content: /*
   * Copyright (C) 2012 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 com.android.server.power;
  
  /**
   * Low-level screen on blocker mechanism which is used to keep the screen off
   * or the contents of the screen hidden until the window manager is ready to show new content.
   */
  interface ScreenOnBlocker {
      /**
       * Acquires the screen on blocker.
       * Prevents the screen from turning on.
       *
       * Calls to acquire() nest and must be matched by the same number
       * of calls to release().
       */
      void acquire();
  
      /**
       * Releases the screen on blocker.
       * Allows the screen to turn on.
       *
       * It is an error to call release() if the screen on blocker has not been acquired.
       * The system may crash.
       */
      void release();
  }
  