implement the new GetSize methods for the filestore blockservices

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

filestore/filestore.go

@@ -154,6 +154,22 @@ func (f *Filestore) Get(c *cid.Cid) (blocks.Block, error) {
 	return f.fm.Get(c)
 }
 
+// GetSize returns the size of the requested block. It may return ErrNotFound
+// when the block is not stored.
+func (f *Filestore) GetSize(c *cid.Cid) (int, error) {
+	size, err := f.bs.GetSize(c)
+	switch err {
+	default:
+		return -1, err
+	case nil:
+		return size, nil
+	case blockstore.ErrNotFound:
+		// try filestore
+	}
+
+	return f.fm.GetSize(c)
+}
+
 // Has returns true if the block with the given Cid is
 // stored in the Filestore.
 func (f *Filestore) Has(c *cid.Cid) (bool, error) {

filestore/fsrefstore.go

@@ -122,6 +122,18 @@ func (f *FileManager) Get(c *cid.Cid) (blocks.Block, error) {
 	return blocks.NewBlockWithCid(out, c)
 }
 
+// GetSize gets the size of the block from the datastore.
+//
+// This method may successfully return the size even if returning the block
+// would fail because the associated file is no longer available.
+func (f *FileManager) GetSize(c *cid.Cid) (int, error) {
+	dobj, err := f.getDataObj(c)
+	if err != nil {
+		return -1, err
+	}
+	return int(dobj.GetSize_()), nil
+}
+
 func (f *FileManager) readDataObj(c *cid.Cid, d *pb.DataObj) ([]byte, error) {
 	if IsURL(d.GetFilePath()) {
 		return f.readURLDataObj(c, d)