The main idea is consider the notmuch database as analogous to the
work-tree. A bare git repo is maintained in the users home directory,
with a tree of the form tags/$message-id/$tag
Like notmuch and git, we have a set of subcommnds, mainly modelled on
git.
Implementation wise, the heavy lifting is in the following functions.
commit xapian -> git
checkout git -> xapian
merge fetched git + git -> xapian
status find differences between xapian, git, and remote git.
The central implementation trick, from an idea I think due to
tomprince on IRC is manipulate the git index directly from the xapian
tag information. The merge routine is still done using a temporary
checkout as I wasn't able to get it working with the index only.
There are also some convenience wrappers around git commands, like "fetch"
that essential just set GIT_DIR in the environment.
In order to encode tags (viewed as octet sequences) into filenames,
we whitelist a smallish set of characters and %hex escape anything outside.
The prefix is omitted in git, which lets one save and restore to
different prefixes (although this is only lightly tested).
Thanks to Tomi Ollila for a huge amount of feedback and patches while
putting this together.
We won't use all of the included build infrastructure files, but adding them
nevertheless helps to track changes that are applied to them upstream.
Signed-off-by: Thomas Schwinge <thomas@schwinge.name>
The original "contrib" name is lousy. Everything in notmuch has been
contributed, and we are integrating as much of it as possible, (rather
than making users grub through contrib looking for useful pieces to
install).
Meanwhile, the only things we have in contrib are command-line
completion scripts, so "completion" makes more sense as a name, (and
helps make "./configure" slightly less ambiguous).
