Bug 1561357 - Implement [Serializable] for DOMException r=smaug,sfink

Skipping stack serialization here as

* it's optional per the spec
* no WPT test exists
* Chrome doesn't support it either
* not sure how it's usable when transferred to other domain.

Differential Revision: https://phabricator.services.mozilla.com/D143625

dom/base/DOMException.cpp

@@ -19,6 +19,9 @@
 #include "mozilla/dom/DOMExceptionBinding.h"
 #include "mozilla/ErrorResult.h"
 
+#include "js/TypeDecls.h"
+#include "js/StructuredClone.h"
+
 using namespace mozilla;
 using namespace mozilla::dom;
 
@@ -182,6 +185,12 @@ Exception::Exception(const nsACString& aMessage, nsresult aResult,
   }
 }
 
+Exception::Exception(nsCString&& aMessage, nsresult aResult, nsCString&& aName)
+    : mMessage(std::move(aMessage)),
+      mResult(aResult),
+      mName(std::move(aName)),
+      mHoldingJSVal(false) {}
+
 Exception::~Exception() {
   if (mHoldingJSVal) {
     MOZ_ASSERT(NS_IsMainThread());
@@ -324,6 +333,9 @@ DOMException::DOMException(nsresult aRv, const nsACString& aMessage,
                            const nsACString& aName, uint16_t aCode,
                            nsIStackFrame* aLocation)
     : Exception(aMessage, aRv, aName, aLocation, nullptr), mCode(aCode) {}
+DOMException::DOMException(nsresult aRv, nsCString&& aMessage,
+                           nsCString&& aName, uint16_t aCode)
+    : Exception(std::move(aMessage), aRv, std::move(aName)), mCode(aCode) {}
 
 void DOMException::ToString(JSContext* aCx, nsACString& aReturn) {
   aReturn.Truncate();
@@ -399,4 +411,54 @@ already_AddRefed<DOMException> DOMException::Create(
   return inst.forget();
 }
 
+static bool ReadAsCString(JSContext* aCx, JSStructuredCloneReader* aReader,
+                          nsCString& aString) {
+  JS::Rooted<JSString*> jsMessage(aCx);
+  if (!JS_ReadString(aReader, &jsMessage)) {
+    return false;
+  }
+  return AssignJSString(aCx, aString, jsMessage);
+}
+
+already_AddRefed<DOMException> DOMException::ReadStructuredClone(
+    JSContext* aCx, nsIGlobalObject* aGlobal,
+    JSStructuredCloneReader* aReader) {
+  uint32_t reserved;
+  nsresult rv;
+  nsCString message;
+  nsCString name;
+  uint16_t code;
+
+  if (!JS_ReadBytes(aReader, &reserved, 4) || !JS_ReadBytes(aReader, &rv, 4) ||
+      !ReadAsCString(aCx, aReader, message) ||
+      !ReadAsCString(aCx, aReader, name) || !JS_ReadBytes(aReader, &code, 2)) {
+    return nullptr;
+  };
+
+  return do_AddRef(
+      new DOMException(rv, std::move(message), std::move(name), code));
+}
+
+bool DOMException::WriteStructuredClone(
+    JSContext* aCx, JSStructuredCloneWriter* aWriter) const {
+  JS::Rooted<JS::Value> messageValue(aCx);
+  JS::Rooted<JS::Value> nameValue(aCx);
+  if (!NonVoidByteStringToJsval(aCx, mMessage, &messageValue) ||
+      !NonVoidByteStringToJsval(aCx, mName, &nameValue)) {
+    return false;
+  }
+
+  JS::Rooted<JSString*> message(aCx, messageValue.toString());
+  JS::Rooted<JSString*> name(aCx, nameValue.toString());
+
+  static_assert(sizeof(nsresult) == 4);
+
+  // A reserved field. Use this to indicate stack serialization support etc.
+  uint32_t reserved = 0;
+  return JS_WriteBytes(aWriter, &reserved, 4) &&
+         JS_WriteBytes(aWriter, &mResult, 4) &&
+         JS_WriteString(aWriter, message) && JS_WriteString(aWriter, name) &&
+         JS_WriteBytes(aWriter, &mCode, 2);
+};
+
 }  // namespace mozilla::dom

dom/base/DOMException.h

@@ -24,6 +24,7 @@
 #include "nsString.h"
 #include "mozilla/dom/BindingDeclarations.h"
 
+class nsIGlobalObject;
 class nsIStackFrame;
 
 nsresult NS_GetNameAndMessageForDOMNSResult(nsresult aNSResult,
@@ -104,6 +105,7 @@ class Exception : public nsIException, public nsWrapperCache {
   Exception(const nsACString& aMessage, nsresult aResult,
             const nsACString& aName, nsIStackFrame* aLocation,
             nsISupports* aData);
+  Exception(nsCString&& aMessage, nsresult aResult, nsCString&& aName);
 
  protected:
   virtual ~Exception();
@@ -140,6 +142,8 @@ class DOMException : public Exception {
   DOMException(nsresult aRv, const nsACString& aMessage,
                const nsACString& aName, uint16_t aCode,
                nsIStackFrame* aLocation = nullptr);
+  DOMException(nsresult aRv, nsCString&& aMessage, nsCString&& aName,
+               uint16_t aCode);
 
   NS_INLINE_DECL_REFCOUNTING_INHERITED(DOMException, Exception)
 
@@ -171,6 +175,12 @@ class DOMException : public Exception {
   static already_AddRefed<DOMException> Create(nsresult aRv,
                                                const nsACString& aMessage);
 
+  static already_AddRefed<DOMException> ReadStructuredClone(
+      JSContext* aCx, nsIGlobalObject* aGlobal,
+      JSStructuredCloneReader* aReader);
+  bool WriteStructuredClone(JSContext* aCx,
+                            JSStructuredCloneWriter* aWriter) const;
+
  protected:
   virtual ~DOMException() = default;
 

dom/base/StructuredCloneTags.h

@@ -96,7 +96,7 @@ enum StructuredCloneTags {
 
   // IMPORTANT: Don't change the order of these enum values. You could break
   // IDB.
-  EMPTY_SLOT_8,
+  SCTAG_DOM_DOMEXCEPTION,
 
   // IMPORTANT: Don't change the order of these enum values. You could break
   // IDB.

dom/webidl/DOMException.webidl

@@ -4,7 +4,7 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * The origin of this IDL file is
- * http://dom.spec.whatwg.org/#exception-domexception
+ * https://webidl.spec.whatwg.org/#idl-DOMException
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
@@ -31,7 +31,7 @@ interface mixin ExceptionMembers
   readonly attribute DOMString               filename;
   // Valid line numbers begin at '1'. '0' indicates unknown.
   readonly attribute unsigned long           lineNumber;
-  // Valid column numbers begin at 0. 
+  // Valid column numbers begin at 0.
   // We don't have an unambiguous indicator for unknown.
   readonly attribute unsigned long           columnNumber;
 
@@ -65,7 +65,8 @@ Exception includes ExceptionMembers;
 // XXXkhuey this is an 'exception', not an interface, but we don't have any
 // parser or codegen mechanisms for dealing with exceptions.
 [ExceptionClass,
- Exposed=(Window, Worker)]
+ Exposed=(Window, Worker),
+ Serializable]
 interface DOMException {
   constructor(optional DOMString message = "", optional DOMString name);
 

js/public/StructuredClone.h

@@ -729,6 +729,9 @@ JS_PUBLIC_API bool JS_ReadUint32Pair(JSStructuredCloneReader* r, uint32_t* p1,
 JS_PUBLIC_API bool JS_ReadBytes(JSStructuredCloneReader* r, void* p,
                                 size_t len);
 
+JS_PUBLIC_API bool JS_ReadString(JSStructuredCloneReader* r,
+                                 JS::MutableHandleString str);
+
 JS_PUBLIC_API bool JS_ReadDouble(JSStructuredCloneReader* r, double* v);
 
 JS_PUBLIC_API bool JS_ReadTypedArray(JSStructuredCloneReader* r,

js/src/vm/StructuredClone.cpp

@@ -477,6 +477,8 @@ struct JSStructuredCloneReader {
   // Any value passed to JS_ReadStructuredClone.
   void* closure;
 
+  friend bool JS_ReadString(JSStructuredCloneReader* r,
+                            JS::MutableHandleString str);
   friend bool JS_ReadTypedArray(JSStructuredCloneReader* r,
                                 MutableHandleValue vp);
 };
@@ -3561,6 +3563,23 @@ JS_PUBLIC_API bool JS_ReadBytes(JSStructuredCloneReader* r, void* p,
   return r->input().readBytes(p, len);
 }
 
+JS_PUBLIC_API bool JS_ReadString(JSStructuredCloneReader* r,
+                                 MutableHandleString str) {
+  uint32_t tag, data;
+  if (!r->input().readPair(&tag, &data)) {
+    return false;
+  }
+
+  if (tag == SCTAG_STRING) {
+    str.set(r->readString(data));
+    return true;
+  }
+
+  JS_ReportErrorNumberASCII(r->context(), GetErrorMessage, nullptr,
+                            JSMSG_SC_BAD_SERIALIZED_DATA, "expected string");
+  return false;
+}
+
 JS_PUBLIC_API bool JS_ReadDouble(JSStructuredCloneReader* r, double* v) {
   return r->input().readDouble(v);
 }

testing/web-platform/meta/html/infrastructure/safe-passing-of-structured-data/structuredclone_0.html.ini

@@ -5,15 +5,9 @@
   [Error.message: getter is ignored when cloning]
     expected: FAIL
 
-  [DOMException objects created by the UA can be cloned]
-    expected: FAIL
-
   [EvalError objects can be cloned]
     expected: FAIL
 
-  [DOMException objects can be cloned]
-    expected: FAIL
-
   [URIError objects can be cloned]
     expected: FAIL