only look at first 1kb of data.yaml when building tree

server/tree.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"io"
 	"io/ioutil"
 	"os"
 	"path"
@@ -92,7 +93,7 @@ func (tree Tree) getRoot(pid ID, withContent, withDeleted bool) (Branch, error)
 	}
 	for _, entry := range entries {
 		if entry.Name() == "data.yaml" {
-			if b, err := ioutil.ReadFile(path.Join(tree.root, entry.Name())); err != nil {
+			if b, err := peekFile(withContent, path.Join(tree.root, entry.Name())); err != nil {
 				return Branch{}, err
 			} else if err := yaml.Unmarshal(b, &m.Leaf); err != nil {
 				return Branch{}, err
@@ -115,6 +116,19 @@ func (tree Tree) getRoot(pid ID, withContent, withDeleted bool) (Branch, error)
 	return m, nil
 }
 
+func peekFile(all bool, path string) ([]byte, error) {
+	if !all {
+		return ioutil.ReadFile(path)
+	}
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	r := io.LimitReader(f, 1024)
+	return ioutil.ReadAll(r)
+}
+
 func (tree Tree) toDir(id ID) string {
 	return path.Dir(tree.toData(id))
 }