Refactor more function return values

gate/image/snapshot.go

@@ -664,11 +664,11 @@ func putString(dest []byte, s string) (tail []byte) {
 	return dest[len(s):]
 }
 
-func putVaruint32Before(dest []byte, offset int, x uint32) (n int) {
+func putVaruint32Before(dest []byte, offset int, x uint32) int {
 	var temp [binary.MaxVarintLen32]byte
-	n = binary.PutUvarint(temp[:], uint64(x))
+	n := binary.PutUvarint(temp[:], uint64(x))
 	copy(dest[offset-n:], temp[:n])
-	return
+	return n
 }
 
 func mapOldSection(offset int64, dest, src []*manifest.ByteRange, i section.ID) int64 {

gate/packet/fmt.go

@@ -30,7 +30,7 @@ func (code Code) String() string {
 	}
 }
 
-func (b Buf) String() (s string) {
+func (b Buf) String() string {
 	var (
 		size  string
 		index string
@@ -46,7 +46,7 @@ func (b Buf) String() (s string) {
 		index = fmt.Sprintf(" index=%d", i)
 	}
 
-	s = fmt.Sprintf("size=%s code=%s domain=%s%s", size, b.Code(), b.Domain(), index)
+	s := fmt.Sprintf("size=%s code=%s domain=%s%s", size, b.Code(), b.Domain(), index)
 
 	switch b.Domain() {
 	case DomainFlow:
@@ -55,7 +55,8 @@ func (b Buf) String() (s string) {
 	case DomainData:
 		s += DataBuf(b).string()
 	}
-	return
+
+	return s
 }
 
 func (b FlowBuf) String() string {
@@ -74,13 +75,13 @@ func (b DataBuf) String() string {
 	return Buf(b).String() + b.string()
 }
 
-func (b DataBuf) string() (s string) {
-	s = fmt.Sprintf(" id=%d", b.ID())
+func (b DataBuf) string() string {
+	s := fmt.Sprintf(" id=%d", b.ID())
 	if n := b.DataLen(); n > 0 {
 		s += fmt.Sprintf(" datalen=%d", n)
 	}
 	if x := b.Note(); x != 0 {
 		s += fmt.Sprintf(" note=%d", x)
 	}
-	return
+	return s
 }

gate/runtime/io.go

@@ -19,34 +19,34 @@ import (
 	"gate.computer/internal/file"
 )
 
-func popServiceBuffers(frozen *snapshot.Buffers) (services []snapshot.Service) {
+func popServiceBuffers(frozen *snapshot.Buffers) []snapshot.Service {
 	if frozen == nil {
-		return
+		return nil
 	}
 
-	services = frozen.Services
+	ss := frozen.Services
 	frozen.Services = nil
-	return
+	return ss
 }
 
-func popInputBuffer(frozen *snapshot.Buffers) (input []byte) {
+func popInputBuffer(frozen *snapshot.Buffers) []byte {
 	if frozen == nil {
-		return
+		return nil
 	}
 
-	input = frozen.Input
+	b := frozen.Input
 	frozen.Input = nil
-	return
+	return b
 }
 
-func popOutputBuffer(frozen *snapshot.Buffers) (output []byte) {
+func popOutputBuffer(frozen *snapshot.Buffers) []byte {
 	if frozen == nil {
-		return
+		return nil
 	}
 
-	output = frozen.Output
+	b := frozen.Output
 	frozen.Output = nil
-	return
+	return b
 }
 
 type read struct {

gate/runtime/service.go

@@ -133,14 +133,14 @@ func (discoverer *serviceDiscoverer) checkPacket(p packet.Buf) (packet.Buf, erro
 	return p, nil
 }
 
-func makeServicesPacket(domain packet.Domain, services []ServiceState) (resp packet.Buf) {
-	resp = packet.Make(packet.CodeServices, domain, packet.ServicesHeaderSize+len(services))
+func makeServicesPacket(domain packet.Domain, services []ServiceState) packet.Buf {
+	resp := packet.Make(packet.CodeServices, domain, packet.ServicesHeaderSize+len(services))
 	resp.SetSize()
 	binary.LittleEndian.PutUint16(resp[packet.OffsetServicesCount:], uint16(len(services)))
 
 	for i, s := range services {
 		resp[packet.ServicesHeaderSize+i] = s.flags
 	}
 
-	return
+	return resp
 }

gate/server/account.go

@@ -37,17 +37,17 @@ func newAccount(pri *principal.ID) *account {
 	}
 }
 
-func (acc *account) shutdown(lock serverLock) (is map[string]accountInstance) {
+func (acc *account) shutdown(lock serverLock) map[string]accountInstance {
 	ps := acc.programs
 	acc.programs = nil
 
 	for prog := range ps {
 		prog.unref(lock)
 	}
 
-	is = acc.instances
+	is := acc.instances
 	acc.instances = nil
-	return
+	return is
 }
 
 // ensureProgramRef adds program reference unless already found.  It must not

gate/server/web/request.go

@@ -214,13 +214,13 @@ func popOptionalActionParam(w http.ResponseWriter, r *http.Request, s *webserver
 	return false
 }
 
-func mustPopOptionalLastFunctionParam(w http.ResponseWriter, r *http.Request, s *webserver, query url.Values) (value string) {
-	value = popOptionalLastParam(w, r, s, query, api.ParamFunction)
+func mustPopOptionalLastFunctionParam(w http.ResponseWriter, r *http.Request, s *webserver, query url.Values) string {
+	value := popOptionalLastParam(w, r, s, query, api.ParamFunction)
 	if value != "" && !api.FunctionRegexp.MatchString(value) {
 		respondInvalidFunction(w, r, s, value)
 		panic(responded)
 	}
-	return
+	return value
 }
 
 func mustNotHaveParams(w http.ResponseWriter, r *http.Request, s *webserver, query url.Values) {

gate/service/registry.go

@@ -141,17 +141,19 @@ func (r *Registry) Clone() *Registry {
 
 // Catalog of service metadata.  Only the services which are discoverable in
 // this context are included.
-func (r *Registry) Catalog(ctx context.Context) (services []Service) {
+func (r *Registry) Catalog(ctx context.Context) []Service {
 	m := make(map[string]string)
 	r.catalog(ctx, m)
 
+	services := make([]Service, 0, len(m))
+
 	for name, revision := range m {
 		if revision != "" {
 			services = append(services, Service{name, revision})
 		}
 	}
 
-	return
+	return services
 }
 
 func (r *Registry) catalog(ctx context.Context, m map[string]string) {
@@ -168,18 +170,15 @@ func (r *Registry) catalog(ctx context.Context, m map[string]string) {
 	}
 }
 
-func (r *Registry) lookup(name string) (result Factory) {
+func (r *Registry) lookup(name string) Factory {
 	for {
-		var found bool
-
-		result, found = r.factories[name]
-		if found {
-			return
+		if f, found := r.factories[name]; found {
+			return f
 		}
 
 		r = r.parent
 		if r == nil {
-			return
+			return nil
 		}
 	}
 }

grpc/client/client.go

@@ -339,17 +339,17 @@ func receiveForward(ctx context.Context, code packet.Code, out chan<- packet.Thu
 	}
 }
 
-func receiveBuffer(initial packet.Buf, stream api.Instance_ReceiveClient, abort func(error)) (buf []byte) {
+func receiveBuffer(initial packet.Buf, stream api.Instance_ReceiveClient, abort func(error)) []byte {
 	initial.SetSize()
-	buf = initial
+	buf := initial
 
 	for {
 		r, err := stream.Recv()
 		if err != nil {
 			if err != io.EOF {
 				abort(err)
 			}
-			return
+			return buf
 		}
 
 		p := mustBePacket(r.Value, abort)