Add flush mechanism to buffered Primitives

There are the classes BufferedDecompositionPrimitive2D
and BufferedDecompositionGroupPrimitive2D that offer
a unified mechanism to preserve/buffer the decomposition
of a Primitive, independent of the complexity. This may
include e.g. the pixel representation of a 3D Scene,
for Charts/CustomShapes and others.

Until now these were refreshed when the objects change,
or when the buffered decomposition decides that it is
necessary, but there was no general mechanism in place
to clean these up while the Primitive owning them was
alive/used. This is not a big thing in Draw/Impress
since this would only be relevant when zooming deep into
a SdrPage, so the non-vislible parts would still hold
data that would not be needed. But for Calc and Writer
this is more relevant: A 3D Chart on the 1st page of a
Writer document would be held buffered all the time a
user would work on pages below that. This is good for
guaranteeing fast re-visualization when scrolling up
again, but until then would just block memory.

So I added this general mechanism that allows activating
flushing timer-based, on Seconds. The default is null
seconds, thus deactivated. It should only be used for
Primitives that can get expensive, not for all.
NOTE: I checked activating for all Primitives to be on
the safe side, works.

It is now (initially) activated for:
- GlowPrimitive2D
- GraphicPrimitive2D
- MetafilePrimitive2D
- ScenePrimitive2D
- ShadowPrimitive2D (softShadow)
- SoftEdgePrimitive2D
- SdrCustomShapePrimitive2D
- SdrGrafPrimitive2D

These are the usual suspects that may use some memory
to buffer their decomposition (for good reasons, each
repaint uses it). Other Primitives which may show need
to be treated this way can easily be added, just by
calling setCallbackSeconds(s) in their constructor. This
is true for all Primitives derived from the two classes
mentioned above.

NOTE: Too short buffering times are *not* useful - e.g.
for a expensive-to-be-recreated 3D chart representation
this may not pay out, so I chose times in a way that try
to respect this.

NOTE: This change needs
7397fa7cdfc33f5a079df42e4d6cfa59ae9e062d to work
correctly (thanks to sberg for this). Without this the
office hangs/does not terminate regularly in trying to
destroy the 'TimerManager'.

Change-Id: Id4802afcb6d12480bb2935cc1ef67fe443b3b788
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160926
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>

2 files changed, 34 insertions, 17 deletions

diff --git a/include/drawinglayer/primitive2d/BufferedDecompositionGroupPrimitive2D.hxx b/include/drawinglayer/primitive2d/BufferedDecompositionGroupPrimitive2D.hxx
index a1cfee38798f..c3bc54e5fca3 100644
--- a/include/drawinglayer/primitive2d/BufferedDecompositionGroupPrimitive2D.hxx
+++ b/include/drawinglayer/primitive2d/BufferedDecompositionGroupPrimitive2D.hxx
@@ -21,6 +21,7 @@
 
 #include <drawinglayer/drawinglayerdllapi.h>
 #include <drawinglayer/primitive2d/groupprimitive2d.hxx>
+#include <salhelper/timer.hxx>
 
 namespace drawinglayer::primitive2d
 {
@@ -35,25 +36,32 @@ namespace drawinglayer::primitive2d
 class DRAWINGLAYER_DLLPUBLIC BufferedDecompositionGroupPrimitive2D : public GroupPrimitive2D
 {
 private:
+    // exclusive helper for Primitive2DFlusher
+    friend void flushBufferedDecomposition(BufferedDecompositionGroupPrimitive2D&);
+
     /// a sequence used for buffering the last create2DDecomposition() result
     Primitive2DContainer maBuffered2DDecomposition;
 
+    /// offer callback mechanism to flush buffered content timer-based
+    ::rtl::Reference<::salhelper::Timer> maCallbackTimer;
+    sal_uInt16 maCallbackSeconds;
+
 protected:
     /// identical to BufferedDecompositionPrimitive2D, see there please
-    const Primitive2DContainer& getBuffered2DDecomposition() const
-    {
-        return maBuffered2DDecomposition;
-    }
-    void setBuffered2DDecomposition(Primitive2DContainer&& rNew)
-    {
-        maBuffered2DDecomposition = std::move(rNew);
-    }
+    const Primitive2DContainer& getBuffered2DDecomposition() const;
+    void setBuffered2DDecomposition(Primitive2DContainer&& rNew);
 
     /// method which is to be used to implement the local decomposition of a 2D group primitive.
     virtual void
     create2DDecomposition(Primitive2DContainer& rContainer,
                           const geometry::ViewInformation2D& rViewInformation) const = 0;
 
+    // when changing from null (which is inactive) to a count of seconds, the
+    // callback mechanism to flush buffered content timer-based will be activated.
+    // it is protected since the idea is that this gets called in the constructor
+    // of derived classes.
+    void setCallbackSeconds(sal_uInt16 nNew) { maCallbackSeconds = nNew; }
+
 public:
     /// constructor/destructor. For GroupPrimitive2D we need the child parameter, too.
     BufferedDecompositionGroupPrimitive2D(Primitive2DContainer&& aChildren);
diff --git a/include/drawinglayer/primitive2d/BufferedDecompositionPrimitive2D.hxx b/include/drawinglayer/primitive2d/BufferedDecompositionPrimitive2D.hxx
index 8087a6544dc0..68d40e006a6f 100644
--- a/include/drawinglayer/primitive2d/BufferedDecompositionPrimitive2D.hxx
+++ b/include/drawinglayer/primitive2d/BufferedDecompositionPrimitive2D.hxx
@@ -22,6 +22,7 @@
 #include <drawinglayer/drawinglayerdllapi.h>
 #include <drawinglayer/primitive2d/Primitive2DContainer.hxx>
 #include <drawinglayer/primitive2d/baseprimitive2d.hxx>
+#include <salhelper/timer.hxx>
 
 namespace drawinglayer::geometry
 {
@@ -62,35 +63,43 @@ namespace drawinglayer::primitive2d
 class DRAWINGLAYERCORE_DLLPUBLIC BufferedDecompositionPrimitive2D : public BasePrimitive2D
 {
 private:
+    // exclusive helper for Primitive2DFlusher
+    friend void flushBufferedDecomposition(BufferedDecompositionPrimitive2D&);
+
     /// a sequence used for buffering the last create2DDecomposition() result
     Primitive2DContainer maBuffered2DDecomposition;
 
+    /// offer callback mechanism to flush buffered content timer-based
+    ::rtl::Reference<::salhelper::Timer> maCallbackTimer;
+    sal_uInt16 maCallbackSeconds;
+
     /// When a shadow wraps a list of primitives, this primitive wants to influence the transparency
     /// of the shadow.
-    sal_uInt16 mnTransparenceForShadow = 0;
+    sal_uInt16 mnTransparenceForShadow;
 
 protected:
     /** access methods to maBuffered2DDecomposition. The usage of this methods may allow
         later thread-safe stuff to be added if needed. Only to be used by getDecomposition()
         implementations for buffering the last decomposition.
      */
-    const Primitive2DContainer& getBuffered2DDecomposition() const
-    {
-        return maBuffered2DDecomposition;
-    }
-    void setBuffered2DDecomposition(Primitive2DContainer&& rNew)
-    {
-        maBuffered2DDecomposition = std::move(rNew);
-    }
+    const Primitive2DContainer& getBuffered2DDecomposition() const;
+    void setBuffered2DDecomposition(Primitive2DContainer&& rNew);
 
     /** method which is to be used to implement the local decomposition of a 2D primitive. */
     virtual void
     create2DDecomposition(Primitive2DContainer& rContainer,
                           const geometry::ViewInformation2D& rViewInformation) const = 0;
 
+    // when changing from null (which is inactive) to a count of seconds, the
+    // callback mechanism to flush buffered content timer-based will be activated.
+    // it is protected since the idea is that this gets called in the constructor
+    // of derived classes.
+    void setCallbackSeconds(sal_uInt16 nNew) { maCallbackSeconds = nNew; }
+
 public:
     // constructor/destructor
     BufferedDecompositionPrimitive2D();
+    virtual ~BufferedDecompositionPrimitive2D();
 
     /** The getDecomposition default implementation will on demand use create2DDecomposition() if
         maBuffered2DDecomposition is empty. It will set maBuffered2DDecomposition to this obtained decomposition