dioxus_core/
arena.rs

1use crate::innerlude::ScopeOrder;
2use crate::{virtual_dom::VirtualDom, ScopeId};
3
4/// An Element's unique identifier.
5///
6/// `ElementId` is a `usize` that is unique across the entire VirtualDOM - but not unique across time. If a component is
7/// unmounted, then the `ElementId` will be reused for a new component.
8#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
9#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
10pub struct ElementId(pub usize);
11
12/// An Element that can be bubbled to's unique identifier.
13///
14/// `BubbleId` is a `usize` that is unique across the entire VirtualDOM - but not unique across time. If a component is
15/// unmounted, then the `BubbleId` will be reused for a new component.
16#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
17#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
18pub(crate) struct MountId(pub(crate) usize);
19
20impl Default for MountId {
21    fn default() -> Self {
22        Self::PLACEHOLDER
23    }
24}
25
26impl MountId {
27    pub(crate) const PLACEHOLDER: Self = Self(usize::MAX);
28
29    pub(crate) fn as_usize(self) -> Option<usize> {
30        if self.mounted() {
31            Some(self.0)
32        } else {
33            None
34        }
35    }
36
37    #[allow(unused)]
38    pub(crate) fn mounted(self) -> bool {
39        self != Self::PLACEHOLDER
40    }
41}
42
43#[derive(Debug, Clone, Copy)]
44pub struct ElementRef {
45    // the pathway of the real element inside the template
46    pub(crate) path: ElementPath,
47
48    // The actual element
49    pub(crate) mount: MountId,
50}
51
52#[derive(Clone, Copy, Debug)]
53pub struct ElementPath {
54    pub(crate) path: &'static [u8],
55}
56
57impl VirtualDom {
58    pub(crate) fn next_element(&mut self) -> ElementId {
59        let mut elements = self.runtime.elements.borrow_mut();
60        ElementId(elements.insert(None))
61    }
62
63    pub(crate) fn reclaim(&mut self, el: ElementId) {
64        if !self.try_reclaim(el) {
65            tracing::error!("cannot reclaim {:?}", el);
66        }
67    }
68
69    pub(crate) fn try_reclaim(&mut self, el: ElementId) -> bool {
70        // We never reclaim the unmounted elements or the root element
71        if el.0 == 0 || el.0 == usize::MAX {
72            return true;
73        }
74
75        let mut elements = self.runtime.elements.borrow_mut();
76        elements.try_remove(el.0).is_some()
77    }
78
79    // Drop a scope without dropping its children
80    //
81    // Note: This will not remove any ids from the arena
82    pub(crate) fn drop_scope(&mut self, id: ScopeId) {
83        let height = {
84            let scope = self.scopes.remove(id.0);
85            let context = scope.state();
86            context.height
87        };
88
89        self.dirty_scopes.remove(&ScopeOrder::new(height, id));
90
91        // If this scope was a suspense boundary, remove it from the resolved scopes
92        self.resolved_scopes.retain(|s| s != &id);
93    }
94}
95
96impl ElementPath {
97    pub(crate) fn is_descendant(&self, small: &[u8]) -> bool {
98        small.len() <= self.path.len() && small == &self.path[..small.len()]
99    }
100}
101
102#[test]
103fn is_descendant() {
104    let event_path = ElementPath {
105        path: &[1, 2, 3, 4, 5],
106    };
107
108    assert!(event_path.is_descendant(&[1, 2, 3, 4, 5]));
109    assert!(event_path.is_descendant(&[1, 2, 3, 4]));
110    assert!(event_path.is_descendant(&[1, 2, 3]));
111    assert!(event_path.is_descendant(&[1, 2]));
112    assert!(event_path.is_descendant(&[1]));
113
114    assert!(!event_path.is_descendant(&[1, 2, 3, 4, 5, 6]));
115    assert!(!event_path.is_descendant(&[2, 3, 4]));
116}
117
118impl PartialEq<&[u8]> for ElementPath {
119    fn eq(&self, other: &&[u8]) -> bool {
120        self.path.eq(*other)
121    }
122}
dioxus_core/arena.rs

dioxus_core/
arena.rs
