Create a copy of the iterator before turning it into a stream

A functional language shouldn't modify the iterator, but instead keep
advancing. As we can't stop in any particular point, we still just use
a stream.

lib/geef/iterator.ex

@@ -9,15 +9,25 @@ defrecord Geef.Iterator, Record.extract(:geef_iterator, from: "src/geef_records.
     end
   end
 
-
-  def stream(iter = Iterator[]) do
-    &stream(iter, &1, &2)
+  def new(iterator) do
+    set_elem(iterator, 0, Geef.Iterator)
   end
 
-  def stream(iter = Iterator[type: ref], acc, fun) do
+  def stream!(Iterator[type: :ref, repo: repo, regexp: regexp]) do
+    iter =
+      case :geef_ref.iterator(repo, regexp) do
+        {:ok, iter} ->
+          Iterator.new iter
+        {:error, error} ->
+          raise Geef.IteratorError, message: error
+      end
+    &do_stream(iter, &1, &2)
+  end
+
+  defp do_stream(iter = Iterator[type: :ref], acc, fun) do
     case :geef_ref.next(rebind(iter)) do
       {:ok, ref} ->
-        stream(iter, fun.(Reference.new(ref), acc), fun)
+        do_stream(iter, fun.(Reference.new(ref), acc), fun)
       {:error, :iterover} ->
         acc
       {:error, error} ->

src/geef_records.hrl

@@ -13,7 +13,7 @@
 -record(geef_request, {service :: atom(), path :: binary(), host :: binary()}).
 -record(geef_tree_entry, {mode, type, id, name}).
 -record(geef_signature, {name :: iolist(), email :: iolist(), time :: geef_time()}).
--record(geef_iterator, {type :: atom(), handle}).
+-record(geef_iterator, {type :: atom(), repo :: pid(), regexp :: iolist(), handle}).
 
 -type geef_reference() :: #geef_reference{name :: binary(), target :: binary() | geef_oid()}.
 -type geef_oid() :: #geef_oid{oid :: binary()}.

src/geef_ref.erl

@@ -44,7 +44,7 @@ lookup(Repo, Refname) ->
 iterator(Repo, Regexp) ->
     case geef_repo:iterator(Repo, Regexp) of
 	{ok, Handle} ->
-	    {ok, #geef_iterator{type=ref, handle=Handle}};
+	    {ok, #geef_iterator{type=ref, repo=Repo, regexp=Regexp, handle=Handle}};
 	Other ->
 	    Other
     end.