This simplifies the implementation of remotes. The only required
interface is now `List` which is a simple one level directory list.
Optionally remotes may implement `ListR` if they have an efficient way
of doing a recursive list.
This makes directory listings much more efficient (one less
transaction needed) and also fixes#1439 (which was caused by having
to look up a directory name with quotes in which isn't dealt with well
by the list routine) by not doing a directory lookup at all.
* Add options to Put, PutUnchecked and Update for all Fses
* Use these to create HashOption
* Implement this in local
* Pass the option in fs.Copy
This has the effect that we only calculate hashes we need to in the
local Fs which speeds up transfers significantly.
Optional interfaces are becoming more important in rclone,
--track-renames and --backup-dir both rely on them.
Up to this point rclone has used interface upgrades to define optional
behaviour on Fs objects. However when one Fs object wraps another it
is very difficult for this scheme to work accurately. rclone has
relied on specific error messages being returned when the interface
isn't supported - this is unsatisfactory because it means you have to
call the interface to see whether it is supported.
This change enables accurate detection of optional interfaces by use
of a Features struct as returned by an obligatory Fs.Features()
method. The Features struct contains flags and function pointers
which can be tested against nil to see whether they can be used.
As a result crypt and hubic can accurately reflect the capabilities of
the underlying Fs they are wrapping.
If remote:path points to a file make NewFs return a sentinel error
fs.ErrorIsFile and an Fs which points to the parent.
Use this to remove the LimitedFs and just add this file to the
--files-from list.
This means that server side operations can be used also.
Fixes#518Fixes#545
This should fix duplicate files on drive and 409 errors on
amazonclouddrive however it will slow down the upload slightly as
another roundtrip will be needed.
None of the other Fses needed adjusting.
Fixes#483
Gives more accurate error propagation, control of depth of recursion
and short circuit recursion where possible.
Most of the the heavy lifting is done in the "fs" package, making file
system implementations a bit simpler.
This commit contains some code originally by Klaus Post.
Fixes#316
