diff: futureproof "stop feeding the backend early" logic

Refactor the "do not stop feeding the backend early" logic into a small
helper function and use it in both run_diff_files() and diff_tree() that
has the stop-early optimization. We may later add other types of diffcore
transformation that require to look at the whole result like diff-filter
does, and having the logic in a single place is essential for longer term
maintainability.

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

1 files changed, 1 insertions, 3 deletions

diff --git a/diff-lib.c b/diff-lib.c
index bfa6503..869d8f0 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -73,9 +73,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 		struct cache_entry *ce = active_cache[i];
 		int changed;
 
-		if (DIFF_OPT_TST(&revs->diffopt, QUICK) &&
-		    !revs->diffopt.filter &&
-		    DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
+		if (diff_can_quit_early(&revs->diffopt))
 			break;
 
 		if (!ce_path_match(ce, revs->prune_data))