This is better than using the equivilant actions for export remotes,
especially for getting content, since the ContentIdentifier checking
means we can be sure (enough) that the content is valid to not force
verification of content. Which allows getting keys of types that cannot
be verified.
Also, reorganized the internals of adjustExportImport which was becoming
very hard to follow. Now it's clear what each method does in each case.
Ah, it seemed too easy before when I was implementing importrree only,
and it was because all the key-based actions needed to be handled too.
Mostly copied from isexport, and this works. It does seem that
an import remote could use retrieveExportWithContentIdentifier
rather than retrieveExport, and checkPresentExportWithContentIdentifier
rather than checkPresentExport, which would both be more accurate.
Importtree only remotes are new; importtree remotes used to always also be
exporttree, so were untrusted.
Since an import remote is one that can be edited by something other than
git-annex, it's clearly not trustworthy at all.
In cd1676d604, it stopped using that to avoid surprising behavior
when the location log and remote content were out of sync.
But, it seems that may have changed some behavior users relied on as
well, and also Remote.hasKeyCheap should be faster than checking then
location log.
So, try Remote.hasKeyCheap first, and only if it does not have the key,
fall back to checking the location log. If the location log still thinks
it's present, go ahead and try to get it, so the user will see a failure
rather than silently skipping a file what whereis says is on the remote.
This does make slightly slower the case where the remote does not have
the key, and location log and Remote.hasKeyCheap agree, since it now
checks both. But only 1 stat slower.
This may or may not make the OSX build work on a newer version of OSX
than the one that's currently being used for release builds. I have not
been able to find good docs about how exactly to get back from such a
value to the actual path to the library that the linker would use.
And vice-versa, but it's better to use '/' for portability.
Notably, standardPreferredContent contains "archive/*" and that might not
match if the filename ends up coming in with the slashes the other way
around.
I do think this was a reversion, but I have not tracked back to what
version. While involving the remote config, it's not the same class of
problems that I kept having to chase down for a while after the remote
config parser reworking.
git -c was already propagated via environment, but need this for
consistency.
Also, notice it does not use gitAnnexChildProcess to run the
transferrer. So nothing is done about avoid it taking the
pid lock. It's possible that the caller is already doing something that
took the pid lock, and if so, the transferrer will certianly fail,
since it needs to take the pid lock too. This may prevent combining
annex.stalldetection with annex.pidlock, but I have not verified it's
really a problem. If it was, it seems git-annex would have to take
the pid lock when starting a transferrer, and hold it until shutdown,
or would need to take pid lock when starting to use a transferrer,
and hold it until done with a transfer and then drop it. The latter
would require starting the transferrer with pid locking disabled for the
child process, so assumes that the transferrer does not do anyting that
needs locking when not running a transfer.
This is common in some feeds, which might mix some items with enclosures,
with others that link to posts or whatever. Before this, it would try to
use youtube-dl and fail, or if youtube-dl was not allowed, it would
incorrectly complain that an url was supported by youtube-dl.
