Clean up diff implementation for review

This fixes several bugs, updates tests and docs, eliminates the
FILE* assumption in favor of printing callbacks for the diff patch
formatter helpers, and adds a "diff" example function that can
perform a diff from the command line.

1 files changed, 36 insertions, 0 deletions

diff --git a/tests-clar/diff/diff_helpers.h b/tests-clar/diff/diff_helpers.h
index a75dd912c..4c3e7580e 100644
--- a/tests-clar/diff/diff_helpers.h
+++ b/tests-clar/diff/diff_helpers.h
@@ -1,4 +1,40 @@
 #include "fileops.h"
+#include "git2/diff.h"
 
 extern git_tree *resolve_commit_oid_to_tree(
 	git_repository *repo, const char *partial_oid);
+
+typedef struct {
+	int files;
+	int file_adds;
+	int file_dels;
+	int file_mods;
+
+	int hunks;
+	int hunk_new_lines;
+	int hunk_old_lines;
+
+	int lines;
+	int line_ctxt;
+	int line_adds;
+	int line_dels;
+} diff_expects;
+
+extern int diff_file_fn(
+	void *cb_data,
+	git_diff_delta *delta,
+	float progress);
+
+extern int diff_hunk_fn(
+	void *cb_data,
+	git_diff_delta *delta,
+	git_diff_range *range,
+	const char *header,
+	size_t header_len);
+
+extern int diff_line_fn(
+	void *cb_data,
+	git_diff_delta *delta,
+	char line_origin,
+	const char *content,
+	size_t content_len);