added a function to immediately return

tests/testdata

@@ -1 +1 @@
-Subproject commit 7497b116a019beb26215cbea4028df068dea06be
+Subproject commit b5eb9900ee2147b40d3e681fe86efa4fd693959a

whisper/mailserver/mailserver.go

@@ -21,15 +21,16 @@ import (
 	"encoding/binary"
 	"fmt"
 
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rlp"
 	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
-	"github.com/syndtr/goleveldb/leveldb"
-	"github.com/syndtr/goleveldb/leveldb/errors"
-	"github.com/syndtr/goleveldb/leveldb/opt"
-	"github.com/syndtr/goleveldb/leveldb/util"
 )
 
 // WMailServer represents the state data of the mailserver.
@@ -122,9 +123,28 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 	}
 
 	ok, lower, upper, bloom := s.validateRequest(peer.ID(), request)
-	if ok {
-		s.processRequest(peer, lower, upper, bloom)
+	if !ok {
+		return
 	}
+
+	s.processRequest(peer, lower, upper, bloom)
+}
+
+
+// DeliverMail responds with saved messages upon request by the
+// messages' owner.
+func (s *WMailServer) DeliverResponsiveMail(peer *whisper.Peer, request *whisper.Envelope) []*whisper.Envelope {
+	if peer == nil {
+		log.Error("Whisper peer is nil")
+		return nil
+	}
+
+	ok, lower, upper, bloom := s.validateRequest(peer.ID(), request)
+	if !ok {
+		return nil
+	}
+
+	return s.processRequest(nil, lower, upper, bloom)
 }
 
 func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bloom []byte) []*whisper.Envelope {

whisper/whisperv6/doc.go

@@ -49,6 +49,7 @@ const (
 	messagesCode         = 1   // normal whisper message
 	powRequirementCode   = 2   // PoW requirement
 	bloomFilterExCode    = 3   // bloom filter exchange
+	requestMessages      = 100 // peer-to-peer message, used by Dapp protocol
 	p2pRequestCode       = 126 // peer-to-peer message, used by Dapp protocol
 	p2pMessageCode       = 127 // peer-to-peer message (to be consumed by the peer, but not forwarded any further)
 	NumberOfMessageCodes = 128
@@ -89,4 +90,5 @@ const (
 type MailServer interface {
 	Archive(env *Envelope)
 	DeliverMail(whisperPeer *Peer, request *Envelope)
+	DeliverResponsiveMail(whisperPeer *Peer, request *Envelope) []*Envelope
 }

whisper/whisperv6/whisper.go

@@ -768,6 +768,17 @@ func (whisper *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 				}
 				whisper.mailServer.DeliverMail(p, &request)
 			}
+		case requestMessages:
+			if whisper.mailServer != nil {
+				var request Envelope
+				if err := packet.Decode(&request); err != nil {
+					log.Warn("failed to decode p2p request message, peer will be disconnected", "peer", p.peer.ID(), "err", err)
+					return errors.New("invalid p2p request")
+				}
+				r := whisper.mailServer.DeliverResponsiveMail(p, &request)
+
+				p2p.Send(p.ws, messagesCode, r)
+			}
 		default:
 			// New message types might be implemented in the future versions of Whisper.
 			// For forward compatibility, just ignore.