From a092794804b2f7cbd656e439305d29bfa96ad2b9 Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Thu, 4 Sep 2014 19:34:43 -0700
Subject: [PATCH] use error to report error

---
 go/filer/directory_in_map.go | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/go/filer/directory_in_map.go b/go/filer/directory_in_map.go
index 051ff31fe..46a626f77 100644
--- a/go/filer/directory_in_map.go
+++ b/go/filer/directory_in_map.go
@@ -28,7 +28,7 @@ type DirectoryManagerInMap struct {
 	isLoading bool
 }
 
-func (dm *DirectoryManagerInMap) NewDirectoryEntryInMap(parent *DirectoryEntryInMap, name string) (d *DirectoryEntryInMap) {
+func (dm *DirectoryManagerInMap) NewDirectoryEntryInMap(parent *DirectoryEntryInMap, name string) (d *DirectoryEntryInMap, err error) {
 	writeLock.Lock()
 	defer writeLock.Unlock()
 	d = &DirectoryEntryInMap{Name: name, Parent: parent, SubDirectories: make(map[string]*DirectoryEntryInMap)}
@@ -38,7 +38,7 @@ func (dm *DirectoryManagerInMap) NewDirectoryEntryInMap(parent *DirectoryEntryIn
 	}
 	n := len(parts)
 	if n <= 0 {
-		return d
+		return nil, fmt.Errorf("Failed to create folder %s/%s", parent.Name, name)
 	}
 	for i := 0; i < n/2; i++ {
 		parts[i], parts[n-1-i] = parts[n-1-i], parts[i]
@@ -46,7 +46,7 @@ func (dm *DirectoryManagerInMap) NewDirectoryEntryInMap(parent *DirectoryEntryIn
 	dm.max++
 	d.Id = dm.max
 	dm.log("add", "/"+strings.Join(parts, "/"), strconv.Itoa(int(d.Id)))
-	return d
+	return d, nil
 }
 
 func (dm *DirectoryManagerInMap) log(words ...string) {
@@ -162,7 +162,11 @@ func (dm *DirectoryManagerInMap) loadDirectory(dirPath string, dirId DirectoryId
 			if i != len(parts)-1 {
 				return fmt.Errorf("%s should be created after parent %s!", dirPath, parts[i])
 			}
-			sub = dm.NewDirectoryEntryInMap(dir, parts[i])
+			var err error
+			sub, err = dm.NewDirectoryEntryInMap(dir, parts[i])
+			if err != nil {
+				return err
+			}
 			if sub.Id != dirId {
 				return fmt.Errorf("%s should be have id %v instead of %v!", dirPath, sub.Id, dirId)
 			}
@@ -183,7 +187,11 @@ func (dm *DirectoryManagerInMap) makeDirectory(dirPath string) (dir *DirectoryEn
 	for i := 1; i < len(parts); i++ {
 		sub, ok := dir.SubDirectories[parts[i]]
 		if !ok {
-			sub = dm.NewDirectoryEntryInMap(dir, parts[i])
+		  var err error
+			sub, err = dm.NewDirectoryEntryInMap(dir, parts[i])
+			if err != nil {
+			  return nil, false
+			}
 			dir.SubDirectories[parts[i]] = sub
 			created = true
 		}