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euv_core/reactive/signal/
struct.rs

1use crate::*;
2
3/// Inner state of a signal, holding the value and subscribed listeners.
4///
5/// This struct is not exposed directly; use `Signal` instead.
6#[derive(CustomDebug, Data, New)]
7pub(crate) struct SignalInner<T>
8where
9    T: Clone,
10{
11    /// The current value of the signal.
12    #[debug(skip)]
13    #[get(pub(crate))]
14    #[get_mut(pub(crate))]
15    #[set(pub(crate))]
16    pub(crate) value: T,
17    /// Callbacks to invoke when the value changes.
18    #[debug(skip)]
19    #[get(pub(crate))]
20    #[get_mut(pub(crate))]
21    #[set(pub(crate))]
22    pub(crate) listeners: Vec<Box<dyn FnMut()>>,
23    /// Whether this signal is still active. Set to `false` by `deactivate()`
24    /// (and `clear_signal_listeners_by_addr`) to make subsequent `set()` calls
25    /// complete no-ops (no value update, no listener invocation, no
26    /// `schedule_signal_update()`), ensuring stale closures like orphaned
27    /// `setInterval` handlers or pending `spawn_local` futures become harmless.
28    #[get(pub(crate), type(copy))]
29    #[get_mut(pub(crate))]
30    #[set(pub(crate))]
31    pub(crate) alive: bool,
32    /// IDs of dynamic nodes that depend on this signal for precise dirty marking.
33    /// When this signal changes, only these dynamic nodes are marked dirty
34    /// instead of broadcasting to all registered dynamic nodes.
35    #[debug(skip)]
36    #[get(pub(crate))]
37    #[get_mut(pub(crate))]
38    #[set(pub(crate))]
39    #[new(skip)]
40    pub(crate) dependents: Vec<usize>,
41}
42
43/// A reactive signal handle.
44///
45/// Allows reading, writing, and subscribing to changes.
46/// Implements `Clone` and `Copy` for ergonomic use; all copies share the same
47/// underlying state. The inner state is heap-allocated via `Box` and accessed
48/// through a raw pointer stored as a `usize`. The allocation is tracked in a
49/// global registry for lifecycle management. The `Copy` semantics are safe
50/// because only the pointer address is copied — the actual heap allocation
51/// is owned by the registry.
52#[derive(CustomDebug, Data, Eq, New, PartialEq)]
53pub struct Signal<T>
54where
55    T: Clone + PartialEq + 'static,
56{
57    /// Address of the heap-allocated inner state (`*mut SignalInner<T>`).
58    #[debug(skip)]
59    #[get(pub(crate), type(copy))]
60    #[get_mut(pub(crate))]
61    #[set(pub(crate))]
62    pub(crate) inner: usize,
63    /// Marker for the generic type parameter (uses fn pointer to be `Copy`
64    /// regardless of `T`).
65    #[debug(skip)]
66    #[get(pub(crate), type(copy))]
67    #[get_mut(pub(crate))]
68    #[set(pub(crate))]
69    pub(crate) _marker: PhantomData<fn() -> T>,
70}
71
72/// A `Sync` wrapper for single-threaded global `Signal` access.
73///
74/// SAFETY: This type is only safe to use in single-threaded contexts
75/// (e.g., WASM). It implements `Sync` to allow usage as a `static`
76/// variable, but concurrent access from multiple threads would be
77/// undefined behavior.
78#[derive(CustomDebug, Data, New)]
79pub struct SignalCell<T>
80where
81    T: Clone + PartialEq + 'static,
82{
83    /// Interior-mutable storage for an optional signal handle.
84    #[debug(skip)]
85    #[get(pub(crate))]
86    #[get_mut(pub(crate))]
87    #[set(pub(crate))]
88    pub(crate) inner: UnsafeCell<Option<Signal<T>>>,
89}
90
91/// A `Sync` wrapper for single-threaded global `HashSet` access.
92///
93/// SAFETY: This type is only safe to use in single-threaded contexts
94/// (e.g., WASM). It implements `Sync` to allow usage as a `static mut`
95/// variable, but concurrent access from multiple threads would be
96/// undefined behavior.
97#[derive(Data, Debug, New)]
98pub(crate) struct SignalInnerRegistryCell(
99    /// Interior-mutable storage for the signal inner registry.
100    #[get(pub(crate))]
101    #[get_mut(pub(crate))]
102    #[set(pub(crate))]
103    pub(crate) UnsafeCell<Option<HashSet<usize>>>,
104);