examples/core/plugin/main.cpp

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/*
  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.

  This file is part of the TerraLib - a Framework for building GIS enabled
  applications.

  TerraLib is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License,
  or (at your option) any later version.

  TerraLib is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with TerraLib. See COPYING. If not, write to
  TerraLib Team at <terralib-team@terralib.org>.
 */

/*!
  \file terralib/examples/core/plugin/main.cpp

  \brief Examples for the Terralib Plugin Module

  \author Matheus Cavassan Zaglia
*/

// TerraLib
#include <terralib/core/plugin.h>
#include <terralib/core/utils.h>

// STL
#include <cstdlib>
#include <iostream>

void InitPluginSystem()
{
  // prepare PluginEngineManager with all known plugin engines.
  std::unique_ptr<te::core::AbstractPluginEngine> cppengine(
      new te::core::CppPluginEngine());

  te::core::PluginEngineManager::instance().insert(std::move(cppengine));
}

void WithoutPluginManager()
{
  // plugins will be loaded with C++ plugin engine
  te::core::AbstractPluginEngine& plugin_engine =
      te::core::PluginEngineManager::instance().get("C++");

  // find fisrt plugin manifest file, read the manifest, load plugin and start
  // it
  std::string p1_manifest_file =
      te::core::FindInTerraLibPath("example/plugins/plugin1.teplg.json");

  te::core::PluginInfo p1_info =
      te::core::JSONPluginInfoSerializer(p1_manifest_file);

  std::unique_ptr<te::core::AbstractPlugin> p1(plugin_engine.load(p1_info));

  p1->startup();

  // find second plugin manifest file, read the manifest, load plugin and start
  // it
  std::string p3_manifest_file =
      te::core::FindInTerraLibPath("example/plugins/plugin3.teplg.json");

  te::core::PluginInfo p3_info =
      te::core::JSONPluginInfoSerializer(p3_manifest_file);

  std::unique_ptr<te::core::AbstractPlugin> p3(plugin_engine.load(p3_info));

  p3->startup();

  // stop all plugins and unload them
  p3->shutdown();
  plugin_engine.unload(std::move(p3));

  p1->shutdown();
  plugin_engine.unload(std::move(p1));
}

void WithPluginManager()
{
  // Load all the config files for the plugins.
  std::vector<te::core::PluginInfo> v_pInfo;

  v_pInfo.push_back(te::core::JSONPluginInfoSerializer(
      te::core::FindInTerraLibPath("example/plugins/plugin1.teplg.json")));
  v_pInfo.push_back(te::core::JSONPluginInfoSerializer(
      te::core::FindInTerraLibPath("example/plugins/plugin2.teplg.json")));
  v_pInfo.push_back(te::core::JSONPluginInfoSerializer(
      te::core::FindInTerraLibPath("example/plugins/plugin3.teplg.json")));
  v_pInfo.push_back(te::core::JSONPluginInfoSerializer(
      te::core::FindInTerraLibPath("example/plugins/plugin4.teplg.json")));

  // Insert all the plugins stored in the vector from a given PluginInfo.
  v_pInfo = te::core::plugin::TopologicalSort(v_pInfo);

  for(const te::core::PluginInfo& pinfo : v_pInfo)
  {
    te::core::PluginManager::instance().insert(pinfo);
    te::core::PluginManager::instance().load(pinfo.name);
  }

  // get all the loaded plugins
  std::vector<te::core::PluginInfo> pVec =
      te::core::PluginManager::instance().getLoadedPlugins();

  // unload it in the reverse order
  for (auto plugin = pVec.rbegin(); plugin != pVec.rend(); ++plugin)
  {
    te::core::PluginManager::instance().stop(plugin->name);
    te::core::PluginManager::instance().unload(plugin->name);
  }
  te::core::PluginManager::instance().clear();
}

int main(int argc, char* argv[])
{
  try
  {
    te::core::plugin::InitializePluginSystem();
    WithoutPluginManager();
    WithPluginManager();
    te::core::plugin::FinalizePluginSystem();
  }
  catch(boost::exception& e)
  {
    std::string* err = boost::get_error_info<te::ErrorDescription>(e);
    std::cerr << *err << std::endl;
  }

  return EXIT_SUCCESS;
}