|  | // 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 tonic { | 
|  |  | 
|  | 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; | 
|  | } | 
|  | } |