From 2a491ded000adf452d6eaf9f920a8c4c3cc42fee Mon Sep 17 00:00:00 2001
From: Zoe Roux <zoe.roux@zoriya.dev>
Date: Fri, 19 Jan 2024 21:37:52 +0100
Subject: [PATCH] Fix rw mutexes handling

---
 transcoder/src/filestream.go | 18 ++++++------------
 transcoder/src/tracker.go    | 28 ++++++++++++++--------------
 transcoder/src/transcoder.go | 15 +++++++--------
 3 files changed, 27 insertions(+), 34 deletions(-)

diff --git a/transcoder/src/filestream.go b/transcoder/src/filestream.go
index 7c9d78cf..65084c53 100644
--- a/transcoder/src/filestream.go
+++ b/transcoder/src/filestream.go
@@ -20,9 +20,9 @@ type FileStream struct {
 	CanTransmux bool
 	Info        *MediaInfo
 	streams     map[Quality]*VideoStream
-	vlock       sync.RWMutex
+	vlock       sync.Mutex
 	audios      map[int32]*AudioStream
-	alock       sync.RWMutex
+	alock       sync.Mutex
 }
 
 func GetOutPath() string {
@@ -201,16 +201,13 @@ func (fs *FileStream) GetMaster() string {
 }
 
 func (fs *FileStream) getVideoStream(quality Quality) *VideoStream {
-	fs.vlock.RLock()
+	fs.vlock.Lock()
+	defer fs.vlock.Unlock()
 	stream, ok := fs.streams[quality]
-	fs.vlock.RUnlock()
 
 	if ok {
 		return stream
 	}
-
-	fs.vlock.Lock()
-	defer fs.vlock.Unlock()
 	fs.streams[quality] = NewVideoStream(fs, quality)
 	return fs.streams[quality]
 }
@@ -226,16 +223,13 @@ func (fs *FileStream) GetVideoSegment(quality Quality, segment int32) (string, e
 }
 
 func (fs *FileStream) getAudioStream(audio int32) *AudioStream {
-	fs.alock.RLock()
+	fs.alock.Lock()
+	defer fs.alock.Unlock()
 	stream, ok := fs.audios[audio]
-	fs.alock.RUnlock()
 
 	if ok {
 		return stream
 	}
-
-	fs.alock.Lock()
-	defer fs.alock.Unlock()
 	fs.audios[audio] = NewAudioStream(fs, audio)
 	return fs.audios[audio]
 }
diff --git a/transcoder/src/tracker.go b/transcoder/src/tracker.go
index c1d97110..933f1573 100644
--- a/transcoder/src/tracker.go
+++ b/transcoder/src/tracker.go
@@ -124,12 +124,12 @@ func (t *Tracker) KillAudioIfDead(path string, audio int32) bool {
 		}
 	}
 	log.Printf("Nobody is listening audio %d of %s. Killing it", audio, path)
-	t.transcoder.mutex.RLock()
+	t.transcoder.mutex.Lock()
 	stream := t.transcoder.streams[path]
-	t.transcoder.mutex.RUnlock()
+	t.transcoder.mutex.Unlock()
 
-	stream.alock.RLock()
-	defer stream.alock.RUnlock()
+	stream.alock.Lock()
+	defer stream.alock.Unlock()
 	stream.audios[audio].Kill()
 	return true
 }
@@ -141,32 +141,32 @@ func (t *Tracker) KillQualityIfDead(path string, quality Quality) bool {
 		}
 	}
 	log.Printf("Nobody is watching quality %s of %s. Killing it", quality, path)
-	t.transcoder.mutex.RLock()
+	t.transcoder.mutex.Lock()
 	stream := t.transcoder.streams[path]
-	t.transcoder.mutex.RUnlock()
+	t.transcoder.mutex.Unlock()
 
-	stream.vlock.RLock()
-	defer stream.vlock.RUnlock()
+	stream.vlock.Lock()
+	defer stream.vlock.Unlock()
 	stream.streams[quality].Kill()
 	return true
 }
 
 func (t *Tracker) KillOrphanedHeads(path string, quality *Quality, audio int32) {
-	t.transcoder.mutex.RLock()
+	t.transcoder.mutex.Lock()
 	stream := t.transcoder.streams[path]
-	t.transcoder.mutex.RUnlock()
+	t.transcoder.mutex.Unlock()
 
 	if quality != nil {
-		stream.vlock.RLock()
+		stream.vlock.Lock()
 		vstream := stream.streams[*quality]
-		stream.vlock.RUnlock()
+		stream.vlock.Unlock()
 
 		t.killOrphanedeheads(&vstream.Stream)
 	}
 	if audio != -1 {
-		stream.alock.RLock()
+		stream.alock.Lock()
 		astream := stream.audios[audio]
-		stream.alock.RUnlock()
+		stream.alock.Unlock()
 
 		t.killOrphanedeheads(&astream.Stream)
 	}
diff --git a/transcoder/src/transcoder.go b/transcoder/src/transcoder.go
index 78d01052..28a153c9 100644
--- a/transcoder/src/transcoder.go
+++ b/transcoder/src/transcoder.go
@@ -13,7 +13,7 @@ type Transcoder struct {
 	streams map[string]*FileStream
 	// Streams that are staring up
 	preparing  map[string]chan *FileStream
-	mutex      sync.RWMutex
+	mutex      sync.Mutex
 	clientChan chan ClientInfo
 	tracker    *Tracker
 }
@@ -41,10 +41,14 @@ func NewTranscoder() (*Transcoder, error) {
 }
 
 func (t *Transcoder) getFileStream(path string) (*FileStream, error) {
-	t.mutex.RLock()
+	t.mutex.Lock()
 	stream, ok := t.streams[path]
 	channel, preparing := t.preparing[path]
-	t.mutex.RUnlock()
+	if !preparing && !ok {
+		channel = make(chan *FileStream, 1)
+		t.preparing[path] = channel
+	}
+	t.mutex.Unlock()
 
 	if preparing {
 		stream = <-channel
@@ -52,11 +56,6 @@ func (t *Transcoder) getFileStream(path string) (*FileStream, error) {
 			return nil, errors.New("could not transcode file. Try again later")
 		}
 	} else if !ok {
-		t.mutex.Lock()
-		channel = make(chan *FileStream, 1)
-		t.preparing[path] = channel
-		t.mutex.Unlock()
-
 		var err error
 		stream, err = NewFileStream(path)
 		log.Printf("Stream created for %s", path)