content: /*
   * Copyright (C) 2015 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License
   */
  
  package android.service.media;
  
  import android.app.Service;
  import android.content.Intent;
  import android.os.Handler;
  import android.os.IBinder;
  import android.os.Message;
  import android.os.Messenger;
  
  /**
   * Extend this class to implement a camera prewarm service. See
   * {@link android.provider.MediaStore#META_DATA_STILL_IMAGE_CAMERA_PREWARM_SERVICE}.
   */
  public abstract class CameraPrewarmService extends Service {
  
      /**
       * Intent action to bind the service as a prewarm service.
       * @hide
       */
      public static final String ACTION_PREWARM =
              "android.service.media.CameraPrewarmService.ACTION_PREWARM";
  
      /**
       * Message sent by the client indicating that the camera intent has been fired.
       * @hide
       */
      public static final int MSG_CAMERA_FIRED = 1;
  
      private final Handler mHandler = new Handler() {
  
          @Override
          public void handleMessage(Message msg) {
              switch (msg.what) {
                  case MSG_CAMERA_FIRED:
                      mCameraIntentFired = true;
                      break;
                  default:
                      super.handleMessage(msg);
              }
          }
      };
      private boolean mCameraIntentFired;
  
      @Override
      public IBinder onBind(Intent intent) {
          if (ACTION_PREWARM.equals(intent.getAction())) {
              onPrewarm();
              return new Messenger(mHandler).getBinder();
          } else {
              return null;
          }
      }
  
      @Override
      public boolean onUnbind(Intent intent) {
          if (ACTION_PREWARM.equals(intent.getAction())) {
              onCooldown(mCameraIntentFired);
          }
          return false;
      }
  
      /**
       * Called when the camera should be prewarmed.
       */
      public abstract void onPrewarm();
  
      /**
       * Called when prewarm phase is done, either because the camera launch intent has been fired
       * at this point or prewarm is no longer needed. A client should close the camera
       * immediately in the latter case.
       * <p>
       * In case the camera launch intent has been fired, there is no guarantee about the ordering
       * of these two events. Cooldown might happen either before or after the activity has been
       * created that handles the camera intent.
       *
       * @param cameraIntentFired Indicates whether the intent to launch the camera has been
       *                          fired.
       */
      public abstract void onCooldown(boolean cameraIntentFired);
  }
  