1 // Copyright 2014 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_ANDROID_JNI_WEAK_REF_H_
6 #define BASE_ANDROID_JNI_WEAK_REF_H_
10 #include "base/android/scoped_java_ref.h"
11 #include "base/base_export.h"
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.
17 class BASE_EXPORT JavaObjectWeakGlobalRef {
19 JavaObjectWeakGlobalRef();
20 JavaObjectWeakGlobalRef(const JavaObjectWeakGlobalRef& orig);
21 JavaObjectWeakGlobalRef(JavaObjectWeakGlobalRef&& orig) noexcept;
22 JavaObjectWeakGlobalRef(JNIEnv* env, jobject obj);
23 JavaObjectWeakGlobalRef(JNIEnv* env,
24 const base::android::JavaRef<jobject>& obj);
25 virtual ~JavaObjectWeakGlobalRef();
27 void operator=(const JavaObjectWeakGlobalRef& rhs);
28 void operator=(JavaObjectWeakGlobalRef&& rhs);
30 base::android::ScopedJavaLocalRef<jobject> get(JNIEnv* env) const;
32 // Returns true if the weak reference has not been initialized to point at
33 // an object (or ḣas had reset() called).
34 // Do not call this to test if the object referred to still exists! The weak
35 // reference remains initialized even if the target object has been collected.
36 bool is_uninitialized() const { return obj_ == nullptr; }
41 void Assign(const JavaObjectWeakGlobalRef& rhs);
46 // Get the real object stored in the weak reference returned as a
47 // ScopedJavaLocalRef.
48 BASE_EXPORT base::android::ScopedJavaLocalRef<jobject> GetRealObject(
49 JNIEnv* env, jweak obj);
51 #endif // BASE_ANDROID_JNI_WEAK_REF_H_