Add Replica::num_undo_points and exclude undo points from num_operations

taskchampion/lib/src/replica.rs

@@ -360,7 +360,8 @@ pub unsafe extern "C" fn tc_replica_undo(rep: *mut TCReplica, undone_out: *mut i
     )
 }
 
-/// Get the number of local, un-synchronized operations, or -1 on error
+/// Get the number of local, un-synchronized operations (not including undo points), or -1 on
+/// error.
 #[no_mangle]
 pub unsafe extern "C" fn tc_replica_num_local_operations(rep: *mut TCReplica) -> i64 {
     wrap(
@@ -373,6 +374,19 @@ pub unsafe extern "C" fn tc_replica_num_local_operations(rep: *mut TCReplica) ->
     )
 }
 
+/// Get the number of undo points (number of undo calls possible), or -1 on error.
+#[no_mangle]
+pub unsafe extern "C" fn tc_replica_num_undo_points(rep: *mut TCReplica) -> i64 {
+    wrap(
+        rep,
+        |rep| {
+            let count = rep.num_undo_points()? as i64;
+            Ok(count)
+        },
+        -1,
+    )
+}
+
 /// Add an UndoPoint, if one has not already been added by this Replica.  This occurs automatically
 /// when a change is made.  The `force` flag allows forcing a new UndoPoint even if one has already
 /// been created by this Replica, and may be useful when a Replica instance is held for a long time