refactor(archive): replaced int32 with *atomic.Uint32

Author: OlegChuev-MD

README.md

@@ -260,7 +260,7 @@ ghfs [options]
     A download link will appear on top part of the page.
 --archive-max-workers <number>
     Maximum number of concurrent archive operations.
-    Set to -1 for unlimited (default).
+    Set to 0 for unlimited (default).
     When the limit is reached, new archive requests will receive 429 Too Many Requests.
 --archive <url-path> ...
 --archive-user <separator><url-path>[<separator><allowed-username>...] ...

src/param/cli.go

@@ -148,7 +148,7 @@ func NewCliCmd() *goNixArgParser.Command {
 	err = options.AddFlagValues("archivedirsusers", "--archive-dir-user", "", nil, "file system path that allow archive files for specific users, <sep><fs-path>[<sep><user>...]")
 	serverError.CheckFatal(err)
 
-	err = options.AddFlagValue("archivemaxworkers", "--archive-max-workers", "", "-1", "maximum number of concurrent archive operations (-1 for unlimited)")
+	err = options.AddFlagValue("archivemaxworkers", "--archive-max-workers", "", "0", "maximum number of concurrent archive operations (0 for unlimited)")
 	serverError.CheckFatal(err)
 
 	err = options.AddFlag("globalcors", "--global-cors", "GHFS_GLOBAL_CORS", "enable CORS headers for all directories")
@@ -440,7 +440,7 @@ func CmdResultsToParams(results []*goNixArgParser.ParseResult) (params Params, e
 		archiveDirsUsers, _ := result.GetStrings("archivedirsusers")
 		param.ArchiveDirsUsers = SplitAllKeyValues(archiveDirsUsers)
 
-		param.ArchiveMaxWorkers, _ = result.GetInt32("archivemaxworkers")
+		param.ArchiveMaxWorkers, _ = result.GetUint32("archivemaxworkers")
 
 		// global restrict access
 		if result.HasKey("globalrestrictaccess") {

src/param/main.go

@@ -62,7 +62,7 @@ type Param struct {
 	ArchiveUrlsUsers  [][]string // [][path, user...]
 	ArchiveDirs       []string
 	ArchiveDirsUsers  [][]string // [][path, user...]
-	ArchiveMaxWorkers int32
+	ArchiveMaxWorkers uint32
 
 	GlobalCors bool
 	CorsUrls   []string

src/serverHandler/aliasHandler.go

@@ -50,8 +50,8 @@ type aliasHandler struct {
 	archive *hierarchyAvailability
 	cors    *hierarchyAvailability
 
-	archiveMaxWorkers int32
-	archiveWorkers    *int32
+	archiveMaxWorkers uint32
+	archiveWorkers    *atomic.Uint32
 
 	globalRestrictAccess []string
 	restrictAccessUrls   pathStringsList
@@ -146,13 +146,28 @@ func (h *aliasHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 func (h *aliasHandler) createArchive(w http.ResponseWriter, r *http.Request, session *sessionContext, data *responseData) bool {
 	if h.archiveMaxWorkers > 0 {
-		current := atomic.AddInt32(h.archiveWorkers, -1)
-		defer atomic.AddInt32(h.archiveWorkers, 1)
-
-		if current < 0 {
-			data.Status = http.StatusTooManyRequests
-			return false
+		for {
+			current := h.archiveWorkers.Load()
+			if current >= h.archiveMaxWorkers {
+				data.Status = http.StatusTooManyRequests
+				return false
+			}
+			if h.archiveWorkers.CompareAndSwap(current, current+1) {
+				break
+			}
 		}
+
+		defer func() {
+			for {
+				current := h.archiveWorkers.Load()
+				if current == 0 {
+					break // prevent underflow just in case
+				}
+				if h.archiveWorkers.CompareAndSwap(current, current-1) {
+					break
+				}
+			}
+		}()
 	}
 
 	switch session.archiveFormat {

src/serverHandler/vhostHandler.go

@@ -3,6 +3,7 @@ package serverHandler
 import (
 	"net/http"
 	"regexp"
+	"sync/atomic"
 
 	"mjpclab.dev/ghfs/src/param"
 	"mjpclab.dev/ghfs/src/serverError"
@@ -30,8 +31,8 @@ type vhostContext struct {
 	archiveUrlsUsers pathIntsList
 	archiveDirsUsers pathIntsList
 
-	archiveMaxWorkers int32
-	archiveWorkers    *int32
+	archiveMaxWorkers uint32
+	archiveWorkers    *atomic.Uint32
 
 	shows     *regexp.Regexp
 	showDirs  *regexp.Regexp
@@ -99,11 +100,6 @@ func NewVhostHandler(
 		theme = defaultTheme.DefaultTheme
 	}
 
-	var archiveMaxWorkers int32
-	if p.ArchiveMaxWorkers > 0 {
-		archiveMaxWorkers = p.ArchiveMaxWorkers
-	}
-
 	// alias param
 	vhostCtx := &vhostContext{
 		logger: logger,
@@ -124,7 +120,7 @@ func NewVhostHandler(
 		archiveDirsUsers: pathUsernamesToPathUids(users, p.ArchiveDirsUsers),
 
 		archiveMaxWorkers: p.ArchiveMaxWorkers,
-		archiveWorkers:    &archiveMaxWorkers,
+		archiveWorkers:    &atomic.Uint32{},
 
 		shows:     shows,
 		showDirs:  showDirs,