[api] Prototype WeakRef implementation

src/objects.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 47 matching lines @@
 //         - JSBoundFunction
 //         - JSCollection
 //           - JSSet
 //           - JSMap
 //         - JSStringIterator
 //         - JSSetIterator
 //         - JSMapIterator
 //         - JSWeakCollection
 //           - JSWeakMap
 //           - JSWeakSet
+//           - JSWeakRef
 //         - JSRegExp
 //         - JSFunction
 //         - JSGeneratorObject
 //         - JSGlobalObject
 //         - JSGlobalProxy
 //         - JSValue
 //           - JSDate
 //         - JSMessageObject
 //         - JSModuleNamespace
 //       - JSProxy
@@ skipping 314 matching lines @@
   V(JS_MODULE_NAMESPACE_TYPE)                                                  \
   V(JS_ARRAY_TYPE)                                                             \
   V(JS_ARRAY_BUFFER_TYPE)                                                      \
   V(JS_TYPED_ARRAY_TYPE)                                                       \
   V(JS_DATA_VIEW_TYPE)                                                         \
   V(JS_SET_TYPE)                                                               \
   V(JS_MAP_TYPE)                                                               \
   V(JS_SET_ITERATOR_TYPE)                                                      \
   V(JS_MAP_ITERATOR_TYPE)                                                      \
   V(JS_WEAK_MAP_TYPE)                                                          \
-  V(JS_WEAK_SET_TYPE)                                                          \
+  V(JS_WEAK_SET_TYPE)                                                         \
+  V(JS_WEAK_REF_TYPE)                                                          \
   V(JS_PROMISE_CAPABILITY_TYPE)                                                \
   V(JS_PROMISE_TYPE)                                                           \
   V(JS_REGEXP_TYPE)                                                            \
   V(JS_ERROR_TYPE)                                                             \
   V(JS_ASYNC_FROM_SYNC_ITERATOR_TYPE)                                          \
   V(JS_STRING_ITERATOR_TYPE)                                                   \
                                                                                \
   V(JS_TYPED_ARRAY_KEY_ITERATOR_TYPE)                                          \
   V(JS_FAST_ARRAY_KEY_ITERATOR_TYPE)                                           \
   V(JS_GENERIC_ARRAY_KEY_ITERATOR_TYPE)                                        \
@@ skipping 330 matching lines @@
   JS_ARRAY_TYPE,
   JS_ARRAY_BUFFER_TYPE,
   JS_TYPED_ARRAY_TYPE,
   JS_DATA_VIEW_TYPE,
   JS_SET_TYPE,
   JS_MAP_TYPE,
   JS_SET_ITERATOR_TYPE,
   JS_MAP_ITERATOR_TYPE,
   JS_WEAK_MAP_TYPE,
   JS_WEAK_SET_TYPE,
+  JS_WEAK_REF_TYPE,
   JS_PROMISE_CAPABILITY_TYPE,
   JS_PROMISE_TYPE,
   JS_REGEXP_TYPE,
   JS_ERROR_TYPE,
   JS_ASYNC_FROM_SYNC_ITERATOR_TYPE,
   JS_STRING_ITERATOR_TYPE,
 
   JS_TYPED_ARRAY_KEY_ITERATOR_TYPE,
   JS_FAST_ARRAY_KEY_ITERATOR_TYPE,
   JS_GENERIC_ARRAY_KEY_ITERATOR_TYPE,
@@ skipping 108 matching lines @@
   V(DEPENDENT_CODE_SUB_TYPE)                     \
   V(DICTIONARY_ELEMENTS_SUB_TYPE)                \
   V(DICTIONARY_PROPERTIES_SUB_TYPE)              \
   V(EMPTY_PROPERTIES_DICTIONARY_SUB_TYPE)        \
   V(FAST_ELEMENTS_SUB_TYPE)                      \
   V(FAST_PROPERTIES_SUB_TYPE)                    \
   V(FAST_TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE) \
   V(HANDLER_TABLE_SUB_TYPE)                      \
   V(JS_COLLECTION_SUB_TYPE)                      \
   V(JS_WEAK_COLLECTION_SUB_TYPE)                 \
+  V(JS_WEAK_REF_SUB_TYPE)                 \
   V(MAP_CODE_CACHE_SUB_TYPE)                     \
   V(NOSCRIPT_SHARED_FUNCTION_INFOS_SUB_TYPE)     \
   V(NUMBER_STRING_CACHE_SUB_TYPE)                \
   V(OBJECT_TO_CODE_SUB_TYPE)                     \
   V(OPTIMIZED_CODE_LITERALS_SUB_TYPE)            \
   V(OPTIMIZED_CODE_MAP_SUB_TYPE)                 \
   V(PROTOTYPE_USERS_SUB_TYPE)                    \
   V(REGEXP_MULTIPLE_CACHE_SUB_TYPE)              \
   V(RETAINED_MAPS_SUB_TYPE)                      \
   V(SCOPE_INFO_SUB_TYPE)                         \
@@ skipping 168 matching lines @@
   V(JSRegExp)                          \
   V(JSSet)                             \
   V(JSSetIterator)                     \
   V(JSSloppyArgumentsObject)           \
   V(JSStringIterator)                  \
   V(JSTypedArray)                      \
   V(JSValue)                           \
   V(JSWeakCollection)                  \
   V(JSWeakMap)                         \
   V(JSWeakSet)                         \
+  V(JSWeakRef)                         \
   V(Map)                               \
   V(MapCache)                          \
   V(ModuleInfo)                        \
   V(MutableHeapNumber)                 \
   V(Name)                              \
   V(NativeContext)                     \
   V(NormalizedMapCache)                \
   V(ObjectHashSet)                     \
   V(ObjectHashTable)                   \
   V(Oddball)                           \
@@ skipping 8281 matching lines @@
   DECLARE_CAST(JSWeakSet)
 
   // Dispatched behavior.
   DECLARE_PRINTER(JSWeakSet)
   DECLARE_VERIFIER(JSWeakSet)
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSWeakSet);
 };
 
+// The JSWeakRef describes EcmaScript Harmony weak refs
+class JSWeakRef: public JSObject {
+ public:
+  DECL_ACCESSORS(target, WeakCell)
+  DECL_ACCESSORS(executor, JSFunction)
+  DECL_ACCESSORS(holdings, Object)
+
+  DECL_INT_ACCESSORS(flags)
+  // marker to keep target alive until tick is over
+  DECL_BOOLEAN_ACCESSORS(held)
+  // declares that it needs to be executor'd
+  DECL_BOOLEAN_ACCESSORS(queued)
+
+  DECLARE_CAST(JSWeakRef)
+
+  // Dispatched behavior.
+  DECLARE_PRINTER(JSWeakRef)
+  DECLARE_VERIFIER(JSWeakRef)
+
+  static const int kTargetOffset = JSWeakCollection::kSize;
+  static const int kExecutorOffset = kTargetOffset + kPointerSize;
+  static const int kHoldingsOffset = kExecutorOffset + kPointerSize;
+  static const int kFlagsOffset = kHoldingsOffset + kPointerSize;
+  static const int kSize = kFlagsOffset + kPointerSize;
+
+  static const int kHeldBit = 0;
+  static const int kQueuedBit = 1;
+
+  static void Initialize(Handle<JSWeakRef> weak_ref,
+                             Isolate* isolate,
+                             Handle<JSObject> target,
+                             Handle<JSFunction> executor,
+                             Handle<Object> holdings);
+  static void Clear(Handle<JSWeakRef> weak_ref,
+                             Isolate* isolate);
+  static Handle<HeapObject> Value(Handle<JSWeakRef> weak_ref,
+                             Isolate* isolate);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSWeakRef);
+};
+
 
 // Whether a JSArrayBuffer is a SharedArrayBuffer or not.
 enum class SharedFlag { kNotShared, kShared };
 
 
 class JSArrayBuffer: public JSObject {
  public:
   // [backing_store]: backing memory for this array
   DECL_ACCESSORS(backing_store, void)
 
@@ skipping 921 matching lines @@
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_H_