[api] Bring back finalizers on global handles

src/global-handles.cc

 // Copyright 2009 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.
 
 #include "src/global-handles.h"
 
 #include "src/api.h"
 #include "src/v8.h"
 #include "src/vm-state-inl.h"
 
@@ skipping 179 matching lines @@
     // Check for PENDING to ensure correct answer when processing callbacks.
     return state() == PENDING || state() == NEAR_DEATH;
   }
 
   bool IsWeak() const { return state() == WEAK; }
 
   bool IsInUse() const { return state() != FREE; }
 
   bool IsRetainer() const {
     return state() != FREE &&
-           !(state() == NEAR_DEATH && weakness_type() != NORMAL_WEAK);
+           !(state() == NEAR_DEATH && weakness_type() != NORMAL_WEAK &&
+             weakness_type() != FINALIZER_WEAK);
   }
 
   bool IsStrongRetainer() const { return state() == NORMAL; }
 
   bool IsWeakRetainer() const {
     return state() == WEAK || state() == PENDING ||
-           (state() == NEAR_DEATH && weakness_type() == NORMAL_WEAK);
+           (state() == NEAR_DEATH && weakness_type() == NORMAL_WEAK &&
+            weakness_type() != FINALIZER_WEAK);
   }
 
   void MarkPending() {
     DCHECK(state() == WEAK);
     set_state(PENDING);
   }
 
   // Independent flag accessors.
   void MarkIndependent() {
     DCHECK(IsInUse());
@@ skipping 47 matching lines @@
                 v8::WeakCallbackType type) {
     DCHECK(phantom_callback != nullptr);
     DCHECK(IsInUse());
     CHECK_NE(object_, reinterpret_cast<Object*>(kGlobalHandleZapValue));
     set_state(WEAK);
     switch (type) {
       case v8::WeakCallbackType::kParameter:
         set_weakness_type(PHANTOM_WEAK);
         break;
       case v8::WeakCallbackType::kInternalFields:
-      set_weakness_type(PHANTOM_WEAK_2_INTERNAL_FIELDS);
-      break;
+        set_weakness_type(PHANTOM_WEAK_2_INTERNAL_FIELDS);
+        break;
+      case v8::WeakCallbackType::kFinalizer:
+        set_weakness_type(NORMAL_WEAK);
+        break;
     }
     set_parameter(parameter);
     weak_callback_ = reinterpret_cast<WeakCallback>(phantom_callback);
   }
 
   void* ClearWeakness() {
     DCHECK(IsInUse());
     void* p = parameter();
     set_state(NORMAL);
     set_parameter(NULL);
@@ skipping 38 matching lines @@
       return false;
     }
     set_state(NEAR_DEATH);
 
     // Check that we are not passing a finalized external string to
     // the callback.
     DCHECK(!object_->IsExternalOneByteString() ||
            ExternalOneByteString::cast(object_)->resource() != NULL);
     DCHECK(!object_->IsExternalTwoByteString() ||
            ExternalTwoByteString::cast(object_)->resource() != NULL);
-    if (weakness_type() != NORMAL_WEAK) return false;
+    if (weakness_type() != NORMAL_WEAK && weakness_type() != FINALIZER_WEAK) {
+      return false;
+    }
 
     // Leaving V8.
     VMState<EXTERNAL> vmstate(isolate);
     HandleScope handle_scope(isolate);
-    Object** object = location();
-    Handle<Object> handle(*object, isolate);
-    v8::WeakCallbackData<v8::Value, void> data(
-        reinterpret_cast<v8::Isolate*>(isolate), parameter(),
-        v8::Utils::ToLocal(handle));
-    set_parameter(NULL);
-    weak_callback_(data);
+    if (weakness_type() == NORMAL_WEAK) {
+      Object** object = location();
+      Handle<Object> handle(*object, isolate);
+      v8::WeakCallbackData<v8::Value, void> data(
+          reinterpret_cast<v8::Isolate*>(isolate), parameter(),
+          v8::Utils::ToLocal(handle));
+      set_parameter(NULL);
+      weak_callback_(data);
+    } else {
+      void* internal_fields[v8::kInternalFieldsInWeakCallback] = {nullptr,
+                                                                  nullptr};

[noordhuis, 2016/04/14 14:52:36]

Femto-nit, but other places that depend on v8::kInternalFieldsInWeakCallback
seem to use a for loop to initialize the array elements.

[jochen (gone - plz use gerrit), 2016/04/14 15:16:04]

i copied this from
https://code.google.com/p/chromium/codesearch#chromium/src/v8/src/global-hand...

+      v8::WeakCallbackInfo<void> data(reinterpret_cast<v8::Isolate*>(isolate),
+                                      parameter(), internal_fields, nullptr);
+      auto callback = reinterpret_cast<v8::WeakCallbackInfo<void>::Callback>(
+          weak_callback_);
+      callback(data);
+    }
 
     // Absence of explicit cleanup or revival of weak handle
     // in most of the cases would lead to memory leak.
     CHECK(state() != NEAR_DEATH);
     return true;
   }
 
   inline GlobalHandles* GetGlobalHandles();
 
  private:
@@ skipping 286 matching lines @@
 bool GlobalHandles::IsWeak(Object** location) {
   return Node::FromLocation(location)->IsWeak();
 }
 
 void GlobalHandles::IterateWeakRoots(ObjectVisitor* v) {
   for (NodeIterator it(this); !it.done(); it.Advance()) {
     Node* node = it.node();
     if (node->IsWeakRetainer()) {
       // Pending weak phantom handles die immediately. Everything else survives.
       if (node->state() == Node::PENDING &&
-          node->weakness_type() != NORMAL_WEAK) {
-          node->CollectPhantomCallbackData(isolate(),
-                                           &pending_phantom_callbacks_);
+          node->weakness_type() != NORMAL_WEAK &&
+          node->weakness_type() != FINALIZER_WEAK) {
+        node->CollectPhantomCallbackData(isolate(),
+                                         &pending_phantom_callbacks_);
       } else {
         v->VisitPointer(node->location());
       }
     }
   }
 }
 
 
 void GlobalHandles::IdentifyWeakHandles(WeakSlotCallback f) {
   for (NodeIterator it(this); !it.done(); it.Advance()) {
@@ skipping 38 matching lines @@
 
 
 void GlobalHandles::IterateNewSpaceWeakIndependentRoots(ObjectVisitor* v) {
   for (int i = 0; i < new_space_nodes_.length(); ++i) {
     Node* node = new_space_nodes_[i];
     DCHECK(node->is_in_new_space_list());
     if ((node->is_independent() || node->is_partially_dependent()) &&
         node->IsWeakRetainer()) {
       // Pending weak phantom handles die immediately. Everything else survives.
       if (node->state() == Node::PENDING &&
-          node->weakness_type() != NORMAL_WEAK) {
+          node->weakness_type() != NORMAL_WEAK &&
+          node->weakness_type() != FINALIZER_WEAK) {
         node->CollectPhantomCallbackData(isolate(),
                                          &pending_phantom_callbacks_);
       } else {
         v->VisitPointer(node->location());
       }
     }
   }
 }
 
 
@@ skipping 22 matching lines @@
 
 
 void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots(ObjectVisitor* v) {
   for (int i = 0; i < new_space_nodes_.length(); ++i) {
     Node* node = new_space_nodes_[i];
     DCHECK(node->is_in_new_space_list());
     if ((node->is_independent() || !node->is_active()) &&
         node->IsWeakRetainer()) {
       // Pending weak phantom handles die immediately. Everything else survives.
       if (node->state() == Node::PENDING &&
-          node->weakness_type() != NORMAL_WEAK) {
+          node->weakness_type() != NORMAL_WEAK &&
+          node->weakness_type() != FINALIZER_WEAK) {
         node->CollectPhantomCallbackData(isolate(),
                                          &pending_phantom_callbacks_);
       } else {
         v->VisitPointer(node->location());
       }
     }
   }
 }
 
 
@@ skipping 713 matching lines @@
   blocks_[block][offset] = object;
   if (isolate->heap()->InNewSpace(object)) {
     new_space_indices_.Add(size_);
   }
   *index = size_++;
 }
 
 
 }  // namespace internal
 }  // namespace v8