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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2012 Artem Pavlenko, Jean-Francois Doyon
*
* 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#ifndef MAPNIK_THREADS_HPP
#define MAPNIK_THREADS_HPP
#include <boost/thread.hpp>
#include <boost/python.hpp>
namespace mapnik {
class python_thread
{
/* Docs:
http://docs.python.org/c-api/init.html#thread-state-and-the-global-interpreter-lock
*/
public:
static void unblock()
{
#ifdef MAPNIK_DEBUG
if (state.get())
{
std::cerr << "ERROR: Python threads are already unblocked. "
"Unblocking again will loose the current state and "
"might crash later. Aborting!\n";
abort(); //This is a serious error and can't be handled in any other sane way
}
#endif
PyThreadState *_save = 0; //Name defined by python
Py_UNBLOCK_THREADS;
state.reset(_save);
#ifdef MAPNIK_DEBUG
if (!_save) {
thread_support = false;
}
#endif
}
static void block()
{
#ifdef MAPNIK_DEBUG
if (thread_support && !state.get())
{
std::cerr << "ERROR: Trying to restore python thread state, "
"but no state is saved. Can't continue and also "
"can't raise an exception because the python "
"interpreter might be non-function. Aborting!\n";
abort();
}
#endif
PyThreadState *_save = state.release(); //Name defined by python
Py_BLOCK_THREADS;
}
private:
static boost::thread_specific_ptr<PyThreadState> state;
#ifdef MAPNIK_DEBUG
static bool thread_support;
#endif
};
class python_block_auto_unblock
{
public:
python_block_auto_unblock()
{
python_thread::block();
}
~python_block_auto_unblock()
{
python_thread::unblock();
}
};
class python_unblock_auto_block
{
public:
python_unblock_auto_block()
{
python_thread::unblock();
}
~python_unblock_auto_block()
{
python_thread::block();
}
};
} //namespace
#endif // MAPNIK_THREADS_HPP
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