Bug 1353867 - Expose IsCrossOriginWhitelistedProp/AppendCrossOriginWhitelistedPropNames to DOM code. r=bzbarsky

Differential Revision: https://phabricator.services.mozilla.com/D12655

--HG--
extra : moz-landing-system : lando

js/xpconnect/src/xpcpublic.h

@@ -723,6 +723,15 @@ void RegisterJSStackFrame(JS::Realm* aRealm, JSStackFrameBase* aStackFrame);
 void UnregisterJSStackFrame(JS::Realm* aRealm, JSStackFrameBase* aStackFrame);
 void NukeJSStackFrames(JS::Realm* aRealm);
 
+// Check whether the given jsid is a property name (string or symbol) whose
+// value can be gotten cross-origin.  Cross-origin gets always return undefined
+// as the value, unless the Xray actually provides a different value.
+bool IsCrossOriginWhitelistedProp(JSContext* cx, JS::HandleId id);
+
+// Appends to props the jsids for property names (strings or symbols) whose
+// value can be gotten cross-origin.
+bool AppendCrossOriginWhitelistedPropNames(JSContext* cx,
+                                           JS::AutoIdVector& props);
 }  // namespace xpc
 
 namespace mozilla {

js/xpconnect/wrappers/FilteringWrapper.cpp

@@ -10,6 +10,7 @@
 #include "XrayWrapper.h"
 #include "nsJSUtils.h"
 #include "mozilla/ErrorResult.h"
+#include "xpcpublic.h"
 
 #include "jsapi.h"
 #include "js/Symbol.h"
@@ -43,6 +44,37 @@ bool IsCrossOriginWhitelistedProp(JSContext* cx, JS::HandleId id) {
          IsCrossOriginWhitelistedSymbol(cx, id);
 }
 
+bool AppendCrossOriginWhitelistedPropNames(JSContext* cx,
+                                           JS::AutoIdVector& props) {
+  // Add "then" if it's not already in the list.
+  AutoIdVector thenProp(cx);
+  if (!thenProp.append(GetJSIDByIndex(cx, XPCJSContext::IDX_THEN))) {
+    return false;
+  }
+
+  if (!AppendUnique(cx, props, thenProp)) {
+    return false;
+  }
+
+  // Now add the three symbol-named props cross-origin objects have.
+#ifdef DEBUG
+  for (size_t n = 0; n < props.length(); ++n) {
+    MOZ_ASSERT(!JSID_IS_SYMBOL(props[n]),
+               "Unexpected existing symbol-name prop");
+  }
+#endif
+  if (!props.reserve(props.length() +
+                     ArrayLength(sCrossOriginWhitelistedSymbolCodes))) {
+    return false;
+  }
+
+  for (auto code : sCrossOriginWhitelistedSymbolCodes) {
+    props.infallibleAppend(SYMBOL_TO_JSID(JS::GetWellKnownSymbol(cx, code)));
+  }
+
+  return true;
+}
+
 template <typename Policy>
 static bool Filter(JSContext* cx, HandleObject wrapper, AutoIdVector& props) {
   size_t w = 0;
@@ -261,33 +293,7 @@ bool CrossOriginXrayWrapper::ownPropertyKeys(JSContext* cx,
     return false;
   }
 
-  // Add "then" if it's not already in the list.
-  AutoIdVector thenProp(cx);
-  if (!thenProp.append(GetJSIDByIndex(cx, XPCJSContext::IDX_THEN))) {
-    return false;
-  }
-
-  if (!AppendUnique(cx, props, thenProp)) {
-    return false;
-  }
-
-  // Now add the three symbol-named props cross-origin objects have.
-#ifdef DEBUG
-  for (size_t n = 0; n < props.length(); ++n) {
-    MOZ_ASSERT(!JSID_IS_SYMBOL(props[n]),
-               "Unexpected existing symbol-name prop");
-  }
-#endif
-  if (!props.reserve(props.length() +
-                     ArrayLength(sCrossOriginWhitelistedSymbolCodes))) {
-    return false;
-  }
-
-  for (auto code : sCrossOriginWhitelistedSymbolCodes) {
-    props.infallibleAppend(SYMBOL_TO_JSID(JS::GetWellKnownSymbol(cx, code)));
-  }
-
-  return true;
+  return AppendCrossOriginWhitelistedPropNames(cx, props);
 }
 
 bool CrossOriginXrayWrapper::defineProperty(JSContext* cx,

js/xpconnect/wrappers/FilteringWrapper.h

@@ -85,11 +85,6 @@ class CrossOriginXrayWrapper : public SecurityXrayDOM {
                             JS::ObjectOpResult& result) const override;
 };
 
-// Check whether the given jsid is a property name (string or symbol) whose
-// value can be gotten cross-origin.  Cross-origin gets always return undefined
-// as the value, unless the Xray actually provides a different value.
-bool IsCrossOriginWhitelistedProp(JSContext* cx, JS::HandleId id);
-
 }  // namespace xpc
 
 #endif /* __FilteringWrapper_h__ */