allow setting the mutex lock variable name

Makefile

@@ -81,3 +81,7 @@ clean:
 	-rm -f go.*
 	-rm -f *.pb.go
 	-rm -f autogenpb
+
+clean-more:
+	ls -l autogenpb autogenpb.last
+	-rm -f autogenpb.2*

argv.go

@@ -12,6 +12,7 @@ type args struct {
 	Package   string `arg:"--package"                  help:"the package name"`
 	Proto     string `arg:"--proto"                    help:"the .proto filename"`
 	Mutex     bool   `arg:"--mutex"   default:"true"   help:"insert a mutex into protoc .pb.go file"`
+	MutexName string `arg:"--mutex-name"               help:"use a var name for the mutex"`
 	Delete    bool   `arg:"--delete"                   help:"use delete with copy experiment"`
 	DryRun    bool   `arg:"--dry-run"                  help:"check the .proto syntax, but don't do anything"`
 	GoSrc     string `arg:"--go-src"                   help:"default is ~/go/src. could be set to your go.work path"`

generateMutex.go

@@ -75,7 +75,9 @@ func (pb *Files) addMutex(f *File) error {
 	for _, line := range lines {
 		if strings.HasPrefix(line, "package ") {
 			// log.Info("CHANGING package:", line, "to package:", f.Package)
-			fmt.Fprintln(w, "package "+f.Package)
+			if f.Package != "" {
+				fmt.Fprintln(w, "package", f.Package, "// autogenpb changed the package name")
+			}
 			// log.Info("CHANGING package:", line, "to package:main")
 			// fmt.Fprintln(w, "package "+"main")
 			continue
@@ -87,22 +89,27 @@ func (pb *Files) addMutex(f *File) error {
 			continue
 		}
 
-		if f.structMatch(line) {
+		if msg := f.structMatch(line); msg == nil {
-			if argv.Mutex {
-				// log.Info("Adding Mutex to:", line)
 			fmt.Fprintln(w, line)
-				fmt.Fprintln(w, "\tLock sync.RWMutex // auto-added by go.wit.com/apps/autogenpb") // this must be 'Lock' or Marshal() panics?
+		} else {
-				// fmt.Fprintln(w, "\t// auto-added by go.wit.com/apps/autogenpb")
+			fmt.Fprintln(w, line)
-				// fmt.Fprintln(w, "\tsync.RWMutex")
+			if !argv.Mutex {
+				fmt.Fprintln(w, "\t// sync.RWMutex // skipped. argv was  --mutex=false")
+				fmt.Fprintln(w, "")
+				continue
+			}
+			if msg.NoMutex {
+				fmt.Fprintln(w, "\t// sync.RWMutex // skipped. protobuf file has `autogenpb:nomutex`")
+				fmt.Fprintln(w, "")
+				continue
+			}
+			if argv.MutexName == "" {
+				fmt.Fprintln(w, "\tsync.RWMutex // auto-added by go.wit.com/apps/autogenpb") // this must be 'Lock' or Marshal() panics?
 				fmt.Fprintln(w, "")
 			} else {
-				// log.Info("Skipping. Mutex = false for:", line)
+				fmt.Fprintf(w, "\t%s sync.RWMutex // auto-added by go.wit.com/apps/autogenpb\n", argv.MutexName) // this must be 'Lock' or Marshal() panics?
-				fmt.Fprintln(w, line)
-				fmt.Fprintln(w, "\t// Lock sync.RWMutex // autogenpb skipped this. needs --mutex command line arg")
 				fmt.Fprintln(w, "")
 			}
-		} else {
-			fmt.Fprintln(w, line)
 		}
 	}
 	if argv.Mutex {
@@ -117,14 +124,15 @@ func (pb *Files) addMutex(f *File) error {
 }
 
 // is this struct supposed to have a Mutex added?
-func (pf *File) structMatch(line string) bool {
+func (pf *File) structMatch(line string) *MsgName {
 	var msg *MsgName
 	var start string
 
 	msg = pf.Bases
 	start = "type " + msg.Name + " struct {"
 	if strings.HasPrefix(line, start) {
-		return msg.setupMutex(pf.Filebase + "Mu")
+		msg.setupMutex(pf.Filebase + "Mu")
+		return msg
 	}
 
 	// ONLY PASS THIS IF YOU DO NOT WANT TO USE MARSHAL()
@@ -132,26 +140,31 @@ func (pf *File) structMatch(line string) bool {
 	msg = pf.Base
 	start = "type " + msg.Name + " struct {"
 	if strings.HasPrefix(line, start) {
-		return msg.setupMutex(pf.Filebase + "Mu")
+		msg.setupMutex(pf.Filebase + "Mu")
+		return msg
 	}
 
 	for _, msg = range pf.MsgNames {
 		start = "type " + msg.Name + " struct {"
 		if strings.HasPrefix(line, start) {
-			return msg.setupMutex(pf.Filebase + "Mu")
+			msg.setupMutex(pf.Filebase + "Mu")
+			return msg
 		}
 	}
-	return false
+	return nil
 }
 
 // nameMu should probably be lowercase.
 // notsure if it ever makes sense to export a mutex or even if you can
-func (msg *MsgName) setupMutex(nameMu string) bool {
+func (msg *MsgName) setupMutex(nameMu string) {
 	msg.MutexFound = true
 	if msg.NoMutex {
 		msg.Lockname = nameMu
-		return false
+		return
+	}
+	if argv.MutexName == "" {
+		msg.Lockname = "x"
+	} else {
+		msg.Lockname = "x." + argv.MutexName
 	}
-	msg.Lockname = "x.Lock"
-	return true
 }