1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_ANDROID_JNI_WEAK_REF_H_
6#define BASE_ANDROID_JNI_WEAK_REF_H_
7
8#include <jni.h>
9
10#include "base/android/scoped_java_ref.h"
11#include "base/base_export.h"
12
13// Manages WeakGlobalRef lifecycle.
14// This class is not thread-safe w.r.t. get() and reset(). Multiple threads may
15// safely use get() concurrently, but if the user calls reset() (or of course,
16// calls the destructor) they'll need to provide their own synchronization.
17class BASE_EXPORT JavaObjectWeakGlobalRef {
18 public:
19  JavaObjectWeakGlobalRef();
20  JavaObjectWeakGlobalRef(const JavaObjectWeakGlobalRef& orig);
21  JavaObjectWeakGlobalRef(JNIEnv* env, jobject obj);
22  virtual ~JavaObjectWeakGlobalRef();
23
24  void operator=(const JavaObjectWeakGlobalRef& rhs);
25
26  base::android::ScopedJavaLocalRef<jobject> get(JNIEnv* env) const;
27
28  bool is_empty() const { return obj_ == NULL; }
29
30  void reset();
31
32 private:
33  void Assign(const JavaObjectWeakGlobalRef& rhs);
34
35  jweak obj_;
36};
37
38// Get the real object stored in the weak reference returned as a
39// ScopedJavaLocalRef.
40BASE_EXPORT base::android::ScopedJavaLocalRef<jobject> GetRealObject(
41    JNIEnv* env, jweak obj);
42
43#endif  // BASE_ANDROID_JNI_WEAK_REF_H_
44