[PATCH v4 12/16] ref-filter: add support for %(refname:dir) and %(refname:base)

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

Add the options `:dir` and `:base` to the %(refname) atom. The `:dir`
option gives the directory (the part after $GIT_DIR/) of the ref without
the refname. The `:base` option gives the base directory of the given
ref (i.e. the directory following $GIT_DIR/refs/).

Add tests and documentation for the same.

Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
---
 Documentation/git-for-each-ref.txt |  4 +++-
 ref-filter.c                       | 28 +++++++++++++++++++++++++---
 t/t6300-for-each-ref.sh            |  2 ++
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index be763c4..0d7d80f 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -96,7 +96,9 @@ refname::
 	slash-separated path components from the front of the refname
 	(e.g., `%(refname:strip=2)` turns `refs/tags/foo` into `foo`.
 	`<N>` must be a positive integer.  If a displayed ref has fewer
-	components than `<N>`, the command aborts with an error.
+	components than `<N>`, the command aborts with an error. For the base
+	directory of the ref (i.e. foo in refs/foo/bar/boz) append
+	`:base`. For the entire directory path append `:dir`.
 
 objecttype::
 	The type of the object (`blob`, `tree`, `commit`, `tag`).
diff --git a/ref-filter.c b/ref-filter.c
index dc1e404..73e0a7f 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -64,7 +64,7 @@ static struct used_atom {
 		} objectname;
 		enum { S_FULL, S_SHORT } symref;
 		struct {
-			enum { R_NORMAL, R_SHORT, R_STRIP } option;
+			enum { R_BASE, R_DIR, R_NORMAL, R_SHORT, R_STRIP } option;
 			unsigned int strip;
 		} refname;
 	} u;
@@ -243,7 +243,11 @@ static void refname_atom_parser(struct used_atom *atom, const char *arg)
 		if (strtoul_ui(arg, 10, &atom->u.refname.strip) ||
 			atom->u.refname.strip <= 0)
 			die(_("positive value expected refname:strip=%s"), arg);
-	} else
+	} else if (!strcmp(arg, "dir"))
+		atom->u.contents.option = R_DIR;
+	else if (!strcmp(arg, "base"))
+		atom->u.contents.option = R_BASE;
+	else
 		die(_("unrecognized %%(refname) argument: %s"), arg);
 }
 
@@ -1175,7 +1179,25 @@ static const char *get_refname(struct used_atom *atom, struct ref_array_item *re
 		return shorten_unambiguous_ref(ref->refname, warn_ambiguous_refs);
 	else if (atom->u.refname.option == R_STRIP)
 		return strip_ref_components(ref->refname, atom->u.refname.strip);
-	else
+	else if (atom->u.refname.option == R_BASE) {
+		const char *sp, *ep;
+
+		if (skip_prefix(ref->refname, "refs/", &sp)) {
+			ep = strchr(sp, '/');
+			if (!ep)
+				return "";
+			return xstrndup(sp, ep - sp);
+		}
+		return "";
+	} else if (atom->u.refname.option == R_DIR) {
+		const char *sp, *ep;
+
+		sp = ref->refname;
+		ep = strrchr(sp, '/');
+		if (!ep)
+			return "";
+		return xstrndup(sp, ep - sp);
+	} else
 		return ref->refname;
 }
 
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index b06ea1c..36d32d7 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -53,6 +53,8 @@ test_atom head refname refs/heads/master
 test_atom head refname:short master
 test_atom head refname:strip=1 heads/master
 test_atom head refname:strip=2 master
+test_atom head refname:dir refs/heads
+test_atom head refname:base heads
 test_atom head upstream refs/remotes/origin/master
 test_atom head upstream:short origin/master
 test_atom head push refs/remotes/myfork/master
-- 
2.8.0