From 48542395762c74e3287f67c62595ac9fda72e05b Mon Sep 17 00:00:00 2001
From: Bora Alper <boramalper@gmail.com>
Date: Tue, 7 Aug 2018 10:32:12 +0300
Subject: [PATCH] [magneticod] added mutex to
 BT/metadata/Sink.incomingInfoHashes

---
 cmd/magneticod/bittorrent/metadata/leech.go |  2 +-
 cmd/magneticod/bittorrent/metadata/sink.go  | 25 +++++++++++++--------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/cmd/magneticod/bittorrent/metadata/leech.go b/cmd/magneticod/bittorrent/metadata/leech.go
index 22b5729..3ca7397 100644
--- a/cmd/magneticod/bittorrent/metadata/leech.go
+++ b/cmd/magneticod/bittorrent/metadata/leech.go
@@ -309,7 +309,7 @@ func (l *Leech) Do(deadline time.Time) {
 		l.OnError(errors.Wrap(err, "doExHandshake"))
 		return
 	}
-	
+
 	err = l.requestAllPieces()
 	if err != nil {
 		l.OnError(errors.Wrap(err, "requestAllPieces"))
diff --git a/cmd/magneticod/bittorrent/metadata/sink.go b/cmd/magneticod/bittorrent/metadata/sink.go
index 0fa8e10..2842a9c 100644
--- a/cmd/magneticod/bittorrent/metadata/sink.go
+++ b/cmd/magneticod/bittorrent/metadata/sink.go
@@ -2,6 +2,7 @@ package metadata
 
 import (
 	"crypto/rand"
+	"sync"
 	"time"
 
 	"github.com/boramalper/magnetico/pkg/util"
@@ -23,12 +24,13 @@ type Metadata struct {
 }
 
 type Sink struct {
-	clientID           []byte
-	deadline           time.Duration
-	drain              chan Metadata
-	incomingInfoHashes map[[20]byte]struct{}
-	terminated         bool
-	termination        chan interface{}
+	clientID             []byte
+	deadline             time.Duration
+	drain                chan Metadata
+	incomingInfoHashes   map[[20]byte]struct{}
+	incomingInfoHashesMx sync.Mutex
+	terminated           bool
+	termination          chan interface{}
 }
 
 func NewSink(deadline time.Duration) *Sink {
@@ -50,6 +52,8 @@ func (ms *Sink) Sink(res mainline.TrawlingResult) {
 	if ms.terminated {
 		zap.L().Panic("Trying to Sink() an already closed Sink!")
 	}
+	ms.incomingInfoHashesMx.Lock()
+	defer ms.incomingInfoHashesMx.Unlock()
 
 	if _, exists := ms.incomingInfoHashes[res.InfoHash]; exists {
 		return
@@ -62,11 +66,10 @@ func (ms *Sink) Sink(res mainline.TrawlingResult) {
 
 	zap.L().Info("Sunk!", zap.Int("leeches", len(ms.incomingInfoHashes)), util.HexField("infoHash", res.InfoHash[:]))
 
-	leech := NewLeech(res.InfoHash, res.PeerAddr, LeechEventHandlers{
+	go NewLeech(res.InfoHash, res.PeerAddr, LeechEventHandlers{
 		OnSuccess: ms.flush,
 		OnError:   ms.onLeechError,
-	})
-	go leech.Do(time.Now().Add(ms.deadline))
+	}).Do(time.Now().Add(ms.deadline))
 
 	ms.incomingInfoHashes[res.InfoHash] = struct{}{}
 }
@@ -91,11 +94,15 @@ func (ms *Sink) flush(result Metadata) {
 		// metadata!
 		var infoHash [20]byte
 		copy(infoHash[:], result.InfoHash)
+		ms.incomingInfoHashesMx.Lock()
 		delete(ms.incomingInfoHashes, infoHash)
+		ms.incomingInfoHashesMx.Unlock()
 	}
 }
 
 func (ms *Sink) onLeechError(infoHash [20]byte, err error) {
 	zap.L().Debug("leech error", util.HexField("infoHash", infoHash[:]), zap.Error(err))
+	ms.incomingInfoHashesMx.Lock()
 	delete(ms.incomingInfoHashes, infoHash)
+	ms.incomingInfoHashesMx.Unlock()
 }