http.ServeContent Internal Server Error with ObjectOpenFile

[hexadecy]

When we try to serve a resumable object (like an audio file), ObjectOpenFile cannot Seek directly to the end.
Because in http.ServeContent size is determined that way:
size, err := content.Seek(0, io.SeekEnd)

We just add one return as a quickfix in swift.go

func (file *ObjectOpenFile) Seek(offset int64, whence int) (newPos int64, err error) {
	switch whence {
	case 0: // relative to start
		newPos = offset
	case 1: // relative to current
		newPos = file.pos + offset
	case 2: // relative to end
		if !file.lengthOk {
			return file.pos, newError(0, "Length of file unknown so can't seek from end")
		}
		newPos = file.length + offset
                **return**
	default:

[ncw]

So are you suggesting that we treat the Seek(0, io.SeekEnd) as a special case as it is only used to find the size of the file and avoid doing the re-opening of the file.

Is this for efficiency or does it avoid a bug?

[hexadecy]

It's to avoid a bug with the http package.

   115  // The content's Seek method must work: ServeContent uses
   116  // a seek to the end of the content to determine its size.