/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ /************************************************************************* * * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * Copyright 2000, 2010 Oracle and/or its affiliates. * * OpenOffice.org - a multi-platform office productivity suite * * This file is part of OpenOffice.org. * * OpenOffice.org is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License version 3 * only, as published by the Free Software Foundation. * * OpenOffice.org is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License version 3 for more details * (a copy is included in the LICENSE file that accompanied this code). * * You should have received a copy of the GNU Lesser General Public License * version 3 along with OpenOffice.org. If not, see * * for a copy of the LGPLv3 License. * ************************************************************************/ #ifndef COMPHELPER_ACCESSIBLE_CONTEXT_HELPER_HXX #define COMPHELPER_ACCESSIBLE_CONTEXT_HELPER_HXX #include #include #include #include #include #include "comphelper/comphelperdllapi.h" //......................................................................... namespace comphelper { //......................................................................... class AccessibleEventBuffer; //===================================================================== //= IMutex //===================================================================== // This whole thingie here (own mutex classes and such) is a HACK. I hate the SolarMutex. // See below for more explanations .... /** abstract interface for implementing a mutex */ class IMutex { public: virtual void acquire() = 0; virtual void release() = 0; }; //===================================================================== //= OMutexGuard //===================================================================== class OMutexGuard { IMutex* m_pMutex; public: inline OMutexGuard( IMutex* _pMutex ) :m_pMutex( _pMutex ) { if ( m_pMutex ) m_pMutex->acquire(); } inline ~OMutexGuard( ) { if ( m_pMutex ) m_pMutex->release(); } }; //===================================================================== //= OAccessibleContextHelper //===================================================================== class OContextHelper_Impl; typedef ::cppu::WeakAggComponentImplHelper2 < ::com::sun::star::accessibility::XAccessibleContext, ::com::sun::star::accessibility::XAccessibleEventBroadcaster > OAccessibleContextHelper_Base; /** helper class for implementing an AccessibleContext */ class COMPHELPER_DLLPUBLIC OAccessibleContextHelper :public ::comphelper::OBaseMutex ,public OAccessibleContextHelper_Base { private: OContextHelper_Impl* m_pImpl; protected: OAccessibleContextHelper( ); ~OAccessibleContextHelper( ); /** ctor

If you need additional object safety for your class, and want to ensure that your own mutex is locked before the mutex this class provides is, than use this ctor.

Beware that this is a hack. Unfortunately, OpenOffice.org has two different mutex hierarchies, which are not compatible. In addition, wide parts of the code (especially VCL) is not thread-safe, but instead relies on a single global mutex. As a consequence, components using directly or indirectly such code need to care for this global mutex. Yes, this is as ugly as anything.

Note that the external lock is used as additional lock, not as the only one. The own mutex of the instance is used for internal actions, and every action which potentially involves external code (for instance every call to a virtual method overridden by derivees) is additionally and first guarded by with the external lock.

Beware of the lifetime of the lock - you must ensure that the lock exists at least as long as the context does. A good approach to implement the lock may be to derive you own context not only from OAccessibleContextHelper, but also from IMutex.

One more note. This lock is definately not used once the dtor is reached. Means whatever the dtor implementation does, it does not guard the external lock. See this as a contract.
You should ensure the same thing for own derivees which do not supply the lock themself, but get them from yet another derivee.

@see forgetExternalLock */ OAccessibleContextHelper( IMutex* _pExternalLock ); /** late construction @param _rxAccessible the Accessible object which created this context.

If your derived implementation implements the XAccessible (and does not follow the proposed separation of XAccessible from XAccessibleContext), you may pass this here.

The object is hold weak, so it's life time is not affected.

The object is needed for performance reasons: for getAccessibleIndexInParent, all children (which are XAccessible's theirself) of our parent have to be asked. If we know our XAccessible, we can compare it with all the children, instead of asking all children for their context and comparing this context with ourself.

*/ void lateInit( const ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessible >& _rxAccessible ); /** retrieves the creator previously set with lateInit */ ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessible > getAccessibleCreator( ) const; /** forgets the reference to the external lock, if present.

This means any further locking will not be guard the external lock anymore, never.

To be used in derived classes which do not supply the external lock themself, but instead get them passed from own derivees (or clients).

*/ void forgetExternalLock(); public: // XAccessibleEventBroadcaster using WeakAggComponentImplHelperBase::addEventListener; virtual void SAL_CALL addEventListener( const ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleEventListener >& xListener ) throw (::com::sun::star::uno::RuntimeException); using WeakAggComponentImplHelperBase::removeEventListener; virtual void SAL_CALL removeEventListener( const ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleEventListener >& xListener ) throw (::com::sun::star::uno::RuntimeException); // XAccessibleContext - still waiting to be overwritten virtual sal_Int32 SAL_CALL getAccessibleChildCount( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessible > SAL_CALL getAccessibleChild( sal_Int32 i ) throw (::com::sun::star::lang::IndexOutOfBoundsException, ::com::sun::star::uno::RuntimeException) = 0; virtual ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessible > SAL_CALL getAccessibleParent( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual sal_Int16 SAL_CALL getAccessibleRole( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual ::rtl::OUString SAL_CALL getAccessibleDescription( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual ::rtl::OUString SAL_CALL getAccessibleName( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleRelationSet > SAL_CALL getAccessibleRelationSet( ) throw (::com::sun::star::uno::RuntimeException) = 0; virtual ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleStateSet > SAL_CALL getAccessibleStateSet( ) throw (::com::sun::star::uno::RuntimeException) = 0; // XAccessibleContext - default implementations /** default implementation for retrieving the index of this object within the parent

This basic implementation here returns the index i of the child for which <parent>.getAccessibleChild( i ) equals our creator.

*/ virtual sal_Int32 SAL_CALL getAccessibleIndexInParent( ) throw (::com::sun::star::uno::RuntimeException); /** default implementation for retrieving the locale

This basic implementation returns the locale of the parent context, as retrieved via getAccessibleParent()->getAccessibleContext.

*/ virtual ::com::sun::star::lang::Locale SAL_CALL getLocale( ) throw (::com::sun::star::accessibility::IllegalAccessibleComponentStateException, ::com::sun::star::uno::RuntimeException); public: // helper struct for granting selective access rights struct OAccessControl { friend class OContextEntryGuard; friend class OContextHelper_Impl; friend class OExternalLockGuard; private: OAccessControl() { } }; // ensures that the object is alive inline void ensureAlive( const OAccessControl& ) const SAL_THROW( ( ::com::sun::star::lang::DisposedException ) ); inline IMutex* getExternalLock( const OAccessControl& ); inline ::osl::Mutex& GetMutex( const OAccessControl& ); protected: // OComponentHelper virtual void SAL_CALL disposing(); protected: // helper /** notifies all AccessibleEventListeners of a certain event @precond not too be called with our mutex locked @param _nEventId the id of the even. See AccessibleEventType @param _rOldValue the old value to be notified @param _rNewValue the new value to be notified */ virtual void SAL_CALL NotifyAccessibleEvent( const sal_Int16 _nEventId, const ::com::sun::star::uno::Any& _rOldValue, const ::com::sun::star::uno::Any& _rNewValue ); /** records a certain event so that all AccessibleEventListeners can be notified later on. Can even be called with our mutex locked. @param _nEventId the id of the even. See AccessibleEventType @param _rOldValue the old value to be notified @param _rNewValue the new value to be notified @param _rBuffer the buffer that records the event */ virtual void SAL_CALL BufferAccessibleEvent( const sal_Int16 _nEventId, const ::com::sun::star::uno::Any& _rOldValue, const ::com::sun::star::uno::Any& _rNewValue, AccessibleEventBuffer & _rBuffer ); // life time control /// checks whether the object is alive (returns then) or disposed sal_Bool isAlive() const; /// checks for beeing alive. If the object is already disposed (i.e. not alive), an exception is thrown. void ensureAlive() const SAL_THROW( ( ::com::sun::star::lang::DisposedException ) ); /** ensures that the object is disposed. @precond to be called from within the destructor of your derived class only! */ void ensureDisposed( ); /** shortcut for retrieving the context of the parent (returned by getAccessibleParent) */ ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext > implGetParentContext() SAL_THROW( ( ::com::sun::star::uno::RuntimeException ) ); // access to the base class' broadcast helper/mutex ::cppu::OBroadcastHelper& GetBroadcastHelper() { return rBHelper; } const ::cppu::OBroadcastHelper& GetBroadcastHelper() const { return rBHelper; } ::osl::Mutex& GetMutex() { return m_aMutex; } IMutex* getExternalLock( ); }; //--------------------------------------------------------------------- inline void OAccessibleContextHelper::ensureAlive( const OAccessControl& ) const SAL_THROW( ( ::com::sun::star::lang::DisposedException ) ) { ensureAlive(); } //--------------------------------------------------------------------- inline IMutex* OAccessibleContextHelper::getExternalLock( const OAccessControl& ) { return getExternalLock(); } //--------------------------------------------------------------------- inline ::osl::Mutex& OAccessibleContextHelper::GetMutex( const OAccessControl& ) { return GetMutex(); } //===================================================================== //= OContextEntryGuard //===================================================================== typedef ::osl::ClearableMutexGuard OContextEntryGuard_Base; /** helper class for guarding the entry into OAccessibleContextHelper methods.

The class has two responsibilities:

  • it locks the mutex of an OAccessibleContextHelper instance, as long as the guard lives
  • it checks if an given OAccessibleContextHelper instance is alive, else an exception is thrown our of the constructor of the guard

This makes it your first choice (hopefully :) for guarding any interface method implementations of you derived class.

*/ class OContextEntryGuard : public OContextEntryGuard_Base { public: /** constructs the guard

The given context (it's mutex, respectively) is locked, and an exception is thrown if the context is not alive anymore. In the latter case, of course, the mutex is freed, again.

@param _pContext the context which shall be guarded @precond _pContext != NULL */ inline OContextEntryGuard( OAccessibleContextHelper* _pContext ); /** destructs the guard.

The context (it's mutex, respectively) is unlocked.

*/ inline ~OContextEntryGuard(); }; //..................................................................... inline OContextEntryGuard::OContextEntryGuard( OAccessibleContextHelper* _pContext ) :OContextEntryGuard_Base( _pContext->GetMutex( OAccessibleContextHelper::OAccessControl() ) ) { _pContext->ensureAlive( OAccessibleContextHelper::OAccessControl() ); } //..................................................................... inline OContextEntryGuard::~OContextEntryGuard() { } //===================================================================== //= OExternalLockGuard //===================================================================== class OExternalLockGuard :public OMutexGuard ,public OContextEntryGuard { public: inline OExternalLockGuard( OAccessibleContextHelper* _pContext ); inline ~OExternalLockGuard( ); }; //..................................................................... inline OExternalLockGuard::OExternalLockGuard( OAccessibleContextHelper* _pContext ) :OMutexGuard( _pContext->getExternalLock( OAccessibleContextHelper::OAccessControl() ) ) ,OContextEntryGuard( _pContext ) { // #102438# // Only lock the external mutex, // release the ::osl::Mutex of the OAccessibleContextHelper instance. // If you call into another UNO object with locked ::osl::Mutex, // this may lead to dead locks. clear(); } //..................................................................... inline OExternalLockGuard::~OExternalLockGuard( ) { } //......................................................................... } // namespace comphelper //......................................................................... #endif // COMPHELPER_ACCESSIBLE_CONTEXT_HELPER_HXX /* vim:set shiftwidth=4 softtabstop=4 expandtab: */