better state management

src/events.rs

@@ -4,7 +4,7 @@ use std::{
     sync::{Arc, Mutex},
 };
 
-use crate::event;
+use crate::{event, state::StateManager};
 
 event!(Close);
 
@@ -21,15 +21,16 @@ impl std::fmt::Debug for EventHandlerFn {
     }
 }
 
-#[derive(Debug)]
 pub struct EventManager {
     handlers: HashMap<TypeId, Vec<EventHandlerFn>>,
+    states: Option<Arc<StateManager>>,
 }
 
 impl EventManager {
     pub fn new() -> EventManager {
         EventManager {
             handlers: HashMap::new(),
+            states: None,
         }
     }
 
@@ -37,10 +38,14 @@ impl EventManager {
         &mut self,
         mut f: F,
     ) {
+        let states = self.states.clone();
         let wrapper = Arc::new(Mutex::new(
             move |e: &mut EventManager, evt: Box<dyn Event>| {
                 if let Ok(concrete) = evt.as_any().downcast::<E>() {
                     f(e, concrete);
+                    if let Some(states) = &states {
+                        states.clone().flush();
+                    }
                 }
             },
         )) as Arc<Mutex<dyn FnMut(&mut EventManager, Box<dyn Event>)>>;
@@ -68,4 +73,8 @@ impl EventManager {
             std::process::exit(0);
         }
     }
+
+    pub fn set_state_manager(&mut self, states: Arc<StateManager>) {
+        self.states = Some(states);
+    }
 }

src/main.rs

@@ -1,10 +1,8 @@
 use std::sync::Arc;
 
+use crossterm::event::KeyEvent;
 use osui::{
-    element::{
-        input::{Input, InputKeyPress},
-        rect::Rect,
-    },
+    element::rect::Rect,
     events::{Close, EventManager},
     extensions::{keypress::KeyPressExtension, tick_rate::TickRate, ExtensionManager},
     state::StateManager,
@@ -18,42 +16,33 @@ fn main() {
 }
 
 fn app(states: Arc<StateManager>) {
-    states.begin();
     let mut screen = Screen::new();
     let mut extensions = ExtensionManager::new();
     let mut events = EventManager::new();
-    extensions.add(KeyPressExtension);
-    extensions.add(TickRate(255));
 
-    let my_state = states.use_state(String::new());
+    extensions.add(TickRate(50));
+    extensions.add(KeyPressExtension);
+
+    events.set_state_manager(states.clone());
+
+    let count = states.use_state(0);
 
     screen
         .draw(Rect(0xffffff))
         .component(Transform::center().dimensions(30, 3));
 
     screen
-        .draw(format!(
-            "Type exit to exit\nMy-State: {}",
-            my_state.get().trim()
-        ))
-        .component(Transform::new().bottom().margin(0, -1));
+        .draw(format!("Count: {}", count.get()))
+        .component(Transform::center());
 
-    screen
-        .draw(Input::new())
-        .component(Transform::new().bottom());
-
-    events.on(
-        move |events, event: Box<InputKeyPress>| match event.1.code {
-            crossterm::event::KeyCode::Enter => {
-                my_state.set(my_state.get() + &format!("{}\n", event.0));
-                if event.0 == "exit" {
-                    events.dispatch(Close);
-                }
-                my_state.update();
-            }
-            _ => {}
-        },
-    );
+    events.on(move |events, event: Box<KeyEvent>| match event.code {
+        crossterm::event::KeyCode::Enter => {
+            count.set(count.get() + 1);
+        }
+        _ => {
+            events.dispatch(Close);
+        }
+    });
 
     screen.run(&mut events, &mut extensions).unwrap();
 }

src/state.rs

@@ -11,6 +11,7 @@ pub struct StateManager {
     recall: fn(Arc<StateManager>),
     store: Mutex<HashMap<usize, Box<dyn Any + Send + Sync>>>,
     cursor: Mutex<usize>,
+    dirty: Mutex<bool>,
 }
 
 pub struct State<S> {
@@ -25,14 +26,10 @@ impl StateManager {
             recall,
             store: Mutex::new(HashMap::new()),
             cursor: Mutex::new(0),
+            dirty: Mutex::new(false),
         })
     }
 
-    /// Call this at the very top of every “render” before doing any `use_state` calls
-    pub fn begin(&self) {
-        *self.cursor.lock().unwrap() = 0;
-    }
-
     pub fn use_state<S: 'static + Send + Sync>(self: &Arc<Self>, initial: S) -> State<S> {
         // `slot` == position of this call in the render
         let mut cur = self.cursor.lock().unwrap();
@@ -51,9 +48,24 @@ impl StateManager {
             _pd: PhantomData,
         }
     }
+
+    pub fn flush(self: Arc<Self>) {
+        let mut d = self.dirty.lock().unwrap();
+        if *d {
+            *d = false;
+            drop(d);
+
+            *self.cursor.lock().unwrap() = 0;
+            (self.recall)(self)
+        }
+    }
 }
 
 impl<S: 'static + Clone + Send + Sync> State<S> {
+    pub fn dirty(&self) {
+        *self.manager.dirty.lock().unwrap() = true;
+    }
+
     pub fn get(&self) -> S {
         let store = self.manager.store.lock().unwrap();
         let x = store[&self.id]
@@ -74,9 +86,6 @@ impl<S: 'static + Clone + Send + Sync> State<S> {
                 .lock()
                 .unwrap() = val;
         }
-    }
-
-    pub fn update(&self) {
-        (self.manager.recall)(Arc::clone(&self.manager));
+        self.dirty();
     }
 }