Before, it leaked space due to caching lists of keys. Now all necessary
data about keys is calculated as they stream in.
The "nearly constant" is due to getKeysPresent, which builds up a lot
of [] thunks as it traverses .git/annex/objects/. Will deal with it later.
I had not realized what a memory leak the lazy state monad could be,
although I have not seen much evidence of actual leaking in git-annex.
However, if running git-annex on a great many files, this could matter.
The additional Utility.State.changeState adds even more strictness,
avoiding a problem I saw in github-backup where repeatedly modifying
state built up a huge pile of thunks.
Left out the backend usage graph for now, and bad/temp directory sizes
are only displayed when present. Also, disk usage is returned as a string
with units, which I can see changing later.
semitrusted uuids rarely are listed in trust.log, so a special case
is needed to get a list of them. Take the difference of all known uuids
with non-semitrusted uuids.
The backend usage graph shows present keys as well as keys found in the
repository tree, so it will also be populated for bare repositories.
Changed wording to "visible annex keys", which explains why it's 0 in
a bare repository (no keys visible as no tree), and also why it varies
depending on which branch is checked out. This seemed better than doing
something expensive to look up keys from the git-annex branch.
This new approach allows filtering out checks from the default set that are
not appropriate for a command, rather than having to list every check
that is appropriate. It also reduces some boilerplate.
Haskell does not define Eq for functions, so I had to go a long way around
with each check having a unique id. Meh.
Using Sets is the right thing; they have constant size lookup like my
SizeList, and logn insertation, which beats nub to death.
Runs faster than --fast mode did before, and gives accurate counts.
13 seconds total runtime with a warm cache in a repository with 40 thousand
keys.
These were a mistake, they make the type signatures harder to read and
less flexible. The CommandSeek, CommandStart, CommandPerform, and
CommandCleanup types were a good idea, but composing them with the
parameters expected is going too far.
The only remaining vestiage of backends is different types of keys. These
are still called "backends", mostly to avoid needing to change user interface
and configuration. But everything to do with storing keys in different
backends was gone; instead different types of remotes are used.
In the refactoring, lots of code was moved out of odd corners like
Backend.File, to closer to where it's used, like Command.Drop and
Command.Fsck. Quite a lot of dead code was removed. Several data structures
became simpler, which may result in better runtime efficiency. There should
be no user-visible changes.
