phoenix-firestorm/indra/llcommon/llinstancetracker.h

284 lines
7.0 KiB
C++

/**
* @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>
class LL_COMMON_API LLInstanceTrackerBase : public boost::noncopyable
{
protected:
static void * & getInstances(std::type_info const & info);
};
/// 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 : public LLInstanceTrackerBase
{
typedef typename std::map<KEY, T*> InstanceMap;
typedef LLInstanceTracker<T, KEY> MyT;
public:
class instance_iter : public boost::iterator_facade<instance_iter, T, boost::forward_traversal_tag>
{
public:
typedef boost::iterator_facade<instance_iter, T, boost::forward_traversal_tag> super_t;
instance_iter(const typename InstanceMap::iterator& it)
: mIterator(it)
{
++sIterationNestDepth;
}
~instance_iter()
{
--sIterationNestDepth;
}
private:
friend class boost::iterator_core_access;
void increment() { mIterator++; }
bool equal(instance_iter const& other) const
{
return mIterator == other.mIterator;
}
T& dereference() const
{
return *(mIterator->second);
}
typename InstanceMap::iterator mIterator;
};
class key_iter : public boost::iterator_facade<key_iter, KEY, boost::forward_traversal_tag>
{
public:
typedef boost::iterator_facade<key_iter, KEY, boost::forward_traversal_tag> super_t;
key_iter(typename InstanceMap::iterator& it)
: mIterator(it)
{
++sIterationNestDepth;
}
key_iter(const key_iter& other)
: mIterator(other.mIterator)
{
++sIterationNestDepth;
}
~key_iter()
{
--sIterationNestDepth;
}
private:
friend class boost::iterator_core_access;
void increment() { mIterator++; }
bool equal(key_iter const& other) const
{
return mIterator == other.mIterator;
}
KEY& dereference() const
{
return const_cast<KEY&>(mIterator->first);
}
typename InstanceMap::iterator mIterator;
};
static T* getInstance(const KEY& k)
{
typename InstanceMap::const_iterator found = getMap_().find(k);
return (found == getMap_().end()) ? NULL : found->second;
}
static instance_iter beginInstances()
{
return instance_iter(getMap_().begin());
}
static instance_iter endInstances()
{
return instance_iter(getMap_().end());
}
static S32 instanceCount() { return getMap_().size(); }
static key_iter beginKeys()
{
return key_iter(getMap_().begin());
}
static key_iter endKeys()
{
return key_iter(getMap_().end());
}
protected:
LLInstanceTracker(KEY key) { add_(key); }
virtual ~LLInstanceTracker()
{
// it's unsafe to delete instances of this type while all instances are being iterated over.
llassert(sIterationNestDepth == 0);
remove_();
}
virtual void setKey(KEY key) { remove_(); add_(key); }
virtual const KEY& getKey() const { return mInstanceKey; }
private:
void add_(KEY key)
{
mInstanceKey = key;
getMap_()[key] = static_cast<T*>(this);
}
void remove_()
{
getMap_().erase(mInstanceKey);
}
static InstanceMap& getMap_()
{
void * & instances = getInstances(typeid(MyT));
if (! instances)
{
instances = new InstanceMap;
}
return * static_cast<InstanceMap*>(instances);
}
private:
KEY mInstanceKey;
static S32 sIterationNestDepth;
};
template <typename T, typename KEY> S32 LLInstanceTracker<T, KEY>::sIterationNestDepth = 0;
/// explicit specialization for default case where KEY is T*
/// use a simple std::set<T*>
template<typename T>
class LLInstanceTracker<T, T*> : public LLInstanceTrackerBase
{
typedef typename std::set<T*> InstanceSet;
typedef LLInstanceTracker<T, T*> MyT;
public:
/// for completeness of analogy with the generic implementation
static T* getInstance(T* k) { return k; }
static S32 instanceCount() { return getSet_().size(); }
class instance_iter : public boost::iterator_facade<instance_iter, T, boost::forward_traversal_tag>
{
public:
instance_iter(const typename InstanceSet::iterator& it)
: mIterator(it)
{
++sIterationNestDepth;
}
instance_iter(const instance_iter& other)
: mIterator(other.mIterator)
{
++sIterationNestDepth;
}
~instance_iter()
{
--sIterationNestDepth;
}
private:
friend class boost::iterator_core_access;
void increment() { mIterator++; }
bool equal(instance_iter const& other) const
{
return mIterator == other.mIterator;
}
T& dereference() const
{
return **mIterator;
}
typename InstanceSet::iterator mIterator;
};
static instance_iter beginInstances() { return instance_iter(getSet_().begin()); }
static instance_iter endInstances() { return instance_iter(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.
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)
{
getSet_().insert(static_cast<T*>(this));
}
static InstanceSet& getSet_()
{
void * & instances = getInstances(typeid(MyT));
if (! instances)
{
instances = new InstanceSet;
}
return * static_cast<InstanceSet *>(instances);
}
static S32 sIterationNestDepth;
};
template <typename T> S32 LLInstanceTracker<T, T*>::sIterationNestDepth = 0;
#endif