[PATCH 4/6] parse-options: add parse_options_takes_argument()

[Christian Couder <christian.couder@gmail.com>]

Whether an option takes a value, and therefore consumes the next
argument when that value is not stuck to it with an '=', is decided by
its type and its flags. That rule is currently open-coded in
show_gitcomp(), which needs it to decide if it should append an '=' to
the option it completes.

A following commit will need the same rule to find out which options an
early scan of the command line has to skip along with their value.

So let's factor that rule out into a new parse_options_takes_argument()
function, and let's use it in show_gitcomp().

Note that an option with PARSE_OPT_LASTARG_DEFAULT only consumes the
next argument when it isn't the last one, so it is not considered as
taking a value, which is what show_gitcomp() already did.

Signed-off-by: Christian Couder <christian.couder@gmail.com>
---
 parse-options.c | 35 ++++++++++++++++++++++-------------
 parse-options.h | 10 ++++++++++
 2 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/parse-options.c b/parse-options.c
index b3d19446cd..70851a385b 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -841,6 +841,26 @@ static void show_negated_gitcomp(const struct option *opts, int show_all,
 	}
 }
 
+int parse_options_takes_argument(const struct option *opt)
+{
+	switch (opt->type) {
+	case OPTION_STRING:
+	case OPTION_FILENAME:
+	case OPTION_INTEGER:
+	case OPTION_UNSIGNED:
+	case OPTION_CALLBACK:
+		break;
+	default:
+		return 0;
+	}
+
+	if (opt->flags & (PARSE_OPT_NOARG | PARSE_OPT_OPTARG |
+			  PARSE_OPT_LASTARG_DEFAULT))
+		return 0;
+
+	return 1;
+}
+
 static int show_gitcomp(const struct option *opts, int show_all)
 {
 	const struct option *original_opts = opts;
@@ -862,20 +882,9 @@ static int show_gitcomp(const struct option *opts, int show_all)
 			break;
 		case OPTION_GROUP:
 			continue;
-		case OPTION_STRING:
-		case OPTION_FILENAME:
-		case OPTION_INTEGER:
-		case OPTION_UNSIGNED:
-		case OPTION_CALLBACK:
-			if (opts->flags & PARSE_OPT_NOARG)
-				break;
-			if (opts->flags & PARSE_OPT_OPTARG)
-				break;
-			if (opts->flags & PARSE_OPT_LASTARG_DEFAULT)
-				break;
-			suffix = "=";
-			break;
 		default:
+			if (parse_options_takes_argument(opts))
+				suffix = "=";
 			break;
 		}
 		if (opts->flags & PARSE_OPT_COMP_ARG)
diff --git a/parse-options.h b/parse-options.h
index abc73d8399..b96e93508e 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -420,6 +420,16 @@ int parse_options(int argc, const char **argv, const char *prefix,
 		  const char * const usagestr[],
 		  enum parse_opt_flags flags);
 
+/*
+ * Return non-zero if `opt` takes a value, which means that it consumes
+ * the next argument when that value is not stuck to it with an '='.
+ *
+ * Note that an option with PARSE_OPT_LASTARG_DEFAULT only consumes the
+ * next argument when it isn't the last one, so it is not considered as
+ * taking a value here.
+ */
+int parse_options_takes_argument(const struct option *opt);
+
 NORETURN void usage_with_options(const char * const *usagestr,
 				 const struct option *options);
 
-- 
2.55.0.787.g3f9e2241eb.dirty