git_config_maybe_bool()

Some configuration variables can take boolean values in addition to
enumeration specific to them.  Introduce git_config_maybe_bool() that
returns 0 or 1 if the given value is boolean, or -1 if not, so that
a parser for such a variable can check for boolean first and then
parse other kinds of values as a fallback.

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

cache.h

@@ -924,6 +924,7 @@ extern int git_config_int(const char *, const char *);
 extern unsigned long git_config_ulong(const char *, const char *);
 extern int git_config_bool_or_int(const char *, const char *, int *);
 extern int git_config_bool(const char *, const char *);
+extern int git_config_maybe_bool(const char *, const char *);
 extern int git_config_string(const char **, const char *, const char *);
 extern int git_config_pathname(const char **, const char *, const char *);
 extern int git_config_set(const char *, const char *);

config.c

@@ -322,17 +322,30 @@ unsigned long git_config_ulong(const char *name, const char *value)
 	return ret;
 }
 
-int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
+int git_config_maybe_bool(const char *name, const char *value)
 {
-	*is_bool = 1;
 	if (!value)
 		return 1;
 	if (!*value)
 		return 0;
-	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
+	if (!strcasecmp(value, "true")
+	    || !strcasecmp(value, "yes")
+	    || !strcasecmp(value, "on"))
 		return 1;
-	if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
+	if (!strcasecmp(value, "false")
+	    || !strcasecmp(value, "no")
+	    || !strcasecmp(value, "off"))
 		return 0;
+	return -1;
+}
+
+int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
+{
+	int v = git_config_maybe_bool(name, value);
+	if (0 <= v) {
+		*is_bool = 1;
+		return v;
+	}
 	*is_bool = 0;
 	return git_config_int(name, value);
 }