[PATCH 2/4] diff.c: refactor parse_ws_error_highlight()

[Junio C Hamano]

Rename the function to parse_ws_error_highlight_opt(), because it is
meant to parse a command line option, and then refactor the meat of
the function into a helper function that reports the parsed result
which is typically a small unsigned int (these are OR'ed bitmask
after all), or a negative offset that indicates where in the input
string a parse error happened.

Signed-off-by: Junio C Hamano <gits...@pobox.com>
---
 diff.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/diff.c b/diff.c
index 46260ed7a1..d346378600 100644
--- a/diff.c
+++ b/diff.c
@@ -3666,10 +3666,11 @@ static int parse_one_token(const char **arg, const char 
*token)
        return 0;
 }
 
-static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
+static int parse_ws_error_highlight(const char *arg)
 {
        const char *orig_arg = arg;
        unsigned val = 0;
+
        while (*arg) {
                if (parse_one_token(&arg, "none"))
                        val = 0;
@@ -3684,13 +3685,23 @@ static int parse_ws_error_highlight(struct diff_options 
*opt, const char *arg)
                else if (parse_one_token(&arg, "context"))
                        val |= WSEH_CONTEXT;
                else {
-                       error("unknown value after ws-error-highlight=%.*s",
-                             (int)(arg - orig_arg), orig_arg);
-                       return 0;
+                       return -1 - (int)(arg - orig_arg);
                }
                if (*arg)
                        arg++;
        }
+       return val;
+}
+
+static int parse_ws_error_highlight_opt(struct diff_options *opt, const char 
*arg)
+{
+       int val = parse_ws_error_highlight(arg);
+
+       if (val < 0) {
+               error("unknown value after ws-error-highlight=%.*s",
+                     -1 - val, arg);
+               return 0;
+       }
        opt->ws_error_highlight = val;
        return 1;
 }
@@ -3894,7 +3905,7 @@ int diff_opt_parse(struct diff_options *options, const 
char **av, int ac)
        else if (skip_prefix(arg, "--submodule=", &arg))
                return parse_submodule_opt(options, arg);
        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
-               return parse_ws_error_highlight(options, arg);
+               return parse_ws_error_highlight_opt(options, arg);
 
        /* misc options */
        else if (!strcmp(arg, "-z"))
-- 
2.10.1-510-g1ef781f2c1