DynamicLibrary.cxx

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#include "DynamicLibrary.h"
 
#include <cstdlib>
#include <algorithm>
#include <iostream>
#include <mutex>
#include <sstream>
#include <string>
#include <utility>
#include <dlfcn.h>
#include <unistd.h>
 
#include "FullPath.h"
 
namespace {
int incremental_id()
{
   static std::mutex           mutex;
   static int                  count = 0;
   std::lock_guard<std::mutex> lock(mutex);
   return count++;
}
}   // namespace
 
DynamicLibrary::DynamicLibrary(std::string libname_param, bool unique_name) : fLibName(std::move(libname_param))
{
   if(unique_name) {
      std::ostringstream str;
      str << "/tmp/temp_dynlib_" << getpid() << "_" << incremental_id() << ".so";
      fTempName = str.str();
 
      // Need to symlink to full path, not a relative path.
      // If a relative path is given, then the symlink will look for that library
      //  relative to /tmp, instead of relative to the current directory.
      fLibName = full_path(fLibName);
 
      int error = symlink(fLibName.c_str(), fTempName.c_str());
      if(error != 0) {
         return;
         // throw RuntimeSymlinkCreation("Could not make temp symlink");
      }
      fLibrary = dlopen(fTempName.c_str(), RTLD_NOW);
   } else {
      fLibrary = dlopen(fLibName.c_str(), RTLD_NOW);
   }
 
   if(fLibrary == nullptr) {
      throw std::runtime_error(dlerror());
   }
}
 
DynamicLibrary::~DynamicLibrary()
{
   if(fLibrary != nullptr) {
      dlclose(fLibrary);
      if(!fTempName.empty()) {
         unlink(fTempName.c_str());
      }
   }
}
 
DynamicLibrary::DynamicLibrary(DynamicLibrary&& other) noexcept : fLibrary(nullptr)
{
   swap(other);
}
 
DynamicLibrary& DynamicLibrary::operator=(DynamicLibrary&& other) noexcept
{
   swap(other);
   return *this;
}
 
void DynamicLibrary::swap(DynamicLibrary& other) noexcept
{
   std::swap(fLibrary, other.fLibrary);
   std::swap(fLibName, other.fLibName);
   std::swap(fTempName, other.fTempName);
}
 
void* DynamicLibrary::GetSymbol(const char* symbol)
{
   return dlsym(fLibrary, symbol);
}