script: Impl cloning of JSPrincipals (#32706)

* Impl cloning of JSPrincipals

* bincode as workspace dependency

* Update mozjs and cc

components/script/Cargo.toml

@@ -34,6 +34,7 @@ background_hang_monitor_api = { workspace = true }
 backtrace = { workspace = true }
 base = { workspace = true }
 base64 = { workspace = true }
+bincode = { workspace = true }
 bitflags = { workspace = true }
 bluetooth_traits = { workspace = true }
 canvas_traits = { workspace = true }

components/script/dom/bindings/principals.rs

@@ -11,10 +11,15 @@ use js::glue::{
     CreateRustJSPrincipals, DestroyRustJSPrincipals, GetRustJSPrincipalsPrivate,
     JSPrincipalsCallbacks,
 };
-use js::jsapi::{JSPrincipals, JS_DropPrincipals, JS_HoldPrincipals};
+use js::jsapi::{
+    JSContext, JSPrincipals, JSStructuredCloneReader, JSStructuredCloneWriter, JS_DropPrincipals,
+    JS_HoldPrincipals, JS_ReadUint32Pair,
+};
 use js::rust::Runtime;
 use servo_url::MutableOrigin;
 
+use super::structuredclone::StructuredCloneTags;
+
 /// An owned reference to Servo's `JSPrincipals` instance.
 #[repr(transparent)]
 pub struct ServoJSPrincipals(NonNull<JSPrincipals>);
@@ -123,8 +128,60 @@ pub unsafe extern "C" fn destroy_servo_jsprincipal(principals: *mut JSPrincipals
     DestroyRustJSPrincipals(principals);
 }
 
+pub unsafe extern "C" fn write_jsprincipal(
+    principal: *mut JSPrincipals,
+    _cx: *mut JSContext,
+    writer: *mut JSStructuredCloneWriter,
+) -> bool {
+    let Some(principal) = NonNull::new(principal) else {
+        return false;
+    };
+    let obj = ServoJSPrincipalsRef::from_raw_nonnull(principal);
+    let origin = obj.origin();
+    let Ok(bytes_of_origin) = bincode::serialize(&origin) else {
+        return false;
+    };
+    let Ok(len) = bytes_of_origin.len().try_into() else {
+        return false;
+    };
+    if !js::jsapi::JS_WriteUint32Pair(writer, StructuredCloneTags::Principals as u32, len) {
+        return false;
+    }
+    if !js::jsapi::JS_WriteBytes(writer, bytes_of_origin.as_ptr() as _, len as usize) {
+        return false;
+    }
+    true
+}
+
+pub unsafe extern "C" fn read_jsprincipal(
+    _cx: *mut JSContext,
+    reader: *mut JSStructuredCloneReader,
+    principals: *mut *mut JSPrincipals,
+) -> bool {
+    let mut tag: u32 = 0;
+    let mut len: u32 = 0;
+    if !JS_ReadUint32Pair(reader, &mut tag as *mut u32, &mut len as *mut u32) {
+        return false;
+    }
+    if tag != StructuredCloneTags::Principals as u32 {
+        return false;
+    }
+    let mut bytes = vec![0u8; len as usize];
+    if !js::jsapi::JS_ReadBytes(reader, bytes.as_mut_ptr() as _, len as usize) {
+        return false;
+    }
+    let Ok(origin) = bincode::deserialize(&bytes[..]) else {
+        return false;
+    };
+    let principal = ServoJSPrincipals::new(&origin);
+    *principals = principal.as_raw();
+    // we transferred ownership of principal to the caller
+    std::mem::forget(principal);
+    true
+}
+
 const PRINCIPALS_CALLBACKS: JSPrincipalsCallbacks = JSPrincipalsCallbacks {
-    write: None,
+    write: Some(write_jsprincipal),
     isSystemOrAddonPrincipal: Some(principals_is_system_or_addon_principal),
 };
 

components/script/dom/bindings/structuredclone.rs

@@ -44,11 +44,12 @@ use crate::script_runtime::JSContext as SafeJSContext;
 // NOTE: Current values found at https://dxr.mozilla.org/mozilla-central/
 // rev/ff04d410e74b69acfab17ef7e73e7397602d5a68/js/public/StructuredClone.h#323
 #[repr(u32)]
-enum StructuredCloneTags {
+pub(super) enum StructuredCloneTags {
     /// To support additional types, add new tags with values incremented from the last one before Max.
     Min = 0xFFFF8000,
     DomBlob = 0xFFFF8001,
     MessagePort = 0xFFFF8002,
+    Principals = 0xFFFF8003,
     Max = 0xFFFFFFFF,
 }
 

components/script/script_runtime.rs

@@ -30,12 +30,12 @@ use js::jsapi::{
     GetPromiseUserInputEventHandlingState, HandleObject, Heap, InitConsumeStreamCallback,
     InitDispatchToEventLoop, JSContext as RawJSContext, JSGCParamKey, JSGCStatus,
     JSJitCompilerOption, JSObject, JSSecurityCallbacks, JSTracer, JS_AddExtraGCRootsTracer,
-    JS_InitDestroyPrincipalsCallback, JS_RequestInterruptCallback, JS_SetGCCallback,
-    JS_SetGCParameter, JS_SetGlobalJitCompilerOption, JS_SetOffthreadIonCompilationEnabled,
-    JS_SetParallelParsingEnabled, JS_SetSecurityCallbacks, JobQueue, MimeType,
-    PromiseRejectionHandlingState, PromiseUserInputEventHandlingState, SetDOMCallbacks,
-    SetGCSliceCallback, SetJobQueue, SetPreserveWrapperCallbacks, SetProcessBuildIdOp,
-    SetPromiseRejectionTrackerCallback, StreamConsumer as JSStreamConsumer,
+    JS_InitDestroyPrincipalsCallback, JS_InitReadPrincipalsCallback, JS_RequestInterruptCallback,
+    JS_SetGCCallback, JS_SetGCParameter, JS_SetGlobalJitCompilerOption,
+    JS_SetOffthreadIonCompilationEnabled, JS_SetParallelParsingEnabled, JS_SetSecurityCallbacks,
+    JobQueue, MimeType, PromiseRejectionHandlingState, PromiseUserInputEventHandlingState,
+    SetDOMCallbacks, SetGCSliceCallback, SetJobQueue, SetPreserveWrapperCallbacks,
+    SetProcessBuildIdOp, SetPromiseRejectionTrackerCallback, StreamConsumer as JSStreamConsumer,
 };
 use js::jsval::UndefinedValue;
 use js::panic::wrap_panic;
@@ -466,6 +466,7 @@ unsafe fn new_rt_and_cx_with_parent(
     JS_SetSecurityCallbacks(cx, &SECURITY_CALLBACKS);
 
     JS_InitDestroyPrincipalsCallback(cx, Some(principals::destroy_servo_jsprincipal));
+    JS_InitReadPrincipalsCallback(cx, Some(principals::read_jsprincipal));
 
     // Needed for debug assertions about whether GC is running.
     if cfg!(debug_assertions) {