status-go/services/shhext/service.go

172 lines
4.1 KiB
Go

package shhext
import (
"crypto/ecdsa"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
"github.com/status-im/status-go/services/shhext/dedup"
"github.com/syndtr/goleveldb/leveldb"
)
// EnvelopeState in local tracker
type EnvelopeState int
const (
// EnvelopePosted is set when envelope was added to a local whisper queue.
EnvelopePosted EnvelopeState = iota
// EnvelopeSent is set when envelope is sent to atleast one peer.
EnvelopeSent
)
// EnvelopeEventsHandler used for two different event types.
type EnvelopeEventsHandler interface {
EnvelopeSent(common.Hash)
EnvelopeExpired(common.Hash)
}
// Service is a service that provides some additional Whisper API.
type Service struct {
w *whisper.Whisper
tracker *tracker
nodeID *ecdsa.PrivateKey
deduplicator *dedup.Deduplicator
}
// Make sure that Service implements node.Service interface.
var _ node.Service = (*Service)(nil)
// New returns a new Service.
func New(w *whisper.Whisper, handler EnvelopeEventsHandler, db *leveldb.DB) *Service {
track := &tracker{
w: w,
handler: handler,
cache: map[common.Hash]EnvelopeState{},
}
return &Service{
w: w,
tracker: track,
deduplicator: dedup.NewDeduplicator(w, db),
}
}
// Protocols returns a new protocols list. In this case, there are none.
func (s *Service) Protocols() []p2p.Protocol {
return []p2p.Protocol{}
}
// APIs returns a list of new APIs.
func (s *Service) APIs() []rpc.API {
return []rpc.API{
{
Namespace: "shhext",
Version: "1.0",
Service: NewPublicAPI(s),
Public: true,
},
}
}
// Start is run when a service is started.
// It does nothing in this case but is required by `node.Service` interface.
func (s *Service) Start(server *p2p.Server) error {
s.tracker.Start()
s.nodeID = server.PrivateKey
return nil
}
// Stop is run when a service is stopped.
// It does nothing in this case but is required by `node.Service` interface.
func (s *Service) Stop() error {
s.tracker.Stop()
return nil
}
// tracker responsible for processing events for envelopes that we are interested in
// and calling specified handler.
type tracker struct {
w *whisper.Whisper
handler EnvelopeEventsHandler
mu sync.Mutex
cache map[common.Hash]EnvelopeState
wg sync.WaitGroup
quit chan struct{}
}
// Start processing events.
func (t *tracker) Start() {
t.quit = make(chan struct{})
t.wg.Add(1)
go func() {
t.handleEnvelopeEvents()
t.wg.Done()
}()
}
// Stop process events.
func (t *tracker) Stop() {
close(t.quit)
t.wg.Wait()
}
// Add hash to a tracker.
func (t *tracker) Add(hash common.Hash) {
t.mu.Lock()
defer t.mu.Unlock()
t.cache[hash] = EnvelopePosted
}
// handleEnvelopeEvents processes whisper envelope events
func (t *tracker) handleEnvelopeEvents() {
events := make(chan whisper.EnvelopeEvent, 100) // must be buffered to prevent blocking whisper
sub := t.w.SubscribeEnvelopeEvents(events)
defer sub.Unsubscribe()
for {
select {
case <-t.quit:
return
case event := <-events:
t.handleEvent(event)
}
}
}
// handleEvent based on type of the event either triggers
// confirmation handler or removes hash from tracker
func (t *tracker) handleEvent(event whisper.EnvelopeEvent) {
t.mu.Lock()
defer t.mu.Unlock()
switch event.Event {
case whisper.EventEnvelopeSent:
state, ok := t.cache[event.Hash]
// if we didn't send a message using extension - skip it
// if message was already confirmed - skip it
if !ok || state == EnvelopeSent {
return
}
log.Debug("envelope is sent", "hash", event.Hash, "peer", event.Peer)
t.cache[event.Hash] = EnvelopeSent
if t.handler != nil {
t.handler.EnvelopeSent(event.Hash)
}
case whisper.EventEnvelopeExpired:
if state, ok := t.cache[event.Hash]; ok {
log.Debug("envelope expired", "hash", event.Hash, "state", state)
delete(t.cache, event.Hash)
if state == EnvelopeSent {
return
}
if t.handler != nil {
t.handler.EnvelopeExpired(event.Hash)
}
}
}
}