forked from coreos/torus
/
mod.go
113 lines (99 loc) · 2.47 KB
/
mod.go
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package ring
import (
"fmt"
"hash/crc32"
"reflect"
"sort"
"github.com/coreos/torus"
"github.com/coreos/torus/models"
)
type mod struct {
version int
rep int
peers torus.PeerInfoList
peerlist []string
npeers int
}
func init() {
registerRing(Mod, "mod", makeMod)
}
func makeMod(r *models.Ring) (torus.Ring, error) {
rep := int(r.ReplicationFactor)
if rep == 0 {
rep = 1
}
pil := torus.PeerInfoList(r.Peers)
return &mod{
version: int(r.Version),
peers: pil,
peerlist: sort.StringSlice([]string(pil.PeerList())),
rep: rep,
}, nil
}
func (m *mod) GetPeers(key torus.BlockRef) (torus.PeerPermutation, error) {
permute := make([]string, len(m.peerlist))
crc := crc32.ChecksumIEEE(key.ToBytes())
sum := int(crc) % len(m.peers)
copy(permute, m.peerlist[sum:])
copy(permute[len(m.peerlist)-sum:], m.peerlist[:sum])
return torus.PeerPermutation{
Peers: permute,
Replication: m.rep,
}, nil
}
func (m *mod) Members() torus.PeerList { return m.peers.PeerList() }
func (m *mod) Describe() string {
s := fmt.Sprintf("Ring: Mod\nReplication:%d\nPeers:", m.rep)
for _, x := range m.peerlist {
s += fmt.Sprintf("\n\t%s", x)
}
return s
}
func (m *mod) Type() torus.RingType { return Mod }
func (m *mod) Version() int { return m.version }
func (m *mod) Marshal() ([]byte, error) {
var out models.Ring
out.Version = uint32(m.version)
out.ReplicationFactor = uint32(m.rep)
out.Type = uint32(m.Type())
out.Peers = m.peers
return out.Marshal()
}
func (m *mod) AddPeers(peers torus.PeerInfoList) (torus.Ring, error) {
newPeers := m.peers.Union(peers)
if reflect.DeepEqual(newPeers.PeerList(), m.peers.PeerList()) {
return nil, torus.ErrExists
}
newm := &mod{
version: m.version + 1,
rep: m.rep,
peers: newPeers,
peerlist: sort.StringSlice([]string(newPeers.PeerList())),
npeers: len(newPeers),
}
return newm, nil
}
func (m *mod) RemovePeers(pl torus.PeerList) (torus.Ring, error) {
newPeers := m.peers.AndNot(pl)
if len(newPeers) == len(m.peers) {
return nil, torus.ErrNotExist
}
newm := &mod{
version: m.version + 1,
rep: m.rep,
peers: newPeers,
peerlist: sort.StringSlice([]string(newPeers.PeerList())),
npeers: len(newPeers),
}
return newm, nil
}
func (m *mod) ChangeReplication(r int) (torus.Ring, error) {
newm := &mod{
version: m.version + 1,
rep: r,
peers: m.peers,
peerlist: sort.StringSlice([]string(m.peers.PeerList())),
npeers: len(m.peers),
}
return newm, nil
}