[gdal-dev] OGR Feature style API changes: StyleTable on datasources and layers

[brian]

I have two issues with the datasource and layer methods to get and set
style tables.

1) The GetStyleTable(), SetStyleTableDirectly(), and SetStyletable()
methods are not virtual therefore only the memory driver can use them.

2) The SetStyleTableDirectly() and SetStyletable() methods both return
void. it is plausable that a datasource or layer could not support them.

The API changes i am proposing are.

1) make the GetStyleTable(), SetStyleTableDirectly(), and
SetStyletable() methods virtual.

2) make the SetStyleTableDirectly() and SetStyletable() methods return
OGRErr.

If a layer or datasource does not have a style table the GetStyleTable()
method would already return NULL.

I am also wondering if it makes any sence to add a couple of constants
for the TestCapability() methods.

Any feedback would be appreciated.

Brian