If an application had an active CameraDevice instance for the 346 * now-disconnected camera, that application will receive a 347 * {@link CameraDevice.StateListener#onDisconnected disconnection error}.</p> 348 * 349 * <p>The default implementation of this method does nothing.</p> 350 * 351 * @param cameraId The unique identifier of the disconnected camera. 352 */ 353 public void onCameraUnavailable(String cameraId) { 354 // default empty implementation 355 } 356 } 357 358 private ArrayList<String> getOrCreateDeviceIdListLocked() throws CameraAccessException { 359 if (mDeviceIdList == null) { 360 int numCameras = 0; 361 362 try { 363 numCameras = mCameraService.getNumberOfCameras(); 364 } catch(CameraRuntimeException e) { 365 throw e.asChecked(); 366 } catch (RemoteException e) { 367 // impossible 368 return null; 369 } 370 371 mDeviceIdList = new ArrayList<String>(); 372 for (int i = 0; i < numCameras; ++i) { 373 // Non-removable cameras use integers starting at 0 for their 374 // identifiers 375 mDeviceIdList.add(String.valueOf(i)); 376 } 377 378 } 379 return mDeviceIdList; 380 } 381 382 // TODO: this class needs unit tests 383 // TODO: extract class into top level 384 private class CameraServiceListener extends ICameraServiceListener.Stub { 385 386 // Keep up-to-date with ICameraServiceListener.h 387 388 // Device physically unplugged 389 public static final int STATUS_NOT_PRESENT = 0; 390 // Device physically has been plugged in 391 // and the camera can be used exclusively 392 public static final int STATUS_PRESENT = 1; 393 // Device physically has been plugged in 394 // but it will not be connect-able until enumeration is complete 395 public static final int STATUS_ENUMERATING = 2; 396 // Camera is in use by another app and cannot be used exclusively 397 public static final int STATUS_NOT_AVAILABLE = 0x80000000; 398 399 // Camera ID -> Status map 400 private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>(); 401 402 private static final String TAG = "CameraServiceListener"; 403 404 @Override 405 public IBinder asBinder() { 406 return this; 407 } 408 409 private boolean isAvailable(int status) { 410 switch (status) { 411 case STATUS_PRESENT: 412 return true; 413 default: 414 return false; 415 } 416 } 417 418 private boolean validStatus(int status) { 419 switch (status) { 420 case STATUS_NOT_PRESENT: 421 case STATUS_PRESENT: 422 case STATUS_ENUMERATING: 423 case STATUS_NOT_AVAILABLE: 424 return true; 425 default: 426 return false; 427 } 428 } 429 430 @Override 431 public void onStatusChanged(int status, int cameraId) throws RemoteException { 432 synchronized(CameraManager.this.mLock) { 433 434 Log.v(TAG, 435 String.format("Camera id %d has status changed to 0x%x", cameraId, status)); 436 437 final String id = String.valueOf(cameraId); 438 439 if (!validStatus(status)) { 440 Log.e(TAG, String.format("Ignoring invalid device %d status 0x%x", cameraId, 441 status)); 442 return; 443 } 444 445 Integer oldStatus = mDeviceStatus.put(id, status); 446 447 if (oldStatus != null && oldStatus == status) { 448 Log.v(TAG, String.format( 449 "Device status changed to 0x%x, which is what it already was", 450 status)); 451 return; 452 } 453 454 // TODO: consider abstracting out this state minimization + transition 455 // into a separate 456 // more easily testable class 457 // i.e. (new State()).addState(STATE_AVAILABLE) 458 // .addState(STATE_NOT_AVAILABLE) 459 // .addTransition(STATUS_PRESENT, STATE_AVAILABLE), 460 // .addTransition(STATUS_NOT_PRESENT, STATE_NOT_AVAILABLE) 461 // .addTransition(STATUS_ENUMERATING, STATE_NOT_AVAILABLE); 462 // .addTransition(STATUS_NOT_AVAILABLE, STATE_NOT_AVAILABLE); 463 464 // Translate all the statuses to either 'available' or 'not available' 465 // available -> available => no new update 466 // not available -> not available => no new update 467 if (oldStatus != null && isAvailable(status) == isAvailable(oldStatus)) { 468 469 Log.v(TAG, 470 String.format( 471 "Device status was previously available (%d), " + 472 " and is now again available (%d)" + 473 "so no new client visible update will be sent", 474 isAvailable(status), isAvailable(status))); 475 return; 476 } 477 478 final int listenerCount = mListenerMap.size(); 479 for (int i = 0; i < listenerCount; i++) { 480 Handler handler = mListenerMap.valueAt(i); 481 final AvailabilityListener listener = mListenerMap.keyAt(i); 482 if (isAvailable(status)) { 483 handler.post( 484 new Runnable() { 485 @Override 486 public void run() { 487 listener.onCameraAvailable(id); 488 } 489 }); 490 } else { 491 handler.post( 492 new Runnable() { 493 @Override 494 public void run() { 495 listener.onCameraUnavailable(id); 496 } 497 }); 498 } 499 } // for 500 } // synchronized 501 } // onStatusChanged 502 } // CameraServiceListener 503} // CameraManager 504