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Diffstat (limited to 'indra/llcommon/llinstancetracker.h')
| -rw-r--r-- | indra/llcommon/llinstancetracker.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/indra/llcommon/llinstancetracker.h b/indra/llcommon/llinstancetracker.h new file mode 100644 index 0000000000..4945461d62 --- /dev/null +++ b/indra/llcommon/llinstancetracker.h @@ -0,0 +1,190 @@ +/** + * @file llinstancetracker.h + * @brief LLInstanceTracker is a mixin class that automatically tracks object + * instances with or without an associated key + * + * $LicenseInfo:firstyear=2000&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2010, Linden Research, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. + * + * This library 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 for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + */ + +#ifndef LL_LLINSTANCETRACKER_H +#define LL_LLINSTANCETRACKER_H + +#include <map> + +#include "string_table.h" +#include <boost/utility.hpp> +#include <boost/function.hpp> +#include <boost/bind.hpp> +#include <boost/iterator/transform_iterator.hpp> +#include <boost/iterator/indirect_iterator.hpp> + +/// This mix-in class adds support for tracking all instances of the specified class parameter T +/// The (optional) key associates a value of type KEY with a given instance of T, for quick lookup +/// If KEY is not provided, then instances are stored in a simple set +/// @NOTE: see explicit specialization below for default KEY==T* case +template<typename T, typename KEY = T*> +class LLInstanceTracker : boost::noncopyable +{ + typedef typename std::map<KEY, T*> InstanceMap; + typedef boost::function<const KEY&(typename InstanceMap::value_type&)> KeyGetter; + typedef boost::function<T*(typename InstanceMap::value_type&)> InstancePtrGetter; +public: + /// Dereferencing key_iter gives you a const KEY& + typedef boost::transform_iterator<KeyGetter, typename InstanceMap::iterator> key_iter; + /// Dereferencing instance_iter gives you a T& + typedef boost::indirect_iterator< boost::transform_iterator<InstancePtrGetter, typename InstanceMap::iterator> > instance_iter; + + static T* getInstance(const KEY& k) + { + typename InstanceMap::const_iterator found = getMap_().find(k); + return (found == getMap_().end()) ? NULL : found->second; + } + + static key_iter beginKeys() + { + return boost::make_transform_iterator(getMap_().begin(), + boost::bind(&InstanceMap::value_type::first, _1)); + } + static key_iter endKeys() + { + return boost::make_transform_iterator(getMap_().end(), + boost::bind(&InstanceMap::value_type::first, _1)); + } + static instance_iter beginInstances() + { + return instance_iter(boost::make_transform_iterator(getMap_().begin(), + boost::bind(&InstanceMap::value_type::second, _1))); + } + static instance_iter endInstances() + { + return instance_iter(boost::make_transform_iterator(getMap_().end(), + boost::bind(&InstanceMap::value_type::second, _1))); + } + static S32 instanceCount() { return getMap_().size(); } +protected: + LLInstanceTracker(KEY key) { add_(key); } + virtual ~LLInstanceTracker() { remove_(); } + virtual void setKey(KEY key) { remove_(); add_(key); } + virtual const KEY& getKey() const { return mKey; } + +private: + void add_(KEY key) + { + mKey = key; + getMap_()[key] = static_cast<T*>(this); + } + void remove_() + { + getMap_().erase(mKey); + } + + static InstanceMap& getMap_() + { + if (! sInstances) + { + sInstances = new InstanceMap; + } + return *sInstances; + } + +private: + + KEY mKey; + static InstanceMap* sInstances; +}; + +/// explicit specialization for default case where KEY is T* +/// use a simple std::set<T*> +template<typename T> +class LLInstanceTracker<T, T*> +{ + typedef typename std::set<T*> InstanceSet; +public: + /// Dereferencing key_iter gives you a T* (since T* is the key) + typedef typename InstanceSet::iterator key_iter; + /// Dereferencing instance_iter gives you a T& + typedef boost::indirect_iterator<key_iter> instance_iter; + + /// for completeness of analogy with the generic implementation + static T* getInstance(T* k) { return k; } + static S32 instanceCount() { return getSet_().size(); } + + // Instantiate this to get access to iterators for this type. It's a 'guard' in the sense + // that it treats deletes of this type as errors as long as there is an instance of + // this class alive in scope somewhere (i.e. deleting while iterating is bad). + class LLInstanceTrackerScopedGuard + { + public: + LLInstanceTrackerScopedGuard() + { + ++sIterationNestDepth; + } + + ~LLInstanceTrackerScopedGuard() + { + --sIterationNestDepth; + } + + static instance_iter beginInstances() { return instance_iter(getSet_().begin()); } + static instance_iter endInstances() { return instance_iter(getSet_().end()); } + static key_iter beginKeys() { return getSet_().begin(); } + static key_iter endKeys() { return getSet_().end(); } + }; + +protected: + LLInstanceTracker() + { + // it's safe but unpredictable to create instances of this type while all instances are being iterated over. I hate unpredictable. This assert will probably be turned on early in the next development cycle. + //llassert(sIterationNestDepth == 0); + getSet_().insert(static_cast<T*>(this)); + } + virtual ~LLInstanceTracker() + { + // it's unsafe to delete instances of this type while all instances are being iterated over. + llassert(sIterationNestDepth == 0); + getSet_().erase(static_cast<T*>(this)); + } + + LLInstanceTracker(const LLInstanceTracker& other) + { + //llassert(sIterationNestDepth == 0); + getSet_().insert(static_cast<T*>(this)); + } + + static InstanceSet& getSet_() + { + if (! sInstances) + { + sInstances = new InstanceSet; + } + return *sInstances; + } + + static InstanceSet* sInstances; + static S32 sIterationNestDepth; +}; + +template <typename T, typename KEY> typename LLInstanceTracker<T, KEY>::InstanceMap* LLInstanceTracker<T, KEY>::sInstances = NULL; +template <typename T> typename LLInstanceTracker<T, T*>::InstanceSet* LLInstanceTracker<T, T*>::sInstances = NULL; +template <typename T> S32 LLInstanceTracker<T, T*>::sIterationNestDepth = 0; + +#endif |