osrm-backend/include/engine/data_watchdog.hpp
2017-01-14 01:14:29 +01:00

92 lines
2.3 KiB
C++

#ifndef OSRM_ENGINE_DATA_WATCHDOG_HPP
#define OSRM_ENGINE_DATA_WATCHDOG_HPP
#include "engine/datafacade/shared_memory_datafacade.hpp"
#include "storage/shared_barriers.hpp"
#include "storage/shared_datatype.hpp"
#include "storage/shared_memory.hpp"
#include <boost/interprocess/sync/named_upgradable_mutex.hpp>
#include <boost/thread/lock_types.hpp>
#include <boost/thread/locks.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <memory>
#include <thread>
namespace osrm
{
namespace engine
{
// This class monitors the shared memory region that contains the pointers to
// the data and layout regions that should be used. This region is updated
// once a new dataset arrives.
class DataWatchdog
{
public:
DataWatchdog()
: active(true)
, timestamp(0)
{
watcher = std::thread(&DataWatchdog::Run, this);
}
~DataWatchdog()
{
active = false;
barrier.region_condition.notify_all();
watcher.join();
}
// Tries to connect to the shared memory containing the regions table
static bool TryConnect()
{
return storage::SharedMemory::RegionExists(storage::CURRENT_REGION);
}
auto GetDataFacade() const
{
return facade;
}
private:
void Run()
{
boost::interprocess::scoped_lock<boost::interprocess::named_mutex>
current_region_lock(barrier.region_mutex);
auto shared_memory = makeSharedMemory(storage::CURRENT_REGION);
auto current = static_cast<storage::SharedDataTimestamp *>(shared_memory->Ptr());
while (active)
{
if (timestamp != current->timestamp)
{
facade = std::make_shared<datafacade::SharedMemoryDataFacade>(current->region);
timestamp = current->timestamp;
util::Log() << "updated facade to region " << storage::regionToString(current->region)
<< " with timestamp " << current->timestamp;
}
barrier.region_condition.wait(current_region_lock);
}
facade.reset();
util::Log() << "DataWatchdog thread stopped";
}
storage::SharedBarriers barrier;
std::thread watcher;
bool active;
unsigned timestamp;
std::shared_ptr<datafacade::SharedMemoryDataFacade> facade;
};
}
}
#endif