ref-filter: implement '--points-at' option

In 'tag -l' we have '--points-at' option which lets users
list only tags of a given object. Implement this option in
'ref-filter.{c,h}' so that other commands can benefit from this.

This is duplicated from tag.c, we will eventually remove that
when we port tag.c to use ref-filter APIs.

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

diff --git a/builtin/tag.c b/builtin/tag.c
index e36c43e..280981f 100644 (file)
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -56,6 +56,10 @@ static int match_pattern(const char **patterns, const char *ref)
        return 0;
 }
 
+/*
+ * This is currently duplicated in ref-filter.c, and will eventually be
+ * removed as we port tag.c to use the ref-filter APIs.
+ */
 static const unsigned char *match_points_at(const char *refname,
                                            const unsigned char *sha1)
 {

diff --git a/ref-filter.c b/ref-filter.c
index 3fbbbeb..2efe30a 100644 (file)
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -842,6 +842,38 @@ static int match_name_as_path(const char **pattern, const char *refname)
        return 0;
 }
 
+/*
+ * Given a ref (sha1, refname), check if the ref belongs to the array
+ * of sha1s. If the given ref is a tag, check if the given tag points
+ * at one of the sha1s in the given sha1 array.
+ * the given sha1_array.
+ * NEEDSWORK:
+ * 1. Only a single level of inderection is obtained, we might want to
+ * change this to account for multiple levels (e.g. annotated tags
+ * pointing to annotated tags pointing to a commit.)
+ * 2. As the refs are cached we might know what refname peels to without
+ * the need to parse the object via parse_object(). peel_ref() might be a
+ * more efficient alternative to obtain the pointee.
+ */
+static const unsigned char *match_points_at(struct sha1_array *points_at,
+                                           const unsigned char *sha1,
+                                           const char *refname)
+{
+       const unsigned char *tagged_sha1 = NULL;
+       struct object *obj;
+
+       if (sha1_array_lookup(points_at, sha1) >= 0)
+               return sha1;
+       obj = parse_object(sha1);
+       if (!obj)
+               die(_("malformed object at '%s'"), refname);
+       if (obj->type == OBJ_TAG)
+               tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
+       if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
+               return tagged_sha1;
+       return NULL;
+}
+
 /* Allocate space for a new ref_array_item and copy the objectname and flag to it */
 static struct ref_array_item *new_ref_array_item(const char *refname,
                                                 const unsigned char *objectname,
@@ -875,6 +907,9 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
        if (*filter->name_patterns && !match_name_as_path(filter->name_patterns, refname))
                return 0;
 
+       if (filter->points_at.nr && !match_points_at(&filter->points_at, oid->hash, refname))
+               return 0;
+
        /*
         * We do not open the object yet; sort may only need refname
         * to do its job and the resulting list may yet to be pruned

diff --git a/ref-filter.h b/ref-filter.h
index 6997984..c2856b8 100644 (file)
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -42,6 +42,7 @@ struct ref_array {
 
 struct ref_filter {
        const char **name_patterns;
+       struct sha1_array points_at;
 };
 
 struct ref_filter_cbdata {