Difference between revisions of "Projects/Marble/GeoData/PointerVsImplicitShare"

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(Started this page ... first thoughts, multiple possibilities)
 
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To find out which is the wisest I try to look at every single class:
 
To find out which is the wisest I try to look at every single class:
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=== Base data ===
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* '''GeoDataCoordinates''' This one is quite simple. It is not more than a QPoint in GeoCoordinates. This should stay implicilty shared.
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* '''GeoDataLatLonBox''' (GeoDataObject) It seems to nothing more than a QRect for GeoCoordinates. I'm not sure if it must be derived from GeoDataObject
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** '''GeoDataLatLonAltBox''' same for this
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=== Geometric structures ===
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* '''GeoDataGeometry''' The base class for all geometric. We could want a pointer for this, so using it as data may not be the right way.
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** '''GeoDataPoint''' This one uses multiple inheritance (GeoDataCoordinates). I don't think that this is semantically correct.
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=== views ===
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* '''GeoDataAbstractView''' It's nothing more than a view, this could stay implicitly shared.
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** '''GeoDataLookAt''' Same for this as this is a child.

Revision as of 14:29, 31 March 2010

Implicit sharing and storing objects as value is very reasonable for basic data as QStrings, but there are reasonable doubts regarding Placemarks and other GeoData. There are some possibilities:

  • Don't use implicit sharing at all and store all objects on the heap with a pointer to it.
  • Use implicit sharing and storing as value for GeoDataCoordinates only.
  • Use implicit sharing and storing as value for all GeoData classes.

To find out which is the wisest I try to look at every single class:

Base data

  • GeoDataCoordinates This one is quite simple. It is not more than a QPoint in GeoCoordinates. This should stay implicilty shared.
  • GeoDataLatLonBox (GeoDataObject) It seems to nothing more than a QRect for GeoCoordinates. I'm not sure if it must be derived from GeoDataObject
    • GeoDataLatLonAltBox same for this

Geometric structures

  • GeoDataGeometry The base class for all geometric. We could want a pointer for this, so using it as data may not be the right way.
    • GeoDataPoint This one uses multiple inheritance (GeoDataCoordinates). I don't think that this is semantically correct.

views

  • GeoDataAbstractView It's nothing more than a view, this could stay implicitly shared.
    • GeoDataLookAt Same for this as this is a child.

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