diff: refactor COLOR_DIFF from a flag into an int

This lets us store more than just a bit flag for whether we
want color; we can also store whether we want automatic
colors. This can be useful for making the automatic-color
decision closer to the point of use.

This mostly just involves replacing DIFF_OPT_* calls with
manipulations of the flag. The biggest exception is that
calls to DIFF_OPT_TST must check for "o->use_color > 0",
which lets an "unknown" value (i.e., the default) stay at
"no color". In the previous code, a value of "-1" was not
propagated at all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/diff.h b/diff.h
index 6d303c1d50..04a9ad781b 100644
--- a/diff.h
+++ b/diff.h
@@ -58,7 +58,7 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
 #define DIFF_OPT_SILENT_ON_REMOVE    (1 <<  5)
 #define DIFF_OPT_FIND_COPIES_HARDER  (1 <<  6)
 #define DIFF_OPT_FOLLOW_RENAMES      (1 <<  7)
-#define DIFF_OPT_COLOR_DIFF          (1 <<  8)
+/* (1 <<  8) unused */
 /* (1 <<  9) unused */
 #define DIFF_OPT_HAS_CHANGES         (1 << 10)
 #define DIFF_OPT_QUICK               (1 << 11)
@@ -101,6 +101,7 @@ struct diff_options {
 	const char *single_follow;
 	const char *a_prefix, *b_prefix;
 	unsigned flags;
+	int use_color;
 	int context;
 	int interhunkcontext;
 	int break_opt;
@@ -159,7 +160,7 @@ enum color_diff {
 };
 const char *diff_get_color(int diff_use_color, enum color_diff ix);
 #define diff_get_color_opt(o, ix) \
-	diff_get_color(DIFF_OPT_TST((o), COLOR_DIFF), ix)
+	diff_get_color((o)->use_color, ix)
 
 
 extern const char mime_boundary_leader[];