CameraManager.java revision d8c21e8bd09658f5843712f0176db3517ba44c51
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.camera2.impl.CameraMetadataNative; 23import android.hardware.camera2.legacy.CameraDeviceUserShim; 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 private static final String TAG = "CameraManager"; 53 54 /** 55 * This should match the ICameraService definition 56 */ 57 private static final String CAMERA_SERVICE_BINDER_NAME = "media.camera"; 58 private static final int USE_CALLING_UID = -1; 59 60 private final ICameraService mCameraService; 61 private ArrayList<String> mDeviceIdList; 62 63 private final ArrayMap<AvailabilityListener, Handler> mListenerMap = 64 new ArrayMap<AvailabilityListener, Handler>(); 65 66 private final Context mContext; 67 private final Object mLock = new Object(); 68 69 /** 70 * @hide 71 */ 72 public CameraManager(Context context) { 73 mContext = context; 74 75 IBinder cameraServiceBinder = ServiceManager.getService(CAMERA_SERVICE_BINDER_NAME); 76 ICameraService cameraServiceRaw = ICameraService.Stub.asInterface(cameraServiceBinder); 77 78 /** 79 * Wrap the camera service in a decorator which automatically translates return codes 80 * into exceptions, and RemoteExceptions into other exceptions. 81 */ 82 mCameraService = CameraBinderDecorator.newInstance(cameraServiceRaw); 83 84 try { 85 CameraBinderDecorator.throwOnError( 86 CameraMetadataNative.nativeSetupGlobalVendorTagDescriptor()); 87 } catch(CameraRuntimeException e) { 88 throw new IllegalStateException("Failed to setup camera vendor tags", 89 e.asChecked()); 90 } 91 92 try { 93 mCameraService.addListener(new CameraServiceListener()); 94 } catch(CameraRuntimeException e) { 95 throw new IllegalStateException("Failed to register a camera service listener", 96 e.asChecked()); 97 } catch (RemoteException e) { 98 // impossible 99 } 100 } 101 102 /** 103 * Return the list of currently connected camera devices by 104 * identifier. 105 * 106 * <p>Non-removable cameras use integers starting at 0 for their 107 * identifiers, while removable cameras have a unique identifier for each 108 * individual device, even if they are the same model.</p> 109 * 110 * @return The list of currently connected camera devices. 111 */ 112 public String[] getCameraIdList() throws CameraAccessException { 113 synchronized (mLock) { 114 try { 115 return getOrCreateDeviceIdListLocked().toArray(new String[0]); 116 } catch(CameraAccessException e) { 117 // this should almost never happen, except if mediaserver crashes 118 throw new IllegalStateException( 119 "Failed to query camera service for device ID list", e); 120 } 121 } 122 } 123 124 /** 125 * Register a listener to be notified about camera device availability. 126 * 127 * <p>Registering the same listener again will replace the handler with the 128 * new one provided.</p> 129 * 130 * @param listener The new listener to send camera availability notices to 131 * @param handler The handler on which the listener should be invoked, or 132 * {@code null} to use the current thread's {@link android.os.Looper looper}. 133 */ 134 public void addAvailabilityListener(AvailabilityListener listener, Handler handler) { 135 if (handler == null) { 136 Looper looper = Looper.myLooper(); 137 if (looper == null) { 138 throw new IllegalArgumentException( 139 "No handler given, and current thread has no looper!"); 140 } 141 handler = new Handler(looper); 142 } 143 144 synchronized (mLock) { 145 mListenerMap.put(listener, handler); 146 } 147 } 148 149 /** 150 * Remove a previously-added listener; the listener will no longer receive 151 * connection and disconnection callbacks. 152 * 153 * <p>Removing a listener that isn't registered has no effect.</p> 154 * 155 * @param listener The listener to remove from the notification list 156 */ 157 public void removeAvailabilityListener(AvailabilityListener listener) { 158 synchronized (mLock) { 159 mListenerMap.remove(listener); 160 } 161 } 162 163 /** 164 * <p>Query the capabilities of a camera device. These capabilities are 165 * immutable for a given camera.</p> 166 * 167 * @param cameraId The id of the camera device to query 168 * @return The properties of the given camera 169 * 170 * @throws IllegalArgumentException if the cameraId does not match any 171 * currently connected camera device. 172 * @throws CameraAccessException if the camera is disabled by device policy. 173 * @throws SecurityException if the application does not have permission to 174 * access the camera 175 * 176 * @see #getCameraIdList 177 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 178 */ 179 public CameraCharacteristics getCameraCharacteristics(String cameraId) 180 throws CameraAccessException { 181 182 synchronized (mLock) { 183 if (!getOrCreateDeviceIdListLocked().contains(cameraId)) { 184 throw new IllegalArgumentException(String.format("Camera id %s does not match any" + 185 " currently connected camera device", cameraId)); 186 } 187 } 188 189 CameraMetadataNative info = new CameraMetadataNative(); 190 try { 191 mCameraService.getCameraCharacteristics(Integer.valueOf(cameraId), info); 192 } catch(CameraRuntimeException e) { 193 throw e.asChecked(); 194 } catch(RemoteException e) { 195 // impossible 196 return null; 197 } 198 return new CameraCharacteristics(info); 199 } 200 201 /** 202 * Helper for openning a connection to a camera with the given ID. 203 * 204 * @param cameraId The unique identifier of the camera device to open 205 * @param listener The listener for the camera. Must not be null. 206 * @param handler The handler to call the listener on. Must not be null. 207 * 208 * @throws CameraAccessException if the camera is disabled by device policy, 209 * or too many camera devices are already open, or the cameraId does not match 210 * any currently available camera device. 211 * 212 * @throws SecurityException if the application does not have permission to 213 * access the camera 214 * @throws IllegalArgumentException if listener or handler is null. 215 * @return A handle to the newly-created camera device. 216 * 217 * @see #getCameraIdList 218 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 219 */ 220 private CameraDevice openCameraDeviceUserAsync(String cameraId, 221 CameraDevice.StateListener listener, Handler handler) 222 throws CameraAccessException { 223 CameraCharacteristics characteristics = getCameraCharacteristics(cameraId); 224 CameraDevice device = null; 225 try { 226 227 synchronized (mLock) { 228 229 ICameraDeviceUser cameraUser = null; 230 231 android.hardware.camera2.impl.CameraDeviceImpl deviceImpl = 232 new android.hardware.camera2.impl.CameraDeviceImpl( 233 cameraId, 234 listener, 235 handler, 236 characteristics); 237 238 BinderHolder holder = new BinderHolder(); 239 240 ICameraDeviceCallbacks callbacks = deviceImpl.getCallbacks(); 241 int id = Integer.parseInt(cameraId); 242 try { 243 mCameraService.connectDevice(callbacks, id, mContext.getPackageName(), 244 USE_CALLING_UID, holder); 245 cameraUser = ICameraDeviceUser.Stub.asInterface(holder.getBinder()); 246 } catch (CameraRuntimeException e) { 247 if (e.getReason() == CameraAccessException.CAMERA_IN_USE || 248 e.getReason() == CameraAccessException.MAX_CAMERAS_IN_USE || 249 e.getReason() == CameraAccessException.CAMERA_DISABLED || 250 e.getReason() == CameraAccessException.CAMERA_DISCONNECTED || 251 e.getReason() == CameraAccessException.CAMERA_ERROR) { 252 // Received one of the known connection errors 253 // The remote camera device cannot be connected to, so 254 // set the local camera to the startup error state 255 deviceImpl.setRemoteFailure(e); 256 257 if (e.getReason() == CameraAccessException.CAMERA_DISABLED || 258 e.getReason() == CameraAccessException.CAMERA_DISCONNECTED) { 259 // Per API docs, these failures call onError and throw 260 throw e; 261 } 262 } else { 263 // Unexpected failure - rethrow 264 throw e; 265 } 266 } 267 268 // TODO: factor out listener to be non-nested, then move setter to constructor 269 // For now, calling setRemoteDevice will fire initial 270 // onOpened/onUnconfigured callbacks. 271 deviceImpl.setRemoteDevice(cameraUser); 272 device = deviceImpl; 273 } 274 275 } catch (NumberFormatException e) { 276 throw new IllegalArgumentException("Expected cameraId to be numeric, but it was: " 277 + cameraId); 278 } catch (CameraRuntimeException e) { 279 throw e.asChecked(); 280 } catch (RemoteException e) { 281 // impossible 282 } 283 return device; 284 } 285 286 /** 287 * Open a connection to a camera with the given ID. 288 * 289 * <p>Use {@link #getCameraIdList} to get the list of available camera 290 * devices. Note that even if an id is listed, open may fail if the device 291 * is disconnected between the calls to {@link #getCameraIdList} and 292 * {@link #openCamera}.</p> 293 * 294 * <p>Once the camera is successfully opened, {@link CameraDevice.StateListener#onOpened} will 295 * be invoked with the newly opened {@link CameraDevice}. The camera device can then be set up 296 * for operation by calling {@link CameraDevice#createCaptureSession} and 297 * {@link CameraDevice#createCaptureRequest}</p> 298 * 299 * <!-- 300 * <p>Since the camera device will be opened asynchronously, any asynchronous operations done 301 * on the returned CameraDevice instance will be queued up until the device startup has 302 * completed and the listener's {@link CameraDevice.StateListener#onOpened onOpened} method is 303 * called. The pending operations are then processed in order.</p> 304 * --> 305 * <p>If the camera becomes disconnected during initialization 306 * after this function call returns, 307 * {@link CameraDevice.StateListener#onDisconnected} with a 308 * {@link CameraDevice} in the disconnected state (and 309 * {@link CameraDevice.StateListener#onOpened} will be skipped).</p> 310 * 311 * <p>If opening the camera device fails, then the device listener's 312 * {@link CameraDevice.StateListener#onError onError} method will be called, and subsequent 313 * calls on the camera device will throw a {@link CameraAccessException}.</p> 314 * 315 * @param cameraId 316 * The unique identifier of the camera device to open 317 * @param listener 318 * The listener which is invoked once the camera is opened 319 * @param handler 320 * The handler on which the listener should be invoked, or 321 * {@code null} to use the current thread's {@link android.os.Looper looper}. 322 * 323 * @throws CameraAccessException if the camera is disabled by device policy, 324 * or the camera has become or was disconnected. 325 * 326 * @throws IllegalArgumentException if cameraId or the listener was null, 327 * or the cameraId does not match any currently or previously available 328 * camera device. 329 * 330 * @throws SecurityException if the application does not have permission to 331 * access the camera 332 * 333 * @see #getCameraIdList 334 * @see android.app.admin.DevicePolicyManager#setCameraDisabled 335 */ 336 public void openCamera(String cameraId, final CameraDevice.StateListener listener, 337 Handler handler) 338 throws CameraAccessException { 339 340 if (cameraId == null) { 341 throw new IllegalArgumentException("cameraId was null"); 342 } else if (listener == null) { 343 throw new IllegalArgumentException("listener was null"); 344 } else if (handler == null) { 345 if (Looper.myLooper() != null) { 346 handler = new Handler(); 347 } else { 348 throw new IllegalArgumentException( 349 "Looper doesn't exist in the calling thread"); 350 } 351 } 352 353 openCameraDeviceUserAsync(cameraId, listener, handler); 354 } 355 356 /** 357 * Interface for listening to camera devices becoming available or 358 * unavailable. 359 * 360 * <p>Cameras become available when they are no longer in use, or when a new 361 * removable camera is connected. They become unavailable when some 362 * application or service starts using a camera, or when a removable camera 363 * is disconnected.</p> 364 * 365 * @see addAvailabilityListener 366 */ 367 public static abstract class AvailabilityListener { 368 369 /** 370 * A new camera has become available to use. 371 * 372 * <p>The default implementation of this method does nothing.</p> 373 * 374 * @param cameraId The unique identifier of the new camera. 375 */ 376 public void onCameraAvailable(String cameraId) { 377 // default empty implementation 378 } 379 380 /** 381 * A previously-available camera has become unavailable for use. 382 * 383 * <p>If an application had an active CameraDevice instance for the 384 * now-disconnected camera, that application will receive a 385 * {@link CameraDevice.StateListener#onDisconnected disconnection error}.</p> 386 * 387 * <p>The default implementation of this method does nothing.</p> 388 * 389 * @param cameraId The unique identifier of the disconnected camera. 390 */ 391 public void onCameraUnavailable(String cameraId) { 392 // default empty implementation 393 } 394 } 395 396 private ArrayList<String> getOrCreateDeviceIdListLocked() throws CameraAccessException { 397 if (mDeviceIdList == null) { 398 int numCameras = 0; 399 400 try { 401 numCameras = mCameraService.getNumberOfCameras(); 402 } catch(CameraRuntimeException e) { 403 throw e.asChecked(); 404 } catch (RemoteException e) { 405 // impossible 406 return null; 407 } 408 409 mDeviceIdList = new ArrayList<String>(); 410 CameraMetadataNative info = new CameraMetadataNative(); 411 for (int i = 0; i < numCameras; ++i) { 412 // Non-removable cameras use integers starting at 0 for their 413 // identifiers 414 boolean isDeviceSupported = false; 415 try { 416 mCameraService.getCameraCharacteristics(i, info); 417 if (!info.isEmpty()) { 418 isDeviceSupported = true; 419 } else { 420 throw new AssertionError("Expected to get non-empty characteristics"); 421 } 422 } catch(IllegalArgumentException e) { 423 // Got a BAD_VALUE from service, meaning that this 424 // device is not supported. 425 } catch(CameraRuntimeException e) { 426 throw e.asChecked(); 427 } catch(RemoteException e) { 428 // impossible 429 } 430 431 if (isDeviceSupported) { 432 mDeviceIdList.add(String.valueOf(i)); 433 } 434 } 435 436 } 437 return mDeviceIdList; 438 } 439 440 // TODO: this class needs unit tests 441 // TODO: extract class into top level 442 private class CameraServiceListener extends ICameraServiceListener.Stub { 443 444 // Keep up-to-date with ICameraServiceListener.h 445 446 // Device physically unplugged 447 public static final int STATUS_NOT_PRESENT = 0; 448 // Device physically has been plugged in 449 // and the camera can be used exclusively 450 public static final int STATUS_PRESENT = 1; 451 // Device physically has been plugged in 452 // but it will not be connect-able until enumeration is complete 453 public static final int STATUS_ENUMERATING = 2; 454 // Camera is in use by another app and cannot be used exclusively 455 public static final int STATUS_NOT_AVAILABLE = 0x80000000; 456 457 // Camera ID -> Status map 458 private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>(); 459 460 private static final String TAG = "CameraServiceListener"; 461 462 @Override 463 public IBinder asBinder() { 464 return this; 465 } 466 467 private boolean isAvailable(int status) { 468 switch (status) { 469 case STATUS_PRESENT: 470 return true; 471 default: 472 return false; 473 } 474 } 475 476 private boolean validStatus(int status) { 477 switch (status) { 478 case STATUS_NOT_PRESENT: 479 case STATUS_PRESENT: 480 case STATUS_ENUMERATING: 481 case STATUS_NOT_AVAILABLE: 482 return true; 483 default: 484 return false; 485 } 486 } 487 488 @Override 489 public void onStatusChanged(int status, int cameraId) throws RemoteException { 490 synchronized(CameraManager.this.mLock) { 491 492 Log.v(TAG, 493 String.format("Camera id %d has status changed to 0x%x", cameraId, status)); 494 495 final String id = String.valueOf(cameraId); 496 497 if (!validStatus(status)) { 498 Log.e(TAG, String.format("Ignoring invalid device %d status 0x%x", cameraId, 499 status)); 500 return; 501 } 502 503 Integer oldStatus = mDeviceStatus.put(id, status); 504 505 if (oldStatus != null && oldStatus == status) { 506 Log.v(TAG, String.format( 507 "Device status changed to 0x%x, which is what it already was", 508 status)); 509 return; 510 } 511 512 // TODO: consider abstracting out this state minimization + transition 513 // into a separate 514 // more easily testable class 515 // i.e. (new State()).addState(STATE_AVAILABLE) 516 // .addState(STATE_NOT_AVAILABLE) 517 // .addTransition(STATUS_PRESENT, STATE_AVAILABLE), 518 // .addTransition(STATUS_NOT_PRESENT, STATE_NOT_AVAILABLE) 519 // .addTransition(STATUS_ENUMERATING, STATE_NOT_AVAILABLE); 520 // .addTransition(STATUS_NOT_AVAILABLE, STATE_NOT_AVAILABLE); 521 522 // Translate all the statuses to either 'available' or 'not available' 523 // available -> available => no new update 524 // not available -> not available => no new update 525 if (oldStatus != null && isAvailable(status) == isAvailable(oldStatus)) { 526 527 Log.v(TAG, 528 String.format( 529 "Device status was previously available (%d), " + 530 " and is now again available (%d)" + 531 "so no new client visible update will be sent", 532 isAvailable(status), isAvailable(status))); 533 return; 534 } 535 536 final int listenerCount = mListenerMap.size(); 537 for (int i = 0; i < listenerCount; i++) { 538 Handler handler = mListenerMap.valueAt(i); 539 final AvailabilityListener listener = mListenerMap.keyAt(i); 540 if (isAvailable(status)) { 541 handler.post( 542 new Runnable() { 543 @Override 544 public void run() { 545 listener.onCameraAvailable(id); 546 } 547 }); 548 } else { 549 handler.post( 550 new Runnable() { 551 @Override 552 public void run() { 553 listener.onCameraUnavailable(id); 554 } 555 }); 556 } 557 } // for 558 } // synchronized 559 } // onStatusChanged 560 } // CameraServiceListener 561} // CameraManager 562