status-go/_assets/patches/geth/0033-mailserver-response-contains-cursor.patch

diff --git a/whisper/whisperv6/events.go b/whisper/whisperv6/events.go
index 1665539..fe7570e 100644
--- a/whisper/whisperv6/events.go
+++ b/whisper/whisperv6/events.go
@@ -13,10 +13,14 @@ const (
 	EventEnvelopeSent EventType = "envelope.sent"
 	// EventEnvelopeExpired fires when envelop expired
 	EventEnvelopeExpired EventType = "envelope.expired"
+	// EventEnvelopeAvailable fires when envelop is available for filters
+	EventEnvelopeAvailable EventType = "envelope.available"
 	// EventMailServerRequestCompleted fires after mailserver sends all the requested messages
 	EventMailServerRequestCompleted EventType = "mailserver.request.completed"
 	// EventMailServerRequestExpired fires after mailserver the request TTL ends
 	EventMailServerRequestExpired EventType = "mailserver.request.expired"
+	// EventMailServerEnvelopeArchived fires after an envelope has been archived
+	EventMailServerEnvelopeArchived EventType = "mailserver.envelope.archived"
 )
 
 // EnvelopeEvent used for envelopes events.
@@ -24,4 +28,5 @@ type EnvelopeEvent struct {
 	Event EventType
 	Hash  common.Hash
 	Peer  discover.NodeID
+	Data  interface{}
 }
diff --git a/whisper/whisperv6/whisper.go b/whisper/whisperv6/whisper.go
index 91d4482..6a937a2 100644
--- a/whisper/whisperv6/whisper.go
+++ b/whisper/whisperv6/whisper.go
@@ -49,6 +49,12 @@ type Statistics struct {
 	totalMessagesCleared int
 }
 
+// MailServerResponse is the response payload sent by the mailserver
+type MailServerResponse struct {
+	LastEnvelopeHash common.Hash
+	Cursor           []byte
+}
+
 const (
 	maxMsgSizeIdx           = iota // Maximal message length allowed by the whisper node
 	overflowIdx                    // Indicator of message queue overflow
@@ -378,8 +384,8 @@ func (whisper *Whisper) RequestHistoricMessages(peerID []byte, envelope *Envelop
 	return p2p.Send(p.ws, p2pRequestCode, envelope)
 }
 
-func (whisper *Whisper) SendHistoricMessageResponse(peer *Peer, requestID common.Hash) error {
-	size, r, err := rlp.EncodeToReader(requestID)
+func (whisper *Whisper) SendHistoricMessageResponse(peer *Peer, payload []byte) error {
+	size, r, err := rlp.EncodeToReader(payload)
 	if err != nil {
 		return err
 	}
@@ -835,15 +841,49 @@ func (whisper *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 			}
 		case p2pRequestCompleteCode:
 			if p.trusted {
-				var requestID common.Hash
-				if err := packet.Decode(&requestID); err != nil {
+				var payload []byte
+				if err := packet.Decode(&payload); err != nil {
 					log.Warn("failed to decode response message, peer will be disconnected", "peer", p.peer.ID(), "err", err)
 					return errors.New("invalid request response message")
 				}
 
+				// check if payload is
+				// - requestID or
+				// - requestID + lastEnvelopeHash or
+				// - requestID + lastEnvelopeHash + cursor
+				// requestID is the hash of the request envelope.
+				// lastEnvelopeHash is the last envelope sent by the mail server
+				// cursor is the db key, 36 bytes: 4 for the timestamp + 32 for the envelope hash.
+				// length := len(payload)
+
+				if len(payload) < common.HashLength || len(payload) > common.HashLength*3+4 {
+					log.Warn("invalid response message, peer will be disconnected", "peer", p.peer.ID(), "err", err, "payload size", len(payload))
+					return errors.New("invalid response size")
+				}
+
+				var (
+					requestID        common.Hash
+					lastEnvelopeHash common.Hash
+					cursor           []byte
+				)
+
+				requestID = common.BytesToHash(payload[:common.HashLength])
+
+				if len(payload) >= common.HashLength*2 {
+					lastEnvelopeHash = common.BytesToHash(payload[common.HashLength : common.HashLength*2])
+				}
+
+				if len(payload) >= common.HashLength*2+36 {
+					cursor = payload[common.HashLength*2 : common.HashLength*2+36]
+				}
+
 				whisper.envelopeFeed.Send(EnvelopeEvent{
 					Hash:  requestID,
 					Event: EventMailServerRequestCompleted,
+					Data: &MailServerResponse{
+						LastEnvelopeHash: lastEnvelopeHash,
+						Cursor:           cursor,
+					},
 				})
 			}
 		default:
@@ -927,6 +967,10 @@ func (whisper *Whisper) add(envelope *Envelope, isP2P bool) (bool, error) {
 		whisper.postEvent(envelope, isP2P) // notify the local node about the new message
 		if whisper.mailServer != nil {
 			whisper.mailServer.Archive(envelope)
+			whisper.envelopeFeed.Send(EnvelopeEvent{
+				Hash:  envelope.Hash(),
+				Event: EventMailServerEnvelopeArchived,
+			})
 		}
 	}
 	return true, nil
@@ -985,9 +1029,17 @@ func (whisper *Whisper) processQueue() {
 
 		case e = <-whisper.messageQueue:
 			whisper.filters.NotifyWatchers(e, false)
+			whisper.envelopeFeed.Send(EnvelopeEvent{
+				Hash:  e.Hash(),
+				Event: EventEnvelopeAvailable,
+			})
 
 		case e = <-whisper.p2pMsgQueue:
 			whisper.filters.NotifyWatchers(e, true)
+			whisper.envelopeFeed.Send(EnvelopeEvent{
+				Hash:  e.Hash(),
+				Event: EventEnvelopeAvailable,
+			})
 		}
 	}
 }