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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192

//! type extractor or application state.

use core::{fmt, ops::Deref};

use crate::{context::WebContext, error::Error, handler::FromRequest};

/// borrow trait for extracting typed field from application state
#[diagnostic::on_unimplemented(
    message = "`{T}` can not be borrowed from {Self}",
    label = "{Self} must impl BorrowState trait for borrowing {T} from app state",
    note = "consider add `impl BorrowState<{T}> for {Self}`"
)]
pub trait BorrowState<T>
where
    T: ?Sized,
{
    fn borrow(&self) -> &T;
}

impl<T> BorrowState<T> for T
where
    T: ?Sized,
{
    #[inline]
    fn borrow(&self) -> &T {
        self
    }
}

/// App state extractor.
/// S type must be the same with the type passed to App::with_xxx_state(S).
pub struct StateRef<'a, S>(pub &'a S)
where
    S: ?Sized;

impl<S> fmt::Debug for StateRef<'_, S>
where
    S: fmt::Debug,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "StateRef({:?})", self.0)
    }
}

impl<S> fmt::Display for StateRef<'_, S>
where
    S: fmt::Display,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "StateRef({})", self.0)
    }
}

impl<S> Deref for StateRef<'_, S> {
    type Target = S;

    #[inline]
    fn deref(&self) -> &Self::Target {
        self.0
    }
}

impl<'a, 'r, C, B, T> FromRequest<'a, WebContext<'r, C, B>> for StateRef<'a, T>
where
    C: BorrowState<T>,
    T: ?Sized + 'static,
{
    type Type<'b> = StateRef<'b, T>;
    type Error = Error<C>;

    #[inline]
    async fn from_request(ctx: &'a WebContext<'r, C, B>) -> Result<Self, Self::Error> {
        Ok(StateRef(ctx.state().borrow()))
    }
}

/// App state extractor for owned value.
/// S type must be the same with the type passed to App::with_xxx_state(S).
pub struct StateOwn<S>(pub S);

impl<S> fmt::Debug for StateOwn<S>
where
    S: fmt::Debug,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "StateOwn({:?})", self.0)
    }
}

impl<S> fmt::Display for StateOwn<S>
where
    S: fmt::Display,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "StateOwn({})", self.0)
    }
}

impl<S> Deref for StateOwn<S> {
    type Target = S;

    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl<'a, 'r, C, B, T> FromRequest<'a, WebContext<'r, C, B>> for StateOwn<T>
where
    C: BorrowState<T>,
    T: Clone,
{
    type Type<'b> = StateOwn<T>;
    type Error = Error<C>;

    #[inline]
    async fn from_request(ctx: &'a WebContext<'r, C, B>) -> Result<Self, Self::Error> {
        Ok(StateOwn(ctx.state().borrow().clone()))
    }
}

#[cfg(test)]
mod test {
    use std::sync::Arc;

    use xitca_unsafe_collection::futures::NowOrPanic;

    use crate::{handler::handler_service, http::WebRequest, route::get, service::Service, App};

    use super::*;

    #[derive(Clone, Debug)]
    struct State {
        field1: String,
        field2: u32,
        field3: Arc<dyn std::any::Any + Send + Sync>,
    }

    impl BorrowState<String> for State {
        fn borrow(&self) -> &String {
            &self.field1
        }
    }

    impl BorrowState<u32> for State {
        fn borrow(&self) -> &u32 {
            &self.field2
        }
    }

    impl BorrowState<dyn std::any::Any + Send + Sync> for State {
        fn borrow(&self) -> &(dyn std::any::Any + Send + Sync) {
            &*self.field3
        }
    }

    async fn handler(
        StateRef(state): StateRef<'_, String>,
        StateRef(state2): StateRef<'_, u32>,
        StateRef(state3): StateRef<'_, State>,
        StateRef(state4): StateRef<'_, dyn std::any::Any + Send + Sync>,
        ctx: &WebContext<'_, State>,
    ) -> String {
        assert_eq!("state", state);
        assert_eq!(&996, state2);
        assert_eq!(state, ctx.state().field1.as_str());
        assert_eq!(state3.field1, ctx.state().field1);
        assert!(state4.downcast_ref::<String>().is_some());
        state.to_string()
    }

    #[test]
    fn state_extract() {
        let state = State {
            field1: String::from("state"),
            field2: 996,
            field3: Arc::new(String::new()),
        };

        App::new()
            .with_state(state)
            .at("/", get(handler_service(handler)))
            .finish()
            .call(())
            .now_or_panic()
            .ok()
            .unwrap()
            .call(WebRequest::default())
            .now_or_panic()
            .unwrap();
    }
}