From 95af1f9ccff32db09dc098103dc5fcec1e9c5aa0 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Sat, 3 Aug 2019 17:44:44 +0100
Subject: [PATCH] fs: fix FixRangeOption so it works with 0 length files

---
 fs/options.go | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/fs/options.go b/fs/options.go
index df62d898a..56eaea4f2 100644
--- a/fs/options.go
+++ b/fs/options.go
@@ -139,6 +139,17 @@ func (o *RangeOption) Decode(size int64) (offset, limit int64) {
 // not exceed filesize. Some remotes (eg Onedrive, Box) don't support
 // range requests which index from the end.
 func FixRangeOption(options []OpenOption, size int64) {
+	if size == 0 {
+		// if size 0 then remove RangeOption~s
+		// replacing with an empty HTTPOption~s which won't be rendered
+		for i := range options {
+			if _, ok := options[i].(*RangeOption); ok {
+				options[i] = &HTTPOption{}
+
+			}
+		}
+		return
+	}
 	for i := range options {
 		option := options[i]
 		if x, ok := option.(*RangeOption); ok {
@@ -148,7 +159,7 @@ func FixRangeOption(options []OpenOption, size int64) {
 				options[i] = x
 			}
 			if x.End > size {
-				x = &RangeOption{Start: x.Start, End: size}
+				x = &RangeOption{Start: x.Start, End: size - 1}
 				options[i] = x
 			}
 		}