feat(extras/store): add Redux-like store impl.

Author: MrDwarf7

.extras/snippets/redux_store.rs

@@ -0,0 +1,42 @@
+use std::sync::{RwLock, RwLockReadGuard};
+
+#[allow(dead_code)]
+pub struct Store<T, U> {
+    name:      String,
+    state:     RwLock<T>,
+    listeners: RwLock<Vec<fn(&T, &U)>>,
+    reducer:   fn(&mut T, &U),
+}
+
+#[allow(dead_code)]
+impl<T, U> Store<T, U> {
+    pub fn create_store<S: Into<String>>(name: S, reducer: fn(&mut T, &U), initial_state: T) -> Store<T, U> {
+        Store {
+            name: name.into(),
+            state: RwLock::new(initial_state),
+            listeners: RwLock::new(Vec::new()),
+            reducer,
+        }
+    }
+
+    pub fn subscribe(&self, listener: fn(&T, &U)) {
+        let mut listeners = self.listeners.write().expect("Could not write subscriber");
+        listeners.push(listener);
+    }
+
+    pub fn get_state(&self) -> RwLockReadGuard<T> {
+        if let Err(_) = self.state.try_read() {
+            warn!("Get State Called for `{}`, but would block", self.name);
+        }
+
+        self.state.read().expect("Could not get state")
+    }
+
+    pub fn dispatch(&self, action: U) {
+        (self.reducer)(&mut self.state.write().expect("Could not write state"), &action);
+
+        for listener in &*self.listeners.read().expect("Could not notify listeners") {
+            listener(&self.get_state(), &action)
+        }
+    }
+}