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 androidx.test.internal.platform.os;
  
  import android.view.View;
  import androidx.annotation.RestrictTo;
  
  /**
   * An API for advancing the looper when its in a paused or controlled state.
   *
   * <p>Implementations should be loaded via {@link
   * androidx.test.internal.platform.ServiceLoaderWrapper}
   *
   * @hide
   */
  @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP) // used by core and espresso
  public interface ControlledLooper {
  
    /**
     * Executes all queued main looper tasks until its idle.
     *
     * <p>Intended to be used in unit test environments where main thread looper is in a paused state.
     */
    void drainMainThreadUntilIdle();
  
    /** Generate window focus event for given view. */
    void simulateWindowFocus(View decorView);
  
    /** Returns true if registerFrameCommitCallback() and addOnDrawListener callbacks are supported */
    default boolean areDrawCallbacksSupported() {
      return false;
    }
  
    public static final ControlledLooper NO_OP_CONTROLLED_LOOPER =
        new ControlledLooper() {
          @Override
          public void drainMainThreadUntilIdle() {}
  
          @Override
          public void simulateWindowFocus(View decorView) {}
  
          @Override
          public boolean areDrawCallbacksSupported() {
            return true;
          }
        };
  }
  