1 files changed, 77 insertions, 0 deletions
diff --git a/chromium/v8/src/handles/off-thread-transfer-handle-storage-inl.h b/chromium/v8/src/handles/off-thread-transfer-handle-storage-inl.h
new file mode 100644
index 00000000000..8a0682d9c76
--- /dev/null
+++ b/chromium/v8/src/handles/off-thread-transfer-handle-storage-inl.h
@@ -0,0 +1,77 @@
+// Copyright 2020 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_OFF_THREAD_TRANSFER_HANDLE_STORAGE_INL_H_
+#define V8_HANDLES_OFF_THREAD_TRANSFER_HANDLE_STORAGE_INL_H_
+
+#include "src/handles/handles-inl.h"
+#include "src/handles/off-thread-transfer-handle-storage.h"
+
+namespace v8 {
+namespace internal {
+
+OffThreadTransferHandleStorage::OffThreadTransferHandleStorage(
+    Address* off_thread_handle_location,
+    std::unique_ptr<OffThreadTransferHandleStorage> next)
+    : handle_location_(off_thread_handle_location),
+      next_(std::move(next)),
+      state_(kOffThreadHandle) {
+  CheckValid();
+}
+
+void OffThreadTransferHandleStorage::ConvertFromOffThreadHandleOnFinish() {
+  CheckValid();
+  DCHECK_EQ(state_, kOffThreadHandle);
+  raw_obj_ptr_ = *handle_location_;
+  state_ = kRawObject;
+  CheckValid();
+}
+
+void OffThreadTransferHandleStorage::ConvertToHandleOnPublish(
+    Isolate* isolate, DisallowHeapAllocation* no_gc) {
+  CheckValid();
+  DCHECK_EQ(state_, kRawObject);
+  handle_location_ = handle(Object(raw_obj_ptr_), isolate).location();
+  state_ = kHandle;
+  CheckValid();
+}
+
+Address* OffThreadTransferHandleStorage::handle_location() const {
+  CheckValid();
+  DCHECK_EQ(state_, kHandle);
+  return handle_location_;
+}
+
+void OffThreadTransferHandleStorage::CheckValid() const {
+#ifdef DEBUG
+  Object obj;
+
+  switch (state_) {
+    case kHandle:
+    case kOffThreadHandle:
+      DCHECK_NOT_NULL(handle_location_);
+      obj = Object(*handle_location_);
+      break;
+    case kRawObject:
+      obj = Object(raw_obj_ptr_);
+      break;
+  }
+
+  // Smis are always fine.
+  if (obj.IsSmi()) return;
+
+  // The main-thread handle should not be in off-thread space, and vice verse.
+  // Raw object pointers can point to the main-thread heap during Publish, so
+  // we don't check that.
+  DCHECK_IMPLIES(state_ == kOffThreadHandle,
+                 Heap::InOffThreadSpace(HeapObject::cast(obj)));
+  DCHECK_IMPLIES(state_ == kHandle,
+                 !Heap::InOffThreadSpace(HeapObject::cast(obj)));
+#endif
+}
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_HANDLES_OFF_THREAD_TRANSFER_HANDLE_STORAGE_INL_H_