GenericReader.h

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/*
   For more information, please see: http://software.sci.utah.edu

   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
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///
///@author
///   Steven G. Parker
///   Department of Computer Science
///   University of Utah
///@date  July 1994
///

#ifndef MODULES_DATAIO_GENERIC_READER_H
#define MODULES_DATAIO_GENERIC_READER_H

#include <boost/filesystem.hpp>
#include <Core/Datatypes/String.h>
#include <Core/Algorithms/Base/AlgorithmVariableNames.h>
#include <Core/Thread/Mutex.h>
#include <Dataflow/Network/Module.h>

namespace SCIRun {
  namespace Modules {
    namespace DataIO {

template <class HType, class PortTag> 
class GenericReader : public SCIRun::Dataflow::Networks::Module,
  public Has1InputPort<StringPortTag>,
  public Has2OutputPorts<PortTag, StringPortTag>
{
public:
  GenericReader(const std::string &name, const std::string &category, const std::string &package, const std::string& stateFilename);

  virtual void execute();
  INPUT_PORT(0, Filename, String);
  //OUTPUT_PORT(0, Object, PortType);
  OUTPUT_PORT(1, FileLoaded, String);

protected:
  std::string filename_;
  StaticPortName<typename HType::element_type, 0> objectPortName_;
  //GuiFilename gui_filename_;
  //GuiString gui_from_env_;

  time_t old_filemodification_;

  virtual bool useCustomImporter(const std::string& filename) const = 0;
  virtual bool call_importer(const std::string &filename, HType & handle) { return false; }

  static Core::Thread::Mutex fileCheckMutex_;
  static bool file_exists(const std::string & filename);
};


template <class HType, class PortTag> 
GenericReader<HType, PortTag>::GenericReader(const std::string &name,
                    const std::string &cat, const std::string &pack, const std::string& objectPortName)
  : SCIRun::Dataflow::Networks::Module(SCIRun::Dataflow::Networks::ModuleLookupInfo(name, cat, pack)),
    //gui_filename_(get_ctx()->subVar("filename"), ""),
    //gui_from_env_(get_ctx()->subVar("from-env"),""),
    objectPortName_(SCIRun::Dataflow::Networks::PortId(0, objectPortName)),
    old_filemodification_(0)
{
  INITIALIZE_PORT(Filename);
  INITIALIZE_PORT(FileLoaded);
}

template <class HType, class PortTag> 
Core::Thread::Mutex GenericReader<HType,PortTag>::fileCheckMutex_("GenericReader");

template <class HType, class PortTag> 
bool
  GenericReader<HType, PortTag>::file_exists(const std::string & filename)
{
  //BOOST FILESYSTEM BUG: it is not thread-safe. TODO: need to meld this locking code into the ENSURE_FILE_EXISTS macro.
  Core::Thread::Guard guard(GenericReader<HType, PortTag>::fileCheckMutex_.get());
  return boost::filesystem::exists(filename);
}

template <class HType, class PortTag> 
void
GenericReader<HType, PortTag>::execute()
{
#ifdef SCIRUN4_CODE_TO_BE_ENABLED_LATER
  bool filename_changed = gui_filename_.changed();
  
  if (gui_from_env_.get() != "")
  {
    std::string filename_from_env = gui_from_env_.get(); 
    if (sci_getenv(filename_from_env))
    {
      std::string envfilename = sci_getenv(filename_from_env);
      gui_filename_.set(envfilename);
      get_ctx()->reset();
      filename_changed = true;
    }
  }
#endif

  // If there is an optional input string set the filename to it in the GUI.
  /// @todo: this will be a common pattern for file loading. Perhaps it will be a base class method someday...
  auto fileOption = getOptionalInput(Filename);
  if (!fileOption)
    filename_ = get_state()->getValue(SCIRun::Core::Algorithms::Variables::Filename).getString();
  else
    filename_ = (*fileOption)->value();
  
  // Read the status of this file so we can compare modification timestamps

  if (filename_.empty()) 
  {
    error("No file has been selected.  Please choose a file.");
    return;
  } 
  else if (!file_exists(filename_)) 
  {
    if (!useCustomImporter(filename_))
    {
      error("File '" + filename_ + "' not found.");
      return;
    }
    else
    {
      warning("File '" + filename_ + "' not found.  Maybe the plugin can find it?");
    }
  }

  // If we haven't read yet, or if it's a new filename, 
  //  or if the datestamp has changed -- then read...

  time_t new_filemodification = boost::filesystem::last_write_time(filename_);

  if( 
#ifdef SCIRUN4_CODE_TO_BE_ENABLED_LATER
    inputs_changed_ || filename_changed ||
      new_filemodification != old_filemodification_ ||
      !oport_cached(0) ||
      !oport_cached("Filename") 
#else
    true
#endif
      )
  {
    update_state(Executing);  
    old_filemodification_ = new_filemodification;

    HType handle;

    remark("loading file " +filename_);
    
    if (useCustomImporter(filename_))
    {
      if (!call_importer(filename_, handle))
      {
        error("Import failed.");
        return;
      }
    }
    else
    {
      PiostreamPtr stream = auto_istream(filename_, getLogger());
      if (!stream)
      {
        error("Error reading file '" + filename_ + "'.");
        return;
      }
    
      // Read the file
      Pio(*stream, handle);

      if (!handle || stream->error())
      {
        error("Error reading data from file '" + filename_ +"'.");
        return;
      }
    }

    Core::Datatypes::StringHandle shandle(new Core::Datatypes::String(filename_));
    sendOutput(FileLoaded, shandle);
    sendOutput(objectPortName_, handle);
  }

}

} }}

#endif