Add tag-peeling support

c_src/geef.c

@@ -6,6 +6,7 @@
 #include "commit.h"
 #include "tree.h"
 #include "blob.h"
+#include "tag.h"
 #include "library.h"
 #include "revwalk.h"
 #include "index.h"
@@ -162,6 +163,7 @@ static ErlNifFunc geef_funcs[] =
 	{"tree_bypath", 2, geef_tree_bypath},
 	{"blob_size", 1, geef_blob_size},
 	{"blob_content", 1, geef_blob_content},
+	{"tag_peel", 1, geef_tag_peel},
 	{"library_version", 0, geef_library_version},
 	{"revwalk_new",  1,    geef_revwalk_new},
 	{"revwalk_push", 3,    geef_revwalk_push},

c_src/tag.c

@@ -0,0 +1,35 @@
+#include <git2.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "oid.h"
+#include "geef.h"
+#include "tree.h"
+
+ERL_NIF_TERM
+geef_tag_peel(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
+{
+	geef_object *obj, *peeled;
+	ERL_NIF_TERM term_peeled;
+
+	if (!enif_get_resource(env, argv[0], geef_object_type, (void **) &obj))
+		return enif_make_badarg(env);
+
+	if (git_object_type(obj->obj) != GIT_OBJ_TAG)
+		return enif_make_badarg(env);
+
+	peeled = enif_alloc_resource(geef_object_type, sizeof(geef_object));
+	if (!obj)
+		return geef_oom(env);
+
+	if (git_tag_peel(&peeled->obj, (git_tag *)obj->obj) < 0)
+		return geef_error(env);
+
+	peeled->repo = obj->repo;
+	enif_keep_resource(peeled->repo);
+
+	term_peeled = enif_make_resource(env, peeled);
+	enif_release_resource(peeled);
+
+	return enif_make_tuple3(env, atoms.ok, geef_object_type2atom(git_object_type(peeled->obj)), term_peeled);
+}

c_src/tag.h

@@ -0,0 +1,6 @@
+#ifndef GEEF_TAG_H
+#define GEEF_TAG_H
+
+ERL_NIF_TERM geef_tag_peel(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
+
+#endif

src/geef_nif.erl

@@ -101,6 +101,10 @@ blob_size(_ObjHandle) ->
 blob_content(_ObjHandle) ->
     nif_error(?LINE).
 
+-spec tag_peel(term()) -> {ok, atom(), term()} | {error, term()}.
+tag_peel(_Tag) ->
+    ?NIF_FN.
+
 -spec library_version() -> {integer, integer, integer}.
 library_version() ->
     nif_error(?LINE).

src/geef_tag.erl

@@ -0,0 +1,22 @@
+-module(geef_tag).
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+-endif.
+
+-export([lookup/2, peel/1]).
+
+-include("geef_records.hrl").
+
+-spec lookup(pid(), geef_oid() | iolist()) -> {ok, geef_object()} | {error, term()}.
+lookup(Repo, Id) ->
+    geef_object:lookup(Repo, Id, tag).
+
+-spec peel(geef_object()) -> {ok, geef_object()} | {error, term()}.
+peel(#geef_object{type=tag, handle=Handle}) ->
+    case geef_nif:tag_peel(Handle) of
+    	{ok, Type, PeeledHandle} ->
+	    {ok, #geef_object{type=Type, handle=PeeledHandle}};
+	Err = {error, _} ->
+	    Err
+    end.