164 lines
4.1 KiB
C++
164 lines
4.1 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2015 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#ifndef MAPNIK_POOL_HPP
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#define MAPNIK_POOL_HPP
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// mapnik
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#include <mapnik/util/singleton.hpp>
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#include <mapnik/util/noncopyable.hpp>
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// boost
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#include <memory>
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#ifdef MAPNIK_THREADSAFE
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#include <mutex>
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#endif
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// stl
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#include <algorithm> // std::max
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#include <deque>
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namespace mapnik
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{
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template <typename T,template <typename> class Creator>
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class Pool : private util::noncopyable
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{
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using HolderType = std::shared_ptr<T>;
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using ContType = std::deque<HolderType>;
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Creator<T> creator_;
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unsigned initialSize_;
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unsigned maxSize_;
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ContType pool_;
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#ifdef MAPNIK_THREADSAFE
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mutable std::mutex mutex_;
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#endif
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public:
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Pool(const Creator<T>& creator,unsigned initialSize, unsigned maxSize)
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:creator_(creator),
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initialSize_(initialSize),
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maxSize_(maxSize)
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{
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for (unsigned i=0; i < initialSize_; ++i)
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{
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HolderType conn(creator_());
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if (conn->isOK())
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pool_.push_back(conn);
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}
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}
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HolderType borrowObject()
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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typename ContType::iterator itr=pool_.begin();
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while ( itr!=pool_.end())
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{
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if (!itr->unique())
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{
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++itr;
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}
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else if ((*itr)->isOK())
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{
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return *itr;
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}
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else
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{
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itr=pool_.erase(itr);
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}
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}
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// all connection have been taken, check if we allowed to grow pool
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if (pool_.size() < maxSize_)
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{
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HolderType conn(creator_());
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if (conn->isOK())
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{
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pool_.push_back(conn);
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return conn;
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}
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}
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return HolderType();
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}
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unsigned size() const
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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return pool_.size();
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}
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unsigned max_size() const
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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return maxSize_;
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}
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void set_max_size(unsigned size)
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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maxSize_ = std::max(maxSize_,size);
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}
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unsigned initial_size() const
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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return initialSize_;
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}
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void set_initial_size(unsigned size)
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{
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#ifdef MAPNIK_THREADSAFE
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std::lock_guard<std::mutex> lock(mutex_);
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#endif
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if (size > initialSize_)
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{
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initialSize_ = size;
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unsigned total_size = pool_.size();
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// ensure we don't have ghost obj's in the pool.
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if (total_size < initialSize_)
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{
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unsigned grow_size = initialSize_ - total_size ;
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for (unsigned i=0; i < grow_size; ++i)
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{
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HolderType conn(creator_());
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if (conn->isOK())
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pool_.push_back(conn);
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}
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}
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}
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}
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};
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}
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#endif // MAPNIK_POOL_HPP
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