func (p *Backend) queryGetCacheEntry(param *specs.RrdQuery,
resp *specs.RrdResp) (*cacheEntry, error) {
// form empty response
resp.Vs = []*specs.RRDData{}
resp.Host = param.Host
resp.Name = param.Name
e := p.cache.get(param.Csum())
if e == nil {
return nil, specs.ErrNoent
}
resp.Type = e.typ()
resp.Step = int(e.e.step)
param.Start = param.Start - param.Start%int64(resp.Step)
param.End = param.End - param.End%int64(resp.Step) + int64(resp.Step)
if param.End-param.Start-int64(resp.Step) < 1 {
return nil, specs.ErrParam
}
return e, nil
}
