16745: Keep a SiteFileSystem alive for multiple read requests.

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

diff --git a/sdk/go/arvados/fs_base.go b/sdk/go/arvados/fs_base.go
index d06aba3695adc37f3d74057de2568778bcd9f9c9..2478641df5478639c92ff2b4d0f57d847165eee7 100644 (file)
--- a/sdk/go/arvados/fs_base.go
+++ b/sdk/go/arvados/fs_base.go
@@ -31,6 +31,10 @@ var (
        ErrPermission        = os.ErrPermission
 )
 
+type syncer interface {
+       Sync() error
+}
+
 // A File is an *os.File-like interface for reading and writing files
 // in a FileSystem.
 type File interface {
@@ -102,6 +106,9 @@ type FileSystem interface {
        // path is "", flush all dirs/streams; otherwise, flush only
        // the specified dir/stream.
        Flush(path string, shortBlocks bool) error
+
+       // Estimate current memory usage.
+       MemorySize() int64
 }
 
 type inode interface {
@@ -152,6 +159,7 @@ type inode interface {
        sync.Locker
        RLock()
        RUnlock()
+       MemorySize() int64
 }
 
 type fileinfo struct {
@@ -225,6 +233,13 @@ func (*nullnode) Child(name string, replace func(inode) (inode, error)) (inode,
        return nil, ErrNotADirectory
 }
 
+func (*nullnode) MemorySize() int64 {
+       // Types that embed nullnode should report their own size, but
+       // if they don't, we at least report a non-zero size to ensure
+       // a large tree doesn't get reported as 0 bytes.
+       return 64
+}
+
 type treenode struct {
        fs       FileSystem
        parent   inode
@@ -299,6 +314,31 @@ func (n *treenode) Readdir() (fi []os.FileInfo, err error) {
        return
 }
 
+func (n *treenode) Sync() error {
+       n.RLock()
+       defer n.RUnlock()
+       for _, inode := range n.inodes {
+               syncer, ok := inode.(syncer)
+               if !ok {
+                       return ErrInvalidOperation
+               }
+               err := syncer.Sync()
+               if err != nil {
+                       return err
+               }
+       }
+       return nil
+}
+
+func (n *treenode) MemorySize() (size int64) {
+       n.RLock()
+       defer n.RUnlock()
+       for _, inode := range n.inodes {
+               size += inode.MemorySize()
+       }
+       return
+}
+
 type fileSystem struct {
        root inode
        fsBackend
@@ -576,7 +616,9 @@ func (fs *fileSystem) remove(name string, recursive bool) error {
 }
 
 func (fs *fileSystem) Sync() error {
-       log.Printf("TODO: sync fileSystem")
+       if syncer, ok := fs.root.(syncer); ok {
+               return syncer.Sync()
+       }
        return ErrInvalidOperation
 }
 
@@ -585,6 +627,10 @@ func (fs *fileSystem) Flush(string, bool) error {
        return ErrInvalidOperation
 }
 
+func (fs *fileSystem) MemorySize() int64 {
+       return fs.root.MemorySize()
+}
+
 // rlookup (recursive lookup) returns the inode for the file/directory
 // with the given name (which may contain "/" separators). If no such
 // file/directory exists, the returned node is nil.