git-gui: Internalize symbolic-ref HEAD reading logic

To improve performance on fork+exec impoverished systems (such as
Windows) we want to avoid running git-symbolic-ref on every rescan
if we can do so.  A quick way to implement such an avoidance is to
just read the HEAD ref ourselves; we'll either see it as a symref
(starts with "ref: ") or we'll see it as a detached head (40 hex
digits).  In either case we can treat that as our current branch.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
1 file changed
tree: a61de33163a574aa7d5c05c7d2021fd0c424fb2a
  1. lib/
  2. .gitignore
  3. git-gui.sh
  4. GIT-VERSION-GEN
  5. Makefile