// addPPDHashToPrinters fetches description, PPD hash, manufacturer, model for
// all argument printers, concurrently.
//
// Returns a new printer slice, because it can shrink due to raw or
// mis-configured printers.
func (c *CUPS) addDescriptionToPrinters(printers []lib.Printer) []lib.Printer {
var wg sync.WaitGroup
ch := make(chan *lib.Printer, len(printers))
for i := range printers {
if !lib.PrinterIsRaw(printers[i]) {
wg.Add(1)
go func(p *lib.Printer) {
if description, ppdHash, manufacturer, model, err := c.pc.getDescription(p.Name); err == nil {
p.Description.Absorb(description)
p.CapsHash = ppdHash
p.Manufacturer = manufacturer
p.Model = model
ch <- p
} else {
glog.Error(err)
}
wg.Done()
}(&printers[i])
}
}
wg.Wait()
close(ch)
result := make([]lib.Printer, 0, len(ch))
for printer := range ch {
result = append(result, *printer)
}
return result
}
// filterRawPrinters removes raw printers from the slice.
func filterRawPrinters(printers []lib.Printer) []lib.Printer {
result := make([]lib.Printer, 0, len(printers))
for i := range printers {
if !lib.PrinterIsRaw(printers[i]) {
result = append(result, printers[i])
}
}
return result
}