Move generated bindings to script_bindings (#36323)

This is the final step of #1799, where the majority of the generated
code for the JS bindings is now compiled as part of the script_bindings
build step. The remaining pieces in script must live there because they
refer to concrete DOM types; all code in script_bindings is generic over
the
[DomTypes](https://doc.servo.org/script/dom/bindings/codegen/DomTypes/trait.DomTypes.html)
trait.

My testing with incremental builds shows me a 12 second reduction in
build times on my 2024 M4 Macbook Pro when modifying code in the script
crate after these changes. Before this PR those changes took 20 seconds
to rebuild Servo, and now they take 8 seconds.

Testing: Existing WPT tests ensure no regressions.
Fixes: #1799

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

1 files changed, 83 insertions, 20 deletions

diff --git a/components/script_bindings/utils.rs b/components/script_bindings/utils.rs
index 001360e07ff..95f742c9a06 100644
--- a/components/script_bindings/utils.rs
+++ b/components/script_bindings/utils.rs
@@ -5,17 +5,23 @@
 use std::ffi::CString;
 use std::os::raw::{c_char, c_void};
 use std::ptr::{self, NonNull};
+use std::slice;
 
 use js::conversions::ToJSValConvertible;
+use js::gc::Handle;
 use js::glue::{
     CallJitGetterOp, CallJitMethodOp, CallJitSetterOp, JS_GetReservedSlot,
     RUST_FUNCTION_VALUE_TO_JITINFO,
 };
 use js::jsapi::{
     AtomToLinearString, CallArgs, ExceptionStackBehavior, GetLinearStringCharAt,
-    GetLinearStringLength, GetNonCCWObjectGlobal, HandleObject as RawHandleObject, Heap,
-    JS_ClearPendingException, JS_IsExceptionPending, JSAtom, JSContext, JSJitInfo, JSObject,
-    JSTracer, MutableHandleValue as RawMutableHandleValue, ObjectOpResult, StringIsArrayIndex,
+    GetLinearStringLength, GetNonCCWObjectGlobal, HandleId as RawHandleId,
+    HandleObject as RawHandleObject, Heap, JS_ClearPendingException,
+    JS_DeprecatedStringHasLatin1Chars, JS_EnumerateStandardClasses,
+    JS_GetLatin1StringCharsAndLength, JS_IsExceptionPending, JS_IsGlobalObject,
+    JS_ResolveStandardClass, JSAtom, JSContext, JSJitInfo, JSObject, JSTracer,
+    MutableHandleIdVector as RawMutableHandleIdVector, MutableHandleValue as RawMutableHandleValue,
+    ObjectOpResult, StringIsArrayIndex,
 };
 use js::jsval::{JSVal, UndefinedValue};
 use js::rust::wrappers::{
@@ -29,11 +35,13 @@ use js::rust::{
 use js::{JS_CALLEE, rooted};
 use malloc_size_of::MallocSizeOfOps;
 
+use crate::DomTypes;
 use crate::codegen::Globals::Globals;
 use crate::codegen::InheritTypes::TopTypeId;
 use crate::codegen::PrototypeList::{self, MAX_PROTO_CHAIN_LENGTH, PROTO_OR_IFACE_LENGTH};
 use crate::conversions::{PrototypeCheck, jsstring_to_str, private_from_proto_check};
 use crate::error::throw_invalid_this;
+use crate::interfaces::DomHelpers;
 use crate::script_runtime::{CanGc, JSContext as SafeJSContext};
 use crate::str::DOMString;
 use crate::trace::trace_object;
@@ -77,24 +85,24 @@ unsafe impl Sync for DOMJSClass {}
 
 /// The index of the slot where the object holder of that interface's
 /// unforgeable members are defined.
-pub const DOM_PROTO_UNFORGEABLE_HOLDER_SLOT: u32 = 0;
+pub(crate) const DOM_PROTO_UNFORGEABLE_HOLDER_SLOT: u32 = 0;
 
 /// The index of the slot that contains a reference to the ProtoOrIfaceArray.
 // All DOM globals must have a slot at DOM_PROTOTYPE_SLOT.
-pub const DOM_PROTOTYPE_SLOT: u32 = js::JSCLASS_GLOBAL_SLOT_COUNT;
+pub(crate) const DOM_PROTOTYPE_SLOT: u32 = js::JSCLASS_GLOBAL_SLOT_COUNT;
 
 /// The flag set on the `JSClass`es for DOM global objects.
 // NOTE: This is baked into the Ion JIT as 0 in codegen for LGetDOMProperty and
 // LSetDOMProperty. Those constants need to be changed accordingly if this value
 // changes.
-pub const JSCLASS_DOM_GLOBAL: u32 = js::JSCLASS_USERBIT1;
+pub(crate) const JSCLASS_DOM_GLOBAL: u32 = js::JSCLASS_USERBIT1;
 
 /// Returns the ProtoOrIfaceArray for the given global object.
 /// Fails if `global` is not a DOM global object.
 ///
 /// # Safety
 /// `global` must point to a valid, non-null JS object.
-pub unsafe fn get_proto_or_iface_array(global: *mut JSObject) -> *mut ProtoOrIfaceArray {
+pub(crate) unsafe fn get_proto_or_iface_array(global: *mut JSObject) -> *mut ProtoOrIfaceArray {
     assert_ne!(((*get_object_class(global)).flags & JSCLASS_DOM_GLOBAL), 0);
     let mut slot = UndefinedValue();
     JS_GetReservedSlot(global, DOM_PROTOTYPE_SLOT, &mut slot);
@@ -112,7 +120,7 @@ pub type ProtoOrIfaceArray = [*mut JSObject; PROTO_OR_IFACE_LENGTH];
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `found` must point to a valid, non-null bool.
-pub unsafe fn get_property_on_prototype(
+pub(crate) unsafe fn get_property_on_prototype(
     cx: *mut JSContext,
     proxy: HandleObject,
     receiver: HandleValue,
@@ -206,7 +214,7 @@ pub fn get_array_index_from_id(id: HandleId) -> Option<u32> {
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 #[allow(clippy::result_unit_err)]
-pub unsafe fn find_enum_value<'a, T>(
+pub(crate) unsafe fn find_enum_value<'a, T>(
     cx: *mut JSContext,
     v: HandleValue,
     pairs: &'a [(&'static str, T)],
@@ -285,7 +293,7 @@ pub unsafe fn get_dictionary_property(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 #[allow(clippy::result_unit_err)]
-pub unsafe fn set_dictionary_property(
+pub(crate) unsafe fn set_dictionary_property(
     cx: *mut JSContext,
     object: HandleObject,
     property: &str,
@@ -325,7 +333,7 @@ pub unsafe fn has_property_on_prototype(
 ///
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
-pub unsafe fn delete_property_by_id(
+pub(crate) unsafe fn delete_property_by_id(
     cx: *mut JSContext,
     object: HandleObject,
     id: HandleId,
@@ -404,7 +412,7 @@ unsafe fn generic_call<const EXCEPTION_TO_REJECTION: bool>(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_method<const EXCEPTION_TO_REJECTION: bool>(
+pub(crate) unsafe extern "C" fn generic_method<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -417,7 +425,7 @@ pub unsafe extern "C" fn generic_method<const EXCEPTION_TO_REJECTION: bool>(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_getter<const EXCEPTION_TO_REJECTION: bool>(
+pub(crate) unsafe extern "C" fn generic_getter<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -430,7 +438,7 @@ pub unsafe extern "C" fn generic_getter<const EXCEPTION_TO_REJECTION: bool>(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_lenient_getter<const EXCEPTION_TO_REJECTION: bool>(
+pub(crate) unsafe extern "C" fn generic_lenient_getter<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -458,7 +466,7 @@ unsafe extern "C" fn call_setter(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_setter(
+pub(crate) unsafe extern "C" fn generic_setter(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -471,7 +479,7 @@ pub unsafe extern "C" fn generic_setter(
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_lenient_setter(
+pub(crate) unsafe extern "C" fn generic_lenient_setter(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -484,7 +492,7 @@ pub unsafe extern "C" fn generic_lenient_setter(
 ///
 /// `cx` must point to a valid, non-null JSContext.
 /// `vp` must point to a VALID, non-null JSVal.
-pub unsafe extern "C" fn generic_static_promise_method(
+pub(crate) unsafe extern "C" fn generic_static_promise_method(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -508,7 +516,7 @@ pub unsafe extern "C" fn generic_static_promise_method(
 ///
 /// # Safety
 /// `cx` must point to a valid, non-null JSContext.
-pub unsafe fn exception_to_promise(
+pub(crate) unsafe fn exception_to_promise(
     cx: *mut JSContext,
     rval: RawMutableHandleValue,
     _can_gc: CanGc,
@@ -533,7 +541,7 @@ pub unsafe fn exception_to_promise(
 /// # Safety
 /// `tracer` must point to a valid, non-null JSTracer.
 /// `obj` must point to a valid, non-null JSObject.
-pub unsafe fn trace_global(tracer: *mut JSTracer, obj: *mut JSObject) {
+pub(crate) unsafe fn trace_global(tracer: *mut JSTracer, obj: *mut JSObject) {
     let array = get_proto_or_iface_array(obj);
     for proto in (*array).iter() {
         if !proto.is_null() {
@@ -557,7 +565,7 @@ impl<T> AsVoidPtr for T {
 }
 
 // Generic method for returning c_char from caller
-pub trait AsCCharPtrPtr {
+pub(crate) trait AsCCharPtrPtr {
     fn as_c_char_ptr(&self) -> *const c_char;
 }
 
@@ -566,3 +574,58 @@ impl AsCCharPtrPtr for [u8] {
         self as *const [u8] as *const c_char
     }
 }
+
+/// Enumerate lazy properties of a global object.
+pub(crate) unsafe extern "C" fn enumerate_global<D: DomTypes>(
+    cx: *mut JSContext,
+    obj: RawHandleObject,
+    _props: RawMutableHandleIdVector,
+    _enumerable_only: bool,
+) -> bool {
+    assert!(JS_IsGlobalObject(obj.get()));
+    if !JS_EnumerateStandardClasses(cx, obj) {
+        return false;
+    }
+    for init_fun in <D as DomHelpers<D>>::interface_map().values() {
+        init_fun(SafeJSContext::from_ptr(cx), Handle::from_raw(obj));
+    }
+    true
+}
+
+/// Resolve a lazy global property, for interface objects and named constructors.
+pub(crate) unsafe extern "C" fn resolve_global<D: DomTypes>(
+    cx: *mut JSContext,
+    obj: RawHandleObject,
+    id: RawHandleId,
+    rval: *mut bool,
+) -> bool {
+    assert!(JS_IsGlobalObject(obj.get()));
+    if !JS_ResolveStandardClass(cx, obj, id, rval) {
+        return false;
+    }
+    if *rval {
+        return true;
+    }
+    if !id.is_string() {
+        *rval = false;
+        return true;
+    }
+
+    let string = id.to_string();
+    if !JS_DeprecatedStringHasLatin1Chars(string) {
+        *rval = false;
+        return true;
+    }
+    let mut length = 0;
+    let ptr = JS_GetLatin1StringCharsAndLength(cx, ptr::null(), string, &mut length);
+    assert!(!ptr.is_null());
+    let bytes = slice::from_raw_parts(ptr, length);
+
+    if let Some(init_fun) = <D as DomHelpers<D>>::interface_map().get(bytes) {
+        init_fun(SafeJSContext::from_ptr(cx), Handle::from_raw(obj));
+        *rval = true;
+    } else {
+        *rval = false;
+    }
+    true
+}