[Freeciv-Dev] Re: (PR#8521) sha.c crashes

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=8521 >

Raimar Falke wrote:

>>Which leads me to conclude that destroy_unit should be removed and 
>>unit_clone should be clone_unit_virtual.
> 
>>A "virtual" unit is the part of the unit allocation that is common 
>>between client and server.  We don't need two concepts for this.
> 
> Uhhh. Care to cite something? AFAIK virtual means that the unit
> doesn't exists (a virtual unit in the client is unknown to the server,
> a virtual unit in the server-ai is unknown to the server,...). The
> original reason for it was that some function's wanted "struct unit *"
> so so you created a virtual unit to pass into them. It was first
> introduced by Gregory in the air goto patches:
> 
> +/**********************************************************
> + * Create a virtual unit to use in build want estimation
> + *********************************************************/
> +struct unit *create_unit_virtual(struct player *pplayer, int x, int y,
> +                                Unit_Type_id type, bool make_veteran)

Yes.  And the units used by the historian agent are "virtual" units in 
this sense.  They aren't a part of the normal hierarchy (unit hash, 
pplayer->units, ptile->units) but are tracked internally by sha.c.

> So we should drop the _virtual and just name it
> "unit_create". "unit_destroy" can then be used for both "unit_create"
> and "unit_clone". unittools.c:create_unit should be renamed to
> unittools.c:server_create_unit or similar to denote that more work is
> done here.

Possibly.  This is just a matter of semantics, however.

My point is that there are only two concepts: server/client unit and 
virtual unit.  A server/client unit is a subset/subclass of a virtual 
unit.  This may not be how the concept of a virtual unit started but it 
has undeniably evolved into this.

jason