run_diff_files(): clarify computation of sha1 validity

Remove the need to have duplicated "if there is a change then feed
null_sha1 and otherwise sha1 from the cache entry" for the "new"
side of the diff by introducing two temporary variables to point
at the object name of the old and the new side of the blobs.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff-lib.c b/diff-lib.c
index 875aff864391ed037627462ac39c314f248b5ae6..a85c4971ac8ece6397c05d0674bbac8c75cf219f 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -101,6 +101,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
                struct cache_entry *ce = active_cache[i];
                int changed;
                unsigned dirty_submodule = 0;
+               const unsigned char *old_sha1, *new_sha1;
 
                if (diff_can_quit_early(&revs->diffopt))
                        break;
@@ -224,9 +225,12 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
                                continue;
                }
                oldmode = ce->ce_mode;
+               old_sha1 = ce->sha1;
+               new_sha1 = changed ? null_sha1 : ce->sha1;
                diff_change(&revs->diffopt, oldmode, newmode,
-                           ce->sha1, (changed ? null_sha1 : ce->sha1),
-                           !is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
+                           old_sha1, new_sha1,
+                           !is_null_sha1(old_sha1),
+                           !is_null_sha1(new_sha1),
                            ce->name, 0, dirty_submodule);
 
        }