all: Store assets as strings (#6611)

Storing assets as []byte requires every compiled-in asset to be copied
into writable memory at program startup. That currently takes up 1.6MB
per syncthing process. Strings stay in the RODATA section and should be
shared between processes running the same binary.

cmd/strelaypoolsrv/main.go

@@ -1,11 +1,8 @@
 // Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
 
-//go:generate go run ../../script/genassets.go gui >auto/gui.go
-
 package main
 
 import (
-	"bytes"
 	"compress/gzip"
 	"context"
 	"crypto/tls"
@@ -302,16 +299,15 @@ func handleAssets(w http.ResponseWriter, r *http.Request) {
 	}
 	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 		w.Header().Set("Content-Encoding", "gzip")
+		w.Header().Set("Content-Length", strconv.Itoa(len(bs)))
+		io.WriteString(w, bs)
 	} else {
 		// ungzip if browser not send gzip accepted header
 		var gr *gzip.Reader
-		gr, _ = gzip.NewReader(bytes.NewReader(bs))
-		bs, _ = ioutil.ReadAll(gr)
+		gr, _ = gzip.NewReader(strings.NewReader(bs))
+		io.Copy(w, gr)
 		gr.Close()
 	}
-	w.Header().Set("Content-Length", fmt.Sprintf("%d", len(bs)))
-
-	w.Write(bs)
 }
 
 func mimeTypeForFile(file string) string {