1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

//! Ergonomic interface with shared state.
use std::rc::Rc;

use yew::{Callback, Properties};

use super::handler::{GlobalHandler, Handler, Reduction, StorageHandler};

type Model<T> = <T as Handler>::Model;

/// Allows any `Properties` to have shared state.
pub trait SharedState {
    type Handle: Handle;
    fn handle(&mut self) -> &mut Self::Handle;
}

/// Primary shared state interface
pub trait Handle {
    type Handler: Handler;

    /// Current state.
    fn state(&self) -> &Model<Self::Handler>;
    /// Callback to use for updating state.
    fn callback(&self) -> &Callback<Reduction<Model<Self::Handler>>>;
    #[doc(hidden)]
    fn __set_local(
        &mut self,
        state: &Rc<Model<Self::Handler>>,
        callback: &Callback<Reduction<Model<Self::Handler>>>,
    );

    /// Apply a function that may mutate shared state.
    /// Changes are not immediate, and must be handled in `Component::change`.
    fn reduce(&self, f: impl FnOnce(&mut Model<Self::Handler>) + 'static) {
        self.callback().emit(Box::new(f))
    }

    /// Convenience method for modifying shared state directly from a callback.
    /// The callback event is ignored here, see `reduce_callback_with` for the alternative.
    fn reduce_callback<T: 'static>(
        &self,
        f: impl FnOnce(&mut Model<Self::Handler>) + Copy + 'static,
    ) -> Callback<T>
    where
        Model<Self::Handler>: 'static,
    {
        self.callback()
            .reform(move |_| Box::new(move |state| f(state)))
    }

    /// Convenience method for modifying shared state directly from a callback.
    /// Similar to `reduce_callback` but it also accepts the fired event.
    fn reduce_callback_with<T: 'static>(
        &self,
        f: impl FnOnce(T, &mut Model<Self::Handler>) + Copy + 'static,
    ) -> Callback<T>
    where
        Model<Self::Handler>: 'static,
    {
        self.callback()
            .reform(move |e| Box::new(move |state| f(e, state)))
    }
}

/// A handle for io with state handlers
#[derive(Default, Properties)]
pub struct StateHandle<T, H>
where
    T: Default + Clone + 'static,
    H: Handler,
{
    #[prop_or_default]
    state: Rc<T>,
    #[prop_or_default]
    callback: Callback<Reduction<T>>,
    #[prop_or_default]
    _mark: std::marker::PhantomData<H>,
}

impl<T, H> Clone for StateHandle<T, H>
where
    T: Default + Clone + 'static,
    H: Handler,
{
    fn clone(&self) -> Self {
        Self {
            state: self.state.clone(),
            callback: self.callback.clone(),
            _mark: Default::default(),
        }
    }
}

impl<T, H> PartialEq for StateHandle<T, H>
where
    T: Default + PartialEq + Clone + 'static,
    H: Handler,
{
    fn eq(&self, other: &Self) -> bool {
        self.state == other.state && self.callback == other.callback
    }
}

impl<T, H> Handle for StateHandle<T, H>
where
    T: Default + Clone,
    H: Handler<Model = T>,
{
    type Handler = H;

    fn callback(&self) -> &Callback<Reduction<T>> {
        &self.callback
    }

    fn state(&self) -> &T {
        &self.state
    }

    fn __set_local(&mut self, state: &Rc<T>, callback: &Callback<Reduction<T>>) {
        self.state = state.clone();
        self.callback = callback.clone();
    }
}

impl<T, H> SharedState for StateHandle<T, H>
where
    T: Default + Clone + 'static,
    H: Handler<Model = T>,
{
    type Handle = Self;

    fn handle(&mut self) -> &mut Self::Handle {
        self
    }
}

/// Handle for basic shared state.
pub type GlobalHandle<T> = StateHandle<T, GlobalHandler<T>>;
/// Handle for shared state with persistent storage.
pub type StorageHandle<T> = StateHandle<T, StorageHandler<T>>;