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.usb;
  
  /**
   * Detects and reports ALSA jack state and events.
   */
  public final class UsbAlsaJackDetector implements Runnable {
      private static final String TAG = "UsbAlsaJackDetector";
  
      private static native boolean nativeHasJackDetect(int card);
      private native boolean nativeJackDetect(int card);
      private native boolean nativeOutputJackConnected(int card);
      private native boolean nativeInputJackConnected(int card);
  
      private boolean mStopJackDetect = false;
      private UsbAlsaDevice mAlsaDevice;
  
      /* use startJackDetect to create a UsbAlsaJackDetector */
      private UsbAlsaJackDetector(UsbAlsaDevice device) {
          mAlsaDevice = device;
      }
  
      /** If jack detection is detected on the given Alsa Device,
       * create and return a UsbAlsaJackDetector which will update wired device state
       * each time a jack detection event is registered.
       *
       * @returns UsbAlsaJackDetector if jack detect is supported, or null.
       */
      public static UsbAlsaJackDetector startJackDetect(UsbAlsaDevice device) {
          if (!nativeHasJackDetect(device.getCardNum())) {
              return null;
          }
          UsbAlsaJackDetector jackDetector = new UsbAlsaJackDetector(device);
  
          // This thread will exit once the USB device disappears.
          // It can also be convinced to stop with pleaseStop().
          new Thread(jackDetector, "USB jack detect thread").start();
          return jackDetector;
      }
  
      public boolean isInputJackConnected() {
          return nativeInputJackConnected(mAlsaDevice.getCardNum());
      }
  
      public boolean isOutputJackConnected() {
          return nativeOutputJackConnected(mAlsaDevice.getCardNum());
      }
  
      /**
       * Stop the jack detect thread from calling back into UsbAlsaDevice.
       * This doesn't force the thread to stop (which is deprecated in java and dangerous due to
       * locking issues), but will cause the thread to exit at the next safe opportunity.
       */
      public void pleaseStop() {
          synchronized (this) {
              mStopJackDetect = true;
          }
      }
  
      /**
       * Called by nativeJackDetect each time a jack detect event is reported.
       * @return false when the jackDetect thread should stop.  true otherwise.
       */
      public boolean jackDetectCallback() {
          synchronized (this) {
              if (mStopJackDetect) {
                  return false;
              }
              mAlsaDevice.updateWiredDeviceConnectionState(true);
          }
          return true;
      }
  
      /**
       * This will call jackDetectCallback each time it detects a jack detect event.
       * If jackDetectCallback returns false, this function will return.
       */
      public void run() {
          nativeJackDetect(mAlsaDevice.getCardNum());
      }
  }
  
  