// urlwrite and urlread, a curl front-end for octave
/*

Copyright (C) 2006-2012 Alexander Barth
Copyright (C) 2009 David Bateman

This file is part of Octave.

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

Octave 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 General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

// Author: Alexander Barth <abarth@marine.usf.edu>
// Adapted-By: jwe

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string>
#include <fstream>
#include <iomanip>
#include <iostream>

#include "dir-ops.h"
#include "file-ops.h"
#include "file-stat.h"
#include "oct-env.h"
#include "oct-handle.h"
#include "glob-match.h"
#include "singleton-cleanup.h"

#include "defun-dld.h"
#include "error.h"
#include "oct-obj.h"
#include "ov-cell.h"
#include "pager.h"
#include "oct-map.h"
#include "oct-refcount.h"
#include "unwind-prot.h"

static void
delete_file (const std::string& file)
{
  octave_unlink (file);
}

class base_url_transfer
{
private:

  static void reset_path (const base_url_transfer *curl_xfer)
  {
    curl_xfer->cwd ("..");
  }

public:

  friend class url_transfer;

  base_url_transfer (void)
    : count (1), host (), userpwd (), valid (false), ascii_mode (false),
      ok (true), errmsg () { }

  base_url_transfer (const std::string& host_arg,
                     const std::string& /* user_arg */,
                     const std::string& /* passwd */)
    : count (1), host (host_arg), userpwd (), valid (false),
      ascii_mode (false), ok (true), errmsg () { }

  base_url_transfer (const std::string& /* url */,
                     const std::string& /* method */,
                     const Array<std::string>& /* param */,
                     std::ostream& /* os */)
    : count (1), host (), userpwd (), valid (false), ascii_mode (false),
      ok (true), errmsg () { }

  virtual ~base_url_transfer (void) { }

  bool is_valid (void) const { return valid; }

  bool good (void) const { return valid && ok; }

  virtual void perform (void) const { }

  virtual std::string lasterror (void) const { return errmsg; }

  virtual void set_ostream (std::ostream& /* os */) const { }

  virtual void set_istream (std::istream& /* is */) const { }

  virtual void ascii (void) { }

  virtual void binary (void) { }

  bool is_ascii (void) const { return ascii_mode; }

  bool is_binary (void) const { return !ascii_mode; }

  virtual void cwd (const std::string& /* path */) const { } 

  virtual void del (const std::string& /* file */) const { }

  virtual void rmdir (const std::string& /* path */) const { }

  virtual void mkdir (const std::string& /* path */) const { }

  virtual void rename (const std::string& /* oldname */,
                       const std::string& /* newname */) const { }

  virtual void put (const std::string& /* file */,
                    std::istream& /* is */) const { }

  virtual void get (const std::string& /* file */,
                    std::ostream& /* os */) const { }

  void mget_directory (const std::string& directory,
                       const std::string& target) const
  {
    std::string sep = file_ops::dir_sep_str ();
    file_stat fs (directory);

    if (!fs || !fs.is_dir ())
      {
        std::string msg;
        int status = octave_mkdir (directory, 0777, msg);

        if (status < 0)
          {
            ok = false;
            errmsg = "__ftp_mget__: can not create directory '"
              + target + sep + directory + "': " + msg;
            return;
          }
      }

    cwd (directory);

    if (good ())
      {
        unwind_protect_safe frame;

        frame.add_fcn (reset_path, this);

        string_vector sv = list ();

        for (octave_idx_type i = 0; i < sv.length (); i++)
          {
            time_t ftime;
            bool fisdir;
            double fsize;

            get_fileinfo (sv(i), fsize, ftime, fisdir);

            if (fisdir)
              mget_directory (sv(i), target + directory + sep);
            else
              {
                std::string realfile = target + directory + sep + sv(i);

                std::ofstream ofile (realfile.c_str (),
                                     std::ios::out | std::ios::binary);

                if (! ofile.is_open ())
                  {
                    ok = false;
                    errmsg = "__ftp_mget__: unable to open file";
                    break;
                  }

                unwind_protect_safe frame2;

                frame2.add_fcn (delete_file, realfile);

                get (sv(i), ofile);

                ofile.close ();

                if (good ())
                  frame2.discard ();
              }

            if (! good ())
              break;
          }
      }
  }

  string_vector mput_directory (const std::string& base,
                                const std::string& directory) const
  {
    string_vector file_list;

    std::string realdir
      = (base.length () == 0
         ? directory : base + file_ops::dir_sep_str () + directory);

    mkdir (directory);

    if (! good ())
      return file_list;

    cwd (directory);

    if (good ())
      {
        unwind_protect_safe frame;

        frame.add_fcn (reset_path, this);

        dir_entry dirlist (realdir);

        if (dirlist)
          {
            string_vector files = dirlist.read ();

            for (octave_idx_type i = 0; i < files.length (); i++)
              {
                std::string file = files (i);

                if (file == "." || file == "..")
                  continue;

                std::string realfile = realdir + file_ops::dir_sep_str () + file;
                file_stat fs (realfile);

                if (! fs.exists ())
                  {
                    ok = false;
                    errmsg = "__ftp__mput: file '" + realfile
                      + "' does not exist";
                    break;
                  }

                if (fs.is_dir ())
                  {
                    file_list.append (mput_directory (realdir, file));

                    if (! good ())
                      break;
                  }
                else
                  {
                    // FIXME Does ascii mode need to be flagged here?
                    std::ifstream ifile (realfile.c_str (), std::ios::in |
                                         std::ios::binary);

                    if (! ifile.is_open ())
                      {
                        ok = false;
                        errmsg = "__ftp_mput__: unable to open file '"
                          + realfile + "'";
                        break;
                      }

                    put (file, ifile);

                    ifile.close ();

                    if (! good ())
                      break;

                    file_list.append (realfile);
                  }
              }
          }
        else
          {
            ok = false;
            errmsg = "__ftp_mput__: can not read the directory '"
              + realdir + "'";
          }
      }
  }

  virtual void dir (void) const { }

  virtual string_vector list (void) const { return string_vector (); }

  virtual void get_fileinfo (const std::string& /* filename */,
                             double& /* filesize */,
                             time_t& /* filetime */,
                             bool& /* fileisdir */) const { }

  virtual std::string pwd (void) const { return std::string (); }

protected:

  octave_refcount<size_t> count;
  std::string host;
  std::string userpwd;
  bool valid;
  bool ascii_mode;
  mutable bool ok;
  mutable std::string errmsg;

private:

  // No copying!

  base_url_transfer (const base_url_transfer&);

  base_url_transfer& operator = (const base_url_transfer&);
};

#ifdef HAVE_CURL

#include <curl/curl.h>
#include <curl/curlver.h>
#include <curl/easy.h>

static int
write_data (void *buffer, size_t size, size_t nmemb, void *streamp)
{
  std::ostream& stream = *(static_cast<std::ostream*> (streamp));
  stream.write (static_cast<const char*> (buffer), size*nmemb);
  return (stream.fail () ? 0 : size * nmemb);
}

static int
read_data (void *buffer, size_t size, size_t nmemb, void *streamp)
{
  std::istream& stream = *(static_cast<std::istream*> (streamp));
  stream.read (static_cast<char*> (buffer), size*nmemb);
  if (stream.eof ())
    return stream.gcount ();
  else
    return (stream.fail () ? 0 : size * nmemb);
}

static size_t
throw_away (void *, size_t size, size_t nmemb, void *)
{
  return static_cast<size_t>(size * nmemb);
}

// I'd love to rewrite this as a private method of the url_transfer
// class, but you can't pass the va_list from the wrapper SETOPT to
// the curl_easy_setopt function.
#define SETOPT(option, parameter) \
  do \
    { \
      CURLcode res = curl_easy_setopt (curl, option, parameter); \
      if (res != CURLE_OK) \
        { \
          ok = false; \
          errmsg = curl_easy_strerror (res); \
          return; \
        } \
    } \
  while (0)

// Same as above but with a return value.
#define SETOPTR(option, parameter) \
  do \
    { \
      CURLcode res = curl_easy_setopt (curl, option, parameter); \
      if (res != CURLE_OK) \
        { \
          ok = false; \
          errmsg = curl_easy_strerror (res); \
          return retval; \
        } \
    } \
  while (0)

class curl_transfer : public base_url_transfer
{
public:

  curl_transfer (void)
    : base_url_transfer (), curl (curl_easy_init ()), errnum ()
  {
    if (curl)
      valid = true;
    else
      errmsg = "can not create curl object";
  }

  curl_transfer (const std::string& host_arg, const std::string& user_arg,
                 const std::string& passwd)
    : base_url_transfer (host_arg, user_arg, passwd),
      curl (curl_easy_init ()), errnum ()
  {
    if (curl)
      valid = true;
    else
      {
        errmsg = "can not create curl object";
        return;
      }

    init (user_arg, passwd, std::cin, octave_stdout);

    std::string url ("ftp://" + host_arg);
    SETOPT (CURLOPT_URL, url.c_str ());

    // Setup the link, with no transfer.
    perform ();
  }

  curl_transfer (const std::string& url, const std::string& method,
                 const Array<std::string>& param, std::ostream& os)
    : base_url_transfer (url, method, param, os),
      curl (curl_easy_init ()), errnum ()
  {
    if (curl)
      valid = true;
    else
      {
        errmsg = "can not create curl object";
        return;
      }

    init ("", "", std::cin, os);

    SETOPT (CURLOPT_NOBODY, 0);

    // Restore the default HTTP request method to GET after setting
    // NOBODY to true and back to false.  This is needed for backward
    // compatibility with versions of libcurl < 7.18.2.
    SETOPT (CURLOPT_HTTPGET, 1);

    // Don't need to store the parameters here as we can't change
    // the URL after the object is created
    std::string query_string = form_query_string (param);

    if (method == "get")
      {
        query_string = url + "?" + query_string;
        SETOPT (CURLOPT_URL, query_string.c_str ());
      }
    else if (method == "post")
      {
        SETOPT (CURLOPT_URL, url.c_str ());
        SETOPT (CURLOPT_POSTFIELDS, query_string.c_str ());
      }
    else
      SETOPT (CURLOPT_URL, url.c_str ());

    perform ();
  }

  ~curl_transfer (void)
  {
    if (curl)
      curl_easy_cleanup (curl);
  }

  void perform (void) const
  {
    BEGIN_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;

    errnum = curl_easy_perform (curl);

    if (errnum != CURLE_OK)
      {
        ok = false;
        errmsg = curl_easy_strerror (errnum);
      }

    END_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;
  }

  std::string lasterror (void) const
  {
    return std::string (curl_easy_strerror (errnum));
  }

  void set_ostream (std::ostream& os) const
  {
    SETOPT (CURLOPT_WRITEDATA, static_cast<void*> (&os));
  }

  void set_istream (std::istream& is) const
  {
    SETOPT (CURLOPT_READDATA, static_cast<void*> (&is));
  }

  void ascii (void)
  {
    ascii_mode = true;
    SETOPT (CURLOPT_TRANSFERTEXT, 1);
  }

  void binary (void)
  {
    ascii_mode = false;
    SETOPT (CURLOPT_TRANSFERTEXT, 0);
  }

  void cwd (const std::string& path) const
  {
    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    std::string cmd = "cwd " + path;
    slist = curl_slist_append (slist, cmd.c_str ());
    SETOPT (CURLOPT_POSTQUOTE, slist);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_POSTQUOTE, 0);
  }

  void del (const std::string& file) const
  {
    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    std::string cmd = "dele " + file;
    slist = curl_slist_append (slist, cmd.c_str ());
    SETOPT (CURLOPT_POSTQUOTE, slist);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_POSTQUOTE, 0);
  }

  void rmdir (const std::string& path) const
  {
    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    std::string cmd = "rmd " + path;
    slist = curl_slist_append (slist, cmd.c_str ());
    SETOPT (CURLOPT_POSTQUOTE, slist);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_POSTQUOTE, 0);
  }

  void mkdir (const std::string& path) const
  {
    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    std::string cmd = "mkd " + path;
    slist = curl_slist_append (slist, cmd.c_str ());
    SETOPT (CURLOPT_POSTQUOTE, slist);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_POSTQUOTE, 0);
  }

  void rename (const std::string& oldname, const std::string& newname) const
  {
    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    std::string cmd = "rnfr " + oldname;
    slist = curl_slist_append (slist, cmd.c_str ());
    cmd = "rnto " + newname;
    slist = curl_slist_append (slist, cmd.c_str ());
    SETOPT (CURLOPT_POSTQUOTE, slist);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_POSTQUOTE, 0);
  }

  void put (const std::string& file, std::istream& is) const
  {
    std::string url = "ftp://" + host + "/" + file;
    SETOPT (CURLOPT_URL, url.c_str ());
    SETOPT (CURLOPT_UPLOAD, 1);
    SETOPT (CURLOPT_NOBODY, 0);
    set_istream (is);

    perform ();
    if (! good ())
      return;

    set_istream (std::cin);
    SETOPT (CURLOPT_NOBODY, 1);
    SETOPT (CURLOPT_UPLOAD, 0);
    url = "ftp://" + host;
    SETOPT (CURLOPT_URL, url.c_str ());
  }

  void get (const std::string& file, std::ostream& os) const
  {
    std::string url = "ftp://" + host + "/" + file;
    SETOPT (CURLOPT_URL, url.c_str ());
    SETOPT (CURLOPT_NOBODY, 0);
    set_ostream (os);

    perform ();
    if (! good ())
      return;

    set_ostream (octave_stdout);
    SETOPT (CURLOPT_NOBODY, 1);
    url = "ftp://" + host;
    SETOPT (CURLOPT_URL, url.c_str ());
  }

  void dir (void) const
  {
    std::string url = "ftp://" + host + "/";
    SETOPT (CURLOPT_URL, url.c_str ());
    SETOPT (CURLOPT_NOBODY, 0);

    perform ();
    if (! good ())
      return;

    SETOPT (CURLOPT_NOBODY, 1);
    url = "ftp://" + host;
    SETOPT (CURLOPT_URL, url.c_str ());
  }

  string_vector list (void) const
  {
    string_vector retval;

    std::ostringstream buf;
    std::string url = "ftp://" + host + "/";
    SETOPTR (CURLOPT_WRITEDATA, static_cast<void*> (&buf));
    SETOPTR (CURLOPT_URL, url.c_str ());
    SETOPTR (CURLOPT_DIRLISTONLY, 1);
    SETOPTR (CURLOPT_NOBODY, 0);

    perform ();
    if (! good ())
      return retval;

    SETOPTR (CURLOPT_NOBODY, 1);
    url = "ftp://" + host;
    SETOPTR (CURLOPT_WRITEDATA, static_cast<void*> (&octave_stdout));
    SETOPTR (CURLOPT_DIRLISTONLY, 0);
    SETOPTR (CURLOPT_URL, url.c_str ());

    // Count number of directory entries
    std::string str = buf.str ();
    octave_idx_type n = 0;
    size_t pos = 0;
    while (true)
      {
        pos = str.find_first_of ('\n', pos);
        if (pos == std::string::npos)
          break;
        pos++;
        n++;
      }
    retval.resize (n);
    pos = 0;
    for (octave_idx_type i = 0; i < n; i++)
      {
        size_t newpos = str.find_first_of ('\n', pos);
        if (newpos == std::string::npos)
          break;

        retval(i) = str.substr(pos, newpos - pos);
        pos = newpos + 1;
      }

    return retval;
  }

  void get_fileinfo (const std::string& filename, double& filesize,
                     time_t& filetime, bool& fileisdir) const
  {
    std::string path = pwd ();

    std::string url = "ftp://" + host + "/" + path + "/" + filename;
    SETOPT (CURLOPT_URL, url.c_str ());
    SETOPT (CURLOPT_FILETIME, 1);
    SETOPT (CURLOPT_HEADERFUNCTION, throw_away);
    SETOPT (CURLOPT_WRITEFUNCTION, throw_away);

    // FIXME
    // The MDTM command fails for a directory on the servers I tested
    // so this is a means of testing for directories. It also means
    // I can't get the date of directories!

    perform ();
    if (! good ())
      {
        fileisdir = true;
        filetime = -1;
        filesize = 0;

        return;
      }

    fileisdir = false;
    time_t ft;
    curl_easy_getinfo (curl, CURLINFO_FILETIME, &ft);
    filetime = ft;
    double fs;
    curl_easy_getinfo (curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &fs);
    filesize = fs;

    SETOPT (CURLOPT_WRITEFUNCTION, write_data);
    SETOPT (CURLOPT_HEADERFUNCTION, 0);
    SETOPT (CURLOPT_FILETIME, 0);
    url = "ftp://" + host;
    SETOPT (CURLOPT_URL, url.c_str ());

    // The MDTM command seems to reset the path to the root with the
    // servers I tested with, so cd again into the correct path. Make
    // the path absolute so that this will work even with servers that
    // don't end up in the root after an MDTM command.
    cwd ("/" + path);
  }

  std::string pwd (void) const
  {
    std::string retval;

    struct curl_slist *slist = 0;

    unwind_protect frame;
    frame.add_fcn (curl_slist_free_all, slist);

    slist = curl_slist_append (slist, "pwd");
    SETOPTR (CURLOPT_POSTQUOTE, slist);
    SETOPTR (CURLOPT_HEADERFUNCTION, write_data);

    std::ostringstream buf;
    SETOPTR (CURLOPT_WRITEHEADER, static_cast<void *>(&buf));

    perform ();
    if (! good ())
      return retval;

    retval = buf.str ();

    // Can I assume that the path is alway in "" on the last line
    size_t pos2 = retval.rfind ('"');
    size_t pos1 = retval.rfind ('"', pos2 - 1);
    retval = retval.substr (pos1 + 1, pos2 - pos1 - 1);

    SETOPTR (CURLOPT_HEADERFUNCTION, 0);
    SETOPTR (CURLOPT_WRITEHEADER, 0);
    SETOPTR (CURLOPT_POSTQUOTE, 0);

    return retval;
  }

private:

  CURL *curl;
  mutable CURLcode errnum;

  // No copying!

  curl_transfer (const curl_transfer&);

  curl_transfer& operator = (const curl_transfer&);

  void init (const std::string& user, const std::string& passwd,
             std::istream& is, std::ostream& os)
  {
    // No data transfer by default
    SETOPT (CURLOPT_NOBODY, 1);

    // Set the username and password
    userpwd = user;
    if (! passwd.empty ())
      userpwd += ":" + passwd;
    if (! userpwd.empty ())
      SETOPT (CURLOPT_USERPWD, userpwd.c_str ());

    // Define our callback to get called when there's data to be written.
    SETOPT (CURLOPT_WRITEFUNCTION, write_data);

    // Set a pointer to our struct to pass to the callback.
    SETOPT (CURLOPT_WRITEDATA, static_cast<void*> (&os));

    // Define our callback to get called when there's data to be read
    SETOPT (CURLOPT_READFUNCTION, read_data);

    // Set a pointer to our struct to pass to the callback.
    SETOPT (CURLOPT_READDATA, static_cast<void*> (&is));

    // Follow redirects.
    SETOPT (CURLOPT_FOLLOWLOCATION, true);

    // Don't use EPSV since connecting to sites that don't support it
    // will hang for some time (3 minutes?) before moving on to try PASV
    // instead.
    SETOPT (CURLOPT_FTP_USE_EPSV, false);

    SETOPT (CURLOPT_NOPROGRESS, true);
    SETOPT (CURLOPT_FAILONERROR, true);

    SETOPT (CURLOPT_POSTQUOTE, 0);
    SETOPT (CURLOPT_QUOTE, 0);
  }

  std::string form_query_string (const Array<std::string>& param)
  {
    std::ostringstream query;

    for (int i = 0; i < param.numel (); i += 2)
      {
        std::string name = param(i);
        std::string text = param(i+1);

        // Encode strings.
        char *enc_name = curl_easy_escape (curl, name.c_str (),
                                           name.length ());
        char *enc_text = curl_easy_escape (curl, text.c_str (),
                                           text.length ());

        query << enc_name << "=" << enc_text;

        curl_free (enc_name);
        curl_free (enc_text);

        if (i < param.numel ()-1)
          query << "&";
      }

    query.flush ();

    return query.str ();
  }
};

#undef SETOPT

#endif

#if ! defined (HAVE_CURL)
static void
disabled_error (void)
{
  error ("support for url transfers was disabled when Octave was built");
}
#endif

class url_transfer
{
public:

#if defined (HAVE_CURL)
# define REP_CLASS curl_transfer
#else
# define REP_CLASS base_url_transfer
#endif

  url_transfer (void) : rep (new REP_CLASS ())
  {
#if !defined (HAVE_CURL)
    disabled_error ();
#endif
  }

  url_transfer (const std::string& host, const std::string& user,
                const std::string& passwd)
    : rep (new REP_CLASS (host, user, passwd))
  {
#if !defined (HAVE_CURL)
    disabled_error ();
#endif
  }

  url_transfer (const std::string& url, const std::string& method,
                const Array<std::string>& param, std::ostream& os)
    : rep (new REP_CLASS (url, method, param, os))
  {
#if !defined (HAVE_CURL)
    disabled_error ();
#endif
  }

#undef REP_CLASS

  url_transfer (const url_transfer& h) : rep (h.rep)
  {
    rep->count++;
  }

  ~url_transfer (void)
  {
    if (--rep->count == 0)
      delete rep;
  }

  url_transfer& operator = (const url_transfer& h)
  {
    if (this != &h)
      {
        if (--rep->count == 0)
          delete rep;

        rep = h.rep;
        rep->count++;
      }

    return *this;
  }

  bool is_valid (void) const { return rep->is_valid (); }

  bool good (void) const { return rep->good (); }

  std::string lasterror (void) const { return rep->lasterror (); }

  void set_ostream (std::ostream& os) const { rep->set_ostream (os); }

  void set_istream (std::istream& is) const { rep->set_istream (is); }

  void ascii (void) const { rep->ascii (); }

  void binary (void) const { rep->binary (); }

  bool is_ascii (void) const { return rep->is_ascii (); }

  bool is_binary (void) const { return rep->is_binary (); }

  void cwd (const std::string& path) const { rep->cwd (path); }

  void del (const std::string& file) const { rep->del (file); }

  void rmdir (const std::string& path) const { rep->rmdir (path); }

  void mkdir (const std::string& path) const { rep->mkdir (path); }

  void rename (const std::string& oldname, const std::string& newname) const
  {
    rep->rename (oldname, newname);
  }

  void put (const std::string& file, std::istream& is) const
  {
    rep->put (file, is);
  }

  void get (const std::string& file, std::ostream& os) const
  {
    rep->get (file, os);
  }

  void mget_directory (const std::string& directory,
                       const std::string& target) const
  {
    rep->mget_directory (directory, target);
  }

  string_vector mput_directory (const std::string& base,
                                const std::string& directory) const
  {
    return rep->mput_directory (base, directory);
  }

  void dir (void) const { rep->dir (); }

  string_vector list (void) const { return rep->list (); }

  void get_fileinfo (const std::string& filename, double& filesize,
                     time_t& filetime, bool& fileisdir) const
  {
    rep->get_fileinfo (filename, filesize, filetime, fileisdir);
  }

  std::string pwd (void) const { return rep->pwd (); }

private:

  base_url_transfer *rep;
};

typedef octave_handle curl_handle;

class OCTINTERP_API ch_manager
{
protected:

  ch_manager (void)
    : handle_map (), handle_free_list (),
      next_handle (-1.0 - (rand () + 1.0) / (RAND_MAX + 2.0)) { }

public:

  static void create_instance (void);

  static bool instance_ok (void)
  {
    bool retval = true;

    if (! instance)
      create_instance ();

    if (! instance)
      {
        ::error ("unable to create ch_manager!");

        retval = false;
      }

    return retval;
  }

  static void cleanup_instance (void) { delete instance; instance = 0; }

  static curl_handle get_handle (void)
  {
    return instance_ok ()
      ? instance->do_get_handle () : curl_handle ();
  }

  static void free (const curl_handle& h)
  {
    if (instance_ok ())
      instance->do_free (h);
  }

  static curl_handle lookup (double val)
  {
    return instance_ok () ? instance->do_lookup (val) : curl_handle ();
  }

  static curl_handle lookup (const octave_value& val)
  {
    return val.is_real_scalar ()
      ? lookup (val.double_value ()) : curl_handle ();
  }

  static url_transfer get_object (double val)
  {
    return get_object (lookup (val));
  }

  static url_transfer get_object (const octave_value& val)
  {
    return get_object (lookup (val));
  }

  static url_transfer get_object (const curl_handle& h)
  {
    return instance_ok () ? instance->do_get_object (h) : url_transfer ();
  }

  static curl_handle make_curl_handle (const std::string& host,
                                       const std::string& user,
                                       const std::string& passwd)
  {
    return instance_ok ()
      ? instance->do_make_curl_handle (host, user, passwd) : curl_handle ();
  }

  static Matrix handle_list (void)
  {
    return instance_ok () ? instance->do_handle_list () : Matrix ();
  }

private:

  static ch_manager *instance;

  typedef std::map<curl_handle, url_transfer>::iterator iterator;
  typedef std::map<curl_handle, url_transfer>::const_iterator const_iterator;

  typedef std::set<curl_handle>::iterator free_list_iterator;
  typedef std::set<curl_handle>::const_iterator const_free_list_iterator;

  // A map of handles to curl objects.
  std::map<curl_handle, url_transfer> handle_map;

  // The available curl handles.
  std::set<curl_handle> handle_free_list;

  // The next handle available if handle_free_list is empty.
  double next_handle;

  curl_handle do_get_handle (void);

  void do_free (const curl_handle& h);

  curl_handle do_lookup (double val)
  {
    iterator p = (xisnan (val) ? handle_map.end () : handle_map.find (val));

    return (p != handle_map.end ()) ? p->first : curl_handle ();
  }

  url_transfer do_get_object (const curl_handle& h)
  {
    iterator p = (h.ok () ? handle_map.find (h) : handle_map.end ());

    return (p != handle_map.end ()) ? p->second : url_transfer ();
  }

  curl_handle do_make_curl_handle (const std::string& host,
                                   const std::string& user,
                                   const std::string& passwd)
  {
    curl_handle h = get_handle ();

    url_transfer obj (host, user, passwd);

    if (! error_state)
      handle_map[h] = obj;
    else
      h = curl_handle ();

    return h;
  }

  Matrix do_handle_list (void)
  {
    Matrix retval (1, handle_map.size ());

    octave_idx_type i = 0;
    for (const_iterator p = handle_map.begin (); p != handle_map.end (); p++)
      {
        curl_handle h = p->first;

        retval(i++) = h.value ();
      }

    return retval;
  }
};

void
ch_manager::create_instance (void)
{
  instance = new ch_manager ();

  if (instance)
    singleton_cleanup_list::add (cleanup_instance);
}

static double
make_handle_fraction (void)
{
  static double maxrand = RAND_MAX + 2.0;

  return (rand () + 1.0) / maxrand;
}

curl_handle
ch_manager::do_get_handle (void)
{
  curl_handle retval;

  // Curl handles are negative integers plus some random fractional
  // part.  To avoid running out of integers, we recycle the integer
  // part but tack on a new random part each time.

  free_list_iterator p = handle_free_list.begin ();

  if (p != handle_free_list.end ())
    {
      retval = *p;
      handle_free_list.erase (p);
    }
  else
    {
      retval = curl_handle (next_handle);

      next_handle = std::ceil (next_handle) - 1.0 - make_handle_fraction ();
    }

  return retval;
}

void
ch_manager::do_free (const curl_handle& h)
{
  if (h.ok ())
    {
      iterator p = handle_map.find (h);

      if (p != handle_map.end ())
        {
          // Curl handles are negative integers plus some random
          // fractional part.  To avoid running out of integers, we
          // recycle the integer part but tack on a new random part
          // each time.

          handle_map.erase (p);

          if (h.value () < 0)
            handle_free_list.insert (std::ceil (h.value ()) - make_handle_fraction ());
        }
      else
        error ("ch_manager::free: invalid object %g", h.value ());
    }
}

ch_manager *ch_manager::instance = 0;

DEFUN_DLD (urlwrite, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Loadable Function} {} urlwrite (@var{url}, @var{localfile})\n\
@deftypefnx {Loadable Function} {@var{f} =} urlwrite (@var{url}, @var{localfile})\n\
@deftypefnx {Loadable Function} {[@var{f}, @var{success}] =} urlwrite (@var{url}, @var{localfile})\n\
@deftypefnx {Loadable Function} {[@var{f}, @var{success}, @var{message}] =} urlwrite (@var{url}, @var{localfile})\n\
Download a remote file specified by its @var{url} and save it as\n\
@var{localfile}.  For example:\n\
\n\
@example\n\
@group\n\
urlwrite (\"ftp://ftp.octave.org/pub/octave/README\",\n\
          \"README.txt\");\n\
@end group\n\
@end example\n\
\n\
The full path of the downloaded file is returned in @var{f}.  The\n\
variable @var{success} is 1 if the download was successful,\n\
otherwise it is 0 in which case @var{message} contains an error\n\
message.  If no output argument is specified and an error occurs,\n\
then the error is signaled through Octave's error handling mechanism.\n\
\n\
This function uses libcurl.  Curl supports, among others, the HTTP,\n\
FTP and FILE protocols.  Username and password may be specified in\n\
the URL, for example:\n\
\n\
@example\n\
@group\n\
urlwrite (\"http://username:password@@example.com/file.txt\",\n\
          \"file.txt\");\n\
@end group\n\
@end example\n\
\n\
GET and POST requests can be specified by @var{method} and @var{param}.\n\
The parameter @var{method} is either @samp{get} or @samp{post}\n\
and @var{param} is a cell array of parameter and value pairs.\n\
For example:\n\
\n\
@example\n\
@group\n\
urlwrite (\"http://www.google.com/search\", \"search.html\",\n\
          \"get\", @{\"query\", \"octave\"@});\n\
@end group\n\
@end example\n\
@seealso{urlread}\n\
@end deftypefn")
{
  octave_value_list retval;

  int nargin = args.length ();

  // verify arguments
  if (nargin != 2 && nargin != 4)
    {
      print_usage ();
      return retval;
    }

  std::string url = args(0).string_value ();

  if (error_state)
    {
      error ("urlwrite: URL must be a character string");
      return retval;
    }

  // name to store the file if download is succesful
  std::string filename = args(1).string_value ();

  if (error_state)
    {
      error ("urlwrite: LOCALFILE must be a character string");
      return retval;
    }

  std::string method;
  Array<std::string> param;

  if (nargin == 4)
    {
      method = args(2).string_value ();

      if (error_state)
        {
          error ("urlwrite: METHOD must be \"get\" or \"post\"");
          return retval;
        }

      if (method != "get" && method != "post")
        {
          error ("urlwrite: METHOD must be \"get\" or \"post\"");
          return retval;
        }

      param = args(3).cellstr_value ();

      if (error_state)
        {
          error ("urlwrite: parameters (PARAM) for get and post requests must be given as a cell array of character strings");
          return retval;
        }


      if (param.numel () % 2 == 1 )
        {
          error ("urlwrite: number of elements in PARAM must be even");
          return retval;
        }
    }

  // The file should only be deleted if it doesn't initially exist, we
  // create it, and the download fails.  We use unwind_protect to do
  // it so that the deletion happens no matter how we exit the function.

  file_stat fs (filename);

  std::ofstream ofile (filename.c_str (), std::ios::out | std::ios::binary);

  if (! ofile.is_open ())
    {
      error ("urlwrite: unable to open file");
      return retval;
    }

  unwind_protect_safe frame;

  frame.add_fcn (delete_file, filename);

  url_transfer curl = url_transfer (url, method, param, ofile);

  ofile.close ();

  if (curl.good ())
    frame.discard ();

  if (nargout > 0)
    {
      if (curl.good ())
        {
          retval(2) = std::string ();
          retval(1) = true;
          retval(0) = octave_env::make_absolute (filename);
        }
      else
        {
          retval(2) = curl.lasterror ();
          retval(1) = false;
          retval(0) = std::string ();
        }
    }

  if (nargout < 2 && ! curl.good ())
    error ("urlwrite: %s", curl.lasterror ().c_str ());

  return retval;
}

DEFUN_DLD (urlread, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Loadable Function} {@var{s} =} urlread (@var{url})\n\
@deftypefnx {Loadable Function} {[@var{s}, @var{success}] =} urlread (@var{url})\n\
@deftypefnx {Loadable Function} {[@var{s}, @var{success}, @var{message}] =} urlread (@var{url})\n\
@deftypefnx {Loadable Function} {[@dots{}] =} urlread (@var{url}, @var{method}, @var{param})\n\
Download a remote file specified by its @var{url} and return its content\n\
in string @var{s}.  For example:\n\
\n\
@example\n\
s = urlread (\"ftp://ftp.octave.org/pub/octave/README\");\n\
@end example\n\
\n\
The variable @var{success} is 1 if the download was successful,\n\
otherwise it is 0 in which case @var{message} contains an error\n\
message.  If no output argument is specified and an error occurs,\n\
then the error is signaled through Octave's error handling mechanism.\n\
\n\
This function uses libcurl.  Curl supports, among others, the HTTP,\n\
FTP and FILE protocols.  Username and password may be specified in the\n\
URL@.  For example:\n\
\n\
@example\n\
s = urlread (\"http://user:password@@example.com/file.txt\");\n\
@end example\n\
\n\
GET and POST requests can be specified by @var{method} and @var{param}.\n\
The parameter @var{method} is either @samp{get} or @samp{post}\n\
and @var{param} is a cell array of parameter and value pairs.\n\
For example:\n\
\n\
@example\n\
@group\n\
s = urlread (\"http://www.google.com/search\", \"get\",\n\
            @{\"query\", \"octave\"@});\n\
@end group\n\
@end example\n\
@seealso{urlwrite}\n\
@end deftypefn")
{
  // Octave's return value
  octave_value_list retval;

  int nargin = args.length ();

  // verify arguments
  if (nargin != 1  && nargin != 3)
    {
      print_usage ();
      return retval;
    }

  std::string url = args(0).string_value ();

  if (error_state)
    {
      error ("urlread: URL must be a character string");
      return retval;
    }

  std::string method;
  Array<std::string> param;

  if (nargin == 3)
    {
      method = args(1).string_value ();

      if (error_state)
        {
          error ("urlread: METHOD must be \"get\" or \"post\"");
          return retval;
        }

      if (method != "get" && method != "post")
        {
          error ("urlread: METHOD must be \"get\" or \"post\"");
          return retval;
        }

      param = args(2).cellstr_value ();

      if (error_state)
        {
          error ("urlread: parameters (PARAM) for get and post requests must be given as a cell array of character strings");
          return retval;
        }

      if (param.numel () % 2 == 1 )
        {
          error ("urlread: number of elements in PARAM must be even");
          return retval;
        }
    }

  std::ostringstream buf;

  url_transfer curl = url_transfer (url, method, param, buf);

  if (curl.good ())
    {
      if (nargout > 0)
        {
          // Return empty string if no error occured.
          retval(2) = curl.good () ? "" : curl.lasterror ();
          retval(1) = curl.good ();
          retval(0) = buf.str ();
        }
    }

  if (nargout < 2 && ! curl.good ())
    error ("urlread: %s", curl.lasterror().c_str());

  return retval;
}

DEFUN_DLD (__ftp__, args, ,
  "-*- texinfo -*-\n\
@deftypefn  {Loadable Function} {@var{handle} =} __ftp__ (@var{host})\n\
@deftypefnx {Loadable Function} {@var{handle} =} __ftp__ (@var{host}, @var{username}, @var{password})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();
  std::string host;
  std::string user = "anonymous";
  std::string passwd = "";

  if (nargin < 1 || nargin > 3)
    {
      print_usage ();
      return retval;
    }
  else
    {
      host = args(0).string_value ();

      if (nargin > 1)
        user = args(1).string_value ();

      if (nargin > 2)
        passwd = args(2).string_value ();

      if (! error_state)
        {
          curl_handle ch = ch_manager::make_curl_handle (host, user, passwd);

          if (! error_state)
            retval = ch.value ();
        }
    }

  return retval;
}

DEFUN_DLD (__ftp_pwd__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_pwd__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_pwd__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        retval = curl.pwd ();
      else
        error ("__ftp_pwd__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_cwd__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_cwd__ (@var{handle}, @var{path})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1 && nargin != 2)
    error ("__ftp_cwd__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string path = "";

          if (nargin > 1)
            path = args(1).string_value ();

          if (! error_state)
            curl.cwd (path);
          else
            error ("__ftp_cwd__: expecting path as second argument");
        }
      else
        error ("__ftp_cwd__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_dir__, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_dir__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_dir__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          if (nargout == 0)
            curl.dir ();
          else
            {
              string_vector sv = curl.list ();
              octave_idx_type n = sv.length ();

              if (n == 0)
                {
                  string_vector flds (5);

                  flds(0) = "name";
                  flds(1) = "date";
                  flds(2) = "bytes";
                  flds(3) = "isdir";
                  flds(4) = "datenum";

                  retval = octave_map (flds);
                }
              else
                {
                  octave_map st;

                  Cell filectime (dim_vector (n, 1));
                  Cell filesize (dim_vector (n, 1));
                  Cell fileisdir (dim_vector (n, 1));
                  Cell filedatenum (dim_vector (n, 1));

                  st.assign ("name", Cell (sv));

                  for (octave_idx_type i = 0; i < n; i++)
                    {
                      time_t ftime;
                      bool fisdir;
                      double fsize;

                      curl.get_fileinfo (sv(i), fsize, ftime, fisdir);

                      fileisdir (i) = fisdir;
                      filectime (i) = ctime (&ftime);
                      filesize (i) = fsize;
                      filedatenum (i) = double (ftime);
                    }

                  st.assign ("date", filectime);
                  st.assign ("bytes", filesize);
                  st.assign ("isdir", fileisdir);
                  st.assign ("datenum", filedatenum);

                  retval = st;
                }
            }
        }
      else
        error ("__ftp_dir__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_ascii__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_ascii__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_ascii__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        curl.ascii ();
      else
        error ("__ftp_ascii__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_binary__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_binary__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_binary__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        curl.binary ();
      else
        error ("__ftp_binary__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_close__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_close__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_close__: incorrect number of arguments");
  else
    {
      curl_handle h = ch_manager::lookup (args(0));

      if (error_state)
        return retval;

      if (h.ok ())
        ch_manager::free (h);
      else
        error ("__ftp_close__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_mode__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_mode__ (@var{handle})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 1)
    error ("__ftp_mode__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        retval = (curl.is_ascii () ? "ascii" : "binary");
      else
        error ("__ftp_binary__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_delete__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_delete__ (@var{handle}, @var{path})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 2)
    error ("__ftp_delete__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string file = args(1).string_value ();

          if (! error_state)
            curl.del (file);
          else
            error ("__ftp_delete__: expecting file name as second argument");
        }
      else
        error ("__ftp_delete__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_rmdir__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_rmdir__ (@var{handle}, @var{path})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 2)
    error ("__ftp_rmdir__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string dir = args(1).string_value ();

          if (! error_state)
            curl.rmdir (dir);
          else
            error ("__ftp_rmdir__: expecting directory name as second argument");
        }
      else
        error ("__ftp_rmdir__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_mkdir__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_mkdir__ (@var{handle}, @var{path})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 2)
    error ("__ftp_mkdir__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string dir = args(1).string_value ();

          if (! error_state)
            curl.mkdir (dir);
          else
            error ("__ftp_mkdir__: expecting directory name as second argument");
        }
      else
        error ("__ftp_mkdir__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_rename__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_rename__ (@var{handle}, @var{path})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 3)
    error ("__ftp_rename__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string oldname = args(1).string_value ();
          std::string newname = args(2).string_value ();

          if (! error_state)
            curl.rename (oldname, newname);
          else
            error ("__ftp_rename__: expecting file names for second and third arguments");
        }
      else
        error ("__ftp_rename__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_mput__, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_mput__ (@var{handle}, @var{files})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 2)
    error ("__ftp_mput__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string pat = args(1).string_value ();

          if (! error_state)
            {
              string_vector file_list;

              glob_match pattern (file_ops::tilde_expand (pat));
              string_vector files = pattern.glob ();

              for (octave_idx_type i = 0; i < files.length (); i++)
                {
                  std::string file = files (i);

                  file_stat fs (file);

                  if (! fs.exists ())
                    {
                      error ("__ftp__mput: file does not exist");
                      break;
                    }

                  if (fs.is_dir ())
                    {
                      file_list.append (curl.mput_directory ("", file));

                      if (! curl.good ())
                        {
                          error ("__ftp_mput__: %s", curl.lasterror().c_str());
                          break;
                        }
                    }
                  else
                    {
                      // FIXME Does ascii mode need to be flagged here?
                      std::ifstream ifile (file.c_str (), std::ios::in |
                                           std::ios::binary);

                      if (! ifile.is_open ())
                        {
                          error ("__ftp_mput__: unable to open file");
                          break;
                        }

                      curl.put (file, ifile);

                      ifile.close ();

                      if (! curl.good ())
                        {
                          error ("__ftp_mput__: %s", curl.lasterror().c_str());
                          break;
                        }

                      file_list.append (file);
                    }
                }

              if (nargout > 0)
                retval = file_list;
            }
          else
            error ("__ftp_mput__: expecting file name patter as second argument");
        }
      else
        error ("__ftp_mput__: invalid ftp handle");
    }

  return retval;
}

DEFUN_DLD (__ftp_mget__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {} __ftp_mget__ (@var{handle}, @var{files})\n\
Undocumented internal function\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin != 2 && nargin != 3)
    error ("__ftp_mget__: incorrect number of arguments");
  else
    {
      const url_transfer curl = ch_manager::get_object (args(0));

      if (error_state)
        return retval;

      if (curl.is_valid ())
        {
          std::string file = args(1).string_value ();
          std::string target;

          if (nargin == 3)
            target = args(2).string_value () + file_ops::dir_sep_str ();

          if (! error_state)
            {
              string_vector sv = curl.list ();
              octave_idx_type n = 0;
              glob_match pattern (file);


              for (octave_idx_type i = 0; i < sv.length (); i++)
                {
                  if (pattern.match (sv(i)))
                    {
                      n++;

                      time_t ftime;
                      bool fisdir;
                      double fsize;

                      curl.get_fileinfo (sv(i), fsize, ftime, fisdir);

                      if (fisdir)
                        curl.mget_directory (sv(i), target);
                      else
                        {
                          std::ofstream ofile ((target + sv(i)).c_str (),
                                               std::ios::out |
                                               std::ios::binary);

                          if (! ofile.is_open ())
                            {
                              error ("__ftp_mget__: unable to open file");
                              break;
                            }

                          unwind_protect_safe frame;

                          frame.add_fcn (delete_file, target + sv(i));

                          curl.get (sv(i), ofile);

                          ofile.close ();

                          if (curl.good ())
                            frame.discard ();
                        }

                      if (! curl.good ())
                        {
                          error ("__ftp_mget__: %s", curl.lasterror().c_str());
                          break;
                        }
                    }
                }
              if (n == 0)
                error ("__ftp_mget__: file not found");
            }
          else
            error ("__ftp_mget__: expecting file name and target as second and third arguments");
        }
      else
        error ("__ftp_mget__: invalid ftp handle");
    }

  return retval;
}