class_loader.cpp

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/*
 * 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
 *       documentation and/or other materials provided with the distribution.
 *     * 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
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "class_loader/class_loader.h"

namespace class_loader
{

bool ClassLoader::has_unmananged_instance_been_created_ = false;

bool ClassLoader::hasUnmanagedInstanceBeenCreated()
{
  return ClassLoader::has_unmananged_instance_been_created_;
}

std::string systemLibrarySuffix()
{
  return(Poco::SharedLibrary::suffix());
}

ClassLoader::ClassLoader(const std::string& library_path, bool ondemand_load_unload) :
ondemand_load_unload_(ondemand_load_unload),
library_path_(library_path),
load_ref_count_(0),
plugin_ref_count_(0)
{
  logDebug("class_loader.ClassLoader: Constructing new ClassLoader (%p) bound to library %s.", this, library_path.c_str());
  if(!isOnDemandLoadUnloadEnabled())
    loadLibrary();
}

ClassLoader::~ClassLoader()
{
  logDebug("class_loader.ClassLoader: Destroying class loader, unloading associated library...\n");
  unloadLibrary(); //TODO: while(unloadLibrary() > 0){} ??
}

bool ClassLoader::isLibraryLoaded()
{
  return(class_loader::class_loader_private::isLibraryLoaded(getLibraryPath(), this));
}

bool ClassLoader::isLibraryLoadedByAnyClassloader()
{
  return(class_loader::class_loader_private::isLibraryLoadedByAnybody(getLibraryPath()));
}

void ClassLoader::loadLibrary()
{
  boost::recursive_mutex::scoped_lock lock(load_ref_count_mutex_);
  load_ref_count_ = load_ref_count_ + 1;
  class_loader::class_loader_private::loadLibrary(getLibraryPath(), this);
}

int ClassLoader::unloadLibrary()
{
  return(unloadLibraryInternal(true));
}

int ClassLoader::unloadLibraryInternal(bool lock_plugin_ref_count)
{
  boost::recursive_mutex::scoped_lock load_ref_lock(load_ref_count_mutex_);
  boost::recursive_mutex::scoped_lock plugin_ref_lock;
  if(lock_plugin_ref_count)
    plugin_ref_lock = boost::recursive_mutex::scoped_lock(plugin_ref_count_mutex_);

  if(plugin_ref_count_ > 0)
    logWarn("class_loader.ClassLoader: SEVERE WARNING!!! Attempting to unload library while objects created by this loader exist in the heap! You should delete your objects before attempting to unload the library or destroying the ClassLoader. The library will NOT be unloaded.");
  else
  {
    load_ref_count_ = load_ref_count_ - 1;
    if(load_ref_count_ == 0)
      class_loader::class_loader_private::unloadLibrary(getLibraryPath(), this);
    else if(load_ref_count_ < 0)
      load_ref_count_ = 0;
  }
  return(load_ref_count_);
}

}