Revert of [handles] Sanitize Handle and friends.

src/handles-inl.h

 // Copyright 2006-2008 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_HANDLES_INL_H_
+#define V8_HANDLES_INL_H_
 
 #include "src/api.h"
 #include "src/handles.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
 
-// TODO(bmeurer): Break all include cycles and remove this file!
+namespace v8 {
+namespace internal {
+
+template<typename T>
+Handle<T>::Handle(T* obj) {
+  location_ = HandleScope::CreateHandle(obj->GetIsolate(), obj);
+}
+
+
+template<typename T>
+Handle<T>::Handle(T* obj, Isolate* isolate) {
+  location_ = HandleScope::CreateHandle(isolate, obj);
+}
+
+
+template <typename T>
+inline bool Handle<T>::is_identical_to(const Handle<T> o) const {
+  // Dereferencing deferred handles to check object equality is safe.
+  SLOW_DCHECK(
+      (location_ == NULL || IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
+      (o.location_ == NULL || o.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
+  if (location_ == o.location_) return true;
+  if (location_ == NULL || o.location_ == NULL) return false;
+  return *location_ == *o.location_;
+}
+
+
+template <typename T>
+inline T* Handle<T>::operator*() const {
+  SLOW_DCHECK(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+  return *bit_cast<T**>(location_);
+}
+
+template <typename T>
+inline T** Handle<T>::location() const {
+  SLOW_DCHECK(location_ == NULL ||
+              IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+  return location_;
+}
+
+#ifdef DEBUG
+template <typename T>
+bool Handle<T>::IsDereferenceAllowed(DereferenceCheckMode mode) const {
+  DCHECK(location_ != NULL);
+  Object* object = *bit_cast<T**>(location_);
+  if (object->IsSmi()) return true;
+  HeapObject* heap_object = HeapObject::cast(object);
+  Heap* heap = heap_object->GetHeap();
+  Object** handle = reinterpret_cast<Object**>(location_);
+  Object** roots_array_start = heap->roots_array_start();
+  if (roots_array_start <= handle &&
+      handle < roots_array_start + Heap::kStrongRootListLength &&
+      heap->RootCanBeTreatedAsConstant(
+        static_cast<Heap::RootListIndex>(handle - roots_array_start))) {
+    return true;
+  }
+  if (!AllowHandleDereference::IsAllowed()) return false;
+  if (mode == INCLUDE_DEFERRED_CHECK &&
+      !AllowDeferredHandleDereference::IsAllowed()) {
+    // Accessing cells, maps and internalized strings is safe.
+    if (heap_object->IsCell()) return true;
+    if (heap_object->IsMap()) return true;
+    if (heap_object->IsInternalizedString()) return true;
+    return !heap->isolate()->IsDeferredHandle(handle);
+  }
+  return true;
+}
+#endif
+
+
+
+HandleScope::HandleScope(Isolate* isolate) {
+  HandleScopeData* current = isolate->handle_scope_data();
+  isolate_ = isolate;
+  prev_next_ = current->next;
+  prev_limit_ = current->limit;
+  current->level++;
+}
+
+
+HandleScope::~HandleScope() {
+  CloseScope(isolate_, prev_next_, prev_limit_);
+}
+
+
+void HandleScope::CloseScope(Isolate* isolate,
+                             Object** prev_next,
+                             Object** prev_limit) {
+  HandleScopeData* current = isolate->handle_scope_data();
+
+  std::swap(current->next, prev_next);
+  current->level--;
+  if (current->limit != prev_limit) {
+    current->limit = prev_limit;
+    DeleteExtensions(isolate);
+#ifdef ENABLE_HANDLE_ZAPPING
+    ZapRange(current->next, prev_limit);
+  } else {
+    ZapRange(current->next, prev_next);
+#endif
+  }
+}
+
+
+template <typename T>
+Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) {
+  HandleScopeData* current = isolate_->handle_scope_data();
+
+  T* value = *handle_value;
+  // Throw away all handles in the current scope.
+  CloseScope(isolate_, prev_next_, prev_limit_);
+  // Allocate one handle in the parent scope.
+  DCHECK(current->level > 0);
+  Handle<T> result(CreateHandle<T>(isolate_, value));
+  // Reinitialize the current scope (so that it's ready
+  // to be used or closed again).
+  prev_next_ = current->next;
+  prev_limit_ = current->limit;
+  current->level++;
+  return result;
+}
+
+
+template <typename T>
+T** HandleScope::CreateHandle(Isolate* isolate, T* value) {
+  DCHECK(AllowHandleAllocation::IsAllowed());
+  HandleScopeData* current = isolate->handle_scope_data();
+
+  internal::Object** cur = current->next;
+  if (cur == current->limit) cur = Extend(isolate);
+  // Update the current next field, set the value in the created
+  // handle, and return the result.
+  DCHECK(cur < current->limit);
+  current->next = cur + 1;
+
+  T** result = reinterpret_cast<T**>(cur);
+  *result = value;
+  return result;
+}
+
+
+#ifdef DEBUG
+inline SealHandleScope::SealHandleScope(Isolate* isolate) : isolate_(isolate) {
+  // Make sure the current thread is allowed to create handles to begin with.
+  CHECK(AllowHandleAllocation::IsAllowed());
+  HandleScopeData* current = isolate_->handle_scope_data();
+  // Shrink the current handle scope to make it impossible to do
+  // handle allocations without an explicit handle scope.
+  limit_ = current->limit;
+  current->limit = current->next;
+  level_ = current->level;
+  current->level = 0;
+}
+
+
+inline SealHandleScope::~SealHandleScope() {
+  // Restore state in current handle scope to re-enable handle
+  // allocations.
+  HandleScopeData* current = isolate_->handle_scope_data();
+  DCHECK_EQ(0, current->level);
+  current->level = level_;
+  DCHECK_EQ(current->next, current->limit);
+  current->limit = limit_;
+}
+
+#endif
+
+} }  // namespace v8::internal
+
+#endif  // V8_HANDLES_INL_H_