A undo/redo library.
It uses the Command Pattern where the user
implements the UndoCmd trait for each command and then the commands can be used with the
UndoStack.
[dependencies]
undo = "0.2.0"
extern crate undo;
use std::rc::Rc;
use std::cell::RefCell;
use undo::{UndoCmd, UndoStack};
/// Pops an element from a vector.
#[derive(Clone)]
struct PopCmd {
vec: Rc<RefCell<Vec<i32>>>,
e: Option<i32>,
}
impl UndoCmd for PopCmd {
fn redo(&mut self) {
self.e = self.vec.borrow_mut().pop();
}
fn undo(&mut self) {
self.vec.borrow_mut().push(self.e.unwrap());
self.e = None;
}
}
fn main() {
// We need to use Rc<RefCell> since all commands are going to mutate the vec.
let vec = Rc::new(RefCell::new(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));
let mut undo_stack = UndoStack::new()
.on_clean(|| println!("This is called when the stack changes from dirty to clean!"))
.on_dirty(|| println!("This is called when the stack changes from clean to dirty!"));
let cmd = PopCmd { vec: vec.clone(), e: None };
undo_stack.push(cmd.clone());
undo_stack.push(cmd.clone());
undo_stack.push(cmd.clone());
assert_eq!(vec.borrow().len(), 7);
undo_stack.undo(); // on_dirty is going to be called here.
undo_stack.undo();
undo_stack.undo();
assert_eq!(vec.borrow().len(), 10);
}