| // Copyright 2015 The Chromium 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 "tonic/dart_persistent_value.h" | 
 |  | 
 | #include "tonic/dart_isolate_scope.h" | 
 | #include "tonic/dart_state.h" | 
 |  | 
 | namespace blink { | 
 |  | 
 | DartPersistentValue::DartPersistentValue() : value_(nullptr) { | 
 | } | 
 |  | 
 | DartPersistentValue::DartPersistentValue(DartState* dart_state, | 
 |                                          Dart_Handle value) | 
 |     : value_(nullptr) { | 
 |   Set(dart_state, value); | 
 | } | 
 |  | 
 | DartPersistentValue::~DartPersistentValue() { | 
 |   Clear(); | 
 | } | 
 |  | 
 | void DartPersistentValue::Set(DartState* dart_state, Dart_Handle value) { | 
 |   DCHECK(is_empty()); | 
 |   dart_state_ = dart_state->GetWeakPtr(); | 
 |   value_ = Dart_NewPersistentHandle(value); | 
 | } | 
 |  | 
 | void DartPersistentValue::Clear() { | 
 |   if (!value_ || !dart_state_.get()) | 
 |     return; | 
 |  | 
 |   DartIsolateScope scope(dart_state_->isolate()); | 
 |   Dart_DeletePersistentHandle(value_); | 
 |   dart_state_ = base::WeakPtr<DartState>(); | 
 |   value_ = nullptr; | 
 | } | 
 |  | 
 | Dart_Handle DartPersistentValue::Release() { | 
 |   if (!value_) | 
 |     return nullptr; | 
 |   Dart_Handle local = Dart_HandleFromPersistent(value_); | 
 |   Clear(); | 
 |   return local; | 
 | } | 
 | } |