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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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
15 : * License, Version 2.0 (the "License"); you may not use this file
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 : #ifndef INCLUDED_DBACCESS_SOURCE_SDBTOOLS_CONNECTION_CONNECTIONDEPENDENT_HXX
21 : #define INCLUDED_DBACCESS_SOURCE_SDBTOOLS_CONNECTION_CONNECTIONDEPENDENT_HXX
22 :
23 : #include <com/sun/star/sdbc/XConnection.hpp>
24 : #include <com/sun/star/lang/DisposedException.hpp>
25 : #include <com/sun/star/uno/XComponentContext.hpp>
26 :
27 : #include <cppuhelper/weakref.hxx>
28 : #include <osl/mutex.hxx>
29 :
30 : namespace sdbtools
31 : {
32 :
33 : // ConnectionDependentComponent
34 0 : class ConnectionDependentComponent
35 : {
36 : private:
37 : mutable ::osl::Mutex m_aMutex;
38 : ::com::sun::star::uno::WeakReference< ::com::sun::star::sdbc::XConnection >
39 : m_aConnection;
40 : ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext >
41 : m_aContext;
42 :
43 : /** a hard reference to the connection we're working for
44 :
45 : This member is only valid as long as a EntryGuard is on the stack.
46 : The guard will, in its constructor, set the member, and reset it in its destructor.
47 : This ensures that the connection is only held hard when it's needed, and weak otherwise.
48 : */
49 : ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >
50 : m_xConnection;
51 :
52 : protected:
53 0 : ::osl::Mutex& getMutex() const { return m_aMutex; }
54 :
55 : const ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext >&
56 0 : getContext() const { return m_aContext; }
57 :
58 : protected:
59 : class EntryGuard;
60 :
61 : protected:
62 0 : ConnectionDependentComponent( const ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext > & _rContext )
63 0 : :m_aContext( _rContext )
64 : {
65 0 : }
66 :
67 : /** sets the connection we depend on.
68 :
69 : To be called exactly once.
70 :
71 : @param _rxConnection
72 : the connection to set
73 : */
74 0 : void setWeakConnection( const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >& _rxConnection )
75 : {
76 0 : m_aConnection = _rxConnection;
77 0 : }
78 :
79 : const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >&
80 0 : getConnection() const { return m_xConnection; }
81 :
82 : public:
83 : struct GuardAccess;
84 : friend struct GuardAccess;
85 : /** helper for granting exclusive access to various other methods
86 : */
87 0 : struct GuardAccess { friend class EntryGuard; private: GuardAccess() { } };
88 :
89 0 : ::osl::Mutex& getMutex( GuardAccess ) const { return m_aMutex; }
90 :
91 0 : inline bool acquireConnection( GuardAccess )
92 : {
93 0 : m_xConnection = (::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >)m_aConnection;
94 0 : return m_xConnection.is();
95 : }
96 0 : inline void releaseConnection( GuardAccess )
97 : {
98 0 : m_xConnection.clear();
99 0 : }
100 : };
101 :
102 : // ConnectionDependentComponent::EntryGuard
103 : /** a class for guarding methods of a connection-dependent component
104 :
105 : This class serves multiple purposes:
106 : <ul><li>It ensures multi-threading safety by guarding the component's mutex
107 : as long as it lives.</li>
108 : <li>It ensures that the component's connection is alive. The constructor
109 : throws a DisposedException if no hard reference to the connection can
110 : be obtained.</li>
111 : </ul>
112 : */
113 : class ConnectionDependentComponent::EntryGuard
114 : {
115 : private:
116 : ::osl::MutexGuard m_aMutexGuard;
117 : ConnectionDependentComponent& m_rComponent;
118 :
119 : public:
120 0 : EntryGuard( ConnectionDependentComponent& _rComponent )
121 0 : :m_aMutexGuard( _rComponent.getMutex( ConnectionDependentComponent::GuardAccess() ) )
122 0 : ,m_rComponent( _rComponent )
123 : {
124 0 : if ( !m_rComponent.acquireConnection( ConnectionDependentComponent::GuardAccess() ) )
125 0 : throw ::com::sun::star::lang::DisposedException();
126 0 : }
127 :
128 0 : ~EntryGuard()
129 0 : {
130 0 : m_rComponent.releaseConnection( ConnectionDependentComponent::GuardAccess() );
131 0 : }
132 : };
133 :
134 : } // namespace sdbtools
135 :
136 : #endif // INCLUDED_DBACCESS_SOURCE_SDBTOOLS_CONNECTION_CONNECTIONDEPENDENT_HXX
137 :
138 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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