From 2afed432f7cd6c6ce493181b52aa051dbb219412 Mon Sep 17 00:00:00 2001
From: Zoe Roux <zoe.roux@zoriya.dev>
Date: Sun, 18 Feb 2024 22:23:39 +0100
Subject: [PATCH] Use concurrent map for subtitles

---
 transcoder/main.go           | 50 ++++++++++++++++++++++--------------
 transcoder/src/extract.go    | 39 ++++++++++------------------
 transcoder/src/thumbnails.go |  2 +-
 transcoder/src/utils.go      |  2 +-
 4 files changed, 47 insertions(+), 46 deletions(-)

diff --git a/transcoder/main.go b/transcoder/main.go
index c8ccc73f..44e399d7 100644
--- a/transcoder/main.go
+++ b/transcoder/main.go
@@ -176,12 +176,16 @@ func (h *Handler) GetInfo(c echo.Context) error {
 		return err
 	}
 
+	sha, err := src.GetHash(path)
+	if err != nil {
+		return err
+	}
 	ret, err := src.GetInfo(path)
 	if err != nil {
 		return err
 	}
 	// Run extractors to have them in cache
-	h.extractor.RunExtractor(ret.Path, ret.Sha, &ret.Subtitles)
+	src.Extract(ret.Path, sha)
 	go h.thumbnails.ExtractThumbnail(
 		ret.Path,
 		fmt.Sprintf("%s/thumbnails.png", c.Request().Header.Get("X-Route")),
@@ -195,46 +199,56 @@ func (h *Handler) GetInfo(c echo.Context) error {
 //
 // Path: /attachment/:name
 func (h *Handler) GetAttachment(c echo.Context) error {
+	path, err := GetPath(c)
+	if err != nil {
+		return err
+	}
 	name := c.Param("name")
-
 	if err := SanitizePath(name); err != nil {
 		return err
 	}
 
-	wait, ok := h.extractor.Extract(sha)
-	if !ok {
-		return echo.NewHTTPError(http.StatusBadRequest, "Not extracted yet. Call /info to extract.")
+	sha, err := src.GetHash(path)
+	if err != nil {
+		return err
+	}
+	wait, err := src.Extract(path, sha)
+	if err != nil {
+		return err
 	}
 	<-wait
 
-	path := fmt.Sprintf("%s/%s/att/%s", src.Settings.Metadata, sha, name)
-	return c.File(path)
+	ret := fmt.Sprintf("%s/%s/att/%s", src.Settings.Metadata, sha, name)
+	return c.File(ret)
 }
 
 // Get subtitle
 //
 // Get a specific subtitle.
 //
-// Path: /:sha/subtitle/:name
+// Path: /subtitle/:name
 func (h *Handler) GetSubtitle(c echo.Context) error {
-	sha := c.Param("sha")
-	name := c.Param("name")
-
-	if err := SanitizePath(sha); err != nil {
+	path, err := GetPath(c)
+	if err != nil {
 		return err
 	}
+	name := c.Param("name")
 	if err := SanitizePath(name); err != nil {
 		return err
 	}
 
-	wait, ok := h.extractor.Extract(sha)
-	if !ok {
-		return echo.NewHTTPError(http.StatusBadRequest, "Not extracted yet. Call /info to extract.")
+	sha, err := src.GetHash(path)
+	if err != nil {
+		return err
+	}
+	wait, err := src.Extract(path, sha)
+	if err != nil {
+		return err
 	}
 	<-wait
 
-	path := fmt.Sprintf("%s/%s/sub/%s", src.Settings.Metadata, sha, name)
-	return c.File(path)
+	ret := fmt.Sprintf("%s/%s/sub/%s", src.Settings.Metadata, sha, name)
+	return c.File(ret)
 }
 
 // Get thumbnail sprite
@@ -284,7 +298,6 @@ func (h *Handler) GetThumbnailsVtt(c echo.Context) error {
 
 type Handler struct {
 	transcoder *src.Transcoder
-	extractor  *src.Extractor
 	thumbnails *src.ThumbnailsCreator
 }
 
@@ -300,7 +313,6 @@ func main() {
 	}
 	h := Handler{
 		transcoder: transcoder,
-		extractor:  src.NewExtractor(),
 		thumbnails: src.NewThumbnailsCreator(),
 	}
 
diff --git a/transcoder/src/extract.go b/transcoder/src/extract.go
index 6f2e00ca..fad60be7 100644
--- a/transcoder/src/extract.go
+++ b/transcoder/src/extract.go
@@ -4,36 +4,24 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
-	"sync"
 )
 
-type Extractor struct {
-	extracted map[string]<-chan struct{}
-	lock      sync.RWMutex
-}
+var extracted = NewCMap[string, <-chan struct{}]()
 
-func NewExtractor() *Extractor {
-	return &Extractor{
-		extracted: make(map[string]<-chan struct{}),
-	}
-}
-
-func (e *Extractor) Extract(path string, subs *[]Subtitle) (<-chan struct{}, error) {
-	sha, err := getHash(path)
-	if err != nil {
-		return nil, err
-	}
-
-	e.lock.Lock()
-	existing, ok := e.extracted[sha]
-	if ok {
+func Extract(path string, sha string) (<-chan struct{}, error) {
+	ret := make(chan struct{})
+	existing, created := extracted.GetOrSet(sha, ret)
+	if !created {
 		return existing, nil
 	}
-	ret := make(chan struct{})
-	e.extracted[sha] = ret
-	e.lock.Unlock()
 
 	go func() {
+		info, err := GetInfo(path)
+		if err != nil {
+			extracted.Remove(sha)
+			close(ret)
+			return
+		}
 		attachment_path := fmt.Sprintf("%s/%s/att", Settings.Metadata, sha)
 		subs_path := fmt.Sprintf("%s/%s/sub", Settings.Metadata, sha)
 		os.MkdirAll(attachment_path, 0o644)
@@ -49,7 +37,7 @@ func (e *Extractor) Extract(path string, subs *[]Subtitle) (<-chan struct{}, err
 		)
 		cmd.Dir = attachment_path
 
-		for _, sub := range *subs {
+		for _, sub := range info.Subtitles {
 			if ext := sub.Extension; ext != nil {
 				cmd.Args = append(
 					cmd.Args,
@@ -61,8 +49,9 @@ func (e *Extractor) Extract(path string, subs *[]Subtitle) (<-chan struct{}, err
 		}
 		fmt.Printf("Starting extraction with the command: %s", cmd)
 		cmd.Stdout = nil
-		err := cmd.Run()
+		err = cmd.Run()
 		if err != nil {
+			extracted.Remove(sha)
 			fmt.Println("Error starting ffmpeg extract:", err)
 		}
 		close(ret)
diff --git a/transcoder/src/thumbnails.go b/transcoder/src/thumbnails.go
index bb0e9edf..aed62a85 100644
--- a/transcoder/src/thumbnails.go
+++ b/transcoder/src/thumbnails.go
@@ -68,7 +68,7 @@ func (t *ThumbnailsCreator) ExtractThumbnail(path string, name string) (string,
 
 func extractThumbnail(path string, name string) (string, error) {
 	defer printExecTime("extracting thumbnails for %s", path)()
-	sha, err := getHash(path)
+	sha, err := GetHash(path)
 	if err != nil {
 		return "", err
 	}
diff --git a/transcoder/src/utils.go b/transcoder/src/utils.go
index 74156d46..9fd84e8b 100644
--- a/transcoder/src/utils.go
+++ b/transcoder/src/utils.go
@@ -19,7 +19,7 @@ func printExecTime(message string, args ...any) func() {
 	}
 }
 
-func getHash(path string) (string, error) {
+func GetHash(path string) (string, error) {
 	info, err := os.Stat(path)
 	if err != nil {
 		return "", err