Re: [RFC] [GSoC] Port git-add--interactive.perl:status_cmd to C

Junio C Hamano [off-list ref] writes:

"Daniel Ferreira (theiostream)" [off-list ref] writes:

quoted

Reproducing either of these comparisons "natively" would simply
require running run_diff_index() or run_diff_files() with
DIFF_FORMAT_NUMSTAT and tweaking diff_flush() to format appropriately
for the "interactive--add case".

A more usual way to drive the diff machinery and react to its
findings is to use DIFF_FORMAT_CALLBACK interface, and walk the
collected diff_queue to work on the paths discovered.  The way
wt-status.c builds "Changes to be committed" list out of the
"diff-index --cached" it internally runs and "Changes not staged for
commit" out of the "diff-files" it internally runs would be a good
example to study.

Ahh, you'd also want to show the numstat equivalent and eventually
you'd need to spool the actual textual diff in-core, so that you can
present hunks to the user and have them accepted/rejected
interactively. CALLBACK interface is not a good match for that task.

Of course, using a temporary file to buffer output from diff would
be an obvious and simple workaround (and this is not a performance
critical part of the system---we are talking about end user choosing
hunks interactively after all).  A cleaner may be to spawn diff-index
and diff-files and read from them via pipe into core.