content: /*
   * Copyright (C) 2008 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.launcher3.util;
  
  import android.os.HandlerThread;
  import android.os.Looper;
  import android.os.Process;
  
  import java.util.concurrent.Executor;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Various different executors used in Launcher
   */
  public class Executors {
  
      // These values are same as that in {@link AsyncTask}.
      private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
      private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
      private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
      private static final int KEEP_ALIVE = 1;
  
      /**
       * An {@link Executor} to be used with async task with no limit on the queue size.
       */
      public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(
              CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
              TimeUnit.SECONDS, new LinkedBlockingQueue<>());
  
      /**
       * Returns the executor for running tasks on the main thread.
       */
      public static final LooperExecutor MAIN_EXECUTOR =
              new LooperExecutor(Looper.getMainLooper());
  
      /**
       * A background executor for using time sensitive actions where user is waiting for response.
       */
      public static final LooperExecutor UI_HELPER_EXECUTOR =
              new LooperExecutor(createAndStartNewForegroundLooper("UiThreadHelper"));
  
      /**
       * Utility method to get a started handler thread statically
       */
      public static Looper createAndStartNewLooper(String name) {
          return createAndStartNewLooper(name, Process.THREAD_PRIORITY_DEFAULT);
      }
  
      /**
       * Utility method to get a started handler thread statically with the provided priority
       */
      public static Looper createAndStartNewLooper(String name, int priority) {
          HandlerThread thread = new HandlerThread(name, priority);
          thread.start();
          return thread.getLooper();
      }
  
      /**
       * Similar to {@link #createAndStartNewLooper(String)}, but starts the thread with
       * foreground priority.
       * Think before using
       */
      public static Looper createAndStartNewForegroundLooper(String name) {
          return createAndStartNewLooper(name, Process.THREAD_PRIORITY_FOREGROUND);
      }
  
      /**
       * Executor used for running Launcher model related tasks (eg loading icons or updated db)
       */
      public static final LooperExecutor MODEL_EXECUTOR =
              new LooperExecutor(createAndStartNewLooper("launcher-loader"));
  }
  