reference: add id() to get the sha

c_src/geef.c

@@ -77,6 +77,7 @@ static ErlNifFunc geef_funcs[] =
 	{"reference_glob", 2, geef_reference_glob},
 	{"reference_lookup", 2, geef_reference_lookup},
 	{"reference_resolve", 1, geef_reference_resolve},
+	{"reference_id", 1, geef_reference_id},
 };
 
 ERL_NIF_INIT(geef, geef_funcs, load, NULL, NULL, unload)

c_src/reference.c

@@ -160,6 +160,33 @@ geef_reference_glob(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	return data.list;
 }
 
+static int bin_from_oid(ErlNifBinary *bin, const git_oid *id)
+{
+	if (!enif_alloc_binary(GIT_OID_RAWSZ, bin))
+		return -1;
+
+	memcpy(bin->data, id, GIT_OID_RAWSZ);
+	return 0;
+}
+
+ERL_NIF_TERM
+geef_reference_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
+{
+	geef_ref *ref;
+	ErlNifBinary bin;
+	const git_oid *id;
+
+	if (!enif_get_resource(env, argv[0], geef_ref_type, (void **) &ref))
+		return enif_make_badarg(env);
+
+	id = git_reference_target(ref->ref);
+
+	if (bin_from_oid(&bin, id) < 0)
+		return atoms.error;
+
+	return enif_make_binary(env, &bin);
+}
+
 ERL_NIF_TERM
 geef_reference_to_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
@@ -186,9 +213,8 @@ geef_reference_to_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 		return geef_error(env);
 	}
 
-	if (!enif_alloc_binary(GIT_OID_RAWSZ, &bin))
+	if (bin_from_oid(&bin, &id) < 0)
 		return atoms.error;
 
-	memcpy(bin.data, &id, GIT_OID_RAWSZ);
 	return enif_make_binary(env, &bin);
 }

c_src/reference.h

@@ -15,6 +15,7 @@ ERL_NIF_TERM geef_reference_to_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM a
 ERL_NIF_TERM geef_reference_glob(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
 ERL_NIF_TERM geef_reference_lookup(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
 ERL_NIF_TERM geef_reference_resolve(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
+ERL_NIF_TERM geef_reference_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
 
 void geef_ref_free(ErlNifEnv *env, void *cd);
 

src/geef.erl

@@ -2,7 +2,7 @@
 -export([hex_to_raw/1, repository/1, repository_get_path/1, repository_get_odb/1,
 	 repository_init/2, repository_is_bare/1, repository_get_workdir/1, reference_list/1,
 	 reference_to_id/2, reference_glob/2, reference_lookup/2, reference_resolve/1,
-	 odb_object_exists/2]).
+	 reference_id/1, odb_object_exists/2]).
 -on_load(load_enif/0).
 
 hex_to_raw(_Val) ->
@@ -38,6 +38,9 @@ reference_glob(_Repo, _Glob) ->
 reference_lookup(_Repo, _Refname) ->
     nif_error(?LINE).
 
+reference_id(_Handle) ->
+    nif_error(?LINE).
+
 reference_resolve(_Handle) ->
     nif_error(?LINE).
 

src/reference.erl

@@ -1,5 +1,5 @@
 -module(reference, [Handle]).
--export([resolve/0]).
+-export([resolve/0, id/0]).
 
 resolve() ->
     case geef:reference_resolve(Handle) of
@@ -8,3 +8,7 @@ resolve() ->
 	Other ->
 	    Other
     end.
+
+-spec id() -> binary().
+id() ->
+    geef:reference_id(Handle).