[mapserver-dev] A basic question about mapserver functions

[Mauricio Herrera]

Hello

Really I hope you  can help me with next doubt,I appreciate your help...

Well, I am drawing  a function map of mapserver. Because I would like to
know all internal structure of mapserver. However
I have a problem with DATA. I don't understand what function links  DATA
value (layer->data) with next functions:


   - imageObj *msDrawMap(mapObj *map, int querymap)
   - int msShapefileOpen(shapefileObj *shpfile, char *mode, char *filename,
   int log_failures)


(LoadLayer) file mapfile.c  <----- What is the link function for DATA value?
--------->(msDrawMap) file mapdraw.c
(LoadLayer) file mapfile.c  <----- What is the link function for DATA value?
---------> (msShapefileOpen) file mapshape.c


For example:

1.-loadLayer()-->getString() ---->*linkfunction()*?------->msDrawMap()
                                                      |
                                                filename=layer->data;

2.-loadLayer()-->getString() ---->*linkfunction()*?------->msShapefileOpen()
                                                      |
                                                filename=layer->data;


I know that this  imageObj *msDrawMap(mapObj *map, int querymap) function is
used for rendering the map file. Therefore this function
must know where the data are located ("/usr/local/geo/street")  and DATA
provides this information with (layer-> data) ... but where does it? = S I
can not find the function..


And I  know too that:

loadLayer() this function contain  a (case DATA:)  and  this call the
functions  getString(),msValidateParameter(),msLookupHashTable() and
msFree()..But In what moment DATA sends or provides its value to the
functions msDrawMap() o msShapefileOpen? where is the link function?


I hope you understand me

Thanks

Mauricio
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