fix(dsync): Don't call the finalize hook more than once

dsync/dsync.go

@@ -393,8 +393,8 @@ func (ds *Dsync) ReceiveBlock(sid, hash string, data []byte) ReceiveResponse {
  res := sess.ReceiveBlock(hash, bytes.NewReader(data))
  log.Debugf("received block: %s", res.Hash)
 
- // if we're done transferring, finalize!
- if res.Status == StatusOk && sess.Complete() {
+ // check if transfer has completed, if so finalize it, but only once
+ if res.Status == StatusOk && sess.IsFinalizedOnce() {
  if err := ds.finalizeReceive(sess); err != nil {
  return ReceiveResponse{
  Hash: sess.info.RootCID().String(),

dsync/session.go

@@ -5,6 +5,7 @@ import (
  "fmt"
  "io"
  "math/rand"
+ "sync"
 
  ipld "github.com/ipfs/go-ipld-format"
  coreiface "github.com/ipfs/interface-go-ipfs-core"
@@ -23,6 +24,8 @@ type session struct {
  diff *dag.Manifest
  prog dag.Completion
  progCh chan dag.Completion
+ lock sync.Mutex
+ fin bool
 }
 
 // newSession creates a receive state machine
@@ -99,6 +102,22 @@ func (s *session) completionChanged() {
  s.progCh <- s.prog
 }
 
+// IsFinalizedOnce will return true if the session is complete, but only the first time it is
+// called, even if multiple threads call this function at the same time
+func (s *session) IsFinalizedOnce() bool {
+ if !s.Complete() {
+ return false
+ }
+ ret := false
+ s.lock.Lock()
+ if !s.fin {
+ ret = true
+ s.fin = true
+ }
+ defer s.lock.Unlock()
+ return ret
+}
+
 // the best stack overflow answer evaarrr: https://stackoverflow.com/a/22892986/9416066
 const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
 const (