Use pointers wherever necessary

Make the garbage collector do its job!

cmd/replds/client.go

@@ -14,31 +14,29 @@ import (
 	"git.autistici.org/ai3/tools/replds"
 )
 
-func nodeFromFile(path, rootDir string) (replds.Node, error) {
-	var n replds.Node
+func nodeFromFile(path, rootDir string) (*replds.Node, error) {
 	stat, err := os.Stat(path)
 	if err != nil {
-		return n, err
+		return nil, err
 	}
 	data, err := ioutil.ReadFile(path)
 	if err != nil {
-		return n, err
+		return nil, err
 	}
 
 	rel := path
 	if rootDir != "" {
 		rel, err = filepath.Rel(rootDir, path)
 		if err != nil {
-			return n, err
+			return nil, err
 		}
 	}
 
-	n = replds.Node{
+	return &replds.Node{
 		Path:      rel,
 		Value:     data,
 		Timestamp: stat.ModTime(),
-	}
-	return n, nil
+	}, nil
 }
 
 type putCmd struct {
@@ -108,9 +106,7 @@ func (c *putCmd) Execute(ctx context.Context, f *flag.FlagSet, _ ...interface{})
 	return subcommands.ExitSuccess
 }
 
-type rmCmd struct {
-	root string
-}
+type rmCmd struct{}
 
 func (*rmCmd) Name() string     { return "rm" }
 func (*rmCmd) Synopsis() string { return "Delete one or more files." }
@@ -144,7 +140,7 @@ func (c *rmCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) su
 	now := time.Now()
 	var req replds.SetNodesRequest
 	for _, arg := range f.Args() {
-		req.Nodes = append(req.Nodes, replds.Node{
+		req.Nodes = append(req.Nodes, &replds.Node{
 			Path:      arg,
 			Deleted:   true,
 			Timestamp: now,
@@ -184,7 +180,7 @@ func (c *syncCmd) SetFlags(f *flag.FlagSet) {
 
 func (c *syncCmd) scanPath(base string) map[string]time.Time {
 	m := make(map[string]time.Time)
-	filepath.Walk(base, func(path string, info os.FileInfo, err error) error {
+	if err := filepath.Walk(base, func(path string, info os.FileInfo, err error) error {
 		if err != nil || !info.Mode().IsRegular() {
 			return nil
 		}
@@ -192,7 +188,9 @@ func (c *syncCmd) scanPath(base string) map[string]time.Time {
 			m[rel] = info.ModTime()
 		}
 		return nil
-	})
+	}); err != nil {
+		log.Printf("error: %v", err)
+	}
 	return m
 }
 
@@ -245,7 +243,7 @@ func (c *syncCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 	if c.del {
 		now := time.Now()
 		for _, path := range removed {
-			req.Nodes = append(req.Nodes, replds.Node{
+			req.Nodes = append(req.Nodes, &replds.Node{
 				Path:      path,
 				Deleted:   true,
 				Timestamp: now,

fs.go

@@ -20,9 +20,9 @@ func newFS(dir string) *FS {
 
 // getAllNodes scans the root directory and returns a list of
 // Nodes. All errors are ignored.
-func (f *FS) getAllNodes() []Node {
-	var nodes []Node
-	dirLen := len(f.dir)
+func (f *FS) getAllNodes() []*Node {
+	var nodes []*Node
+	dirOffset := len(f.dir) + 1
 	if err := filepath.Walk(f.dir, func(path string, info os.FileInfo, err error) error {
 		// Ignore errors.
 		if err != nil {
@@ -32,8 +32,8 @@ func (f *FS) getAllNodes() []Node {
 		if !info.Mode().IsRegular() {
 			return nil
 		}
-		nodes = append(nodes, Node{
-			Path:      path[dirLen+1:],
+		nodes = append(nodes, &Node{
+			Path:      path[dirOffset:],
 			Timestamp: info.ModTime(),
 		})
 		return nil
@@ -44,7 +44,7 @@ func (f *FS) getAllNodes() []Node {
 }
 
 // setNode applies a Node to the underlying filesystem.
-func (f *FS) setNode(node Node) error {
+func (f *FS) setNode(node *Node) error {
 	path := filepath.Join(f.dir, node.Path)
 
 	// Tombstone? Then delete the file (ignore errors).

http.go

@@ -84,7 +84,7 @@ func (s *HTTPServer) Handler() http.Handler {
 	return h
 }
 
-func nodes2str(nodes []Node) string {
+func nodes2str(nodes []*Node) string {
 	var tmp []string
 	for _, node := range nodes {
 		tmp = append(tmp, fmt.Sprintf("%s@%d", node.Path, node.Timestamp.Unix()))

server.go

@@ -34,6 +34,15 @@ type Node struct {
 	Deleted bool `json:"deleted,omitempty"`
 }
 
+func (n *Node) Copy() *Node {
+	return &Node{
+		Path:      n.Path,
+		Value:     n.Value,
+		Timestamp: n.Timestamp,
+		Deleted:   n.Deleted,
+	}
+}
+
 func (n *Node) withoutValue() *Node {
 	return &Node{
 		Path:      n.Path,
@@ -42,29 +51,29 @@ func (n *Node) withoutValue() *Node {
 	}
 }
 
-func (n *Node) metadataOnly() Node {
-	return Node{
+func (n *Node) metadataOnly() *Node {
+	return &Node{
 		Path:      n.Path,
 		Timestamp: n.Timestamp,
 	}
 }
 
 type internalGetNodesRequest struct {
-	Nodes []Node `json:"nodes"`
+	Nodes []*Node `json:"nodes"`
 }
 
 type internalGetNodesResponse struct {
-	Nodes   []Node `json:"nodes"`
-	Partial bool   `json:"partial,omitempty"`
+	Nodes   []*Node `json:"nodes"`
+	Partial bool    `json:"partial,omitempty"`
 }
 
 type internalUpdateNodesRequest struct {
-	Nodes []Node `json:"nodes"`
+	Nodes []*Node `json:"nodes"`
 }
 
 // SetNodesRequest is the request type for the SetNodes method.
 type SetNodesRequest struct {
-	Nodes []Node `json:"nodes"`
+	Nodes []*Node `json:"nodes"`
 }
 
 // SetNodesResponse is the response returned by the SetNodes method.
@@ -76,9 +85,9 @@ type SetNodesResponse struct {
 var errTooOld = errors.New("a more recent value exists for this key")
 
 type storage interface {
-	getAllNodes() []Node
+	getAllNodes() []*Node
 	getNodeValue(string) ([]byte, error)
-	setNode(Node) error
+	setNode(*Node) error
 }
 
 // Server for the replicated filesync.
@@ -120,7 +129,7 @@ func NewServer(peers []string, dir string, tlsConfig *clientutil.TLSClientConfig
 	}
 
 	for _, node := range s.storage.getAllNodes() {
-		s.nodes[node.Path] = &node
+		s.nodes[node.Path] = node
 	}
 	if len(s.nodes) > 0 {
 		log.Printf("found %d entries in %s", len(s.nodes), dir)
@@ -156,7 +165,7 @@ func (s *Server) log(fmt string, args ...interface{}) {
 // Update one or more nodes as a "transaction": if one update fails,
 // the rest are aborted (but previous commits are not reverted, yet).
 // Will ping peers with the data when updatePeers is true.
-func (s *Server) doSetNodes(ctx context.Context, nodes []Node, updatePeers bool) (*SetNodesResponse, error) {
+func (s *Server) doSetNodes(ctx context.Context, nodes []*Node, updatePeers bool) (*SetNodesResponse, error) {
 	// Update local state.
 	for _, node := range nodes {
 		cur, ok := s.nodes[node.Path]
@@ -216,13 +225,13 @@ func (s *Server) internalUpdateNodes(ctx context.Context, req *internalUpdateNod
 	return err
 }
 
-func (s *Server) getNodeWithValue(node *Node) (out Node, err error) {
-	out = *node
+func (s *Server) getNodeWithValue(node *Node) (out *Node, err error) {
+	out = node.Copy()
 	out.Value, err = s.storage.getNodeValue(node.Path)
 	return
 }
 
-func nodeDiff(reqNodes []Node, myNodes map[string]*Node, adder func(*Node) bool) ([]string, bool) {
+func nodeDiff(reqNodes []*Node, myNodes map[string]*Node, adder func(*Node) bool) ([]string, bool) {
 	var missing []string
 	tmp := make(map[string]struct{})
 	for _, reqNode := range reqNodes {
@@ -353,7 +362,7 @@ var (
 	maxTSValue int64
 )
 
-func updateMaxTimestamp(nodes []Node) {
+func updateMaxTimestamp(nodes []*Node) {
 	var max int64
 	for _, node := range nodes {
 		t := node.Timestamp.Unix()

server_test.go

@@ -61,7 +61,7 @@ func newTestCluster(t testing.TB, n int, baseDir string) *testCluster {
 	// Create root directories.
 	for i := 0; i < n; i++ {
 		dir := filepath.Join(baseDir, fmt.Sprintf("fs%d", i))
-		os.Mkdir(dir, 0755)
+		os.Mkdir(dir, 0755) // nolint
 		c.dirs = append(c.dirs, dir)
 	}
 
@@ -128,8 +128,8 @@ func TestCluster_SetNodes(t *testing.T) {
 
 	c := s.client(t, 0)
 	resp, err := c.SetNodes(context.Background(), &SetNodesRequest{
-		Nodes: []Node{
-			{
+		Nodes: []*Node{
+			&Node{
 				Path:      "test1",
 				Value:     []byte("test content"),
 				Timestamp: time.Now(),
@@ -159,8 +159,8 @@ func TestCluster_SetNodes_1Broken(t *testing.T) {
 
 	c := s.client(t, 0)
 	resp, err := c.SetNodes(context.Background(), &SetNodesRequest{
-		Nodes: []Node{
-			{
+		Nodes: []*Node{
+			&Node{
 				Path:      "test1",
 				Value:     []byte("test content"),
 				Timestamp: time.Now(),
@@ -207,7 +207,7 @@ func TestCluster_PartialSync(t *testing.T) {
 	}
 	var req SetNodesRequest
 	for i := 0; i < count; i++ {
-		req.Nodes = append(req.Nodes, Node{
+		req.Nodes = append(req.Nodes, &Node{
 			Path:      fmt.Sprintf("test%02d", i),
 			Value:     testVal,
 			Timestamp: time.Now(),