script_bindings/
settings_stack.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::thread;
6
7use js::context::JSContext;
8use js::jsapi::{HideScriptedCaller, UnhideScriptedCaller};
9use js::rust::Runtime;
10
11use crate::DomTypes;
12use crate::interfaces::{DomHelpers, GlobalScopeHelpers};
13use crate::root::Dom;
14
15#[derive(Debug, Eq, JSTraceable, PartialEq)]
16pub enum StackEntryKind {
17    Incumbent,
18    Entry,
19}
20
21#[cfg_attr(crown, expect(crown::unrooted_must_root))]
22#[derive(JSTraceable)]
23pub struct StackEntry<D: DomTypes> {
24    pub global: Dom<D::GlobalScope>,
25    pub kind: StackEntryKind,
26}
27
28/// Wrapper that pushes and pops entries from the script settings stack.
29///
30/// <https://html.spec.whatwg.org/multipage/#prepare-to-run-script>
31/// <https://html.spec.whatwg.org/multipage/#clean-up-after-running-script>
32pub fn run_a_script<D, R, C>(cx: &mut C, global: &D::GlobalScope, f: impl FnOnce(&mut C) -> R) -> R
33where
34    C: AsMut<JSContext>,
35    D: DomTypes,
36{
37    let settings_stack = <D as DomHelpers<D>>::settings_stack();
38    let _span = settings_stack.with(|stack| {
39        trace!("Prepare to run script with {:p}", global);
40        let mut stack = stack.borrow_mut();
41        stack.push(StackEntry {
42            global: Dom::from_ref(global),
43            kind: StackEntryKind::Entry,
44        });
45        profile_traits::info_span!("ScriptEvaluate", url = global.get_url().to_string()).entered()
46    });
47    let result = f(cx);
48    let stack_is_empty = settings_stack.with(|stack| {
49        let mut stack = stack.borrow_mut();
50        let entry = stack.pop().unwrap();
51        assert_eq!(
52            &*entry.global as *const D::GlobalScope, global as *const D::GlobalScope,
53            "Dropped AutoEntryScript out of order."
54        );
55        assert_eq!(entry.kind, StackEntryKind::Entry);
56        trace!("Clean up after running script with {:p}", &*entry.global);
57        stack.is_empty()
58    });
59
60    // Step 5
61    if !thread::panicking() && stack_is_empty {
62        global.perform_a_microtask_checkpoint(cx.as_mut());
63    }
64    result
65}
66
67/// Wrapper that pushes and pops entries from the script settings stack.
68///
69/// <https://html.spec.whatwg.org/multipage/#prepare-to-run-a-callback>
70/// <https://html.spec.whatwg.org/multipage/#clean-up-after-running-a-callback>
71pub fn run_a_callback<D: DomTypes, R>(global: &D::GlobalScope, f: impl FnOnce() -> R) -> R {
72    let settings_stack = <D as DomHelpers<D>>::settings_stack();
73    let cx = Runtime::get().expect("Creating a new incumbent script after runtime shutdown");
74    // <https://html.spec.whatwg.org/multipage/#prepare-to-run-a-callback>
75    // Step 2-3.
76    unsafe {
77        HideScriptedCaller(cx.as_ptr());
78    }
79    settings_stack.with(|stack| {
80        trace!("Prepare to run a callback with {:p}", global);
81        // Step 1.
82        let mut stack = stack.borrow_mut();
83        stack.push(StackEntry {
84            global: Dom::from_ref(global),
85            kind: StackEntryKind::Incumbent,
86        });
87    });
88    let result = f();
89    // <https://html.spec.whatwg.org/multipage/#clean-up-after-running-a-callback>
90    settings_stack.with(|stack| {
91        // Step 4.
92        let mut stack = stack.borrow_mut();
93        let entry = stack.pop().unwrap();
94        // Step 3.
95        assert_eq!(
96            &*entry.global as *const D::GlobalScope as usize,
97            global as *const D::GlobalScope as usize,
98            "Dropped AutoIncumbentScript out of order."
99        );
100        assert_eq!(entry.kind, StackEntryKind::Incumbent);
101        trace!(
102            "Clean up after running a callback with {:p}",
103            &*entry.global
104        );
105    });
106    unsafe {
107        // Step 1-2.
108        UnhideScriptedCaller(cx.as_ptr());
109    }
110    result
111}
script_bindings/settings_stack.rs

script_bindings/
settings_stack.rs
