We already pre-fetched db file paths for the cleanup-case (since
cdb619e4f), now let's generalize this to all indexing.
For now this is mostly performance-neutral (lazy-rescan is slightly
faster); however, this simplifies the code.
Update various places for what we can do with C++20:
- ends_with / starts_with
- std::to_array
- using instead of typedef
- designated initializers
- "[[maybe_unused]]" instead of G_GNUC_UNUSED
Also remove some unnecessary 'static'
Bump the required versions of some libraries / emacs slightly so we can get rid
of some special-casing and work-arounds. These are mostly based on Ubuntu 24.04
LTS, which is rather conservative; so should hopefully not inconvenience any
users.
- compiler: we now require C++20 instead of C++17
- glib & friends: 2.60 => 2.80
- xapian: 1.4 => 1.4.22
- emacs 26.3 => 28.1
Ubuntu 24.04 actually has Emacs 29.3, but that'd perhaps be too big a jump.
Only include xapian.h in one place, so we can have consistent options.
With that in place, we can enable C++ move semantics.
We don't do anything with that yet, but we check in the meson.build file
to see if we have the required xapian version.
Instead of handling transactions in the store, handle it in xapian-db.
Make the code a bit more natural / cleaner-out
Handle transaction automatically (with a batch-size) and add some RAII
Transaction object, which makes all database interaction transactable
for the duration. So, no more need for explicit parameters to
add_message while indexing.
*Usually* we need Xapian's replace_document() API, but when we know a
document (message) is completely new, we can use the faster
add_document(). That is the case with the initial (re)indexing, when
start with an empty database.
Also a few smaller cleanups.
XapianDb is a fairly thing wrapper around Xapian, which handles locking,
exception handling and some tracking.
On top of that, Config add a configuration database for type /
introspectable configuration info.
