func applyRange(txnID int64, kv mvcc.KV, r *etcdserverpb.RangeRequest) (*etcdserverpb.RangeResponse, error) {
resp := &etcdserverpb.RangeResponse{}
resp.Header = &etcdserverpb.ResponseHeader{}
var (
kvs []mvccpb.KeyValue
rev int64
err error
)
if isGteRange(r.RangeEnd) {
r.RangeEnd = []byte{}
}
limit := r.Limit
if r.SortOrder != etcdserverpb.RangeRequest_NONE {
// fetch everything; sort and truncate afterwards
limit = 0
}
if limit > 0 {
// fetch one extra for 'more' flag
limit = limit + 1
}
if txnID != noTxn {
kvs, rev, err = kv.TxnRange(txnID, r.Key, r.RangeEnd, limit, r.Revision)
if err != nil {
return nil, err
}
} else {
kvs, rev, err = kv.Range(r.Key, r.RangeEnd, limit, r.Revision)
if err != nil {
return nil, err
}
}
if r.SortOrder != etcdserverpb.RangeRequest_NONE {
var sorter sort.Interface
switch {
case r.SortTarget == etcdserverpb.RangeRequest_KEY:
sorter = &kvSortByKey{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_VERSION:
sorter = &kvSortByVersion{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_CREATE:
sorter = &kvSortByCreate{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_MOD:
sorter = &kvSortByMod{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_VALUE:
sorter = &kvSortByValue{&kvSort{kvs}}
}
switch {
case r.SortOrder == etcdserverpb.RangeRequest_ASCEND:
sort.Sort(sorter)
case r.SortOrder == etcdserverpb.RangeRequest_DESCEND:
sort.Sort(sort.Reverse(sorter))
}
}
if r.Limit > 0 && len(kvs) > int(r.Limit) {
kvs = kvs[:r.Limit]
resp.More = true
}
resp.Header.Revision = rev
for i := range kvs {
resp.Kvs = append(resp.Kvs, &kvs[i])
}
return resp, nil
}
