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      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 #include "base/android/jni_weak_ref.h"
      6 
      7 #include <utility>
      8 
      9 #include "base/android/jni_android.h"
     10 #include "base/logging.h"
     11 
     12 using base::android::AttachCurrentThread;
     13 
     14 JavaObjectWeakGlobalRef::JavaObjectWeakGlobalRef() : obj_(nullptr) {}
     15 
     16 JavaObjectWeakGlobalRef::JavaObjectWeakGlobalRef(
     17     const JavaObjectWeakGlobalRef& orig)
     18     : obj_(nullptr) {
     19   Assign(orig);
     20 }
     21 
     22 JavaObjectWeakGlobalRef::JavaObjectWeakGlobalRef(JavaObjectWeakGlobalRef&& orig)
     23     : obj_(orig.obj_) {
     24   orig.obj_ = nullptr;
     25 }
     26 
     27 JavaObjectWeakGlobalRef::JavaObjectWeakGlobalRef(JNIEnv* env, jobject obj)
     28     : obj_(env->NewWeakGlobalRef(obj)) {
     29 }
     30 
     31 JavaObjectWeakGlobalRef::JavaObjectWeakGlobalRef(
     32     JNIEnv* env,
     33     const base::android::JavaRef<jobject>& obj)
     34     : obj_(env->NewWeakGlobalRef(obj.obj())) {
     35 }
     36 
     37 JavaObjectWeakGlobalRef::~JavaObjectWeakGlobalRef() {
     38   reset();
     39 }
     40 
     41 void JavaObjectWeakGlobalRef::operator=(const JavaObjectWeakGlobalRef& rhs) {
     42   Assign(rhs);
     43 }
     44 
     45 void JavaObjectWeakGlobalRef::operator=(JavaObjectWeakGlobalRef&& rhs) {
     46   std::swap(obj_, rhs.obj_);
     47 }
     48 
     49 void JavaObjectWeakGlobalRef::reset() {
     50   if (obj_) {
     51     AttachCurrentThread()->DeleteWeakGlobalRef(obj_);
     52     obj_ = nullptr;
     53   }
     54 }
     55 
     56 base::android::ScopedJavaLocalRef<jobject>
     57     JavaObjectWeakGlobalRef::get(JNIEnv* env) const {
     58   return GetRealObject(env, obj_);
     59 }
     60 
     61 base::android::ScopedJavaLocalRef<jobject> GetRealObject(
     62     JNIEnv* env, jweak obj) {
     63   jobject real = nullptr;
     64   if (obj)
     65     real = env->NewLocalRef(obj);
     66   return base::android::ScopedJavaLocalRef<jobject>(env, real);
     67 }
     68 
     69 void JavaObjectWeakGlobalRef::Assign(const JavaObjectWeakGlobalRef& other) {
     70   if (&other == this)
     71     return;
     72 
     73   JNIEnv* env = AttachCurrentThread();
     74   if (obj_)
     75     env->DeleteWeakGlobalRef(obj_);
     76 
     77   obj_ = other.obj_ ? env->NewWeakGlobalRef(other.obj_) : nullptr;
     78 }
     79