Update diff to use iterators

This is a major reorganization of the diff code.  This changes
the diff functions to use the iterators for traversing the
content.  This allowed a lot of code to be simplified.  Also,
this moved the functions relating to outputting a diff into a
new file (diff_output.c).

This includes a number of other changes - adding utility
functions, extending iterators, etc. plus more tests for the
diff code.  This also takes the example diff.c program much
further in terms of emulating git-diff command line options.

1 files changed, 8 insertions, 6 deletions

diff --git a/tests-clar/diff/diff_helpers.c b/tests-clar/diff/diff_helpers.c
index cd5a0f9a..67a4f1c5 100644
--- a/tests-clar/diff/diff_helpers.c
+++ b/tests-clar/diff/diff_helpers.c
@@ -29,12 +29,14 @@ int diff_file_fn(
 	diff_expects *e = cb_data;
 	(void)progress;
 	e->files++;
-	if (delta->old_attr == 0)
-		e->file_adds++;
-	else if (delta->new_attr == 0)
-		e->file_dels++;
-	else
-		e->file_mods++;
+	switch (delta->status) {
+	case GIT_STATUS_ADDED: e->file_adds++; break;
+	case GIT_STATUS_DELETED: e->file_dels++; break;
+	case GIT_STATUS_MODIFIED: e->file_mods++; break;
+	case GIT_STATUS_IGNORED: e->file_ignored++; break;
+	case GIT_STATUS_UNTRACKED: e->file_untracked++; break;
+	default: break;
+	}
 	return 0;
 }