xmlutils.c

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/* SPDX-FileCopyrightText: 2009-2023 Greenbone AG
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

 
#include "xmlutils.h"
 
#include <assert.h>      /* for assert */
#include <errno.h>       /* for errno, EAGAIN, EINTR */
#include <fcntl.h>       /* for fcntl, F_SETFL, O_NONBLOCK */
#include <glib.h>        /* for g_free, GSList, g_markup_parse_context_free */
#include <glib/gtypes.h> /* for GPOINTER_TO_INT, GINT_TO_POINTER, gsize */
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <string.h> /* for strcmp, strerror, strlen */
#include <time.h>   /* for time, time_t */
#include <unistd.h> /* for ssize_t */
 
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "libgvm util"

#define BUFFER_SIZE 1048576

static entity_t
make_entity (const char *name, const char *text)
{
  entity_t entity;
  entity = g_malloc (sizeof (*entity));
  entity->name = g_strdup (name ? name : "");
  entity->text = g_strdup (text ? text : "");
  entity->entities = NULL;
  entity->attributes = NULL;
  return entity;
}

entities_t
next_entities (entities_t entities)
{
  if (entities)
    return (entities_t) entities->next;
  return NULL;
}

entity_t
first_entity (entities_t entities)
{
  if (entities)
    return (entity_t) entities->data;
  return NULL;
}

entity_t
add_entity (entities_t *entities, const char *name, const char *text)
{
  entity_t entity = make_entity (name, text);
  if (entities)
    *entities = g_slist_append (*entities, entity);
  return entity;
}

void
free_entity (entity_t entity)
{
  if (entity)
    {
      g_free (entity->name);
      g_free (entity->text);
      if (entity->attributes)
        g_hash_table_destroy (entity->attributes);
      if (entity->entities)
        {
          GSList *list = entity->entities;
          while (list)
            {
              free_entity (list->data);
              list = list->next;
            }
          g_slist_free (entity->entities);
        }
      g_free (entity);
    }
}

char *
entity_text (entity_t entity)
{
  if (!entity)
    return NULL;
 
  return entity->text;
}

char *
entity_name (entity_t entity)
{
  if (!entity)
    return NULL;
 
  return entity->name;
}

static int
compare_entity_with_name (gconstpointer entity, gconstpointer name)
{
  return strcmp (entity_name ((entity_t) entity), (char *) name);
}

entity_t
entity_child (entity_t entity, const char *name)
{
  if (!entity)
    return NULL;
 
  if (entity->entities)
    {
      entities_t match =
        g_slist_find_custom (entity->entities, name, compare_entity_with_name);
      return match ? (entity_t) match->data : NULL;
    }
  return NULL;
}

const char *
entity_attribute (entity_t entity, const char *name)
{
  if (!entity)
    return NULL;
 
  if (entity->attributes)
    return (const char *) g_hash_table_lookup (entity->attributes, name);
  return NULL;
}

static void
add_attributes (entity_t entity, const gchar **names, const gchar **values)
{
  if (names && values && *names && *values)
    {
      if (entity->attributes == NULL)
        entity->attributes =
          g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
      while (*names && *values)
        {
          if (*values)
            g_hash_table_insert (entity->attributes, g_strdup (*names),
                                 g_strdup (*values));
          names++;
          values++;
        }
    }
}

static void
ignore_start_element (GMarkupParseContext *context, const gchar *element_name,
                      const gchar **attribute_names,
                      const gchar **attribute_values, gpointer user_data,
                      GError **error)
{
  context_data_t *data = (context_data_t *) user_data;
 
  (void) context;
  (void) element_name;
  (void) attribute_names;
  (void) attribute_values;
  (void) error;
 
  data->current = GINT_TO_POINTER (GPOINTER_TO_INT (data->current) + 1);
}

static void
handle_start_element (GMarkupParseContext *context, const gchar *element_name,
                      const gchar **attribute_names,
                      const gchar **attribute_values, gpointer user_data,
                      GError **error)
{
  entity_t entity;
  context_data_t *data = (context_data_t *) user_data;
 
  (void) context;
  (void) error;
  if (data->current)
    {
      entity_t current = (entity_t) data->current->data;
      entity = add_entity (&current->entities, element_name, NULL);
    }
  else
    entity = add_entity (NULL, element_name, NULL);
 
  add_attributes (entity, attribute_names, attribute_values);
 
  /* "Push" the element. */
  if (data->first == NULL)
    data->current = data->first = g_slist_prepend (NULL, entity);
  else
    data->current = g_slist_prepend (data->current, entity);
}

void
xml_handle_start_element (context_data_t *context, const gchar *element_name,
                          const gchar **attribute_names,
                          const gchar **attribute_values)
{
  handle_start_element (NULL, element_name, attribute_names, attribute_values,
                        context, NULL);
}

static void
ignore_end_element (GMarkupParseContext *context, const gchar *element_name,
                    gpointer user_data, GError **error)
{
  context_data_t *data = (context_data_t *) user_data;
 
  (void) context;
  (void) element_name;
  (void) error;
 
  data->current = GINT_TO_POINTER (GPOINTER_TO_INT (data->current) - 1);
  if (data->current == NULL)
    data->done = TRUE;
}

static void
handle_end_element (GMarkupParseContext *context, const gchar *element_name,
                    gpointer user_data, GError **error)
{
  context_data_t *data = (context_data_t *) user_data;
 
  (void) context;
  (void) error;
  (void) element_name;
  assert (data->current && data->first);
  if (data->current == data->first)
    {
      assert (strcmp (element_name,
                      /* The name of the very first entity. */
                      ((entity_t) (data->first->data))->name)
              == 0);
      data->done = TRUE;
      /* "Pop" the element. */
      data->current = g_slist_next (data->current);
    }
  else if (data->current)
    {
      GSList *front;
      /* "Pop" and free the element. */
      front = data->current;
      data->current = g_slist_next (data->current);
      g_slist_free_1 (front);
    }
}

void
xml_handle_end_element (context_data_t *context, const gchar *element_name)
{
  handle_end_element (NULL, element_name, context, NULL);
}

static void
ignore_text (GMarkupParseContext *context, const gchar *text, gsize text_len,
             gpointer user_data, GError **error)
{
  (void) context;
  (void) text;
  (void) text_len;
  (void) user_data;
  (void) error;
}

static void
handle_text (GMarkupParseContext *context, const gchar *text, gsize text_len,
             gpointer user_data, GError **error)
{
  context_data_t *data = (context_data_t *) user_data;
 
  (void) context;
  (void) text_len;
  (void) error;
  entity_t current = (entity_t) data->current->data;
  if (current->text)
    {
      gchar *old = current->text;
      current->text = g_strconcat (current->text, text, NULL);
      g_free (old);
    }
  else
    current->text = g_strdup (text);
}

void
xml_handle_text (context_data_t *context, const gchar *text, gsize text_len)
{
  handle_text (NULL, text, text_len, context, NULL);
}

static void
handle_error (GMarkupParseContext *context, GError *error, gpointer user_data)
{
  (void) context;
  (void) user_data;
  g_message ("   Error: %s\n", error->message);
}

int
try_read_entity_and_string (gnutls_session_t *session, int timeout,
                            entity_t *entity, GString **string_return)
{
  GMarkupParser xml_parser;
  GError *error = NULL;
  GMarkupParseContext *xml_context;
  GString *string;
  int socket;
  time_t last_time;
 
  // Buffer for reading from the manager.
  char *buffer;
 
  /* Record the start time. */
 
  if (time (&last_time) == -1)
    {
      g_warning ("   failed to get current time: %s\n", strerror (errno));
      return -1;
    }
 
  if (timeout > 0)
    {
      /* Turn off blocking. */
 
      socket = GPOINTER_TO_INT (gnutls_transport_get_ptr (*session));
      if (fcntl (socket, F_SETFL, O_NONBLOCK) == -1)
        return -1;
    }
  else
    /* Quiet compiler. */
    socket = 0;
 
  buffer = g_malloc0 (BUFFER_SIZE);
  if (!buffer)
    return -5;
 
  /* Setup return arg. */
 
  if (string_return == NULL)
    string = NULL;
  else if (*string_return == NULL)
    string = g_string_new ("");
  else
    string = *string_return;
 
  /* Create the XML parser. */
 
  if (entity)
    {
      xml_parser.start_element = handle_start_element;
      xml_parser.end_element = handle_end_element;
      xml_parser.text = handle_text;
    }
  else
    {
      xml_parser.start_element = ignore_start_element;
      xml_parser.end_element = ignore_end_element;
      xml_parser.text = ignore_text;
    }
  xml_parser.passthrough = NULL;
  xml_parser.error = handle_error;
 
  context_data_t context_data;
  context_data.done = FALSE;
  context_data.first = NULL;
  context_data.current = NULL;
 
  /* Setup the XML context. */
 
  xml_context =
    g_markup_parse_context_new (&xml_parser, 0, &context_data, NULL);
 
  /* Read and parse, until encountering end of file or error. */
 
  while (1)
    {
      ssize_t count;
      int retries = 10;
      while (1)
        {
          g_debug ("   asking for %i\n", BUFFER_SIZE);
          count = gnutls_record_recv (*session, buffer, BUFFER_SIZE);
          if (count < 0)
            {
              if (count == GNUTLS_E_INTERRUPTED)
                /* Interrupted, try read again. */
                continue;
              if ((timeout > 0) && (count == GNUTLS_E_AGAIN))
                {
                  /* Server still busy, either timeout or try read again. */
                  if ((timeout - (time (NULL) - last_time)) <= 0)
                    {
                      g_warning ("   timeout\n");
                      if (fcntl (socket, F_SETFL, 0L) < 0)
                        g_warning ("%s :failed to set socket flag: %s",
                                   __func__, strerror (errno));
                      g_markup_parse_context_free (xml_context);
                      g_free (buffer);
                      return -4;
                    }
                  continue;
                }
              else if ((timeout == 0) && (count == GNUTLS_E_AGAIN))
                {
                  /* Server still busy, try read again.
                     If there is no timeout set and the server is still not
                     ready, it will try up to 10 times before closing the
                     socket.*/
                  if (retries > 0)
                    {
                      retries = retries - 1;
                      continue;
                    }
                }
 
              if (count == GNUTLS_E_REHANDSHAKE)
                /* Try again. TODO Rehandshake. */
                continue;
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s :failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              return -1;
            }
          if (count == 0)
            {
              /* End of file. */
              g_markup_parse_context_end_parse (xml_context, &error);
              if (error)
                {
                  g_warning ("   End error: %s\n", error->message);
                  g_error_free (error);
                }
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s :failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              return -3;
            }
          break;
        }
 
      g_debug ("<= %.*s\n", (int) count, buffer);
 
      if (string)
        g_string_append_len (string, buffer, count);
 
      g_markup_parse_context_parse (xml_context, buffer, count, &error);
      if (error)
        {
          g_error_free (error);
          if (context_data.first && context_data.first->data)
            {
              free_entity (context_data.first->data);
              g_slist_free_1 (context_data.first);
            }
          if (string && *string_return == NULL)
            g_string_free (string, TRUE);
          if (timeout > 0)
            {
              if (fcntl (socket, F_SETFL, 0L) < 0)
                g_warning ("%s :failed to set socket flag: %s", __func__,
                           strerror (errno));
            }
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          return -2;
        }
      if (context_data.done)
        {
          g_markup_parse_context_end_parse (xml_context, &error);
          if (error)
            {
              g_warning ("   End error: %s\n", error->message);
              g_error_free (error);
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (timeout > 0)
                fcntl (socket, F_SETFL, 0L);
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              return -2;
            }
          if (entity)
            *entity = (entity_t) context_data.first->data;
          if (string)
            *string_return = string;
          if (timeout > 0)
            fcntl (socket, F_SETFL, 0L);
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          return 0;
        }
 
      if ((timeout > 0) && (time (&last_time) == -1))
        {
          g_warning ("   failed to get current time (1): %s\n",
                     strerror (errno));
          if (fcntl (socket, F_SETFL, 0L) < 0)
            g_warning ("%s :failed to set socket flag: %s", __func__,
                       strerror (errno));
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          return -1;
        }
    }
}

static int
try_read_string (gnutls_session_t *session, int timeout,
                 GString **string_return)
{
  GString *string;
  int socket;
  time_t last_time;
  char *buffer; // Buffer for reading from the server.
 
  /* Record the start time. */
 
  if (time (&last_time) == -1)
    {
      g_warning ("   failed to get current time: %s\n", strerror (errno));
      return -1;
    }
 
  if (timeout > 0)
    {
      /* Turn off blocking. */
 
      socket = GPOINTER_TO_INT (gnutls_transport_get_ptr (*session));
      if (fcntl (socket, F_SETFL, O_NONBLOCK) == -1)
        return -1;
    }
  else
    /* Quiet compiler. */
    socket = 0;
 
  buffer = g_malloc0 (BUFFER_SIZE);
  if (!buffer)
    return -5;
 
  /* Setup return arg. */
 
  if (string_return == NULL)
    string = NULL;
  else if (*string_return == NULL)
    string = g_string_new ("");
  else
    string = *string_return;
 
  /* Read until encountering end of file or error. */
 
  while (1)
    {
      ssize_t count;
      int retries = 10;
      while (1)
        {
          g_debug ("   asking for %i\n", BUFFER_SIZE);
          count = gnutls_record_recv (*session, buffer, BUFFER_SIZE);
          if (count < 0)
            {
              if (count == GNUTLS_E_INTERRUPTED)
                /* Interrupted, try read again. */
                continue;
              if ((timeout > 0) && (count == GNUTLS_E_AGAIN))
                {
                  /* Server still busy, either timeout or try read again. */
                  if ((timeout - (time (NULL) - last_time)) <= 0)
                    {
                      g_warning ("   timeout\n");
                      if (fcntl (socket, F_SETFL, 0L) < 0)
                        g_warning ("%s: failed to set socket flag: %s",
                                   __func__, strerror (errno));
                      g_free (buffer);
                      return -4;
                    }
                  continue;
                }
              else if ((timeout == 0) && (count == GNUTLS_E_AGAIN))
                {
                  /* Server still busy, try read again.
                   * If there is no timeout set and the server is still not
                   * ready, it will try up to 10 times before closing the
                   * socket. */
                  if (retries > 0)
                    {
                      retries = retries - 1;
                      continue;
                    }
                }
 
              if (count == GNUTLS_E_REHANDSHAKE)
                /* Try again. TODO Rehandshake. */
                continue;
              if (string && (*string_return == NULL))
                g_string_free (string, TRUE);
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s: failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              g_free (buffer);
              return -1;
            }
          if (count == 0)
            {
              /* End of file. */
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s :failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              if (string)
                *string_return = string;
              g_free (buffer);
              return 0;
            }
          break;
        }
 
      g_debug ("<= %.*s\n", (int) count, buffer);
 
      if (string)
        g_string_append_len (string, buffer, count);
 
      if ((timeout > 0) && (time (&last_time) == -1))
        {
          g_warning ("   failed to get current time (1): %s\n",
                     strerror (errno));
          if (fcntl (socket, F_SETFL, 0L) < 0)
            g_warning ("%s :failed to set socket flag: %s", __func__,
                       strerror (errno));
          g_free (buffer);
          return -1;
        }
    }
}

static int
try_read_string_s (int socket, int timeout, GString **string_return)
{
  GString *string;
  time_t last_time;
  /* Buffer for reading from the socket. */
  char *buffer;
 
  /* Record the start time. */
 
  if (time (&last_time) == -1)
    {
      g_warning ("   failed to get current time: %s\n", strerror (errno));
      return -1;
    }
 
  if (timeout > 0)
    {
      /* Turn off blocking. */
 
      if (fcntl (socket, F_SETFL, O_NONBLOCK) == -1)
        return -1;
    }
 
  buffer = g_malloc0 (BUFFER_SIZE);
  if (!buffer)
    return -5;
 
  /* Setup return arg. */
 
  if (string_return == NULL)
    string = NULL;
  else if (*string_return == NULL)
    string = g_string_sized_new (8192);
  else
    string = *string_return;
 
  /* Read until encountering end of file or error. */
 
  while (1)
    {
      int count;
      while (1)
        {
          g_debug ("   asking for %i\n", BUFFER_SIZE);
          count = read (socket, buffer, BUFFER_SIZE);
          if (count < 0)
            {
              if (errno == EINTR)
                /* Interrupted, try read again. */
                continue;
              if (timeout > 0)
                {
                  if (errno == EAGAIN)
                    {
                      /* Server still busy, either timeout or try read again. */
                      if ((timeout - (time (NULL) - last_time)) <= 0)
                        {
                          g_warning ("   timeout\n");
                          if (fcntl (socket, F_SETFL, 0L) < 0)
                            g_warning ("%s :failed to set socket flag: %s",
                                       __func__, strerror (errno));
                          g_free (buffer);
                          if (string && *string_return == NULL)
                            g_string_free (string, TRUE);
                          return -4;
                        }
                    }
                  continue;
                }
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              if (timeout > 0)
                fcntl (socket, F_SETFL, 0L);
              g_free (buffer);
              return -1;
            }
          if (count == 0)
            {
              /* End of file. */
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s :failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              if (string)
                *string_return = string;
              g_free (buffer);
              return 0;
            }
          break;
        }
 
      g_debug ("<= %.*s\n", (int) count, buffer);
 
      if (string)
        g_string_append_len (string, buffer, count);
 
      if ((timeout > 0) && (time (&last_time) == -1))
        {
          g_warning ("   failed to get current time (1): %s\n",
                     strerror (errno));
          if (fcntl (socket, F_SETFL, 0L) < 0)
            g_warning ("%s :failed to set server socket flag: %s", __func__,
                       strerror (errno));
          g_free (buffer);
          if (string && *string_return == NULL)
            g_string_free (string, TRUE);
          return -1;
        }
    }
}

static int
try_read_entity_and_string_s (int socket, int timeout, entity_t *entity,
                              GString **string_return)
{
  GMarkupParser xml_parser;
  GError *error = NULL;
  GMarkupParseContext *xml_context;
  GString *string;
  time_t last_time;
  /* Buffer for reading from the socket. */
  char *buffer;
 
  /* Record the start time. */
 
  if (time (&last_time) == -1)
    {
      g_warning ("   failed to get current time: %s\n", strerror (errno));
      return -1;
    }
 
  if (timeout > 0)
    {
      /* Turn off blocking. */
 
      if (fcntl (socket, F_SETFL, O_NONBLOCK) == -1)
        return -1;
    }
 
  buffer = g_malloc0 (BUFFER_SIZE);
  if (!buffer)
    return -5;
 
  /* Setup return arg. */
 
  if (string_return == NULL)
    string = NULL;
  else if (*string_return == NULL)
    string = g_string_new ("");
  else
    string = *string_return;
 
  /* Create the XML parser. */
 
  if (entity)
    {
      xml_parser.start_element = handle_start_element;
      xml_parser.end_element = handle_end_element;
      xml_parser.text = handle_text;
    }
  else
    {
      xml_parser.start_element = ignore_start_element;
      xml_parser.end_element = ignore_end_element;
      xml_parser.text = ignore_text;
    }
  xml_parser.passthrough = NULL;
  xml_parser.error = handle_error;
 
  context_data_t context_data;
  context_data.done = FALSE;
  context_data.first = NULL;
  context_data.current = NULL;
 
  /* Setup the XML context. */
 
  xml_context =
    g_markup_parse_context_new (&xml_parser, 0, &context_data, NULL);
 
  /* Read and parse, until encountering end of file or error. */
 
  while (1)
    {
      int count;
      while (1)
        {
          g_debug ("   asking for %i\n", BUFFER_SIZE);
          count = read (socket, buffer, BUFFER_SIZE);
          if (count < 0)
            {
              if (errno == EINTR)
                /* Interrupted, try read again. */
                continue;
              if (timeout > 0)
                {
                  if (errno == EAGAIN)
                    {
                      /* Server still busy, either timeout or try read again. */
                      if ((timeout - (time (NULL) - last_time)) <= 0)
                        {
                          g_warning ("   timeout\n");
                          if (fcntl (socket, F_SETFL, 0L) < 0)
                            g_warning ("%s :failed to set socket flag: %s",
                                       __func__, strerror (errno));
                          g_markup_parse_context_free (xml_context);
                          g_free (buffer);
                          if (string && *string_return == NULL)
                            g_string_free (string, TRUE);
                          return -4;
                        }
                    }
                  continue;
                }
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              if (timeout > 0)
                fcntl (socket, F_SETFL, 0L);
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              return -1;
            }
          if (count == 0)
            {
              /* End of file. */
              g_markup_parse_context_end_parse (xml_context, &error);
              if (error)
                {
                  g_warning ("   End error: %s\n", error->message);
                  g_error_free (error);
                }
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              if (timeout > 0)
                {
                  if (fcntl (socket, F_SETFL, 0L) < 0)
                    g_warning ("%s :failed to set socket flag: %s", __func__,
                               strerror (errno));
                }
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              return -3;
            }
          break;
        }
 
      g_debug ("<= %.*s\n", (int) count, buffer);
 
      if (string)
        g_string_append_len (string, buffer, count);
 
      g_markup_parse_context_parse (xml_context, buffer, count, &error);
      if (error)
        {
          g_error_free (error);
          // FIX there may be multiple entries in list
          if (context_data.first && context_data.first->data)
            {
              free_entity (context_data.first->data);
              g_slist_free_1 (context_data.first);
            }
          if (string && *string_return == NULL)
            g_string_free (string, TRUE);
          if (timeout > 0)
            {
              if (fcntl (socket, F_SETFL, 0L) < 0)
                g_warning ("%s :failed to set socket flag: %s", __func__,
                           strerror (errno));
            }
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          return -2;
        }
      if (context_data.done)
        {
          g_markup_parse_context_end_parse (xml_context, &error);
          if (error)
            {
              g_warning ("   End error: %s\n", error->message);
              g_error_free (error);
              if (context_data.first && context_data.first->data)
                {
                  free_entity (context_data.first->data);
                  g_slist_free_1 (context_data.first);
                }
              if (timeout > 0)
                fcntl (socket, F_SETFL, 0L);
              g_markup_parse_context_free (xml_context);
              g_free (buffer);
              if (string && *string_return == NULL)
                g_string_free (string, TRUE);
              return -2;
            }
          if (entity)
            *entity = (entity_t) context_data.first->data;
          if (string)
            *string_return = string;
          if (timeout > 0)
            fcntl (socket, F_SETFL, 0L);
          g_slist_free (context_data.first);
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          return 0;
        }
 
      if ((timeout > 0) && (time (&last_time) == -1))
        {
          g_warning ("   failed to get current time (1): %s\n",
                     strerror (errno));
          if (fcntl (socket, F_SETFL, 0L) < 0)
            g_warning ("%s :failed to set server socket flag: %s", __func__,
                       strerror (errno));
          g_markup_parse_context_free (xml_context);
          g_free (buffer);
          if (string && *string_return == NULL)
            g_string_free (string, TRUE);
          return -1;
        }
    }
}

int
read_entity_and_string (gnutls_session_t *session, entity_t *entity,
                        GString **string_return)
{
  return try_read_entity_and_string (session, 0, entity, string_return);
}

int
read_entity_and_string_c (gvm_connection_t *connection, entity_t *entity,
                          GString **string_return)
{
  if (connection->tls)
    return try_read_entity_and_string (&connection->session, 0, entity,
                                       string_return);
  return try_read_entity_and_string_s (connection->socket, 0, entity,
                                       string_return);
}

int
read_entity_and_text (gnutls_session_t *session, entity_t *entity, char **text)
{
  if (text)
    {
      GString *string = NULL;
      int ret = read_entity_and_string (session, entity, &string);
      if (ret)
        {
          if (string)
            g_string_free (string, TRUE);
          return ret;
        }
      *text = g_string_free (string, FALSE);
      return 0;
    }
  return read_entity_and_string (session, entity, NULL);
}

int
read_entity_and_text_c (gvm_connection_t *connection, entity_t *entity,
                        char **text)
{
  if (text)
    {
      GString *string = NULL;
      int ret = read_entity_and_string_c (connection, entity, &string);
      if (ret)
        {
          if (string)
            g_string_free (string, TRUE);
          return ret;
        }
      *text = g_string_free (string, FALSE);
      return 0;
    }
  return read_entity_and_string_c (connection, entity, NULL);
}

int
read_text_c (gvm_connection_t *connection, char **text)
{
  GString *string;
  int ret;
 
  if (text == NULL)
    return -2;
 
  string = NULL;
 
  if (connection->tls)
    ret = try_read_string (&connection->session, 0, &string);
  else
    ret = try_read_string_s (connection->socket, 0, &string);
 
  if (ret)
    {
      if (string)
        g_string_free (string, TRUE);
      return ret;
    }
  *text = g_string_free (string, FALSE);
  return 0;
}

int
read_string (gnutls_session_t *session, GString **string)
{
  int ret = 0;
  entity_t entity;
 
  if (!(ret = read_entity_and_string (session, &entity, string)))
    free_entity (entity);
 
  return ret;
}

int
read_string_c (gvm_connection_t *connection, GString **string)
{
  return read_entity_and_string_c (connection, NULL, string);
}

int
try_read_entity (gnutls_session_t *session, int timeout, entity_t *entity)
{
  return try_read_entity_and_string (session, timeout, entity, NULL);
}

int
try_read_entity_c (gvm_connection_t *connection, int timeout, entity_t *entity)
{
  if (connection->tls)
    return try_read_entity_and_string (&connection->session, 0, entity, NULL);
  return try_read_entity_and_string_s (connection->socket, timeout, entity,
                                       NULL);
}

int
read_entity (gnutls_session_t *session, entity_t *entity)
{
  return try_read_entity (session, 0, entity);
}

int
read_entity_s (int socket, entity_t *entity)
{
  return try_read_entity_and_string_s (socket, 0, entity, NULL);
}

int
read_entity_c (gvm_connection_t *connection, entity_t *entity)
{
  return try_read_entity_c (connection, 0, entity);
}

int
parse_entity (const char *string, entity_t *entity)
{
  GMarkupParser xml_parser;
  GError *error = NULL;
  GMarkupParseContext *xml_context;
  context_data_t context_data;
 
  /* Create the XML parser. */
 
  xml_parser.start_element = handle_start_element;
  xml_parser.end_element = handle_end_element;
  xml_parser.text = handle_text;
  xml_parser.passthrough = NULL;
  xml_parser.error = handle_error;
 
  context_data.done = FALSE;
  context_data.first = NULL;
  context_data.current = NULL;
 
  /* Setup the XML context. */
 
  xml_context =
    g_markup_parse_context_new (&xml_parser, 0, &context_data, NULL);
 
  /* Parse the string. */
 
  g_markup_parse_context_parse (xml_context, string, strlen (string), &error);
  if (error)
    {
      g_error_free (error);
      if (context_data.first && context_data.first->data)
        {
          free_entity (context_data.first->data);
          g_slist_free_1 (context_data.first);
        }
      g_markup_parse_context_free (xml_context);
      return -2;
    }
  if (context_data.done)
    {
      g_markup_parse_context_end_parse (xml_context, &error);
      if (error)
        {
          g_warning ("   End error: %s\n", error->message);
          g_error_free (error);
          if (context_data.first && context_data.first->data)
            {
              free_entity (context_data.first->data);
              g_slist_free_1 (context_data.first);
            }
          g_markup_parse_context_free (xml_context);
          return -2;
        }
      *entity = (entity_t) context_data.first->data;
      g_slist_free_1 (context_data.first);
      g_markup_parse_context_free (xml_context);
      return 0;
    }
  if (context_data.first && context_data.first->data)
    {
      free_entity (context_data.first->data);
      g_slist_free_1 (context_data.first);
    }
  g_markup_parse_context_free (xml_context);
  return -3;
}

static void
foreach_print_entity_to_string (gpointer entity, gpointer string)
{
  print_entity_to_string ((entity_t) entity, (GString *) string);
}

static void
foreach_print_attribute_to_string (gpointer name, gpointer value,
                                   gpointer string)
{
  gchar *text_escaped;
  text_escaped = g_markup_escape_text ((gchar *) value, -1);
  g_string_append_printf ((GString *) string, " %s=\"%s\"", (char *) name,
                          text_escaped);
  g_free (text_escaped);
}

void
print_entity_to_string (entity_t entity, GString *string)
{
  gchar *text_escaped = NULL;
  g_string_append_printf (string, "<%s", entity->name);
  if (entity->attributes && g_hash_table_size (entity->attributes))
    g_hash_table_foreach (entity->attributes, foreach_print_attribute_to_string,
                          string);
  g_string_append_printf (string, ">");
  text_escaped = g_markup_escape_text (entity->text, -1);
  g_string_append_printf (string, "%s", text_escaped);
  g_free (text_escaped);
  g_slist_foreach (entity->entities, foreach_print_entity_to_string, string);
  g_string_append_printf (string, "</%s>", entity->name);
}

static void
foreach_print_entity (gpointer entity, gpointer stream)
{
  print_entity ((FILE *) stream, (entity_t) entity);
}

static void
foreach_print_attribute (gpointer name, gpointer value, gpointer stream)
{
  fprintf ((FILE *) stream, " %s=\"%s\"", (char *) name, (char *) value);
}

void
print_entity (FILE *stream, entity_t entity)
{
  gchar *text_escaped = NULL;
  fprintf (stream, "<%s", entity->name);
  if (entity->attributes && g_hash_table_size (entity->attributes))
    g_hash_table_foreach (entity->attributes, foreach_print_attribute, stream);
  fprintf (stream, ">");
  text_escaped = g_markup_escape_text (entity->text, -1);
  fprintf (stream, "%s", text_escaped);
  g_free (text_escaped);
  g_slist_foreach (entity->entities, foreach_print_entity, stream);
  fprintf (stream, "</%s>", entity->name);
  fflush (stream);
}
 
/* "Formatted" (indented) output of entity_t */

static void
foreach_print_attribute_format (gpointer name, gpointer value, gpointer none)
{
  (void) none;
  printf (" %s=\"%s\"", (char *) name, (char *) value);
}

void
print_entity_format (entity_t entity, gpointer indent)
{
  int i = 0;
  int indentation = GPOINTER_TO_INT (indent);
  gchar *text_escaped = NULL;
 
  for (i = 0; i < indentation; i++)
    printf ("  ");
 
  printf ("<%s", entity->name);
  if (entity->attributes && g_hash_table_size (entity->attributes))
    g_hash_table_foreach (entity->attributes, foreach_print_attribute_format,
                          indent);
  printf (">");
 
  text_escaped = g_markup_escape_text (entity->text, -1);
  printf ("%s", text_escaped);
  g_free (text_escaped);
 
  if (entity->entities)
    {
      printf ("\n");
      g_slist_foreach (entity->entities, (GFunc) print_entity_format,
                       GINT_TO_POINTER (indentation + 1));
      for (i = 0; i < indentation; i++)
        printf ("  ");
    }
 
  printf ("</%s>\n", entity->name);
}

static gboolean
compare_find_attribute (gpointer key, gpointer value, gpointer attributes2)
{
  gchar *value2 = g_hash_table_lookup (attributes2, key);
  if (value2 && strcmp (value, value2) == 0)
    return FALSE;
  g_debug ("  compare failed attribute: %s\n", (char *) value);
  return TRUE;
}

int
compare_entities (entity_t entity1, entity_t entity2)
{
  if (entity1 == NULL)
    return entity2 == NULL ? 0 : 1;
  if (entity2 == NULL)
    return 1;
 
  if (strcmp (entity1->name, entity2->name))
    {
      g_debug ("  compare failed name: %s vs %s\n", entity1->name,
               entity2->name);
      return 1;
    }
  if (strcmp (entity1->text, entity2->text))
    {
      g_debug ("  compare failed text %s vs %s (%s)\n", entity1->text,
               entity2->text, entity1->name);
      return 1;
    }
 
  if (entity1->attributes == NULL)
    {
      if (entity2->attributes)
        return 1;
    }
  else
    {
      if (entity2->attributes == NULL)
        return 1;
      if (g_hash_table_find (entity1->attributes, compare_find_attribute,
                             (gpointer) entity2->attributes))
        {
          g_debug ("  compare failed attributes\n");
          return 1;
        }
    }
 
  // FIX entities can be in any order
  GSList *list1 = entity1->entities;
  GSList *list2 = entity2->entities;
  while (list1 && list2)
    {
      if (compare_entities (list1->data, list2->data))
        {
          g_debug ("  compare failed subentity\n");
          return 1;
        }
      list1 = g_slist_next (list1);
      list2 = g_slist_next (list2);
    }
  if (list1 == list2)
    return 0;
  /* More entities in one of the two. */
  g_debug ("  compare failed number of entities (%s)\n", entity1->name);
  return 1;
}

int
xml_count_entities (entities_t entities)
{
  int count = 0;
  while (first_entity (entities))
    {
      entities = next_entities (entities);
      count++;
    }
  return count;
}

void
xml_string_append (GString *xml, const char *format, ...)
{
  gchar *piece;
  va_list args;
 
  va_start (args, format);
  piece = g_markup_vprintf_escaped (format, args);
  va_end (args);
  g_string_append (xml, piece);
  g_free (piece);
}
 
/* XML file utilities */

static void
xml_search_handle_start_element (GMarkupParseContext *ctx,
                                 const gchar *element_name,
                                 const gchar **attribute_names,
                                 const gchar **attribute_values, gpointer data,
                                 GError **error)
{
  (void) ctx;
  (void) error;
 
  xml_search_data_t *search_data = ((xml_search_data_t *) data);
 
  if (strcmp (element_name, search_data->find_element) == 0
      && search_data->found == 0)
    {
      g_debug ("%s: Found element <%s>", __func__, element_name);
 
      if (search_data->find_attributes
          && g_hash_table_size (search_data->find_attributes))
        {
          int index;
          GHashTable *found_attributes;
          found_attributes =
            g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
          index = 0;
          while (attribute_names[index])
            {
              gchar *searched_value;
              searched_value = g_hash_table_lookup (
                search_data->find_attributes, attribute_names[index]);
              if (searched_value
                  && strcmp (searched_value, attribute_values[index]) == 0)
                {
                  g_debug ("%s: Found attribute %s=\"%s\"", __func__,
                           attribute_names[index], searched_value);
                  g_hash_table_add (found_attributes, searched_value);
                }
              index++;
            }
          g_debug ("%s: Found %d of %d attributes", __func__,
                   g_hash_table_size (found_attributes),
                   g_hash_table_size (search_data->find_attributes));
 
          if (g_hash_table_size (found_attributes)
              == g_hash_table_size (search_data->find_attributes))
            {
              search_data->found = 1;
            }
 
          g_hash_table_destroy (found_attributes);
        }
      else
        {
          search_data->found = 1;
        }
    }
}
 
#define XML_FILE_BUFFER_SIZE 1048576
int
find_element_in_xml_file (gchar *file_path, gchar *find_element,
                          GHashTable *find_attributes)
{
  gchar buffer[XML_FILE_BUFFER_SIZE];
  FILE *file;
  int read_len;
  GMarkupParser xml_parser;
  GMarkupParseContext *xml_context;
  xml_search_data_t search_data;
  GError *error = NULL;
 
  search_data.find_element = find_element;
  search_data.find_attributes = find_attributes;
  search_data.found = 0;
 
  /* Create the XML parser. */
  xml_parser.start_element = xml_search_handle_start_element;
  xml_parser.end_element = NULL;
  xml_parser.text = NULL;
  xml_parser.passthrough = NULL;
  xml_parser.error = NULL;
  xml_context = g_markup_parse_context_new (&xml_parser, 0, &search_data, NULL);
 
  file = fopen (file_path, "r");
  if (file == NULL)
    {
      g_markup_parse_context_free (xml_context);
      g_warning ("%s: Failed to open '%s':", __func__, strerror (errno));
      return 0;
    }
 
  while ((read_len = fread (&buffer, sizeof (char), XML_FILE_BUFFER_SIZE, file))
         && g_markup_parse_context_parse (xml_context, buffer, read_len, &error)
         && error == NULL)
    {
    }
  g_markup_parse_context_end_parse (xml_context, &error);
 
  fclose (file);
 
  g_markup_parse_context_free (xml_context);
  return search_data.found;
}
#undef XML_FILE_BUFFER_SIZE
 
/* The new faster parser that uses libxml2. */

int
parse_element (const gchar *string, element_t *element)
{
  xmlDocPtr doc;
 
  LIBXML_TEST_VERSION
 
  if (element)
    *element = NULL;
 
  if (xmlMemSetup (g_free, g_malloc, g_realloc, g_strdup))
    return -4;
 
  doc =
    xmlReadMemory (string, strlen (string), "noname.xml", NULL, XML_PARSE_HUGE);
  if (doc == NULL)
    return -2;
 
  if (element)
    *element = xmlDocGetRootElement (doc);
 
  return 0;
}

void
element_free (element_t element)
{
  if (element)
    {
      assert (element->doc);
      xmlFreeDoc (element->doc);
    }
}

const gchar *
element_name (element_t element)
{
  if (element && (element->type == XML_ELEMENT_NODE))
    return (const gchar *) element->name;
 
  return "";
}

static element_t
find_child (element_t element, const gchar *name)
{
  for (xmlNode *node = element->children; node; node = node->next)
    if (xmlStrcmp (node->name, (const xmlChar *) name) == 0)
      return node;
  return NULL;
}

element_t
element_child (element_t element, const gchar *name)
{
  const gchar *stripped_name;
 
  if (!element)
    return NULL;
 
  stripped_name = strchr (name, ':');
  if (stripped_name)
    {
      element_t child;
 
      /* There was a namespace in the name.
       *
       * First try without the namespace, because libxml2 doesn't consider the
       * namespace in the name when the namespace is defined. */
 
      stripped_name++;
 
      if (*stripped_name == '\0')
        /* Don't search for child with empty stripped name, because we'll
         * find text nodes.  But search with just the namespace for glib
         * compatibility. */
        return find_child (element, name);
 
      child = find_child (element, stripped_name);
      if (child)
        return child;
 
      /* Didn't find anything. */
    }
 
  /* There was no namespace, or we didn't find anything without the namespace.
   *
   * Try with the full name. */
 
  return find_child (element, name);
}

gchar *
element_text (element_t element)
{
  gchar *string;
 
  if (!element)
    return NULL;
 
  string =
    (gchar *) xmlNodeListGetString (element->doc, element->xmlChildrenNode, 1);
  if (string)
    return string;
  string = xmlMalloc (1);
  string[0] = '\0';
  return string;
}

gchar *
element_attribute (element_t element, const gchar *name)
{
  const gchar *stripped_name;
 
  if (!element)
    return NULL;
 
  stripped_name = strchr (name, ':');
  if (stripped_name)
    {
      gchar *attribute;
 
      /* There was a namespace in the name.
       *
       * First try without the namespace, because libxml2 doesn't consider the
       * namespace in the name when the namespace is defined. */
 
      stripped_name++;
 
      if (*stripped_name == '\0')
        /* Don't search for child with empty stripped name, because we'll
         * find text nodes.  But search with just the namespace for glib
         * compatibility. */
        return (gchar *) xmlGetProp (element, (const xmlChar *) name);
 
      attribute =
        (gchar *) xmlGetProp (element, (const xmlChar *) stripped_name);
      if (attribute)
        return attribute;
 
      /* Didn't find anything. */
    }
 
  /* There was no namespace, or we didn't find anything without the namespace.
   *
   * Try with the full name. */
 
  return (gchar *) xmlGetProp (element, (const xmlChar *) name);
}

element_t
element_first_child (element_t element)
{
  if (element)
    {
      element = element->children;
      while (element && (element->type != XML_ELEMENT_NODE))
        element = element->next;
      return element;
    }
  return NULL;
}

element_t
element_next (element_t element)
{
  if (element)
    {
      element = element->next;
      while (element && (element->type != XML_ELEMENT_NODE))
        element = element->next;
      return element;
    }
  return NULL;
}

gchar *
element_to_string (element_t element)
{
  xmlBufferPtr buffer;
  char *xml_string;
 
  // Copy element to ensure XML namespaces are included
  element_t element_copy;
  element_copy = xmlCopyNode (element, 1);
 
  buffer = xmlBufferCreate ();
  xmlNodeDump (buffer, element_copy->doc, element_copy, 0, 0);
  xmlFreeNode (element_copy);
 
  xml_string = g_strdup ((char *) xmlBufferContent (buffer));
 
  xmlBufferFree (buffer);
  return xml_string;
}

void
print_element_to_string (element_t element, GString *string)
{
  gchar *text_escaped, *text;
  element_t ch;
  xmlAttr *attribute;
 
  text_escaped = NULL;
 
  g_string_append_printf (string, "<%s", element_name (element));
 
  attribute = element->properties;
  while (attribute)
    {
      xmlChar *value;
 
      value = xmlNodeListGetString (element->doc, attribute->children, 1);
 
      text_escaped = g_markup_escape_text ((gchar *) value, -1);
      g_string_append_printf (string, " %s=\"%s\"", attribute->name,
                              text_escaped);
      g_free (text_escaped);
 
      xmlFree (value);
 
      attribute = attribute->next;
    }
 
  g_string_append_printf (string, ">");
 
  text = element_text (element);
  text_escaped = g_markup_escape_text (text, -1);
  g_free (text);
  g_string_append_printf (string, "%s", text_escaped);
  g_free (text_escaped);
 
  ch = element_first_child (element);
  while (ch)
    {
      print_element_to_string (ch, string);
      ch = element_next (ch);
    }
 
  g_string_append_printf (string, "</%s>", element_name (element));
}
 
/* XML file iterator */

struct xml_file_iterator_struct
{
  int initialized;              //< Whether the iterator is initialized.
  int output_depth;             //< Tree depth at which to output subelements
  GQueue *element_queue;        //< Queue of parsed XML subelements
  xmlSAXHandler sax_handler;    //< SAX handler structure
  xmlParserCtxtPtr parser_ctxt; //< libXML parser context for building DOM
  gchar *file_path;             //< Path to the XML file being processed
  FILE *file;                   //< Stream pointer for the XML file
  int stack_depth;              // track depth (replaces nodeNr)
};

static void
xml_file_iterator_start_element_ns (void *ctx, const xmlChar *localname,
                                    const xmlChar *prefix, const xmlChar *URI,
                                    int nb_namespaces,
                                    const xmlChar **namespaces,
                                    int nb_attributes, int nb_defaulted,
                                    const xmlChar **attributes)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2StartElementNs (iterator->parser_ctxt, localname, prefix, URI,
                         nb_namespaces, namespaces, nb_attributes, nb_defaulted,
                         attributes);
  iterator->stack_depth++;
}

static void
xml_file_iterator_end_element_ns (void *ctx, const xmlChar *localname,
                                  const xmlChar *prefix, const xmlChar *URI)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2EndElementNs (iterator->parser_ctxt, localname, prefix, URI);
  iterator->stack_depth--;
  if (iterator->stack_depth == iterator->output_depth)
    {
      xmlNodePtr parent, child;
      parent = iterator->parser_ctxt->node;
 
      child = parent->children;
      while (child)
        {
          if (child->type == XML_ELEMENT_NODE)
            {
              xmlDocPtr new_doc = xmlNewDoc ((const xmlChar *) "1.0");
              element_t child_copy;
              child_copy = xmlCopyNode (child, 1);
              xmlDocSetRootElement (new_doc, child_copy);
 
              if (child_copy)
                {
                  g_queue_push_tail (iterator->element_queue, child_copy);
                }
            }
 
          xmlUnlinkNode (child);
          xmlFreeNode (child);
 
          child = parent->children;
        }
    }
}

static void
xml_file_iterator_internal_subset (void *ctx, const xmlChar *name,
                                   const xmlChar *ExternalID,
                                   const xmlChar *SystemID)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2InternalSubset (iterator->parser_ctxt, name, ExternalID, SystemID);
}

static void
xml_file_iterator_external_subset (void *ctx, const xmlChar *name,
                                   const xmlChar *ExternalID,
                                   const xmlChar *SystemID)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2ExternalSubset (iterator->parser_ctxt, name, ExternalID, SystemID);
}

static int
xml_file_iterator_is_standalone (void *ctx)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2IsStandalone (iterator->parser_ctxt);
}

static int
xml_file_iterator_has_internal_subset (void *ctx)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2HasInternalSubset (iterator->parser_ctxt);
}

static int
xml_file_iterator_has_external_subset (void *ctx)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2HasExternalSubset (iterator->parser_ctxt);
}

static xmlParserInputPtr
xml_file_iterator_resolve_entity (void *ctx, const xmlChar *publicId,
                                  const xmlChar *systemId)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2ResolveEntity (iterator->parser_ctxt, publicId, systemId);
}

static xmlEntityPtr
xml_file_iterator_get_entity (void *ctx, const xmlChar *name)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2GetEntity (iterator->parser_ctxt, name);
}

static xmlEntityPtr
xml_file_iterator_get_parameter_entity (void *ctx, const xmlChar *name)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  return xmlSAX2GetParameterEntity (iterator->parser_ctxt, name);
}

static void
xml_file_iterator_entity_decl (void *ctx, const xmlChar *name, int type,
                               const xmlChar *publicId, const xmlChar *systemId,
                               xmlChar *content)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2EntityDecl (iterator->parser_ctxt, name, type, publicId, systemId,
                     content);
}

static void
xml_file_iterator_attribute_decl (void *ctx, const xmlChar *elem,
                                  const xmlChar *fullname, int type, int def,
                                  const xmlChar *defaultValue,
                                  xmlEnumerationPtr tree)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2AttributeDecl (iterator->parser_ctxt, elem, fullname, type, def,
                        defaultValue, tree);
}

static void
xml_file_iterator_element_decl (void *ctx, const xmlChar *name, int type,
                                xmlElementContentPtr content)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2ElementDecl (iterator->parser_ctxt, name, type, content);
}

static void
xml_file_iterator_notation_decl (void *ctx, const xmlChar *name,
                                 const xmlChar *publicId,
                                 const xmlChar *systemId)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2NotationDecl (iterator->parser_ctxt, name, publicId, systemId);
}

static void
xml_file_iterator_unparsed_entity_decl (void *ctx, const xmlChar *name,
                                        const xmlChar *publicId,
                                        const xmlChar *systemId,
                                        const xmlChar *notationName)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2UnparsedEntityDecl (iterator->parser_ctxt, name, publicId, systemId,
                             notationName);
}

static void
xml_file_iterator_set_document_locator (void *ctx, xmlSAXLocatorPtr loc)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2SetDocumentLocator (iterator->parser_ctxt, loc);
}

static void
xml_file_iterator_start_document (void *ctx)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2StartDocument (iterator->parser_ctxt);
}

static void
xml_file_iterator_end_document (void *ctx)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2EndDocument (iterator->parser_ctxt);
}

static void
xml_file_iterator_characters (void *ctx, const xmlChar *ch, int len)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2Characters (iterator->parser_ctxt, ch, len);
}

static void
xml_file_iterator_cdata_block (void *ctx, const xmlChar *ch, int len)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2CDataBlock (iterator->parser_ctxt, ch, len);
}

static void
xml_file_iterator_processing_instruction (void *ctx, const xmlChar *target,
                                          const xmlChar *data)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2ProcessingInstruction (iterator->parser_ctxt, target, data);
}

static void
xml_file_iterator_comment (void *ctx, const xmlChar *value)
{
  xml_file_iterator_t iterator = (xml_file_iterator_t) ctx;
  xmlSAX2Comment (iterator->parser_ctxt, value);
}

static void
xml_file_iterator_init_sax_handler (xmlSAXHandlerPtr hdlr)
{
  hdlr->startElementNs = xml_file_iterator_start_element_ns;
  hdlr->endElementNs = xml_file_iterator_end_element_ns;
  hdlr->error = NULL;
  hdlr->initialized = XML_SAX2_MAGIC;
  hdlr->startElement = NULL;
  hdlr->endElement = NULL;
  hdlr->internalSubset = xml_file_iterator_internal_subset;
  hdlr->externalSubset = xml_file_iterator_external_subset;
  hdlr->isStandalone = xml_file_iterator_is_standalone;
  hdlr->hasInternalSubset = xml_file_iterator_has_internal_subset;
  hdlr->hasExternalSubset = xml_file_iterator_has_external_subset;
  hdlr->resolveEntity = xml_file_iterator_resolve_entity;
  hdlr->getEntity = xml_file_iterator_get_entity;
  hdlr->getParameterEntity = xml_file_iterator_get_parameter_entity;
  hdlr->entityDecl = xml_file_iterator_entity_decl;
  hdlr->attributeDecl = xml_file_iterator_attribute_decl;
  hdlr->elementDecl = xml_file_iterator_element_decl;
  hdlr->notationDecl = xml_file_iterator_notation_decl;
  hdlr->unparsedEntityDecl = xml_file_iterator_unparsed_entity_decl;
  hdlr->setDocumentLocator = xml_file_iterator_set_document_locator;
  hdlr->startDocument = xml_file_iterator_start_document;
  hdlr->endDocument = xml_file_iterator_end_document;
  hdlr->reference = NULL;
  hdlr->characters = xml_file_iterator_characters;
  hdlr->cdataBlock = xml_file_iterator_cdata_block;
  hdlr->ignorableWhitespace = xml_file_iterator_characters;
  hdlr->processingInstruction = xml_file_iterator_processing_instruction;
  hdlr->comment = xml_file_iterator_comment;
  hdlr->warning = xmlParserWarning;
  hdlr->error = xmlParserError;
  hdlr->fatalError = xmlParserError;
}

xml_file_iterator_t
xml_file_iterator_new (void)
{
  return g_malloc0 (sizeof (struct xml_file_iterator_struct));
}

int
xml_file_iterator_init_from_file_path (xml_file_iterator_t iterator,
                                       const char *file_path, int output_depth)
{
  if (iterator == NULL)
    return -1;
 
  if (iterator->initialized)
    return 1;
 
  memset (iterator, 0, sizeof (struct xml_file_iterator_struct));
 
  LIBXML_TEST_VERSION
 
  if (output_depth < 0)
    output_depth = 0;
  iterator->output_depth = output_depth;
 
  iterator->file = fopen (file_path, "rb");
  if (iterator->file == NULL)
    return 2;
 
  iterator->element_queue = g_queue_new ();
 
  iterator->file_path = g_strdup (file_path);
 
  xml_file_iterator_init_sax_handler (&(iterator->sax_handler));
  iterator->parser_ctxt = xmlCreatePushParserCtxt (
    &(iterator->sax_handler), iterator, NULL, 0, iterator->file_path);
  if (iterator->parser_ctxt == NULL)
    return 3;
 
  iterator->initialized = 1;
  iterator->stack_depth = 0;
 
  return 0;
}

void
xml_file_iterator_free (xml_file_iterator_t iterator)
{
  if (iterator == NULL)
    return;
 
  if (iterator->file)
    {
      fclose (iterator->file);
    }
 
  g_free (iterator->file_path);
 
  if (iterator->element_queue)
    {
      g_queue_free_full (iterator->element_queue,
                         (GDestroyNotify) (element_free));
    }
 
  if (iterator->parser_ctxt)
    {
      if (iterator->parser_ctxt->myDoc)
        xmlFreeDoc (iterator->parser_ctxt->myDoc);
      xmlFreeParserCtxt (iterator->parser_ctxt);
    }
 
  g_free (iterator);
}

int
xml_file_iterator_rewind (xml_file_iterator_t iterator)
{
  if (iterator == NULL)
    return 0;
 
  if (iterator->file)
    {
      rewind (iterator->file);
    }
 
  if (iterator->element_queue)
    {
      g_queue_clear_full (iterator->element_queue,
                          (GDestroyNotify) (element_free));
    }
 
  if (iterator->parser_ctxt)
    {
      if (iterator->parser_ctxt->myDoc)
        xmlFreeDoc (iterator->parser_ctxt->myDoc);
      xmlFreeParserCtxt (iterator->parser_ctxt);
      iterator->parser_ctxt = xmlCreatePushParserCtxt (
        &(iterator->sax_handler), iterator, NULL, 0, iterator->file_path);
      if (iterator->parser_ctxt == NULL)
        return 1;
    }
  iterator->stack_depth = 0;
 
  return 0;
}

#define XML_FILE_ITERATOR_BUFFER_SIZE 8192

element_t
xml_file_iterator_next (xml_file_iterator_t iterator, gchar **error)
{
  gboolean continue_read = TRUE;
 
  if (error)
    *error = NULL;
 
  if (iterator->initialized == 0)
    {
      if (error)
        *error = g_strdup ("iterator not initialized");
      return NULL;
    }
 
  while (continue_read && g_queue_is_empty (iterator->element_queue))
    {
      int chars_read;
      char buffer[XML_FILE_ITERATOR_BUFFER_SIZE];
 
      chars_read =
        fread (buffer, 1, XML_FILE_ITERATOR_BUFFER_SIZE, iterator->file);
      if (chars_read == 0)
        {
          if (feof (iterator->file))
            {
              continue_read = FALSE;
            }
          else if (ferror (iterator->file))
            {
              if (error)
                *error = g_strdup ("error reading file");
              return NULL;
            }
        }
      else
        {
          int ret;
          ret = xmlParseChunk (iterator->parser_ctxt, buffer, chars_read,
                               continue_read == 0);
          if (ret)
            {
              if (error)
                {
                  const xmlError *xml_error;
                  xml_error = xmlCtxtGetLastError (iterator->parser_ctxt);
                  *error = g_strdup_printf ("error parsing XML"
                                            " (line %d column %d): %s",
                                            xml_error->line, xml_error->int2,
                                            xml_error->message);
                }
 
              return NULL;
            }
        }
    }
 
  if (!g_queue_is_empty (iterator->element_queue))
    {
      return g_queue_pop_head (iterator->element_queue);
    }
 
  return NULL;
}