Initial commit

util.go

@@ -0,0 +1,104 @@
+package camfish
+
+import "fmt"
+import "log"
+import "time"
+import "iter"
+import "errors"
+import "strconv"
+import "syscall"
+import "os/user"
+import "strings"
+import "context"
+import "sync/atomic"
+import "unicode/utf8"
+
+func defaul[T comparable](value, def T) T {
+	var zero T
+	if value == zero { return def }
+	return value
+}
+
+func panicWrap(ctx context.Context, f func (context.Context) error) (err error) {
+	defer func () {
+		if pan := recover(); pan != nil {
+			if panErr, ok := pan.(error); ok {
+				err = panErr
+			} else {
+				err = errors.New(fmt.Sprint(pan))
+			}
+		}
+	} ()
+	
+	err = f(ctx)
+	return
+}
+
+type atomicDuration atomic.Int64
+type atomicInt64Ptr = *atomic.Int64
+
+func (duration* atomicDuration) Load() time.Duration {
+	return time.Duration((*atomic.Int64)(duration).Load())
+}
+
+func (duration *atomicDuration) Store(newDuration time.Duration) {
+	(*atomic.Int64)(duration).Store(int64(newDuration))
+}
+
+func logActors (actors iter.Seq[Actor]) {
+	output := "actors: "
+	x := utf8.RuneCountInString(output)
+	first := true
+	line := func () {		
+		if output == "" { return }
+		if first {
+			first = false
+			log.Println("(i)", output)
+		} else {
+			log.Println("   ", output)
+		}
+		output = ""
+		x = 0
+	}
+	types := make(map[string] int)
+	for actor := range actors {
+		types[actor.Type()] += 1
+	}
+	for typ, count := range types {
+		if count > 1 {
+			typ += fmt.Sprintf("(%d)", count)
+		}
+		typ += ", "
+		x += 2
+		typeLen := utf8.RuneCountInString(typ)
+		if x + typeLen >= 60 {
+			line()
+		}
+		output += typ
+		x += typeLen
+	}
+	if output != "" {
+		output = strings.TrimSuffix(output, ", ")
+	}
+	line()
+}
+
+func dropPrivelege (usr, group string) error {
+	if group != "" {
+		groupInfo, err := user.LookupGroup(group)
+		if err != nil { return err }
+		gid, err := strconv.Atoi(groupInfo.Gid)
+		if err != nil { return err }
+		err = syscall.Setgid(gid)
+		if err != nil { return err }
+	}
+	if usr != "" {
+		usrInfo, err := user.Lookup(usr)
+		if err != nil { return err }
+		uid, err := strconv.Atoi(usrInfo.Uid)
+		if err != nil { return err }
+		err = syscall.Setuid(uid)
+		if err != nil { return err }
+	}
+	return nil
+}