gecko/widget/xpwidgets/nsIdleService.h

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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2007
 * the Initial Developer. All Rights Reserved.
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 *  Gijs Kruitbosch <gijskruitbosch@gmail.com>
 *  Mike Kristoffersen <moz@mikek.dk>
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#ifndef nsIdleService_h__
#define nsIdleService_h__

#include "nsIIdleService.h"
#include "nsCOMPtr.h"
#include "nsITimer.h"
#include "nsTArray.h"
#include "nsIObserver.h"
#include "nsIIdleService.h"
#include "nsCategoryCache.h"

/**
 * Class we can use to store an observer with its associated idle time
 * requirement and whether or not the observer thinks it's "idle".
 */
class IdleListener {
public:
  nsCOMPtr<nsIObserver> observer;
  PRUint32 reqIdleTime;
  bool isIdle;

  IdleListener(nsIObserver* obs, PRUint32 reqIT, bool aIsIdle = false) :
    observer(obs), reqIdleTime(reqIT), isIdle(aIsIdle) {}
  ~IdleListener() {}
};

// This one will be declared later.
class nsIdleService;

/**
 * Class to handle the daily idle timer.
 */
class nsIdleServiceDaily : public nsIObserver
{
public:
  NS_DECL_ISUPPORTS
  NS_DECL_NSIOBSERVER

  nsIdleServiceDaily(nsIIdleService* aIdleService);

  /**
   * Initializes the daily idle observer.
   * Keep this separated from the constructor, since it could cause pointer
   * corruption due to AddRef/Release of "this".
   */
  void Init();

  virtual ~nsIdleServiceDaily();

private:
  /**
   * @note This is a normal pointer, part to avoid creating a cycle with the
   * idle service, part to avoid potential pointer corruption due to this class
   * being instantiated in the constructor of the service itself.
   */
  nsIIdleService* mIdleService;

  /**
   * Set to true when the instantiated object has a idle observer.
   */
  bool mObservesIdle;

  /**
   * Place to hold the timer used by this class to determine when a day has
   * passed, after that it will wait for idle time to be detected.
   */
  nsCOMPtr<nsITimer> mTimer;

  /**
   * Function that is called back once a day.
   */
  static void DailyCallback(nsITimer* aTimer, void* aClosure);

  /**
   * Cache of observers for the "idle-daily" category.
   */
  nsCategoryCache<nsIObserver> mCategoryObservers;
};

class nsIdleService : public nsIIdleService
{
public:
  nsIdleService();

  // Implement nsIIdleService methods.
  NS_IMETHOD AddIdleObserver(nsIObserver* aObserver, PRUint32 aIdleTime);
  NS_IMETHOD RemoveIdleObserver(nsIObserver* aObserver, PRUint32 aIdleTime);
  NS_IMETHOD GetIdleTime(PRUint32* idleTime);

  void ResetIdleTimeOut();

protected:
  ~nsIdleService();

  /**
   * If there is a platform specific function to poll the system idel time
   * then that must be returned in this function, and the function MUST return
   * true, otherwise then the function should be left unimplemented or made
   * to return false (this can also be used for systems where it depends on
   * the configuration of the system if the idle time can be determined)
   *
   * @param aIdleTime
   *        The idle time in ms.
   *
   * @return true if the idle time could be polled, false otherwise.
   *
   * @note The time returned by this function can be different than the one
   *       returned by GetIdleTime, as that is corrected by any calls to
   *       ResetIdleTimeOut(), unless you overwrite that function too...
   */
  virtual bool PollIdleTime(PRUint32* aIdleTime);

  /**
   * Function that determines if we are in poll mode or not.
   *
   * @return true if polling is supported, false otherwise.
   */
  virtual bool UsePollMode();

  /**
   * Send expired events and start timers.
   *
   * @param aNewObserver
   *        Whether there are new observers to check.
   */
  void CheckAwayState(bool aNewObserver);

private:
  /**
   * Start the internal timer, restart it if it is allready running.
   *
   * @param aDelay
   *        The time in seconds that should pass before the next timeout.
   */

  void StartTimer(PRUint32 aDelay);

  /**
   * Stop the internal timer, it is safe to call this function, even when
   * there are no timers running.
   */
  void StopTimer();

  /**
   * mTimer holds the internal timer used by this class to detect when to poll
   * for idle time, when to check if idle timers should expire etc.
   */
  nsCOMPtr<nsITimer> mTimer;

  /**
   * Array of listeners that wants to be notified about idle time.
   */
  nsTArray<IdleListener> mArrayListeners;

  /**
   * Object keeping track of the daily idle thingy.
   */
  nsRefPtr<nsIdleServiceDaily> mDailyIdle;

  /**
   * Contains the time of the last idle reset or 0 if there haven't been a
   * reset.
   * <p>
   * Time is kept in seconds since the epoch at midnight, January 1, 1970 UTC.
   */
  PRUint32 mLastIdleReset;

  /**
   * The time since the last handled activity (which might be different than
   * mLastIdleReset, since the activity that reset the idle timer could just
   * have happend, and not handled yet).
   * <p>
   * Time is kept in seconds since the epoch at midnight, January 1, 1970 UTC.
   */
  PRUint32 mLastHandledActivity;

  /**
   * Callback function that is called when the internal timer expires.
   */
  static void IdleTimerCallback(nsITimer* aTimer, void* aClosure);

  /**
   * Whether the idle time calculated in the last call to GetIdleTime is
   * actually valid (see nsIdleService.idl - we return 0 when it isn't).
   */
  bool mPolledIdleTimeIsValid;

  /**
   * Check if any listeners were in idle state, notify them that user
   * is back and change them to non-idle state.
   *
   * @param aIdleTime
   *        The idle time in seconds.
   *
   * @return true if any listeners were notified.
   */
  bool TryNotifyBackState(PRUint32 aIdleTime);

  /**
   * Check if any listeners were in non-idle state, notify them that user
   * is idle and change them to idle state.
   *
   * @param aIdleTime
   *        The idle time in seconds.
   *
   * @return true if any listeners were notified.
   */
  bool TryNotifyIdleState(PRUint32 aIdleTime);

  /**
   * Reschedule the idle timer to fire on next checkpoint.
   *
   * @param aIdleTime
   *        The idle time has passed in seconds.
   */
  void RescheduleIdleTimer(PRUint32 aIdleTime);
};

#endif // nsIdleService_h__