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2 /*
3  * This file is part of the LibreOffice project.
4  *
5  * This Source Code Form is subject to the terms of the Mozilla Public
6  * License, v. 2.0. If a copy of the MPL was not distributed with this
7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8  *
9  * This file incorporates work covered by the following license notice:
10  *
11  *   Licensed to the Apache Software Foundation (ASF) under one or more
12  *   contributor license agreements. See the NOTICE file distributed
13  *   with this work for additional information regarding copyright
14  *   ownership. The ASF licenses this file to you under the Apache
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16  *   except in compliance with the License. You may obtain a copy of
17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
18  */
19 
20 #pragma once
21 
22 #if defined __clang__
23 #pragma clang diagnostic push
24 #pragma clang diagnostic ignored "-Wunknown-attributes"
25 #endif
26 #include <jni.h>
27 #if defined __clang__
28 #pragma clang diagnostic pop
29 #endif
30 
31 namespace connectivity::jdbc
32 {
33 
34     /** helper class to hold a local ref to a JNI object
35 
36         Note that this class never actually calls NewLocalRef. It is assumed that all objects
37         passed are already acquired with a local ref (as it usually is the case if you obtain
38         the object from a JNI method).
39     */
40     template< typename T >
41     class LocalRef final
42     {
43     public:
LocalRef(JNIEnv & environment)44         explicit LocalRef( JNIEnv& environment )
45             :m_environment( environment )
46             ,m_object( nullptr )
47         {
48         }
49 
LocalRef(JNIEnv & environment,T object)50         LocalRef( JNIEnv& environment, T object )
51             :m_environment( environment )
52             ,m_object( object )
53         {
54         }
55 
~LocalRef()56         ~LocalRef()
57         {
58             reset();
59         }
60 
release()61         T release()
62         {
63             T t = m_object;
64             m_object = nullptr;
65             return t;
66         }
67 
set(T object)68         void set( T object ) { reset(); m_object = object; }
69 
reset()70         void reset()
71         {
72             if ( m_object != nullptr )
73             {
74                 m_environment.DeleteLocalRef( m_object );
75                 m_object = nullptr;
76             }
77         }
78 
env() const79         JNIEnv& env() const { return m_environment; }
get() const80         T       get() const { return m_object; }
is() const81         bool    is()  const { return m_object != nullptr; }
82 
83     private:
84         LocalRef(LocalRef const &) = delete;
85         LocalRef& operator =(LocalRef const &) = delete;
86 
87         JNIEnv& m_environment;
88         T       m_object;
89     };
90 
91 
92 } // namespace connectivity::jdbc
93 
94 
95 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
96