Again on massive filesystems, the very first character
is likely to bring a likewise massive amount of search
results that we need to maybe query info for, then create
icons and widgets for. While it's impressive we can do
that, it's also expensive and likely pointless, for the
first character.
Typing a second character is however very likely to
considerably reduce the amount of items to categorize and
show. So start actually searching from there.
Testing on a filesystem with 1434099 files indexed, trying 5
semi-random 1 character searches (n, h, t, i, o) returns on
average 168K items (min. 78771, max. 331471), trying 5
semi-random 2 character searches (no, he, th, in, on)
returns on average 34K items (min. 11133, max. 94961),
which is a more approachable set.
Doing this is enough that typing on a filechooser search
entry feels completely fluid.
The search provider should make it sure there are some
specific GFileInfo fields set. Fix the mimetype extraction
from the query, and use that to fill in the missing gaps
the best we can.
When starting a search over a very populated filesystem, it
is possible that typing the first chars will return a too
high number of results. Even though iterating through the
cursor is in itself very fast, extracting the GIO information
from those many files at once is not going to be as fast.
In order to increase interactivity (i.e. not make things
possibly sluggish) iterate the cursor in an idle function
and add search results to the filechooser model little by little.
If the user keeps typing (as it is likely will happen), there
will be better chances to cancel and proceed to the next
query timely. If not, the results will be there soon enough.
As fancy as property paths are, recursive resolution of files
to a location increases the big O complexity enough that it's
not a great option on large homedirs with many indexed files.
Ensure the files are from the right location through a URI
prefix match, which does hits an index. This may dramatically
improve performance on large indexed trees.
Testing this query in an isolated testcase with a total
1434099 indexed files shows that it can run more than 1500 times
per second in this computer (an average of 15200 queries in
several 10 second runs), which presumably is a tad faster than
anyone can type.
Closes: https://gitlab.gnome.org/GNOME/gtk/-/issues/4133
Failure is allowed by nature of GInitable, and this avoids unnecessary
crashing of programs running with G_DEBUG=fatal-criticals.
(cherry picked from commit 6215b38e645f5047d52e625562efccc1e4f85867)
Given it does seem likely Tracker is going to miss the goal to get all
applications ported to Tracker 3, the scenario where there's applications
linking to Tracker 2.x while GTK was built with Tracker 3 support becomes
more likely.
Avoid the upcoming GType clashes if that were the case, and resort to the
good (I lie) old Tracker 2 search engine.
Provide the minimal info necessary. Improves apparent responsiveness
(since we don't visibly clear and repopulate the list) and saves doing
file stat/reads on every file in the result set.
