Before this change, bisync needed to build a full listing for Path1, then a
full listing for Path2, then compare them -- and each of those tasks needed to
finish before the next one could start. In addition to being slow and
inefficient, it also caused real problems if a file changed between the time
bisync checked it on Path1 and the time it checked the corresponding file on
Path2.
This change solves these problems by listing both paths concurrently, using
the same March infrastructure that check and sync use to traverse two
directories in lock-step, optimized by Go's robust concurrency support.
Listings should now be much faster, and any given path is now checked
nearly-instantaneously on both sides, minimizing room for error.
Further discussion:
https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=4.%20Listings%20should%20alternate%20between%20paths%20to%20minimize%20errors
This introduces a few basic color codings to make the terminal output more
readable (and more fun). Rclone's standard --color flag is supported.
(AUTO|NEVER|ALWAYS)
Only a few lines have colors right now -- more will probably be added in
future versions.
Before this change, bisync had no mechanism for "retrying" a file again next
time, in the event of an unexpected and possibly temporary error. After this
change, bisync is now essentially able to mark a file as needing to be
rechecked next time. Bisync does this by keeping one prior listing on hand at
all times. In a low-confidence situation, bisync can revert a given file row
back to its state at the end of the last known successful sync, ensuring that
any subsequent changes will be re-noticed on the next run.
This can potentially be helpful for a dynamically changing file system, where
files may be changing quickly while bisync is working with them.
Before this change, bisync handled copies and deletes in separate operations.
After this change, they are combined in one sync operation, which is faster
and also allows bisync to support --track-renames and --backup-dir.
Bisync uses a --files-from filter containing only the paths bisync has
determined need to be synced. Just like in sync (but in both directions),
if a path is present on the dst but not the src, it's interpreted as a delete
rather than a copy.
