libclass-loader-dev 0.3.8-1build2 / usr / include / class_loader / multi_library_class_loader.h

/*
 * Copyright (c) 2012, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
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 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#ifndef CLASS_LOADER__MULTI_LIBRARY_CLASS_LOADER_H_
#define CLASS_LOADER__MULTI_LIBRARY_CLASS_LOADER_H_

#include <boost/thread.hpp>
#include <map>
#include <string>
#include <vector>

#include "class_loader/class_loader.h"

// TODO(mikaelarguedas) : replace no lints with the explicit keyword in an ABI breaking release

namespace class_loader
{

typedef std::string LibraryPath;
typedef std::map<LibraryPath, class_loader::ClassLoader *> LibraryToClassLoaderMap;
typedef std::vector<ClassLoader *> ClassLoaderVector;

/**
* @class MultiLibraryClassLoader
* @brief A ClassLoader that can bind more than one runtime library
*/
class MultiLibraryClassLoader
{
public:
  /**
   * @brief Constructor for the class
   * @param enable_ondemand_loadunload - Flag indicates if classes are to be loaded/unloaded automatically as class_loader are created and destroyed
   */
  MultiLibraryClassLoader(bool enable_ondemand_loadunload);  // NOLINT(runtime/explicit)

  /**
  * @brief Virtual destructor for class
  */
  virtual ~MultiLibraryClassLoader();

  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version does not look in a specific library for the factory, but rather the first open library that defines the classs
   * @param Base - polymorphic type indicating base class
   * @param class_name - the name of the concrete plugin class we want to instantiate
   * @return A boost::shared_ptr<Base> to newly created plugin
   */
  template<class Base>
  boost::shared_ptr<Base> createInstance(const std::string & class_name)
  {
    CONSOLE_BRIDGE_logDebug(
      "class_loader::MultiLibraryClassLoader: "
      "Attempting to create instance of class type %s.",
      class_name.c_str());
    ClassLoader * loader = getClassLoaderForClass<Base>(class_name);
    if (NULL == loader) {
      throw class_loader::CreateClassException(
              "MultiLibraryClassLoader: Could not create object of class type " +
              class_name +
              " as no factory exists for it. Make sure that the library exists and "
              "was explicitly loaded through MultiLibraryClassLoader::loadLibrary()");
    }

    return loader->createInstance<Base>(class_name);
  }

  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version takes a specific library to make explicit the factory being used
   * @param Base - polymorphic type indicating base class
   * @param class_name - the name of the concrete plugin class we want to instantiate
   * @param library_path - the library from which we want to create the plugin
   * @return A boost::shared_ptr<Base> to newly created plugin
   */
  template<class Base>
  boost::shared_ptr<Base>
  createInstance(const std::string & class_name, const std::string & library_path)
  {
    ClassLoader * loader = getClassLoaderForLibrary(library_path);
    if (NULL == loader) {
      throw class_loader::NoClassLoaderExistsException(
              "Could not create instance as there is no ClassLoader in "
              "MultiLibraryClassLoader bound to library " + library_path +
              " Ensure you called MultiLibraryClassLoader::loadLibrary()");
    }
    return loader->createInstance<Base>(class_name);
  }

#if __cplusplus >= 201103L
  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version does not look in a specific library for the factory, but rather the first open library that defines the classs
   * @param Base - polymorphic type indicating base class
   * @param class_name - the name of the concrete plugin class we want to instantiate
   * @return A unique pointer to newly created plugin
   */
  template<class Base>
  ClassLoader::UniquePtr<Base> createUniqueInstance(const std::string & class_name)
  {
    CONSOLE_BRIDGE_logDebug(
      "class_loader::MultiLibraryClassLoader: Attempting to create instance of class type %s.",
      class_name.c_str());
    ClassLoader * loader = getClassLoaderForClass<Base>(class_name);
    if (nullptr == loader) {
      throw class_loader::CreateClassException(
              "MultiLibraryClassLoader: Could not create object of class type " + class_name +
              " as no factory exists for it. "
              "Make sure that the library exists and was explicitly loaded through "
              "MultiLibraryClassLoader::loadLibrary()");
    }
    return loader->createUniqueInstance<Base>(class_name);
  }

  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version takes a specific library to make explicit the factory being used
   * @param Base - polymorphic type indicating base class
   * @param class_name - the name of the concrete plugin class we want to instantiate
   * @param library_path - the library from which we want to create the plugin
   * @return A unique pointer to newly created plugin
   */
  template<class Base>
  ClassLoader::UniquePtr<Base>
  createUniqueInstance(const std::string & class_name, const std::string & library_path)
  {
    ClassLoader * loader = getClassLoaderForLibrary(library_path);
    if (nullptr == loader) {
      throw class_loader::NoClassLoaderExistsException(
              "Could not create instance as there is no ClassLoader in "
              "MultiLibraryClassLoader bound to library " + library_path +
              " Ensure you called MultiLibraryClassLoader::loadLibrary()");
    }
    return loader->createUniqueInstance<Base>(class_name);
  }
#endif

  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version does not look in a specific library for the factory, but rather the first open library that defines the classs
   * This version should not be used as the plugin system cannot do automated safe loading/unloadings
   * @param Base - polymorphic type indicating base class
   * @param class_name - the name of the concrete plugin class we want to instantiate
   * @return An unmanaged Base* to newly created plugin
   */
  template<class Base>
  Base * createUnmanagedInstance(const std::string & class_name)
  {
    ClassLoader * loader = getClassLoaderForClass<Base>(class_name);
    if (NULL == loader) {
      throw class_loader::CreateClassException(
              "MultiLibraryClassLoader: Could not create class of type " + class_name);
    }
    return loader->createUnmanagedInstance<Base>(class_name);
  }

  /**
   * @brief Creates an instance of an object of given class name with ancestor class Base
   * This version takes a specific library to make explicit the factory being used
   * This version should not be used as the plugin system cannot do automated safe loading/unloadings
   * @param Base - polymorphic type indicating Base class
   * @param class_name - name of class for which we want to create instance
   * @param library_path - the fully qualified path to the runtime library
   */
  template<class Base>
  Base * createUnmanagedInstance(const std::string & class_name, const std::string & library_path)
  {
    ClassLoader * loader = getClassLoaderForLibrary(library_path);
    if (NULL == loader) {
      throw class_loader::NoClassLoaderExistsException(
              "Could not create instance as there is no ClassLoader in MultiLibraryClassLoader "
              "bound to library " + library_path +
              " Ensure you called MultiLibraryClassLoader::loadLibrary()");
    }
    return loader->createUnmanagedInstance<Base>(class_name);
  }

  /**
   * @brief Indicates if a class has been loaded and can be instantiated
   * @param Base - polymorphic type indicating Base class
   * @param class_name - name of class that is be inquired about
   * @return true if loaded, false otherwise
   */
  template<class Base>
  bool isClassAvailable(const std::string & class_name)
  {
    std::vector<std::string> available_classes = getAvailableClasses<Base>();
    return available_classes.end() != std::find(
      available_classes.begin(), available_classes.end(), class_name);
  }

  /**
   * @brief Indicates if a library has been loaded into memory
   * @param library_path - The full qualified path to the runtime library
   * @return true if library is loaded, false otherwise
   */
  bool isLibraryAvailable(const std::string & library_path);

  /**
   * @brief Gets a list of all classes that are loaded by the class loader
   * @param Base - polymorphic type indicating Base class
   * @return A vector<string> of the available classes
   */
  template<class Base>
  std::vector<std::string> getAvailableClasses()
  {
    std::vector<std::string> available_classes;
    ClassLoaderVector loaders = getAllAvailableClassLoaders();
    for (unsigned int c = 0; c < loaders.size(); c++) {
      ClassLoader * current = loaders.at(c);
      std::vector<std::string> loader_classes = current->getAvailableClasses<Base>();
      available_classes.insert(
        available_classes.end(), loader_classes.begin(), loader_classes.end());
    }
    return available_classes;
  }

  /**
   * @brief Gets a list of all classes loaded for a particular library
   * @param Base - polymorphic type indicating Base class
   * @return A vector<string> of the available classes in the passed library
   */
  template<class Base>
  std::vector<std::string> getAvailableClassesForLibrary(const std::string & library_path)
  {
    ClassLoader * loader = getClassLoaderForLibrary(library_path);
    std::vector<std::string> available_classes;
    if (loader) {
      available_classes = loader->getAvailableClasses<Base>();
      return available_classes;
    } else {
      throw class_loader::NoClassLoaderExistsException(
              "There is no ClassLoader in MultiLibraryClassLoader bound to library " +
              library_path +
              " Ensure you called MultiLibraryClassLoader::loadLibrary()");
    }
  }

  /**
   * @brief Gets a list of all libraries opened by this class loader
   @ @return A list of libraries opened by this class loader
   */
  std::vector<std::string> getRegisteredLibraries();

  /**
   * @brief Loads a library into memory for this class loader
   * @param library_path - the fully qualified path to the runtime library
   */
  void loadLibrary(const std::string & library_path);

  /**
   * @brief Unloads a library for this class loader
   * @param library_path - the fully qualified path to the runtime library
   */
  int unloadLibrary(const std::string & library_path);

private:
  /**
   * @brief Indicates if on-demand (lazy) load/unload is enabled so libraries are loaded/unloaded automatically as needed
   */
  bool isOnDemandLoadUnloadEnabled() {return enable_ondemand_loadunload_;}

  /**
   * @brief Gets a handle to the class loader corresponding to a specific runtime library
   * @param library_path - the library from which we want to create the plugin
   * @return A pointer to the ClassLoader*, == NULL if not found
   */
  ClassLoader * getClassLoaderForLibrary(const std::string & library_path);

  /**
   * @brief Gets a handle to the class loader corresponding to a specific class
   * @param class_name - name of class for which we want to create instance
   * @return A pointer to the ClassLoader*, == NULL if not found
   */
  template<typename Base>
  ClassLoader * getClassLoaderForClass(const std::string & class_name)
  {
    ClassLoaderVector loaders = getAllAvailableClassLoaders();
    for (ClassLoaderVector::iterator i = loaders.begin(); i != loaders.end(); ++i) {
      if (!(*i)->isLibraryLoaded()) {
        (*i)->loadLibrary();
      }
      if ((*i)->isClassAvailable<Base>(class_name)) {
        return *i;
      }
    }
    return NULL;
  }

  /**
   * @brief Gets all class loaders loaded within scope
   */
  ClassLoaderVector getAllAvailableClassLoaders();

  /**
   * @brief Destroys all ClassLoaders
   */
  void shutdownAllClassLoaders();

private:
  bool enable_ondemand_loadunload_;
  LibraryToClassLoaderMap active_class_loaders_;
  boost::mutex loader_mutex_;
};


}  // namespace class_loader
#endif  // CLASS_LOADER__MULTI_LIBRARY_CLASS_LOADER_H_