content: /*
   * Copyright (C) 2018 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.deviceidle;
  
  import android.annotation.IntDef;
  
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  
  /**
   * Implemented by OEM and/or Form Factor. System ones are built into the
   * image regardless of build flavour but may still be switched off at run time.
   * Individual feature flags at build time control which are used. We may
   * also explore a local override for quick testing.
   */
  public interface IDeviceIdleConstraint {
  
      /**
       * A state for this constraint to block descent from.
       *
       * <p>These states are a subset of the states in DeviceIdleController that make sense for
       * constraints to be able to block on. For example, {@link #SENSING_OR_ABOVE} clearly has
       * defined "above" and "below" states. However, a hypothetical {@code QUICK_DOZE_OR_ABOVE}
       * state would not have clear semantics as to what transitions should be blocked and which
       * should be allowed.
       */
      @IntDef(flag = false, value = {
              ACTIVE,
              SENSING_OR_ABOVE,
      })
      @Retention(RetentionPolicy.SOURCE)
      @interface MinimumState {}
  
      int ACTIVE = 0;
      int SENSING_OR_ABOVE = 1;
  
      /**
       * Begin tracking events for this constraint.
       *
       * <p>The device idle controller has reached a point where it is waiting for the all-clear
       * from this tracker (possibly among others) in order to continue with progression into
       * idle state. It will not proceed until one of the following happens:
       * <ul>
       *   <li>The constraint reports inactive with {@code .setActive(false)}.</li>
       *   <li>The constraint is unregistered with {@code .unregisterDeviceIdleConstraint(this)}.</li>
       *   <li>A transition timeout in DeviceIdleController fires.
       * </ul>
       */
      void startMonitoring();
  
      /** Stop checking for new events and do not call into LocalService with updates any more. */
      void stopMonitoring();
  }
  