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// file : odb/mysql/connection-factory.hxx
// author : Boris Kolpackov <boris@codesynthesis.com>
// copyright : Copyright (c) 2009-2010 Code Synthesis Tools CC
// license : GNU GPL v2; see accompanying LICENSE file
#ifndef ODB_MYSQL_CONNECTION_FACTORY_HXX
#define ODB_MYSQL_CONNECTION_FACTORY_HXX
#include <vector>
#include <cstddef> // std::size_t
#include <odb/mysql/version.hxx>
#include <odb/mysql/forward.hxx>
#include <odb/mysql/connection.hxx>
#include <odb/details/mutex.hxx>
#include <odb/details/condition.hxx>
#include <odb/details/shared-ptr.hxx>
namespace odb
{
namespace mysql
{
class connection_factory
{
public:
virtual details::shared_ptr<connection>
connect () = 0;
public:
typedef mysql::database database_type;
virtual void
database (database_type&) = 0;
virtual
~connection_factory ();
};
class new_connection_factory: public connection_factory
{
public:
new_connection_factory ()
: db_ (0)
{
}
virtual details::shared_ptr<connection>
connect ();
virtual void
database (database_type&);
private:
new_connection_factory (const new_connection_factory&);
new_connection_factory& operator= (const new_connection_factory&);
private:
database_type* db_;
};
class connection_pool_factory: public connection_factory
{
public:
// The max_connections argument specifies the maximum number of
// concurrent connections this pool will maintain. If this value
// is 0 then the pool will create a new connection every time all
// of the existing connections are in use.
//
// The min_connections argument specifies the minimum number of
// connections that should be maintained by the pool. If the
// number of connections maintained by the pool exceeds this
// number and there are no active waiters for a new connection,
// then the pool will release the excess connections. If this
// value is 0 then the pool will maintain all the connections
// that were ever created.
//
connection_pool_factory (std::size_t max_connections = 0,
std::size_t min_connections = 0)
: max_ (max_connections),
min_ (min_connections),
in_use_ (0),
waiters_ (0),
db_ (0),
cond_ (mutex_)
{
// @@ check min_ <= max_
}
virtual details::shared_ptr<connection>
connect ();
virtual void
database (database_type&);
virtual
~connection_pool_factory ();
private:
connection_pool_factory (const connection_pool_factory&);
connection_pool_factory& operator= (const connection_pool_factory&);
private:
class pooled_connection: public connection
{
public:
// NULL pool value indicates that the connection is not in use.
//
pooled_connection (database_type&, connection_pool_factory*);
private:
static void
zero_counter (void*);
private:
friend class connection_pool_factory;
shared_base::refcount_callback callback_;
connection_pool_factory* pool_;
};
friend class pooled_connection;
typedef std::vector<details::shared_ptr<pooled_connection> > connections;
private:
void
release (pooled_connection*);
private:
const std::size_t max_;
const std::size_t min_;
std::size_t in_use_; // Number of connections currently in use.
std::size_t waiters_; // Number of threads waiting for a connection.
database_type* db_;
connections connections_;
details::mutex mutex_;
details::condition cond_;
};
}
}
#endif // ODB_MYSQL_CONNECTION_FACTORY_HXX
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