ref-filter: add deltabase option

Add new formatting option: deltabase.
If the object is stored as a delta on-disk, this expands
to the 40-hex sha1 of the delta base object.
Otherwise, expands to the null sha1 (40 zeroes).
We have same option in cat-file command.
Hopefully, in the end I will remove formatting code from
cat-file and reuse formatting parts from ref-filter.

Signed-off-by: Olga Telezhnaia <olyatelezhnaya@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/ref-filter.c b/ref-filter.c
index 6753c45660dfc8379f75374b57df05ea29f84904..d8d3718abbf931b0d52a80148f3f5986516cc163 100644 (file)
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -246,6 +246,18 @@ static int objectsize_atom_parser(const struct ref_format *format, struct used_a
        return 0;
 }
 
+static int deltabase_atom_parser(const struct ref_format *format, struct used_atom *atom,
+                                const char *arg, struct strbuf *err)
+{
+       if (arg)
+               return strbuf_addf_ret(err, -1, _("%%(deltabase) does not take arguments"));
+       if (*atom->name == '*')
+               oi_deref.info.delta_base_sha1 = oi_deref.delta_base_oid.hash;
+       else
+               oi.info.delta_base_sha1 = oi.delta_base_oid.hash;
+       return 0;
+}
+
 static int body_atom_parser(const struct ref_format *format, struct used_atom *atom,
                            const char *arg, struct strbuf *err)
 {
@@ -437,6 +449,7 @@ static struct {
        { "objecttype", SOURCE_OTHER, FIELD_STR, objecttype_atom_parser },
        { "objectsize", SOURCE_OTHER, FIELD_ULONG, objectsize_atom_parser },
        { "objectname", SOURCE_OTHER, FIELD_STR, objectname_atom_parser },
+       { "deltabase", SOURCE_OTHER, FIELD_STR, deltabase_atom_parser },
        { "tree", SOURCE_OBJ },
        { "parent", SOURCE_OBJ },
        { "numparent", SOURCE_OBJ, FIELD_ULONG },
@@ -888,7 +901,8 @@ static void grab_common_values(struct atom_value *val, int deref, struct expand_
                } else if (!strcmp(name, "objectsize")) {
                        v->value = oi->size;
                        v->s = xstrfmt("%lu", oi->size);
-               }
+               } else if (!strcmp(name, "deltabase"))
+                       v->s = xstrdup(oid_to_hex(&oi->delta_base_oid));
                else if (deref)
                        grab_objectname(name, &oi->oid, v, &used_atom[i]);
        }