Enum Realm 

enum Realm<'a> {
    AutoRealm(AutoRealm<'a>),
    CurrentRealm(&'a mut CurrentRealm<'a>),
}

Helper type to keep AutoRealm and &mut CurrentRealm alive with Deref to JSContext

Variants

AutoRealm(AutoRealm<'a>)

CurrentRealm(&'a mut CurrentRealm<'a>)

Methods from Deref<Target = JSContext>

pub fn no_gc<'cx>(&'cx self) -> &'cx NoGC

Returns NoGC token bounded to this JSContext. No function that accepts &mut JSContext (read: triggers GC) can be called while this is alive.

pub unsafe fn raw_cx(&mut self) -> *mut JSContext

Obtain RawJSContext mutable pointer.

Safety

No NoGC tokens should be constructed while returned pointer is available to user. In practices this means that one should use the result as direct argument to SpiderMonkey function and not store it in variable.

use mozjs::context::*;
use mozjs::jsapi::JSContext as RawJSContext;

fn SM_function_that_can_trigger_gc(_cx: *mut RawJSContext) {}

fn can_trigger_gc(cx: &mut JSContext) {
    unsafe { SM_function_that_can_trigger_gc(cx.raw_cx()) } // returned pointer is immediately used
    cx.no_gc(); // this is ok because no outstanding raw pointer is alive
}

pub unsafe fn raw_cx_no_gc(&self) -> *mut JSContext

Obtain RawJSContext mutable pointer, that will not be used for GC.

Safety

No &mut calls should be done on JSContext while returned pointer is available. In practices this means that one should use the result as direct argument to SpiderMonkey function and not store it in variable.

use mozjs::context::*;
use mozjs::jsapi::JSContext as RawJSContext;

fn SM_function_that_cannot_trigger_gc(_cx: *mut RawJSContext) {}

fn f(cx: &mut JSContext) {
    unsafe { SM_function_that_cannot_trigger_gc(cx.raw_cx_no_gc()) } // returned pointer is immediately used
}

Trait Implementations

impl<'cx> Deref for Realm<'cx>

type Target = JSContext

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'cx> DerefMut for Realm<'cx>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.