include/svl/broadcast.hxx

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  19 #ifndef INCLUDED_SVL_BROADCAST_HXX
  20 #define INCLUDED_SVL_BROADCAST_HXX
  21
  22 #include <svl/svldllapi.h>
  23
  24 #include <vector>
  25
  26 class SvtListener;
  27 class SfxHint;
  28
  29 class SVL_DLLPUBLIC SvtBroadcaster
  30 {
  31 public:
  32     friend class SvtListener;
  33
  34     typedef std::vector<SvtListener*> ListenersType;
  35
  36 private:
  37     const SvtBroadcaster&   operator=(const SvtBroadcaster &) = delete;
  38
  39     /**
  40      * Ensure that the container doesn't contain any duplicated listener
  41      * entries. As a side effect, the listeners get sorted by pointer values
  42      * after this call.
  43      */
  44     void Normalize() const;
  45
  46     void Add( SvtListener* p );
  47     void Remove( SvtListener* p );
  48
  49 protected:
  50     virtual void            ListenersGone();
  51
  52 public:
  53                             SvtBroadcaster()
  54                                 : mnEmptySlots(0), mnListenersFirstUnsorted(0), mbAboutToDie(false)
  55                                 , mbDisposing(false), mbDestNormalized(true) {}
  56                             SvtBroadcaster( const SvtBroadcaster &rBC );
  57     virtual                 ~SvtBroadcaster();
  58
  59     void                    Broadcast( const SfxHint &rHint );
  60
  61     ListenersType& GetAllListeners();
  62     const ListenersType& GetAllListeners() const;
  63
  64     bool HasListeners() const { return (maListeners.size() - mnEmptySlots) > 0; }
  65
  66     /**
  67      * Listeners and broadcasters are M:N relationship.  If you want to
  68      * destruct them, you easily end up in O(M*N) situation; where for every
  69      * listener, you iterate all broadcasters, to remove that one listener.
  70      *
  71      * To avoid that, use this call to announce to the broadcaster it is going
  72      * to die, and the listeners do not have to bother with removing
  73      * themselves from the broadcaster - the broadcaster will not broadcast
  74      * anything after the PrepareForDestruction() call anyway.
  75      */
  76     void PrepareForDestruction();
  77
  78 private:
  79     /// contains only one of each listener, which is enforced by SvtListener
  80     mutable ListenersType maListeners;
  81
  82     /// When the broadcaster is about to die, collect listeners that asked for removal.
  83     mutable ListenersType maDestructedListeners;
  84
  85     /**
  86         Note that this class is very performance sensitive, so the following fields have been
  87         carefully sized and packed so we can access them quickly, while also taking as little CPU cache
  88         space as possible (because e.g. calc can have a LOT of them)
  89     */
  90     mutable sal_Int32 mnEmptySlots;
  91     // The first item in maListeners that is not sorted. The container can become large, so this optimizes sorting.
  92     mutable sal_Int32 mnListenersFirstUnsorted;
  93     /// Indicate that this broadcaster will be destructed (we indicate this on all ScColumn's broadcasters during the ScTable destruction, eg.)
  94     bool mbAboutToDie:1;
  95     bool mbDisposing:1;
  96     // Whether maDestructedListeners is sorted or not.
  97     mutable bool mbDestNormalized:1;
  98 };
  99
 100
 101 #endif
 102
 103 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */