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 17 package android.hardware.camera2.legacy; 18 19 import android.hardware.camera2.impl.CameraDeviceImpl; 20 import android.hardware.camera2.impl.CameraMetadataNative; 21 import android.os.Handler; 22 import android.util.Log; 23 24 /** 25 * Emulates a the state of a single Camera2 device. 26 * 27 * <p> 28 * This class acts as the state machine for a camera device. Valid state transitions are given 29 * in the table below: 30 * </p> 31 * 32 * <ul> 33 * <li>{@code UNCONFIGURED -> CONFIGURING}</li> 34 * <li>{@code CONFIGURING -> IDLE}</li> 35 * <li>{@code IDLE -> CONFIGURING}</li> 36 * <li>{@code IDLE -> CAPTURING}</li> 37 * <li>{@code IDLE -> IDLE}</li> 38 * <li>{@code CAPTURING -> IDLE}</li> 39 * <li>{@code ANY -> ERROR}</li> 40 * </ul> 41 */ 42 public class CameraDeviceState { 43 private static final String TAG = "CameraDeviceState"; 44 private static final boolean DEBUG = Log.isLoggable(LegacyCameraDevice.DEBUG_PROP, Log.DEBUG); 45 46 private static final int STATE_ERROR = 0; 47 private static final int STATE_UNCONFIGURED = 1; 48 private static final int STATE_CONFIGURING = 2; 49 private static final int STATE_IDLE = 3; 50 private static final int STATE_CAPTURING = 4; 51 52 private static final String[] sStateNames = { "ERROR", "UNCONFIGURED", "CONFIGURING", "IDLE", 53 "CAPTURING"}; 54 55 private int mCurrentState = STATE_UNCONFIGURED; 56 private int mCurrentError = NO_CAPTURE_ERROR; 57 58 private RequestHolder mCurrentRequest = null; 59 60 private Handler mCurrentHandler = null; 61 private CameraDeviceStateListener mCurrentListener = null; 62 63 /** 64 * Error code used by {@link #setCaptureStart} and {@link #setCaptureResult} to indicate that no 65 * error has occurred. 66 */ 67 public static final int NO_CAPTURE_ERROR = -1; 68 69 /** 70 * CameraDeviceStateListener callbacks to be called after state transitions. 71 */ 72 public interface CameraDeviceStateListener { 73 void onError(int errorCode, RequestHolder holder); 74 void onConfiguring(); 75 void onIdle(); 76 void onBusy(); 77 void onCaptureStarted(RequestHolder holder, long timestamp); 78 void onCaptureResult(CameraMetadataNative result, RequestHolder holder); 79 } 80 81 /** 82 * Transition to the {@code ERROR} state. 83 * 84 * <p> 85 * The device cannot exit the {@code ERROR} state. If the device was not already in the 86 * {@code ERROR} state, {@link CameraDeviceStateListener#onError(int, RequestHolder)} will be 87 * called. 88 * </p> 89 * 90 * @param error the error to set. Should be one of the error codes defined in 91 * {@link CameraDeviceImpl.CameraDeviceCallbacks}. 92 */ 93 public synchronized void setError(int error) { 94 mCurrentError = error; 95 doStateTransition(STATE_ERROR); 96 } 97 98 /** 99 * Transition to the {@code CONFIGURING} state, or {@code ERROR} if in an invalid state. 100 * 101 * <p> 102 * If the device was not already in the {@code CONFIGURING} state, 103 * {@link CameraDeviceStateListener#onConfiguring()} will be called. 104 * </p> 105 * 106 * @return {@code false} if an error has occurred. 107 */ 108 public synchronized boolean setConfiguring() { 109 doStateTransition(STATE_CONFIGURING); 110 return mCurrentError == NO_CAPTURE_ERROR; 111 } 112 113 /** 114 * Transition to the {@code IDLE} state, or {@code ERROR} if in an invalid state. 115 * 116 * <p> 117 * If the device was not already in the {@code IDLE} state, 118 * {@link CameraDeviceStateListener#onIdle()} will be called. 119 * </p> 120 * 121 * @return {@code false} if an error has occurred. 122 */ 123 public synchronized boolean setIdle() { 124 doStateTransition(STATE_IDLE); 125 return mCurrentError == NO_CAPTURE_ERROR; 126 } 127 128 /** 129 * Transition to the {@code CAPTURING} state, or {@code ERROR} if in an invalid state. 130 * 131 * <p> 132 * If the device was not already in the {@code CAPTURING} state, 133 * {@link CameraDeviceStateListener#onCaptureStarted(RequestHolder)} will be called. 134 * </p> 135 * 136 * @param request A {@link RequestHolder} containing the request for the current capture. 137 * @param timestamp The timestamp of the capture start in nanoseconds. 138 * @param captureError Report a recoverable error for a single request using a valid 139 * error code for {@code ICameraDeviceCallbacks}, or 140 * {@link #NO_CAPTURE_ERROR} 141 * @return {@code false} if an error has occurred. 142 */ 143 public synchronized boolean setCaptureStart(final RequestHolder request, long timestamp, 144 int captureError) { 145 mCurrentRequest = request; 146 doStateTransition(STATE_CAPTURING, timestamp, captureError); 147 return mCurrentError == NO_CAPTURE_ERROR; 148 } 149 150 /** 151 * Set the result for a capture. 152 * 153 * <p> 154 * If the device was in the {@code CAPTURING} state, 155 * {@link CameraDeviceStateListener#onCaptureResult(CameraMetadataNative, RequestHolder)} will 156 * be called with the given result, otherwise this will result in the device transitioning to 157 * the {@code ERROR} state, 158 * </p> 159 * 160 * @param request The {@link RequestHolder} request that created this result. 161 * @param result The {@link CameraMetadataNative} result to set. 162 * @param captureError Report a recoverable error for a single buffer or result using a valid 163 * error code for {@code ICameraDeviceCallbacks}, or 164 * {@link #NO_CAPTURE_ERROR}. 165 * @return {@code false} if an error has occurred. 166 */ 167 public synchronized boolean setCaptureResult(final RequestHolder request, 168 final CameraMetadataNative result, 169 final int captureError) { 170 if (mCurrentState != STATE_CAPTURING) { 171 Log.e(TAG, "Cannot receive result while in state: " + mCurrentState); 172 mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE; 173 doStateTransition(STATE_ERROR); 174 return mCurrentError == NO_CAPTURE_ERROR; 175 } 176 177 if (mCurrentHandler != null && mCurrentListener != null) { 178 if (captureError != NO_CAPTURE_ERROR) { 179 mCurrentHandler.post(new Runnable() { 180 @Override 181 public void run() { 182 mCurrentListener.onError(captureError, request); 183 } 184 }); 185 } else { 186 mCurrentHandler.post(new Runnable() { 187 @Override 188 public void run() { 189 mCurrentListener.onCaptureResult(result, request); 190 } 191 }); 192 } 193 } 194 return mCurrentError == NO_CAPTURE_ERROR; 195 } 196 197 /** 198 * Set the listener for state transition callbacks. 199 * 200 * @param handler handler on which to call the callbacks. 201 * @param listener the {@link CameraDeviceStateListener} callbacks to call. 202 */ 203 public synchronized void setCameraDeviceCallbacks(Handler handler, 204 CameraDeviceStateListener listener) { 205 mCurrentHandler = handler; 206 mCurrentListener = listener; 207 } 208 209 private void doStateTransition(int newState) { 210 doStateTransition(newState, /*timestamp*/0, NO_CAPTURE_ERROR); 211 } 212 213 private void doStateTransition(int newState, final long timestamp, final int error) { 214 if (newState != mCurrentState) { 215 String stateName = "UNKNOWN"; 216 if (newState >= 0 && newState < sStateNames.length) { 217 stateName = sStateNames[newState]; 218 } 219 Log.i(TAG, "Legacy camera service transitioning to state " + stateName); 220 } 221 222 // If we transitioned into a non-IDLE/non-ERROR state then mark the device as busy 223 if(newState != STATE_ERROR && newState != STATE_IDLE) { 224 if (mCurrentState != newState && mCurrentHandler != null && 225 mCurrentListener != null) { 226 mCurrentHandler.post(new Runnable() { 227 @Override 228 public void run() { 229 mCurrentListener.onBusy(); 230 } 231 }); 232 } 233 } 234 235 switch(newState) { 236 case STATE_ERROR: 237 if (mCurrentState != STATE_ERROR && mCurrentHandler != null && 238 mCurrentListener != null) { 239 mCurrentHandler.post(new Runnable() { 240 @Override 241 public void run() { 242 mCurrentListener.onError(mCurrentError, mCurrentRequest); 243 } 244 }); 245 } 246 mCurrentState = STATE_ERROR; 247 break; 248 case STATE_CONFIGURING: 249 if (mCurrentState != STATE_UNCONFIGURED && mCurrentState != STATE_IDLE) { 250 Log.e(TAG, "Cannot call configure while in state: " + mCurrentState); 251 mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE; 252 doStateTransition(STATE_ERROR); 253 break; 254 } 255 if (mCurrentState != STATE_CONFIGURING && mCurrentHandler != null && 256 mCurrentListener != null) { 257 mCurrentHandler.post(new Runnable() { 258 @Override 259 public void run() { 260 mCurrentListener.onConfiguring(); 261 } 262 }); 263 } 264 mCurrentState = STATE_CONFIGURING; 265 break; 266 case STATE_IDLE: 267 if (mCurrentState == STATE_IDLE) { 268 break; 269 } 270 271 if (mCurrentState != STATE_CONFIGURING && mCurrentState != STATE_CAPTURING) { 272 Log.e(TAG, "Cannot call idle while in state: " + mCurrentState); 273 mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE; 274 doStateTransition(STATE_ERROR); 275 break; 276 } 277 278 if (mCurrentState != STATE_IDLE && mCurrentHandler != null && 279 mCurrentListener != null) { 280 mCurrentHandler.post(new Runnable() { 281 @Override 282 public void run() { 283 mCurrentListener.onIdle(); 284 } 285 }); 286 } 287 mCurrentState = STATE_IDLE; 288 break; 289 case STATE_CAPTURING: 290 if (mCurrentState != STATE_IDLE && mCurrentState != STATE_CAPTURING) { 291 Log.e(TAG, "Cannot call capture while in state: " + mCurrentState); 292 mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE; 293 doStateTransition(STATE_ERROR); 294 break; 295 } 296 297 if (mCurrentHandler != null && mCurrentListener != null) { 298 if (error != NO_CAPTURE_ERROR) { 299 mCurrentHandler.post(new Runnable() { 300 @Override 301 public void run() { 302 mCurrentListener.onError(error, mCurrentRequest); 303 } 304 }); 305 } else { 306 mCurrentHandler.post(new Runnable() { 307 @Override 308 public void run() { 309 mCurrentListener.onCaptureStarted(mCurrentRequest, timestamp); 310 } 311 }); 312 } 313 } 314 mCurrentState = STATE_CAPTURING; 315 break; 316 default: 317 throw new IllegalStateException("Transition to unknown state: " + newState); 318 } 319 } 320 321 322 } 323
