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| -rw-r--r-- | cppuhelper/source/weak.cxx | 561 |
1 files changed, 561 insertions, 0 deletions
diff --git a/cppuhelper/source/weak.cxx b/cppuhelper/source/weak.cxx new file mode 100644 index 000000000..e51f9ccf8 --- /dev/null +++ b/cppuhelper/source/weak.cxx @@ -0,0 +1,561 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ + +#include <sal/config.h> +#include <sal/log.hxx> + +#include <osl/diagnose.h> +#include <cppuhelper/weakagg.hxx> +#include <cppuhelper/exc_hlp.hxx> +#include <cppuhelper/queryinterface.hxx> + +#include <com/sun/star/lang/DisposedException.hpp> + +#include <algorithm> +#include <vector> +#include <mutex> + +using namespace osl; +using namespace com::sun::star::uno; + +namespace cppu +{ + +// due to static Reflection destruction from usr, there must be a mutex leak (#73272#) +// this is used to lock all instances of OWeakConnectionPoint and OWeakRefListener as well as OWeakObject::m_pWeakConnectionPoint +static std::mutex * gpWeakMutex = new std::mutex; + + +//-- OWeakConnectionPoint ---------------------------------------------------- + +class OWeakConnectionPoint: public XAdapter +{ +public: + /** + Hold the weak object without an acquire (only the pointer). + */ + explicit OWeakConnectionPoint( OWeakObject* pObj ) + : m_aRefCount( 0 ) + , m_pObject(pObj) + {} + + // noncopyable + OWeakConnectionPoint(const OWeakConnectionPoint&) = delete; + const OWeakConnectionPoint& operator=(const OWeakConnectionPoint&) = delete; + + // XInterface + Any SAL_CALL queryInterface( const Type & rType ) override; + void SAL_CALL acquire() noexcept override; + void SAL_CALL release() noexcept override; + + // XAdapter + css::uno::Reference< css::uno::XInterface > SAL_CALL queryAdapted() override; + void SAL_CALL addReference( const css::uno::Reference< css::uno::XReference >& xRef ) override; + void SAL_CALL removeReference( const css::uno::Reference< css::uno::XReference >& xRef ) override; + + /// Called from the weak object if the reference count goes to zero. + /// + /// @throws css::uno::RuntimeException + void dispose(); + +private: + virtual ~OWeakConnectionPoint() {} + + /// The reference counter. + oslInterlockedCount m_aRefCount; + /// The weak object + OWeakObject* m_pObject; + /// The container to hold the weak references + std::vector<Reference<XReference>> m_aReferences; +}; + +// XInterface +Any SAL_CALL OWeakConnectionPoint::queryInterface( const Type & rType ) +{ + return ::cppu::queryInterface( + rType, static_cast< XAdapter * >( this ), static_cast< XInterface * >( this ) ); +} + +// XInterface +void SAL_CALL OWeakConnectionPoint::acquire() noexcept +{ +#ifdef DBG_UTIL + // catch things early which have been deleted and then re-acquired + assert(m_aRefCount != -1); +#endif + osl_atomic_increment( &m_aRefCount ); +} + +// XInterface +void SAL_CALL OWeakConnectionPoint::release() noexcept +{ + if (! osl_atomic_decrement( &m_aRefCount )) + { +#ifdef DBG_UTIL + m_aRefCount = -1; +#endif + delete this; + } +} + +void OWeakConnectionPoint::dispose() +{ + std::vector<Reference<XReference>> aCopy; + { // only hold the mutex while we access the field + std::scoped_lock aGuard(*cppu::gpWeakMutex); + // OWeakObject is not the only owner of this, so clear m_pObject + // so that queryAdapted() won't use it now that it's dead + m_pObject = nullptr; + // other code is going to call removeReference while we are doing this, so we need a + // copy, but since we are disposing and going away, we can just take the original data + aCopy.swap(m_aReferences); + } + Any ex; + for (const Reference<XReference> & i : aCopy ) + { + try + { + i->dispose(); + } + catch (css::lang::DisposedException &) {} + catch (RuntimeException &) + { + ex = cppu::getCaughtException(); + } + } + if (ex.hasValue()) + { + cppu::throwException(ex); + } +} + +// XInterface +Reference< XInterface > SAL_CALL OWeakConnectionPoint::queryAdapted() +{ + Reference< XInterface > ret; + + { + std::scoped_lock guard(*gpWeakMutex); + + if (!m_pObject) + return ret; + + oslInterlockedCount n = osl_atomic_increment( &m_pObject->m_refCount ); + + if (n <= 1) + { + // Another thread wait in the dispose method at the guard + osl_atomic_decrement( &m_pObject->m_refCount ); + return ret; + } + } + + // n is now > 1 + // The reference is incremented. The object cannot be destroyed. + // Release the guard at the earliest point. + // WeakObject has a (XInterface *) cast operator + ret = *m_pObject; + osl_atomic_decrement( &m_pObject->m_refCount ); + + return ret; +} + +// XInterface +void SAL_CALL OWeakConnectionPoint::addReference(const Reference< XReference >& rRef) +{ + std::scoped_lock aGuard(*gpWeakMutex); + m_aReferences.push_back( rRef ); +} + +// XInterface +void SAL_CALL OWeakConnectionPoint::removeReference(const Reference< XReference >& rRef) +{ + std::scoped_lock aGuard(*gpWeakMutex); + // Search from end because the thing that last added a ref is most likely to be the + // first to remove a ref. + // It's not really valid to compare the pointer directly, but it's faster. + auto it = std::find_if(m_aReferences.rbegin(), m_aReferences.rend(), + [&rRef](const Reference<XReference>& rxRef) { return rxRef.get() == rRef.get(); }); + if (it != m_aReferences.rend()) { + m_aReferences.erase( it.base()-1 ); + return; + } + // interface not found, use the correct compare method + it = std::find(m_aReferences.rbegin(), m_aReferences.rend(), rRef); + if ( it != m_aReferences.rend() ) + m_aReferences.erase( it.base()-1 ); +} + + +//-- OWeakObject ------------------------------------------------------- + +// XInterface +Any SAL_CALL OWeakObject::queryInterface( const Type & rType ) +{ + return ::cppu::queryInterface( + rType, + static_cast< XWeak * >( this ), static_cast< XInterface * >( this ) ); +} + +// XInterface +void SAL_CALL OWeakObject::acquire() noexcept +{ + osl_atomic_increment( &m_refCount ); +} + +// XInterface +void SAL_CALL OWeakObject::release() noexcept +{ + if (osl_atomic_decrement( &m_refCount ) == 0) { + // notify/clear all weak-refs before object's dtor is executed + // (which may check weak-refs to this object): + disposeWeakConnectionPoint(); + // destroy object: + delete this; + } +} + +void OWeakObject::disposeWeakConnectionPoint() +{ + OSL_PRECOND( m_refCount == 0, "OWeakObject::disposeWeakConnectionPoint: only to be called with a ref count of 0!" ); + if (m_pWeakConnectionPoint != nullptr) { + OWeakConnectionPoint * const p = m_pWeakConnectionPoint; + m_pWeakConnectionPoint = nullptr; + try { + p->dispose(); + } + catch (RuntimeException const& exc) { + SAL_WARN( "cppuhelper", exc ); + } + p->release(); + } +} + +OWeakObject::~OWeakObject() COVERITY_NOEXCEPT_FALSE +{ +} + +// XWeak +Reference< XAdapter > SAL_CALL OWeakObject::queryAdapter() +{ + if (!m_pWeakConnectionPoint) + { + // only acquire mutex if member is not created + std::scoped_lock aGuard( *gpWeakMutex ); + if( !m_pWeakConnectionPoint ) + { + OWeakConnectionPoint * p = new OWeakConnectionPoint(this); + p->acquire(); + m_pWeakConnectionPoint = p; + } + } + + return m_pWeakConnectionPoint; +} + + +//-- OWeakAggObject ---------------------------------------------------- + +OWeakAggObject::~OWeakAggObject() +{ +} + +// XInterface +void OWeakAggObject::acquire() noexcept +{ + Reference<XInterface > x( xDelegator ); + if (x.is()) + x->acquire(); + else + OWeakObject::acquire(); +} + +// XInterface +void OWeakAggObject::release() noexcept +{ + Reference<XInterface > x( xDelegator ); + if (x.is()) + x->release(); + else + OWeakObject::release(); +} + +// XInterface +Any OWeakAggObject::queryInterface( const Type & rType ) +{ + Reference< XInterface > x( xDelegator ); // harden ref + return (x.is() ? x->queryInterface( rType ) : queryAggregation( rType )); +} + +// XAggregation +Any OWeakAggObject::queryAggregation( const Type & rType ) +{ + return ::cppu::queryInterface( + rType, + static_cast< XInterface * >( static_cast< OWeakObject * >( this ) ), + static_cast< XAggregation * >( this ), + static_cast< XWeak * >( this ) ); +} + +// XAggregation +void OWeakAggObject::setDelegator( const Reference<XInterface > & rDelegator ) +{ + xDelegator = rDelegator; +} + +} + +namespace com::sun::star::uno +{ + + +//-- OWeakRefListener ----------------------------------------------------- + +class OWeakRefListener final : public XReference +{ +public: + explicit OWeakRefListener(const Reference< XInterface >& xInt); + explicit OWeakRefListener(const Reference< XWeak >& xInt); + virtual ~OWeakRefListener(); + + // noncopyable + OWeakRefListener(const OWeakRefListener&) = delete; + const OWeakRefListener& operator=(const OWeakRefListener&) = delete; + + // XInterface + Any SAL_CALL queryInterface( const Type & rType ) override; + void SAL_CALL acquire() noexcept override; + void SAL_CALL release() noexcept override; + + // XReference + void SAL_CALL dispose() override; + + /// The reference counter. + oslInterlockedCount m_aRefCount; + /// The connection point of the weak object, guarded by getWeakMutex() + Reference< XAdapter > m_XWeakConnectionPoint; +}; + +OWeakRefListener::OWeakRefListener(const Reference< XInterface >& xInt) + : m_aRefCount( 1 ) +{ + try + { + Reference< XWeak > xWeak( Reference< XWeak >::query( xInt ) ); + + if (xWeak.is()) + { + m_XWeakConnectionPoint = xWeak->queryAdapter(); + + if (m_XWeakConnectionPoint.is()) + { + m_XWeakConnectionPoint->addReference(static_cast<XReference*>(this)); + } + } + } + catch (RuntimeException &) { OSL_ASSERT( false ); } // assert here, but no unexpected() + osl_atomic_decrement( &m_aRefCount ); +} + +OWeakRefListener::OWeakRefListener(const Reference< XWeak >& xWeak) + : m_aRefCount( 1 ) +{ + m_XWeakConnectionPoint = xWeak->queryAdapter(); + + if (m_XWeakConnectionPoint.is()) + { + m_XWeakConnectionPoint->addReference(static_cast<XReference*>(this)); + } + osl_atomic_decrement( &m_aRefCount ); +} + +OWeakRefListener::~OWeakRefListener() +{ + try + { + if (m_XWeakConnectionPoint.is()) + { + acquire(); // don't die again + m_XWeakConnectionPoint->removeReference(static_cast<XReference*>(this)); + } + } + catch (RuntimeException &) { OSL_ASSERT( false ); } // assert here, but no unexpected() +} + +// XInterface +Any SAL_CALL OWeakRefListener::queryInterface( const Type & rType ) +{ + return ::cppu::queryInterface( + rType, static_cast< XReference * >( this ), static_cast< XInterface * >( this ) ); +} + +// XInterface +void SAL_CALL OWeakRefListener::acquire() noexcept +{ + osl_atomic_increment( &m_aRefCount ); +} + +// XInterface +void SAL_CALL OWeakRefListener::release() noexcept +{ + if( ! osl_atomic_decrement( &m_aRefCount ) ) + delete this; +} + +void SAL_CALL OWeakRefListener::dispose() +{ + Reference< XAdapter > xAdp; + { + std::scoped_lock guard(*cppu::gpWeakMutex); + if( m_XWeakConnectionPoint.is() ) + { + xAdp = m_XWeakConnectionPoint; + m_XWeakConnectionPoint.clear(); + } + } + + if( xAdp.is() ) + xAdp->removeReference(static_cast<XReference*>(this)); +} + + +//-- WeakReferenceHelper ---------------------------------------------------------- + +WeakReferenceHelper::WeakReferenceHelper(const Reference< XInterface >& xInt) + : m_pImpl( nullptr ) +{ + if (xInt.is()) + { + m_pImpl = new OWeakRefListener(xInt); + m_pImpl->acquire(); + } +} + +WeakReferenceHelper::WeakReferenceHelper(const Reference< XWeak >& xWeak) + : m_pImpl( nullptr ) +{ + if (xWeak.is()) + { + m_pImpl = new OWeakRefListener(xWeak); + m_pImpl->acquire(); + } +} + +WeakReferenceHelper::WeakReferenceHelper(const WeakReferenceHelper& rWeakRef) + : m_pImpl( nullptr ) +{ + Reference< XInterface > xInt( rWeakRef.get() ); + if (xInt.is()) + { + m_pImpl = new OWeakRefListener(xInt); + m_pImpl->acquire(); + } +} + +void WeakReferenceHelper::clear() +{ + try + { + if (m_pImpl) + { + m_pImpl->dispose(); + m_pImpl->release(); + m_pImpl = nullptr; + } + } + catch (RuntimeException &) { OSL_ASSERT( false ); } // assert here, but no unexpected() +} + +WeakReferenceHelper& WeakReferenceHelper::operator=(const WeakReferenceHelper& rWeakRef) +{ + if (this == &rWeakRef) + { + return *this; + } + Reference< XInterface > xInt( rWeakRef.get() ); + return operator = ( xInt ); +} + +WeakReferenceHelper & WeakReferenceHelper::operator =( + WeakReferenceHelper && other) +{ + clear(); + std::swap(m_pImpl, other.m_pImpl); + return *this; +} + +WeakReferenceHelper & SAL_CALL +WeakReferenceHelper::operator= (const Reference< XInterface > & xInt) +{ + try + { + clear(); + if (xInt.is()) + { + m_pImpl = new OWeakRefListener(xInt); + m_pImpl->acquire(); + } + } + catch (RuntimeException &) { OSL_ASSERT( false ); } // assert here, but no unexpected() + return *this; +} + +WeakReferenceHelper & +WeakReferenceHelper::operator= (const Reference< XWeak > & xWeak) +{ + clear(); + if (xWeak) + { + m_pImpl = new OWeakRefListener(xWeak); + m_pImpl->acquire(); + } + return *this; +} + +WeakReferenceHelper::~WeakReferenceHelper() +{ + clear(); +} + +Reference< XInterface > WeakReferenceHelper::get() const +{ + try + { + Reference< XAdapter > xAdp; + { + // must lock to access m_XWeakConnectionPoint + std::scoped_lock guard(*cppu::gpWeakMutex); + if( m_pImpl && m_pImpl->m_XWeakConnectionPoint.is() ) + xAdp = m_pImpl->m_XWeakConnectionPoint; + } + + if (xAdp.is()) + return xAdp->queryAdapted(); + } + catch (RuntimeException &) + { + OSL_ASSERT( false ); + } // assert here, but no unexpected() + + return Reference< XInterface >(); +} + +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |