packbuilder: add git_packbuilder_foreach

Let the user get each object as a buffer+size pair so they can handle
the packfile content as they need to.

include/git2/pack.h

@@ -78,6 +78,16 @@ GIT_EXTERN(int) git_packbuilder_insert_tree(git_packbuilder *pb, const git_oid *
 GIT_EXTERN(int) git_packbuilder_write(git_packbuilder *pb, const char *file);
 
 /**
+ * Create the new pack and pass each object to the callback
+ *
+ * @param pb the packbuilder
+ * @param cb the callback to call with each packed object's buffer
+ * @param data the callback's data
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_packbuilder_foreach(git_packbuilder *pb, int (*cb)(void *buf, size_t size, void *data), void *data);
+
+/**
  * Free the packbuilder and all associated data
  *
  * @param pb The packbuilder

src/pack-objects.c

@@ -1237,6 +1237,12 @@ int git_packbuilder_send(git_packbuilder *pb, git_transport *t)
 	return write_pack(pb, &send_pack_file, t);
 }
 
+int git_packbuilder_foreach(git_packbuilder *pb, int (*cb)(void *buf, size_t size, void *payload), void *payload)
+{
+	PREPARE_PACK;
+	return write_pack(pb, cb, payload);
+}
+
 int git_packbuilder_write_buf(git_buf *buf, git_packbuilder *pb)
 {
 	PREPARE_PACK;

tests-clar/pack/packbuilder.c

@@ -28,12 +28,12 @@ void test_pack_packbuilder__cleanup(void)
 	git_packbuilder_free(_packbuilder);
 	git_revwalk_free(_revwalker);
 	git_indexer_free(_indexer);
+	_indexer = NULL;
 	git_repository_free(_repo);
 }
 
-void test_pack_packbuilder__create_pack(void)
+static void seed_packbuilder(void)
 {
-	git_transfer_progress stats;
 	git_oid oid, *o;
 	unsigned int i;
 
@@ -58,10 +58,37 @@ void test_pack_packbuilder__create_pack(void)
 					git_commit_tree_oid((git_commit *)obj)));
 		git_object_free(obj);
 	}
+}
+
+void test_pack_packbuilder__create_pack(void)
+{
+	git_transfer_progress stats;
 
+	seed_packbuilder();
 	cl_git_pass(git_packbuilder_write(_packbuilder, "testpack.pack"));
 
 	cl_git_pass(git_indexer_new(&_indexer, "testpack.pack"));
 	cl_git_pass(git_indexer_run(_indexer, &stats));
 	cl_git_pass(git_indexer_write(_indexer));
 }
+
+static git_transfer_progress stats;
+static int foreach_cb(void *buf, size_t len, void *payload)
+{
+	git_indexer_stream *idx = (git_indexer_stream *) payload;
+
+	cl_git_pass(git_indexer_stream_add(idx, buf, len, &stats));
+
+	return 0;
+}
+
+void test_pack_packbuilder__foreach(void)
+{
+	git_indexer_stream *idx;
+
+	seed_packbuilder();
+	cl_git_pass(git_indexer_stream_new(&idx, ".", NULL, NULL));
+	cl_git_pass(git_packbuilder_foreach(_packbuilder, foreach_cb, idx));
+	cl_git_pass(git_indexer_stream_finalize(idx, &stats));
+	git_indexer_stream_free(idx);
+}