This makes the diff functions that take callbacks both take
the payload parameter after the callback function pointers and
pass the payload as the last argument to the callback function
instead of the first. This should make them consistent with
other callbacks across the API.
This improves the naming for the rename related functionality
moving it to be called `git_diff_find_similar()` and renaming
all the associated constants, etc. to make more sense.
I also moved the new code (plus the existing `git_diff_merge`)
into a new file `diff_tform.c` where I can put new functions
related to manipulating git diff lists.
This also updates the implementation significantly from the
last revision fixing some ordering issues (where break-rewrite
needs to be handled prior to copy and rename detection) and
improving config option handling.
This implements the basis for diff rename and copy detection,
although it is based on simple SHA comparison right now instead
of using a matching algortihm. Just as `git_diff_merge` can be
used as a post-pass on diffs to emulate certain command line
behaviors, there is a new API `git_diff_detect` which will
update a diff list in-place, adjusting some deltas to RENAMED
or COPIED state (and also, eventually, splitting MODIFIED deltas
where the change is too large into DELETED/ADDED pairs).
This also adds a new test repo that will hold rename/copy/split
scenarios. Right now, it just has exact-match rename and copy,
but the tests are written to use tree diffs, so we should be able
to add new test scenarios easily without breaking tests.
