Fixes an issue on Windows where mounting the local filesystem in network mode failed
when not using option --volname. Reason was that the volume name in network mode
is a network share path in the basic UNC format, and characters that are invalid
in regular file and directory names are also invalid in such a path. And the default
volume name would typically include a '?', which is invalid, from the unc path of
the local, e.g. "\\server\\? C Temp".
The fix is to use an encoder to encode invalid characters such as '?' with the unicode
equivalent, similar to how rclone encodes filesystem paths in normal operations,
when mounting in network mode. Also performs some automatic cleanup of path separators,
but in general, tries to be conservative on restrictions, and instead rely on --volname
being set to something realistic.
Existing strategy to replace the two characters ':' and '/' with space, regardless of
mounting mode variant, was removed. For network mode the new approach handles these in
a better way. Also the existing method did not apply at all when using the implicit
network mode where volume names are taken from mountpath instead of volname option
("rclone mount remote:path/to/files \\cloud\remote"). For non-network mode they were not
needed.
Default volume names, when not specified by user, will be different with this change.
See: #6234
Before this change, the device name was always the remote:path rclone
was configured with. However this can contain sensitive information
and it appears in the `mount` output, so `--devname` allows the user
to configure it.
See: https://forum.rclone.org/t/rclone-mount-blomp-problem/29151/11
This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.
This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
Current way of checking whether mountpoint has been already mounted (directory
list) can result in race if rclone runs under Automount (classic or systemd).
This patch adopts Linux ProcFS for the check. Note that mountpoint is considered
empty if it's tagged as "mounted" by autofs. Also ProcFS is used to check whether
rclone mount was successful (ie. tagged by a string containing "rclone").
On macOS/BSD where ProcFS is unavailable the old method is still used.
This patch also moves a few utility functions unchanged to utils.go:
CheckOverlap, CheckAllowings, SetVolumeName.
