[RFC/PATCH 3/9] for-each-ref: add '--points-at' option

[Karthik Nayak <karthik.188@gmail.com>]

Add the '--points-at' option provided by 'ref-filter'. The
option lets the user to pick only refs which point to a particular
commit.

Add Documentation for the same.

Based-on-patch-by: Jeff King <peff@peff.net>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 Documentation/git-for-each-ref.txt | 3 +++
 builtin/for-each-ref.c             | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 7f8d9a5..e9f6a8a 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -10,6 +10,7 @@ SYNOPSIS
 [verse]
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
+		   [--points-at <object>]
 
 DESCRIPTION
 -----------
@@ -62,6 +63,8 @@ OPTIONS
 	the specified host language.  This is meant to produce
 	a scriptlet that can directly be `eval`ed.
 
+--points-at <object>::
+	Only list tags of the given object.
 
 FIELD NAMES
 -----------
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 4d2d024..b9d180a 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -7,6 +7,7 @@
 
 static char const * const for_each_ref_usage[] = {
 	N_("git for-each-ref [<options>] [<pattern>]"),
+	N_("git for-each-ref [--points-at <object>]"),
 	NULL
 };
 
@@ -17,6 +18,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 	struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
 	int maxcount = 0, quote_style = 0;
 	struct ref_filter_cbdata ref_cbdata;
+	memset(&ref_cbdata, 0, sizeof(ref_cbdata));
 
 	struct option opts[] = {
 		OPT_BIT('s', "shell", &quote_style,
@@ -33,6 +35,9 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		OPT_STRING(  0 , "format", &format, N_("format"), N_("format to use for the output")),
 		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
 			    N_("field name to sort on"), &parse_opt_ref_sorting),
+		OPT_CALLBACK(0, "points-at", &ref_cbdata.filter.points_at,
+			     N_("object"), N_("print only tags of the object"),
+			     parse_opt_points_at),
 		OPT_END(),
 	};
 
@@ -54,7 +59,6 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 	/* for warn_ambiguous_refs */
 	git_config(git_default_config, NULL);
 
-	memset(&ref_cbdata, 0, sizeof(ref_cbdata));
 	ref_cbdata.filter.name_patterns = argv;
 	filter_refs(for_each_rawref, &ref_cbdata);
 
-- 
2.4.2