1 files changed, 98 insertions, 0 deletions
diff --git a/src/tree.c b/src/tree.c
index 91e7f7164..21376bae7 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -930,3 +930,101 @@ int git_tree_diff(git_tree *a, git_tree *b, git_tree_diff_cb cb, void *data)
 exit:
 	return error;
 }
+
+struct diff_index_cbdata {
+	git_index *index;
+	unsigned int i;
+	git_tree_diff_cb cb;
+	void *data;
+};
+
+static int cmp_tentry_ientry(git_tree_entry *tentry, git_index_entry *ientry)
+{
+	int cmp;
+
+	cmp = tentry->attr - ientry->mode;
+	if (cmp != 0)
+		return cmp;
+
+	return git_oid_cmp(&tentry->oid, &ientry->oid);
+}
+
+static void make_tentry(git_tree_entry *tentry, git_index_entry *ientry, git_buf *buf)
+{
+	memset(tentry, 0x0, sizeof(git_tree_entry));
+	tentry->attr = ientry->mode;
+	git_oid_cpy(&tentry->oid, &ientry->oid);
+	if (buf != NULL) {
+		tentry->filename = buf->ptr;
+		tentry->filename_len = buf->size;
+	}
+}
+
+static int diff_index_cb(const char *root, git_tree_entry *tentry, void *data)
+{
+	struct diff_index_cbdata *cbdata = (struct diff_index_cbdata *) data;
+	git_index_entry *ientry = git_index_get(cbdata->index, cbdata->i);
+	git_tree_entry fake_entry;
+	git_buf fn_buf = GIT_BUF_INIT;
+	int cmp, error = GIT_SUCCESS;
+
+	if (ENTRY_IS_TREE(tentry))
+		return GIT_SUCCESS;
+
+	git_buf_puts(&fn_buf, root);
+	git_buf_puts(&fn_buf, tentry->filename);
+
+	if (!ientry) {
+		error = signal_deletion(tentry, cbdata->cb, cbdata->data);
+		goto exit;
+	}
+
+	/* Like with 'git diff-index', the index is the right side*/
+	cmp = strcmp(git_buf_cstr(&fn_buf), ientry->path);
+	if (cmp == 0) {
+		cbdata->i++;
+		if (!cmp_tentry_ientry(tentry, ientry))
+			goto exit;
+		/* modification */
+		make_tentry(&fake_entry, ientry, &fn_buf);
+		if ((error = signal_modification(tentry, &fake_entry, cbdata->cb, cbdata->data)) < 0)
+			goto exit;
+	} else if (cmp < 0) {
+		/* deletion */
+		memcpy(&fake_entry, tentry, sizeof(git_tree_entry));
+		fake_entry.filename = fn_buf.ptr;
+		fake_entry.filename_len = fn_buf.size;
+		if ((error = signal_deletion(tentry, cbdata->cb, cbdata->data)) < 0)
+			goto exit;
+	} else {
+		/* addition */
+		cbdata->i++;
+		make_tentry(&fake_entry, ientry, &fn_buf);
+		if ((error = signal_addition(&fake_entry, cbdata->cb, cbdata->data)) < 0)
+			goto exit;
+		/*
+		 * The index has an addition. This means that we need to use
+		 * the next entry in the index without advancing the tree
+		 * walker, so call ourselves with the same tree state.
+		 */
+		if ((error = diff_index_cb(root, tentry, data)) < 0)
+			goto exit;
+	}
+
+ exit:
+	git_buf_free(&fn_buf);
+	return error;
+}
+
+int git_tree_diff_index_recursive(git_tree *tree, git_index *index, git_tree_diff_cb cb, void *data)
+{
+	struct diff_index_cbdata cbdata;
+	char dummy_path[GIT_PATH_MAX];
+
+	cbdata.index = index;
+	cbdata.i = 0;
+	cbdata.cb = cb;
+	cbdata.data = data;
+
+	return tree_walk_post(tree, diff_index_cb, dummy_path, 0, &cbdata);
+}