Reorganize diff and add basic diff driver

This is a significant reorganization of the diff code to break it
into a set of more clearly distinct files and to document the new
organization.  Hopefully this will make the diff code easier to
understand and to extend.

This adds a new `git_diff_driver` object that looks of diff driver
information from the attributes and the config so that things like
function content in diff headers can be provided.  The full driver
spec is not implemented in the commit - this is focused on the
reorganization of the code and putting the driver hooks in place.

This also removes a few #includes from src/repository.h that were
overbroad, but as a result required extra #includes in a variety
of places since including src/repository.h no longer results in
pulling in the whole world.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/diff_xdiff.h b/src/diff_xdiff.h
new file mode 100644
index 000000000..c547b00cf
--- /dev/null
+++ b/src/diff_xdiff.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_diff_xdiff_h__
+#define INCLUDE_diff_xdiff_h__
+
+#include "diff.h"
+#include "diff_patch.h"
+#include "xdiff/xdiff.h"
+
+/* A git_xdiff_output is a git_diff_output with extra fields necessary
+ * to use libxdiff.  Calling git_xdiff_init() will set the diff_cb field
+ * of the output to use xdiff to generate the diffs.
+ */
+typedef struct {
+	git_diff_output output;
+
+	xdemitconf_t config;
+	xpparam_t    params;
+	xdemitcb_t   callback;
+} git_xdiff_output;
+
+void git_xdiff_init(git_xdiff_output *xo, const git_diff_options *opts);
+
+#endif