4 files changed, 31 insertions, 6 deletions
diff --git a/components/script/dom/bindings/callback.rs b/components/script/dom/bindings/callback.rs
index 178c74e888f..998e48b5fbe 100644
--- a/components/script/dom/bindings/callback.rs
+++ b/components/script/dom/bindings/callback.rs
@@ -15,7 +15,7 @@ use js::jsapi::{
 };
 use js::jsval::{JSVal, ObjectValue, UndefinedValue};
 use js::rust::wrappers::{JS_GetProperty, JS_WrapObject};
-use js::rust::{MutableHandleObject, Runtime};
+use js::rust::{HandleObject, MutableHandleObject, Runtime};
 
 use crate::dom::bindings::codegen::Bindings::WindowBinding::Window_Binding::WindowMethods;
 use crate::dom::bindings::error::{report_pending_exception, Error, Fallible};
@@ -206,9 +206,25 @@ impl CallbackInterface {
     }
 }
 
+pub trait ThisReflector {
+    fn jsobject(&self) -> *mut JSObject;
+}
+
+impl <T: DomObject> ThisReflector for T {
+    fn jsobject(&self) -> *mut JSObject {
+        self.reflector().get_jsobject().get()
+    }
+}
+
+impl <'a> ThisReflector for HandleObject<'a> {
+    fn jsobject(&self) -> *mut JSObject {
+        self.get()
+    }    
+}
+
 /// Wraps the reflector for `p` into the realm of `cx`.
-pub fn wrap_call_this_object<T: DomObject>(cx: JSContext, p: &T, mut rval: MutableHandleObject) {
-    rval.set(p.reflector().get_jsobject().get());
+pub fn wrap_call_this_object<T: ThisReflector>(cx: JSContext, p: &T, mut rval: MutableHandleObject) {
+    rval.set(p.jsobject());
     assert!(!rval.get().is_null());
 
     unsafe {
diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 291ec47a0b0..bb0351a20fa 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -7212,7 +7212,7 @@ class CGCallback(CGClass):
               })
         return [ClassMethod(method.name + '_', method.returnType, args,
                             bodyInHeader=True,
-                            templateArgs=["T: DomObject"],
+                            templateArgs=["T: ThisReflector"],
                             body=bodyWithThis,
                             visibility='pub'),
                 ClassMethod(method.name + '__', method.returnType, argsWithoutThis,
diff --git a/components/script/dom/bindings/import.rs b/components/script/dom/bindings/import.rs
index f2c6a5e2b81..6509acc2207 100644
--- a/components/script/dom/bindings/import.rs
+++ b/components/script/dom/bindings/import.rs
@@ -19,7 +19,7 @@ pub mod base {
 
     pub use crate::dom::bindings::callback::{
         wrap_call_this_object, CallSetup, CallbackContainer, CallbackFunction, CallbackInterface,
-        CallbackObject, ExceptionHandling,
+        CallbackObject, ExceptionHandling, ThisReflector,
     };
     pub use crate::dom::bindings::codegen::Bindings::AudioNodeBinding::{
         ChannelCountMode, ChannelCountModeValues, ChannelInterpretation,
diff --git a/components/script/dom/underlyingsourcecontainer.rs b/components/script/dom/underlyingsourcecontainer.rs
index a6d6d750ce1..8c6387c924a 100644
--- a/components/script/dom/underlyingsourcecontainer.rs
+++ b/components/script/dom/underlyingsourcecontainer.rs
@@ -16,6 +16,8 @@ use crate::dom::globalscope::GlobalScope;
 use crate::dom::promise::Promise;
 use crate::dom::readablestreamdefaultcontroller::ReadableStreamDefaultController;
 use crate::js::conversions::ToJSValConvertible;
+use js::jsapi::JSObject;
+use std::ptr;
 
 /// <https://streams.spec.whatwg.org/#underlying-source-api>
 /// The `Js` variant corresponds to
@@ -85,11 +87,18 @@ impl UnderlyingSourceContainer {
     }
 
     /// <https://streams.spec.whatwg.org/#dom-underlyingsource-pull>
+    #[allow(unsafe_code)]
     pub fn call_pull_algorithm(&self, controller: Controller) -> Option<Rc<Promise>> {
         if let UnderlyingSourceType::Js(source) = &self.underlying_source_type {
             let global = self.global();
             let promise = if let Some(pull) = &source.pull {
-                pull.Call_(&*self, controller, ExceptionHandling::Report)
+                let cx = GlobalScope::get_cx();
+                rooted!(in(*cx) let mut this_object = ptr::null_mut::<JSObject>());
+                unsafe {
+                    source.to_jsobject(*cx, this_object.handle_mut());
+                }
+                let this_handle = this_object.handle();
+                pull.Call_(&this_handle, controller, ExceptionHandling::Report)
                     .expect("Pull algorithm call failed")
             } else {
                 let promise = Promise::new(&*global);