[PATCH 2/3] perfcounter: bring new OPT_CALLBACK_DEFAULT option

[Frederic Weisbecker <fweisbec@gmail.com>]

There is no predefined macro to create an option that can
have a custom value or a default one if none is given.

This patch provides a new helper OPT_CALLBACK_DEFAULT() which
defines such kind of option.

For example, considering an option -c, we want to get the default
value in the following cases:

./perf command -c -d
./perf command -d -c

And the foo value when it's given:

./perf command -c foo -d
./perf command -d -c foo

That's also why PARSE_OPT_LASTARG_DEFAULT is extended here
to support default values whatever the position of the option, not
only in the end.

Should it now be renamed to PARSE_OPT_ARG_DEFAULT ?

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 tools/perf/util/parse-options.c |    3 ++-
 tools/perf/util/parse-options.h |    2 ++
 2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index 9a897b7..1bf6719 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -20,7 +20,8 @@ static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
 	if (p->opt) {
 		*arg = p->opt;
 		p->opt = NULL;
-	} else if (p->argc == 1 && (opt->flags & PARSE_OPT_LASTARG_DEFAULT)) {
+	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 ||
+		    **(p->argv + 1) == '-')) {
 		*arg = (const char *)opt->defval;
 	} else if (p->argc > 1) {
 		p->argc--;
diff --git a/tools/perf/util/parse-options.h b/tools/perf/util/parse-options.h
index 15c8aba..8aa3464 100644
--- a/tools/perf/util/parse-options.h
+++ b/tools/perf/util/parse-options.h
@@ -104,6 +104,8 @@ struct option {
 	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = "time", .help = (h), .callback = parse_opt_approxidate_cb }
 #define OPT_CALLBACK(s, l, v, a, h, f) \
 	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), (a), .help = (h), .callback = (f) }
+#define OPT_CALLBACK_DEFAULT(s, l, v, a, h, f, d) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), (a), .help = (h), .callback = (f), .defval = (intptr_t)d, .flags = PARSE_OPT_LASTARG_DEFAULT }
 
 /* parse_options() will filter out the processed options and leave the
  * non-option argments in argv[].
-- 
1.6.2.3