13111: Propagate errors in Child().

[arvados.git] / sdk / go / arvados / fs_site.go

diff --git a/sdk/go/arvados/fs_site.go b/sdk/go/arvados/fs_site.go
index c8d7360ae420bfdd46b8325c5a6abc7eb9c058b3..701711e21777b5645f923e4258b2e4b2cdf1dce4 100644 (file)
--- a/sdk/go/arvados/fs_site.go
+++ b/sdk/go/arvados/fs_site.go
@@ -37,7 +37,7 @@ func (c *Client) SiteFileSystem(kc keepClient) FileSystem {
                },
                inodes: make(map[string]inode),
        }
-       root.inode.Child("by_id", func(inode) inode {
+       root.inode.Child("by_id", func(inode) (inode, error) {
                return &vdirnode{
                        inode: &treenode{
                                fs:     fs,
@@ -50,10 +50,10 @@ func (c *Client) SiteFileSystem(kc keepClient) FileSystem {
                                },
                        },
                        create: fs.mountCollection,
-               }
+               }, nil
        })
-       root.inode.Child("home", func(inode) inode {
-               return fs.newProjectNode(fs.root, "home", "")
+       root.inode.Child("home", func(inode) (inode, error) {
+               return fs.newProjectNode(fs.root, "home", ""), nil
        })
        return fs
 }
@@ -104,18 +104,23 @@ type vdirnode struct {
        create func(parent inode, name string) inode
 }
 
-func (vn *vdirnode) Child(name string, _ func(inode) inode) inode {
-       return vn.inode.Child(name, func(existing inode) inode {
-               if existing != nil {
-                       return existing
-               } else if vn.create == nil {
-                       return nil
+func (vn *vdirnode) Child(name string, replace func(inode) (inode, error)) (inode, error) {
+       return vn.inode.Child(name, func(existing inode) (inode, error) {
+               if existing == nil && vn.create != nil {
+                       existing = vn.create(vn, name)
+                       if existing != nil {
+                               existing.SetParent(vn, name)
+                               vn.inode.(*treenode).fileinfo.modTime = time.Now()
+                       }
                }
-               n := vn.create(vn, name)
-               if n != nil {
-                       n.SetParent(vn, name)
-                       vn.inode.(*treenode).fileinfo.modTime = time.Now()
+               if replace == nil {
+                       return existing, nil
+               } else if tryRepl, err := replace(existing); err != nil {
+                       return existing, err
+               } else if tryRepl != existing {
+                       return existing, ErrInvalidArgument
+               } else {
+                       return existing, nil
                }
-               return n
        })
 }