Diff iterators

This refactors the diff output code so that an iterator object
can be used to traverse and generate the diffs, instead of just
the `foreach()` style with callbacks.  The code has been rearranged
so that the two styles can still share most functions.

This also replaces `GIT_REVWALKOVER` with `GIT_ITEROVER` and uses
that as a common error code for marking the end of iteration when
using a iterator style of object.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/status.c b/src/status.c
index 3d3d15d77..0a5fbdcbf 100644
--- a/src/status.c
+++ b/src/status.c
@@ -151,6 +151,9 @@ cleanup:
 	git_diff_list_free(idx2head);
 	git_diff_list_free(wd2idx);
 
+	if (err == GIT_EUSER)
+		giterr_clear();
+
 	return err;
 }