1 files changed, 28 insertions, 1 deletions
diff --git a/Source/JavaScriptCore/heap/Weak.h b/Source/JavaScriptCore/heap/Weak.h
index 0938249b8..e5e0a97ec 100644
--- a/Source/JavaScriptCore/heap/Weak.h
+++ b/Source/JavaScriptCore/heap/Weak.h
@@ -26,9 +26,10 @@
 #ifndef Weak_h
 #define Weak_h
 
-#include <wtf/Assertions.h>
 #include "PassWeak.h"
 #include "WeakSetInlines.h"
+#include <wtf/Assertions.h>
+#include <wtf/HashMap.h>
 
 namespace JSC {
 
@@ -150,6 +151,32 @@ template<typename T> inline WeakImpl* Weak<T>::hashTableDeletedValue()
     return reinterpret_cast<WeakImpl*>(-1);
 }
 
+// This function helps avoid modifying a weak table while holding an iterator into it. (Object allocation
+// can run a finalizer that modifies the table. We avoid that by requiring a pre-constructed object as our value.)
+template<typename T, typename U> inline void weakAdd(HashMap<T, Weak<U> >& map, const T& key, PassWeak<U> value)
+{
+    ASSERT(!map.get(key));
+    map.set(key, value); // The table may still have a zombie for value.
+}
+
+template<typename T, typename U> inline void weakRemove(HashMap<T, Weak<U> >& map, const T& key, typename Weak<U>::GetType value)
+{
+    typename HashMap<T, Weak<U> >::iterator it = map.find(key);
+    ASSERT_UNUSED(value, value);
+    ASSERT(it != map.end());
+    ASSERT(it->second.was(value));
+    ASSERT(!it->second);
+    map.remove(it);
+}
+
+template<typename T> inline void weakClear(Weak<T>& weak, typename Weak<T>::GetType value)
+{
+    ASSERT_UNUSED(value, value);
+    ASSERT(weak.was(value));
+    ASSERT(!weak);
+    weak.clear();
+}
+
 } // namespace JSC
 
 namespace WTF {