Fix parsing relative URLs starting with // (#702)

* Fix parsing relative URLs starting with //

* Improve test

1 files changed, 8 insertions, 3 deletions

diff --git a/uri.go b/uri.go
index 21ab3ae..80e5bf3 100644
--- a/uri.go
+++ b/uri.go
@@ -263,9 +263,14 @@ func (u *URI) Parse(host, uri []byte) {
 func (u *URI) parse(host, uri []byte, isTLS bool) {
 	u.Reset()
 
-	scheme, host, uri := splitHostURI(host, uri)
-	u.scheme = append(u.scheme, scheme...)
-	lowercaseBytes(u.scheme)
+	if len(host) == 0 || bytes.Contains(uri, strColonSlashSlash) {
+		scheme, newHost, newURI := splitHostURI(host, uri)
+		u.scheme = append(u.scheme, scheme...)
+		lowercaseBytes(u.scheme)
+		host = newHost
+		uri = newURI
+	}
+
 	if isTLS {
 		u.scheme = append(u.scheme[:0], strHTTPS...)
 	}