tree: implement tree diffing

For each difference in the trees, the callback gets called with the
relevant information so the user can fill in their own data
structures.

Signed-off-by: Carlos Martín Nieto <carlos@cmartin.tk>

1 files changed, 34 insertions, 0 deletions

diff --git a/include/git2/tree.h b/include/git2/tree.h
index fefd4c6c3..3ff017fbf 100644
--- a/include/git2/tree.h
+++ b/include/git2/tree.h
@@ -314,5 +314,39 @@ enum git_treewalk_mode {
 GIT_EXTERN(int) git_tree_walk(git_tree *tree, git_treewalk_cb callback, int mode, void *payload);
 
 /** @} */
+
+typedef enum {
+	GIT_STATUS_ADDED = 1,
+	GIT_STATUS_DELETED = 2,
+	GIT_STATUS_MODIFIED = 3,
+} git_status_t;
+
+typedef struct {
+	unsigned int old_attr;
+	unsigned int new_attr;
+	git_oid old_oid;
+	git_oid new_oid;
+	git_status_t status;
+	const char *path;
+} git_tree_diff_data;
+
+typedef int (*git_tree_diff_cb)(const git_tree_diff_data *ptr, void *data);
+
+/**
+ * Diff two trees
+ *
+ * Compare two trees. For each difference in the trees, the callback
+ * will be called with a git_tree_diff_data filled with the relevant
+ * information.
+ *
+ * @param old the "old" tree
+ * @param newer the "newer" tree
+ * @param cb callback
+ * @param data data to give to the callback
+ * @return GIT_SUCCESS or an error code
+ */
+int git_tree_diff(git_tree *old, git_tree *newer, git_tree_diff_cb cb, void *data);
+
+
 GIT_END_DECL
 #endif