136 lines
4.6 KiB
C++
136 lines
4.6 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#pragma once
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#include <com/sun/star/sdbc/XConnection.hpp>
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#include <com/sun/star/lang/DisposedException.hpp>
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#include <com/sun/star/uno/XComponentContext.hpp>
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#include <cppuhelper/weakref.hxx>
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#include <osl/mutex.hxx>
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#include <utility>
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namespace sdbtools
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{
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// ConnectionDependentComponent
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class ConnectionDependentComponent
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{
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private:
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mutable ::osl::Mutex m_aMutex;
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css::uno::WeakReference< css::sdbc::XConnection >
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m_aConnection;
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css::uno::Reference< css::uno::XComponentContext >
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m_aContext;
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/** a hard reference to the connection we're working for
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This member is only valid as long as a EntryGuard is on the stack.
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The guard will, in its constructor, set the member, and reset it in its destructor.
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This ensures that the connection is only held hard when it's needed, and weak otherwise.
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*/
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css::uno::Reference< css::sdbc::XConnection >
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m_xConnection;
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protected:
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::osl::Mutex& getMutex() const { return m_aMutex; }
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const css::uno::Reference< css::uno::XComponentContext >&
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getContext() const { return m_aContext; }
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protected:
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class EntryGuard;
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protected:
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explicit ConnectionDependentComponent( css::uno::Reference< css::uno::XComponentContext > _xContext )
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:m_aContext(std::move( _xContext ))
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{
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}
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/** sets the connection we depend on.
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To be called exactly once.
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@param _rxConnection
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the connection to set
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*/
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void setWeakConnection( const css::uno::Reference< css::sdbc::XConnection >& _rxConnection )
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{
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m_aConnection = _rxConnection;
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}
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const css::uno::Reference< css::sdbc::XConnection >&
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getConnection() const { return m_xConnection; }
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public:
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struct GuardAccess;
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friend struct GuardAccess;
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/** helper for granting exclusive access to various other methods
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*/
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struct GuardAccess { friend class EntryGuard; private: GuardAccess() { } };
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::osl::Mutex& getMutex( GuardAccess ) const { return m_aMutex; }
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bool acquireConnection( GuardAccess )
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{
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m_xConnection.set(m_aConnection);
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return m_xConnection.is();
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}
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void releaseConnection( GuardAccess )
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{
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m_xConnection.clear();
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}
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};
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// ConnectionDependentComponent::EntryGuard
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/** a class for guarding methods of a connection-dependent component
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This class serves multiple purposes:
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<ul><li>It ensures multi-threading safety by guarding the component's mutex
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as long as it lives.</li>
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<li>It ensures that the component's connection is alive. The constructor
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throws a DisposedException if no hard reference to the connection can
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be obtained.</li>
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</ul>
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*/
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class ConnectionDependentComponent::EntryGuard
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{
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private:
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::osl::MutexGuard m_aMutexGuard;
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ConnectionDependentComponent& m_rComponent;
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public:
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explicit EntryGuard( ConnectionDependentComponent& _rComponent )
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:m_aMutexGuard( _rComponent.getMutex( ConnectionDependentComponent::GuardAccess() ) )
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,m_rComponent( _rComponent )
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{
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if ( !m_rComponent.acquireConnection( ConnectionDependentComponent::GuardAccess() ) )
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throw css::lang::DisposedException();
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}
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~EntryGuard()
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{
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m_rComponent.releaseConnection( ConnectionDependentComponent::GuardAccess() );
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}
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};
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} // namespace sdbtools
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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