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

use std::cell::{Cell, Ref, RefCell};

use crate::{innerlude::Scheduler, scope_context::ScopeContext, scopes::ScopeId};
use std::rc::Rc;

thread_local! {
    static RUNTIMES: RefCell<Vec<Rc<Runtime>>> = RefCell::new(vec![]);
}

/// Pushes a new scope onto the stack
pub(crate) fn push_runtime(runtime: Rc<Runtime>) {
    RUNTIMES.with(|stack| stack.borrow_mut().push(runtime));
}

/// Pops a scope off the stack
pub(crate) fn pop_runtime() {
    RUNTIMES.with(|stack| stack.borrow_mut().pop());
}

/// Runs a function with the current runtime
pub(crate) fn with_runtime<F, R>(f: F) -> Option<R>
where
    F: FnOnce(&Runtime) -> R,
{
    RUNTIMES.with(|stack| {
        let stack = stack.borrow();
        stack.last().map(|r| f(r))
    })
}

/// Runs a function with the current scope
pub(crate) fn with_current_scope<F, R>(f: F) -> Option<R>
where
    F: FnOnce(&ScopeContext) -> R,
{
    with_runtime(|runtime| {
        runtime
            .current_scope_id()
            .and_then(|scope| runtime.get_context(scope).map(|sc| f(&sc)))
    })
    .flatten()
}

/// A global runtime that is shared across all scopes that provides the async runtime and context API
pub struct Runtime {
    pub(crate) scope_contexts: RefCell<Vec<Option<ScopeContext>>>,
    pub(crate) scheduler: Rc<Scheduler>,

    // We use this to track the current scope
    pub(crate) scope_stack: RefCell<Vec<ScopeId>>,
    pub(crate) rendering: Cell<bool>,
}

impl Runtime {
    pub(crate) fn new(scheduler: Rc<Scheduler>) -> Rc<Self> {
        Rc::new(Self {
            scheduler,

            scope_contexts: Default::default(),

            scope_stack: Default::default(),

            rendering: Cell::new(true),
        })
    }

    /// Get the current runtime
    pub fn current() -> Option<Rc<Self>> {
        RUNTIMES.with(|stack| stack.borrow().last().cloned())
    }

    /// Create a scope context. This slab is synchronized with the scope slab.
    pub(crate) fn create_context_at(&self, id: ScopeId, context: ScopeContext) {
        let mut contexts = self.scope_contexts.borrow_mut();
        if contexts.len() <= id.0 {
            contexts.resize_with(id.0 + 1, Default::default);
        }
        contexts[id.0] = Some(context);
    }

    pub(crate) fn remove_context(&self, id: ScopeId) {
        self.scope_contexts.borrow_mut()[id.0] = None;
    }

    /// Get the current scope id
    pub(crate) fn current_scope_id(&self) -> Option<ScopeId> {
        self.scope_stack.borrow().last().copied()
    }

    /// Get the context for any scope given its ID
    ///
    /// This is useful for inserting or removing contexts from a scope, or rendering out its root node
    pub(crate) fn get_context(&self, id: ScopeId) -> Option<Ref<'_, ScopeContext>> {
        Ref::filter_map(self.scope_contexts.borrow(), |contexts| {
            contexts.get(id.0).and_then(|f| f.as_ref())
        })
        .ok()
    }
}

/// A gaurd for a new runtime. This must be used to override the current runtime when importing components from a dynamic library that has it's own runtime.
///
/// ```rust
/// use dioxus::prelude::*;
///
/// fn main() {
///     let virtual_dom = VirtualDom::new(app);
/// }
///
/// fn app(cx: Scope) -> Element {
///     render!{ Component { runtime: Runtime::current().unwrap() } }
/// }
///
/// // In a dynamic library
/// #[derive(Props)]
/// struct ComponentProps {
///    runtime: std::rc::Rc<Runtime>,
/// }
///
/// impl PartialEq for ComponentProps {
///     fn eq(&self, _other: &Self) -> bool {
///         true
///     }
/// }
///
/// fn Component(cx: Scope<ComponentProps>) -> Element {
///     cx.use_hook(|| RuntimeGuard::new(cx.props.runtime.clone()));
///
///     render! { div {} }
/// }
/// ```
pub struct RuntimeGuard(Rc<Runtime>);

impl RuntimeGuard {
    /// Create a new runtime guard that sets the current Dioxus runtime. The runtime will be reset when the guard is dropped
    pub fn new(runtime: Rc<Runtime>) -> Self {
        push_runtime(runtime.clone());
        Self(runtime)
    }
}

impl Drop for RuntimeGuard {
    fn drop(&mut self) {
        pop_runtime();
    }
}