Speedup destruction of sheets with too many listeners & broadcasters.

Listeners and broadcasters are M:N relationship.  If you want to
destruct them, you easily end up in O(M*N) situation; where for every
listener, you iterate all broadcasters, to remove that one listener.

To avoid that, announce to the broadcasters that they are going to die, and the
listeners do not have to bother with removing themselves from the broadcaster.
The broadcaster will not broadcast anything after the PrepareForDesctruction()
call anyway.

Change-Id: I68d78b23e73bcbb944de9139448b2c20dfa14f62

1 files changed, 13 insertions, 0 deletions

diff --git a/include/svl/broadcast.hxx b/include/svl/broadcast.hxx
index 6a6bc03c6fd6..d122e02594c6 100644
--- a/include/svl/broadcast.hxx
+++ b/include/svl/broadcast.hxx
@@ -60,8 +60,21 @@ public:
 
     bool HasListeners() const;
 
+    /**
+     * Listeners and broadcasters are M:N relationship.  If you want to
+     * destruct them, you easily end up in O(M*N) situation; where for every
+     * listener, you iterate all broadcasters, to remove that one listener.
+     *
+     * To avoid that, use this call to announce to the broadcaster it is going
+     * to die, and the listeners do not have to bother with removing
+     * themselves from the broadcaster - the broadcaster will not broadcast
+     * anything after the PrepareForDesctruction() call anyway.
+     */
+    void PrepareForDestruction() { mbAboutToDie = true; }
+
 private:
     ListenersType maListeners;
+    bool mbAboutToDie:1;
     bool mbDisposing:1;
     bool mbNormalized:1;
 };