Auto merge of #23816 - marmeladema:issue-20377, r=jdm

Wrapping unsafe raw JSContext pointers in a safe struct. Part 1.

Wrapping unsafe raw JSContext pointers in a safe struct. Issue #20377.

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<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] create a struct JSContext(*mut jsapi::JSContext) type
- [x] implement Deref for this new type so it's easy to obtain the inner context pointer
- [x] add an unsafe from_ptr static method that returns a new instance of the type
- [x] start by changing various Argument uses in CodegenRust.py for python classes that inherit from CGAbstractMethod
- [x] convert the python code that interacts with CGClass (CGCallback, CGCallbackFunction, CGCallbackFunctionImpl, CGCallbackInterface) and any rust code that interacts with it
- [x] update CGDictionary and any rust code that interacts with it
- [x] make the code generator declare trait methods that accept the new type instead of *mut JSContext (CGInterfaceTrait)
- [x] modify GlobalScope::get_cx to return a SafeJSContext

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<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

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1 files changed, 9 insertions, 10 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index d7e77ef9243..85639964710 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -102,6 +102,7 @@ use crate::dom::wheelevent::WheelEvent;
 use crate::dom::window::{ReflowReason, Window};
 use crate::dom::windowproxy::WindowProxy;
 use crate::fetch::FetchCanceller;
+use crate::script_runtime::JSContext;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use crate::script_thread::{MainThreadScriptMsg, ScriptThread};
 use crate::stylesheet_set::StylesheetSetRef;
@@ -117,7 +118,7 @@ use euclid::default::Point2D;
 use html5ever::{LocalName, Namespace, QualName};
 use hyper_serde::Serde;
 use ipc_channel::ipc::{self, IpcSender};
-use js::jsapi::{JSContext, JSObject, JSRuntime};
+use js::jsapi::{JSObject, JSRuntime};
 use keyboard_types::{Key, KeyState, Modifiers};
 use metrics::{
     InteractiveFlag, InteractiveMetrics, InteractiveWindow, ProfilerMetadataFactory,
@@ -4218,11 +4219,7 @@ impl DocumentMethods for Document {
 
     #[allow(unsafe_code)]
     // https://html.spec.whatwg.org/multipage/#dom-tree-accessors:dom-document-nameditem-filter
-    unsafe fn NamedGetter(
-        &self,
-        _cx: *mut JSContext,
-        name: DOMString,
-    ) -> Option<NonNull<JSObject>> {
+    fn NamedGetter(&self, _cx: JSContext, name: DOMString) -> Option<NonNull<JSObject>> {
         #[derive(JSTraceable, MallocSizeOf)]
         struct NamedElementFilter {
             name: Atom,
@@ -4270,7 +4267,7 @@ impl DocumentMethods for Document {
         }
         let name = Atom::from(name);
         let root = self.upcast::<Node>();
-        {
+        unsafe {
             // Step 1.
             let mut elements = root
                 .traverse_preorder(ShadowIncluding::No)
@@ -4291,9 +4288,11 @@ impl DocumentMethods for Document {
         // Step 4.
         let filter = NamedElementFilter { name: name };
         let collection = HTMLCollection::create(self.window(), root, Box::new(filter));
-        Some(NonNull::new_unchecked(
-            collection.reflector().get_jsobject().get(),
-        ))
+        unsafe {
+            Some(NonNull::new_unchecked(
+                collection.reflector().get_jsobject().get(),
+            ))
+        }
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-tree-accessors:supported-property-names