message: Fixed concurrent OpenCL cache folder name generation
diff: @@ -2070,6 +2070,9 @@ struct Context::Impl
  std::string& getPrefixString()
  {
  + if (prefix.empty())
  + {
  + cv::AutoLock lock(program_cache_mutex);
  if (prefix.empty())
  {
  CV_Assert(!devices.empty());
  @@ -2088,11 +2091,15 @@ struct Context::Impl
  }
  }
  }
  + }
  return prefix;
  }
  std::string& getPrefixBase()
  {
  + if (prefix_base.empty())
  + {
  + cv::AutoLock lock(program_cache_mutex);
  if (prefix_base.empty())
  {
  const Device& d = devices[0];
  @@ -2110,6 +2117,7 @@ struct Context::Impl
  }
  }
  }
  + }
  return prefix_base;
  }
  