CanLibLoaderLin.cpp

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#include "CanLibLoaderLin.h"
#include <string>
#include <stdexcept>
#include <sstream>
#include <boost/filesystem.hpp>
#include <LogIt.h>

#include "dlfcn.h"
//typedef void* (*f_CCanAccess)();

namespace CanModule
{

typedef CCanAccess* f_canAccess();

CanLibLoaderLin::CanLibLoaderLin(const std::string& libName)
: CanLibLoader(libName), p_dynamicLibrary(0)
{
        LOG(Log::TRC, lh) << "inherited logItComponentHandle= " << lh;
        dynamicallyLoadLib(libName);
        createCanAccess();
}
CanLibLoaderLin::~CanLibLoaderLin() {
        dlclose(p_dynamicLibrary);
}

void CanLibLoaderLin::dynamicallyLoadLib(const std::string& libName)
{
        //The library is loaded through dlopen (Linux API)
        std::ostringstream ss;
        ss << "lib" << libName << "can.so";
        LOG(Log::DBG, lh) << "Proceeding to load library " << ss.str();
        p_dynamicLibrary = dlopen(ss.str().c_str(), RTLD_NOW);
        //We check for errors while loading the library
        if (p_dynamicLibrary == 0)
        {
                char *err = dlerror();
                if (err) {
                        std::ostringstream msg;
                        msg << "Error: could not load dynamic library ["<<ss.str()<<"], current working directory ["<<boost::filesystem::current_path()<<"] error: "<<err;
                        LOG(Log::ERR, lh) << msg.str();
                        throw std::runtime_error(msg.str());
                }
        }       
}

CCanAccess*  CanLibLoaderLin::createCanAccess()
{
        f_canAccess *canAccess;
        canAccess = (f_canAccess*)dlsym(p_dynamicLibrary,"getCanBusAccess");
        // We check for errors again. If there is an error the library is released from memory.
        char *err = dlerror();
        if (err) {
                LOG(Log::ERR, lh) << "Error: could not locate the function, error: [" << err << "]";
                throw std::runtime_error("Error: could not locate the function");//TODO: add library name to message
        }
        if (!canAccess)
        {
                dlclose(p_dynamicLibrary);
                LOG(Log::ERR, lh) << "Error: could not locate the function, error: [" << err << "]";
                throw std::runtime_error("Error: could not locate the function");//TODO: add library name to message    
        }
        // We call the function getHalAccess we got from the library. This will give us a pointer to an object, which we store.
        return canAccess();
}
}