include/vcl/task.hxx

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  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
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  19
  20 #ifndef INCLUDED_VCL_TASK_HXX
  21 #define INCLUDED_VCL_TASK_HXX
  22
  23 #include <vcl/dllapi.h>
  24
  25 struct ImplSchedulerData;
  26
  27 enum class TaskPriority
  28 {
  29     HIGHEST,       ///< These events should run very fast!
  30     DEFAULT,       ///< Default priority used, e.g. the default timer priority
  31     // Input from the OS event queue is processed before HIGH_IDLE tasks.
  32     HIGH_IDLE,     ///< Important idle events to be run before processing drawing events
  33     RESIZE,        ///< Resize runs before repaint, so we won't paint twice
  34     REPAINT,       ///< All repaint events should go in here
  35     POST_PAINT,    ///< Everything running directly after painting
  36     DEFAULT_IDLE,  ///< Default idle priority
  37     LOWEST         ///< Low, very idle cleanup tasks
  38 };
  39
  40 #define PRIO_COUNT (static_cast<int>(TaskPriority::LOWEST) + 1)
  41
  42 class VCL_DLLPUBLIC Task
  43 {
  44     friend class Scheduler;
  45     friend struct ImplSchedulerData;
  46
  47     ImplSchedulerData *mpSchedulerData; ///< Pointer to the element in scheduler list
  48     const char        *mpDebugName;     ///< Useful for debugging
  49     TaskPriority       mePriority;      ///< Task priority
  50     bool               mbActive;        ///< Currently in the scheduler
  51     bool               mbStatic;        ///< Is a static object
  52
  53 protected:
  54     static void StartTimer( sal_uInt64 nMS );
  55
  56     const ImplSchedulerData* GetSchedulerData() const { return mpSchedulerData; }
  57
  58     virtual void SetDeletionFlags();
  59
  60     /**
  61      * How long (in MS) until the Task is ready to be dispatched?
  62      *
  63      * Simply return Scheduler::ImmediateTimeoutMs if you're ready, like an
  64      * Idle. If you have to return Scheduler::InfiniteTimeoutMs, you probably
  65      * need another mechanism to wake up the Scheduler or rely on other
  66      * Tasks to be scheduled, or simply use a polling Timer.
  67      *
  68      * @param nTimeNow the current time
  69      * @return the sleep time of the Task to become ready
  70      */
  71     virtual sal_uInt64 UpdateMinPeriod( sal_uInt64 nTimeNow ) const = 0;
  72
  73 public:
  74     Task( const char *pDebugName );
  75     Task( const Task& rTask );
  76     virtual ~Task() COVERITY_NOEXCEPT_FALSE;
  77     Task& operator=( const Task& rTask );
  78
  79     void            SetPriority(TaskPriority ePriority);
  80     TaskPriority    GetPriority() const { return mePriority; }
  81
  82     const char     *GetDebugName() const { return mpDebugName; }
  83
  84     // Call handler
  85     virtual void    Invoke() = 0;
  86
  87     /**
  88      * Schedules the task for execution
  89      *
  90      * If the timer is already active, it's reset!
  91      * Check with Task::IsActive() to prevent reset.
  92      *
  93      * If you unset bStartTimer, the Task must call Task::StartTimer(...) to be correctly scheduled!
  94      * Otherwise it might just be picked up when the Scheduler runs the next time.
  95      *
  96      * @param bStartTimer if false, don't schedule the Task by calling Task::StartTimer(0).
  97      */
  98     virtual void Start(bool bStartTimer = true);
  99     void            Stop();
 100
 101     bool            IsActive() const { return mbActive; }
 102
 103     /**
 104      * This function must be called for static tasks, so the Task destructor
 105      * ignores the scheduler mutex, as it may not be available anymore.
 106      * The cleanup is still correct, as it has already happened in
 107      * DeInitScheduler call well before the static destructor calls.
 108      */
 109     void            SetStatic() { mbStatic = true; }
 110     bool            IsStatic() const { return mbStatic; }
 111 };
 112
 113 #endif // INCLUDED_VCL_TASK_HXX
 114
 115 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */