///////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2010 Artyom Beilis (Tonkikh) <artyomtnk@yahoo.com>
//
// This program 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, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 program. If not, see <http://www.gnu.org/licenses/>.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef CPPDB_POOL_H
#define CPPDB_POOL_H
#include <cppdb/defs.h>
#include <cppdb/ref_ptr.h>
#include <cppdb/mutex.h>
#include <cppdb/utils.h>
#include <memory>
#include <list>
namespace cppdb {
class connection_info;
namespace backend {
class connection;
}
///
/// \brief Connections pool, allows to handle multiple connections for specific connection string.
///
/// Note connections_manager provide more generic interface and hides pools inside it. So you
/// generally should not use this class directly.
///
/// Unlike connections_manager, it uses pool by default unless its size defined as 0.
///
/// All this class member functions are thread safe to use from several threads for the same object
///
class CPPDB_API pool : public ref_counted {
pool();
pool(pool const &);
void operator=(pool const &);
pool(connection_info const &ci);
public:
/// Create new pool for \a connection_string
static ref_ptr<pool> create(std::string const &connection_string);
/// Create new pool for a parsed connection string \a ci
static ref_ptr<pool> create(connection_info const &ci);
~pool();
///
/// Get a open a connection, it may be fetched either from pool or new one may be created
///
ref_ptr<backend::connection> open();
///
/// Collect connections that were not used for a long time (close them)
///
void gc();
/// \cond INTERNAL
void put(backend::connection *c_in);
/// \endcond
private:
ref_ptr<backend::connection> get();
struct data;
std::auto_ptr<data> d;
struct entry {
entry() : last_used(0) {}
ref_ptr<backend::connection> conn;
time_t last_used;
};
typedef std::list<entry> pool_type;
// non-mutable members
size_t limit_;
int life_time_;
connection_info ci_;
// mutex protected begin
mutex lock_;
size_t size_;
pool_type pool_;
// mutex protected end
};
}
#endif
