deft 0.15.0

Cross platform ui framework
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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161

use crate::mrc::{Mrc, MrcWeak, UpgradeError};
use std::any::Any;
use std::collections::HashMap;
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};

pub struct StateId<T> {
    id: u32,
    _phantom: PhantomData<T>,
}

pub struct StateManager {
    next_id: u32,
    states: HashMap<u32, Box<dyn Any>>,
}

pub enum StateData<T> {
    Hosting(MrcWeak<T>),
    SelfManaged(Mrc<T>),
}

pub struct State<T> {
    id: u32,
    store: StateData<T>,
}

impl<T> PartialEq for State<T> {
    fn eq(&self, other: &Self) -> bool {
        self.id == other.id
    }
}

impl<T> Clone for State<T> {
    fn clone(&self) -> Self {
        let weak = match &self.store {
            StateData::Hosting(d) => d.clone(),
            StateData::SelfManaged(d) => d.as_weak(),
        };
        Self {
            id: self.id,
            store: StateData::Hosting(weak),
        }
    }
}

impl<T> State<T> {
    pub fn invalid() -> State<T> {
        State {
            id: 0,
            store: StateData::Hosting(MrcWeak::new()),
        }
    }
    pub fn upgrade_mut(&self) -> Result<StateMutRef<'_, T>, UpgradeError> {
        match &self.store {
            StateData::Hosting(d) => {
                let data = d.upgrade()?;
                Ok(StateMutRef {
                    state_data: &self.store,
                    data,
                })
            }
            StateData::SelfManaged(d) => Ok(StateMutRef {
                state_data: &self.store,
                data: d.clone(),
            }),
        }
    }
}

pub struct StateMutRef<'a, T> {
    state_data: &'a StateData<T>,
    data: Mrc<T>,
}

impl<'a, T> Deref for StateMutRef<'a, T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        &self.data
    }
}

impl<'a, T> DerefMut for StateMutRef<'a, T> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.data
    }
}

impl StateManager {
    pub fn new() -> StateManager {
        Self {
            next_id: 1,
            states: Default::default(),
        }
    }

    pub fn new_state<T: 'static>(&mut self, state: T) -> State<T> {
        let id = self.next_id;
        self.next_id += 1;

        let data = Mrc::new(state);
        let weak = data.as_weak();
        self.states.insert(id, Box::new(data));
        State {
            id,
            store: StateData::Hosting(weak),
        }
    }

    pub fn new_self_managed_state<T: 'static>(&mut self, state: T) -> State<T> {
        let id = self.next_id;
        self.next_id += 1;

        let data = Mrc::new(state);
        State {
            id,
            store: StateData::SelfManaged(data),
        }
    }

    pub fn remove_state<T>(&mut self, state: &State<T>) {
        self.states.remove(&state.id);
    }

    pub fn get_state<T: 'static>(&self, id: u32) -> Option<State<T>> {
        if let Some(data) = self.states.get(&id) {
            let raw_data = data.deref();
            if let Some(r) = raw_data.downcast_ref::<Mrc<T>>() {
                return Some(State {
                    id,
                    store: StateData::Hosting(r.as_weak()),
                });
            }
        }
        None
    }
}

#[cfg(test)]
pub mod tests {
    use crate::state::StateManager;

    struct MyState {
        num: u32,
    }
    #[test]
    fn test_upgrade_mut() {
        let mut sm = StateManager::new();
        let my_state = MyState { num: 162534 };
        let state = sm.new_state(my_state);

        {
            let state_mut_ref = state.upgrade_mut().unwrap();
            assert_eq!(162534, state_mut_ref.num);
        }

        sm.remove_state(&state);
        let upgrade_result = state.upgrade_mut();
        assert!(upgrade_result.is_err());
    }
}