script_bindings/
script_runtime.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::cell::Cell;
6use std::marker::PhantomData;
7use std::ops::Deref;
8
9use js::jsapi::JSContext as RawJSContext;
10
11#[derive(Clone, Copy)]
12#[repr(transparent)]
13pub struct JSContext(*mut RawJSContext);
14
15#[expect(unsafe_code)]
16impl JSContext {
17    /// Create a new [`JSContext`] object from the given raw pointer.
18    ///
19    /// # Safety
20    ///
21    /// The `RawJSContext` argument must point to a valid `RawJSContext` in memory.
22    pub unsafe fn from_ptr(raw_js_context: *mut RawJSContext) -> Self {
23        JSContext(raw_js_context)
24    }
25
26    /// For compatibility with [js::context::JSContext]
27    pub fn raw_cx(&self) -> *mut RawJSContext {
28        self.0
29    }
30
31    /// For compatibility with [js::context::JSContext]
32    pub fn raw_cx_no_gc(&self) -> *mut RawJSContext {
33        self.0
34    }
35}
36
37impl Deref for JSContext {
38    type Target = *mut RawJSContext;
39
40    fn deref(&self) -> &Self::Target {
41        &self.0
42    }
43}
44
45thread_local!(
46    static THREAD_ACTIVE: Cell<bool> = const { Cell::new(true) };
47);
48
49pub fn runtime_is_alive() -> bool {
50    THREAD_ACTIVE.with(|t| t.get())
51}
52
53pub fn mark_runtime_dead() {
54    THREAD_ACTIVE.with(|t| t.set(false));
55}
56
57#[derive(Clone, Copy, Debug)]
58/// A compile-time marker that there are operations that could trigger a JS garbage collection
59/// operation within the current stack frame. It is trivially copyable, so it should be passed
60/// as a function argument and reused when calling other functions whenever possible. Since it
61/// is only meaningful within the current stack frame, it is impossible to move it to a different
62/// thread or into a task that will execute asynchronously.
63pub struct CanGc(PhantomData<*mut ()>);
64
65impl CanGc {
66    /// Create a new CanGc value, representing that a GC operation is possible within the
67    /// current stack frame.
68    pub fn note() -> CanGc {
69        CanGc(PhantomData)
70    }
71}
script_bindings/script_runtime.rs

script_bindings/
script_runtime.rs
