PluginLoader.h

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/*
** This file is part of eOn.
**
** SPDX-License-Identifier: BSD-3-Clause
**
** Copyright (c) 2010--present, eOn Development Team
** All rights reserved.
**
** Repo:
** https://github.com/TheochemUI/eOn
*/
#pragma once

 
#include "eon/DynLib.h"
 
#include <mutex>
#include <stdexcept>
#include <string>
#include <unordered_map>
#include <vector>
 
namespace eonc {
 
class PluginLoader {
public:
  static PluginLoader &instance();

  void add_config_paths(const std::string &colon_paths);

  template <typename Fn>
  Fn load_sym(const char *lib_base, const char *sym_name) {
    dynlib::Handle h = open_lib(lib_base);
    if (!h)
      return nullptr;
    return dynlib::loadSym<Fn>(h, sym_name);
  }

  [[noreturn]] void throw_not_found(const char *lib_base,
                                    const char *description) const;

  [[nodiscard]] bool lib_present(const char *lib_base) const;

  [[nodiscard]] const std::vector<std::string> &search_paths() const noexcept {
    return m_search_paths;
  }
 
  PluginLoader(const PluginLoader &) = delete;
  PluginLoader &operator=(const PluginLoader &) = delete;
 
private:
  PluginLoader();
  ~PluginLoader();
 
  dynlib::Handle open_lib(const char *lib_base);
  std::vector<std::string> lib_names(const char *lib_base) const;
  void append_paths(const std::string &path_str, char sep);
 
  std::vector<std::string> m_search_paths;
  mutable std::mutex m_mutex;
  std::unordered_map<std::string, dynlib::Handle> m_handles;
  std::string m_last_load_error;
  bool m_last_load_saw_file = false;
};
 
} // namespace eonc