github.com/Bytom/bytom@v1.1.2-0.20210127130405-ae40204c0b09/p2p/peer_set.go (about) 1 package p2p 2 3 import ( 4 "sync" 5 ) 6 7 // IPeerSet has a (immutable) subset of the methods of PeerSet. 8 type IPeerSet interface { 9 Has(key string) bool 10 Get(key string) *Peer 11 List() []*Peer 12 Size() int 13 } 14 15 //----------------------------------------------------------------------------- 16 17 // PeerSet is a special structure for keeping a table of peers. 18 // Iteration over the peers is super fast and thread-safe. 19 type PeerSet struct { 20 mtx sync.Mutex 21 lookup map[string]*peerSetItem 22 list []*Peer 23 } 24 25 type peerSetItem struct { 26 peer *Peer 27 index int 28 } 29 30 // NewPeerSet creates a new peerSet with a list of initial capacity of 256 items. 31 func NewPeerSet() *PeerSet { 32 return &PeerSet{ 33 lookup: make(map[string]*peerSetItem), 34 list: make([]*Peer, 0, 256), 35 } 36 } 37 38 // Add adds the peer to the PeerSet. 39 // Returns false if peer with key (PubKeyEd25519) is already set 40 func (ps *PeerSet) Add(peer *Peer) error { 41 ps.mtx.Lock() 42 defer ps.mtx.Unlock() 43 44 if ps.lookup[peer.Key] != nil { 45 return ErrDuplicatePeer 46 } 47 48 ps.lookup[peer.Key] = &peerSetItem{peer, len(ps.list)} 49 ps.list = append(ps.list, peer) 50 return nil 51 } 52 53 func (ps *PeerSet) DoFilter(ip string, pubKey string) error { 54 if ps.Has(pubKey) { 55 return ErrDuplicatePeer 56 } 57 58 return nil 59 } 60 61 // Get looks up a peer by the provided peerKey. 62 func (ps *PeerSet) Get(peerKey string) *Peer { 63 ps.mtx.Lock() 64 defer ps.mtx.Unlock() 65 item, ok := ps.lookup[peerKey] 66 if ok { 67 return item.peer 68 } 69 return nil 70 } 71 72 // Has returns true if the PeerSet contains 73 // the peer referred to by this peerKey. 74 func (ps *PeerSet) Has(peerKey string) bool { 75 ps.mtx.Lock() 76 defer ps.mtx.Unlock() 77 _, ok := ps.lookup[peerKey] 78 return ok 79 } 80 81 // List threadsafe list of peers. 82 func (ps *PeerSet) List() []*Peer { 83 ps.mtx.Lock() 84 defer ps.mtx.Unlock() 85 return ps.list 86 } 87 88 // Remove discards peer if the peer was previously memoized. 89 func (ps *PeerSet) Remove(peer *Peer) { 90 ps.mtx.Lock() 91 defer ps.mtx.Unlock() 92 item := ps.lookup[peer.Key] 93 if item == nil { 94 return 95 } 96 97 index := item.index 98 // Copy the list but without the last element. 99 // (we must copy because we're mutating the list) 100 newList := make([]*Peer, len(ps.list)-1) 101 copy(newList, ps.list) 102 // If it's the last peer, that's an easy special case. 103 if index == len(ps.list)-1 { 104 ps.list = newList 105 delete(ps.lookup, peer.Key) 106 return 107 } 108 109 // Move the last item from ps.list to "index" in list. 110 lastPeer := ps.list[len(ps.list)-1] 111 lastPeerKey := lastPeer.Key 112 lastPeerItem := ps.lookup[lastPeerKey] 113 newList[index] = lastPeer 114 lastPeerItem.index = index 115 ps.list = newList 116 delete(ps.lookup, peer.Key) 117 } 118 119 // Size returns the number of unique items in the peerSet. 120 func (ps *PeerSet) Size() int { 121 ps.mtx.Lock() 122 defer ps.mtx.Unlock() 123 return len(ps.list) 124 }