githubmirror/libmodulemd

modulemd/modulemd-yaml-util.c
1 851 строка50 KB
Petr Písař
Correct a typo in a comment
05 май 2023, 12:53
05 май 2023, 12:531b5f74e
/*
 * This file is part of libmodulemd
 * Copyright (C) 2017-2020 Stephen Gallagher
 *
 * Fedora-License-Identifier: MIT
 * SPDX-2.0-License-Identifier: MIT
 * SPDX-3.0-License-Identifier: MIT
 *
 * This program is free software.
 * For more information on the license, see COPYING.
 * For more information on free software, see <https://www.gnu.org/philosophy/free-sw.en.html>.
 */

#include "config.h"
#include "modulemd-errors.h"
#include "private/modulemd-subdocument-info-private.h"
#include "private/modulemd-util.h"
#include "private/modulemd-yaml.h"
#include <errno.h>
#include <glib.h>
#include <inttypes.h>
#include <yaml.h>


GQuark
modulemd_yaml_error_quark (void)
{
  return g_quark_from_static_string ("modulemd-yaml-error-quark");
}


void
modulemd_yaml_string_free (modulemd_yaml_string *yaml_string)
{
  g_clear_pointer (&yaml_string->str, g_free);
  g_clear_pointer (&yaml_string, g_free);
}


int
write_yaml_string (void *data, unsigned char *buffer, size_t size)
{
  modulemd_yaml_string *yaml_string = (modulemd_yaml_string *)data;
  gsize total;

  if (!g_size_checked_add (&total, yaml_string->len, size + 1))
    {
      return 0;
    }

  yaml_string->str = g_realloc_n (yaml_string->str, total, sizeof (char));

  memcpy (yaml_string->str + yaml_string->len, buffer, size);
  yaml_string->len += size;
  yaml_string->str[yaml_string->len] = '\0';

  return 1;
}


const gchar *
mmd_yaml_get_event_name (yaml_event_type_t type)
{
  switch (type)
    {
    case YAML_NO_EVENT: return "YAML_NO_EVENT";

    case YAML_STREAM_START_EVENT: return "YAML_STREAM_START_EVENT";

    case YAML_STREAM_END_EVENT: return "YAML_STREAM_END_EVENT";

    case YAML_DOCUMENT_START_EVENT: return "YAML_DOCUMENT_START_EVENT";

    case YAML_DOCUMENT_END_EVENT: return "YAML_DOCUMENT_END_EVENT";

    case YAML_ALIAS_EVENT: return "YAML_ALIAS_EVENT";

    case YAML_SCALAR_EVENT: return "YAML_SCALAR_EVENT";

    case YAML_SEQUENCE_START_EVENT: return "YAML_SEQUENCE_START_EVENT";

    case YAML_SEQUENCE_END_EVENT: return "YAML_SEQUENCE_END_EVENT";

    case YAML_MAPPING_START_EVENT: return "YAML_MAPPING_START_EVENT";

    case YAML_MAPPING_END_EVENT: return "YAML_MAPPING_END_EVENT";
    }

  /* Should be unreachable */
  return "Unknown YAML Event";
}


gboolean
mmd_emitter_start_stream (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  yaml_emitter_set_unicode (emitter, TRUE);

  ret = yaml_stream_start_event_initialize (&event, YAML_UTF8_ENCODING);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the stream start event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (
    emitter, &event, error, "Could not start the YAML stream");

  return TRUE;
}


gboolean
mmd_emitter_end_stream (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_stream_end_event_initialize (&event);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the stream end event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not end the YAML stream");

  return TRUE;
}


gboolean
mmd_emitter_start_document (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_document_start_event_initialize (&event, NULL, NULL, NULL, 0);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the document start event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (
    emitter, &event, error, "Could not start the YAML document");

  return TRUE;
}


gboolean
mmd_emitter_end_document (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_document_end_event_initialize (&event, 0);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the document end event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (
    emitter, &event, error, "Could not end the YAML document");

  return TRUE;
}


gboolean
mmd_emitter_start_mapping (yaml_emitter_t *emitter,
                           yaml_mapping_style_t style,
                           GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_mapping_start_event_initialize (&event, NULL, NULL, 1, style);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the mapping start event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not start the mapping");

  return TRUE;
}


gboolean
mmd_emitter_end_mapping (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_mapping_end_event_initialize (&event);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the mapping end event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not end the mapping");

  return TRUE;
}


gboolean
mmd_emitter_start_sequence (yaml_emitter_t *emitter,
                            yaml_sequence_style_t style,
                            GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_sequence_start_event_initialize (&event, NULL, NULL, 1, style);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the sequence start event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not start the sequence");

  return TRUE;
}


gboolean
mmd_emitter_end_sequence (yaml_emitter_t *emitter, GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  ret = yaml_sequence_end_event_initialize (&event);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the sequence end event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not end the sequence");

  return TRUE;
}


gboolean
mmd_emitter_scalar (yaml_emitter_t *emitter,
                    const gchar *scalar,
                    yaml_scalar_style_t style,
                    GError **error)
{
  int ret;
  MMD_INIT_YAML_EVENT (event);

  g_debug ("SCALAR: %s", scalar);
  ret = yaml_scalar_event_initialize (&event,
                                      NULL,
                                      NULL,
                                      (yaml_char_t *)scalar,
                                      (int)strlen (scalar),
                                      1,
                                      1,
                                      style);
  if (!ret)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EVENT_INIT,
                   "Could not initialize the scalar event");
      return FALSE;
    }

  MMD_EMIT_WITH_EXIT (emitter, &event, error, "Could not emit scalar value");

  return TRUE;
}


/**
 * mmd_string_is_empty_or_a_number
 * @string (in) (nullable)
 *
 * A purpose is to catch the strings which could be mistaken with a number.
 *
 * Returns: True if the @string is %NULL, empty, or looks like a number.
 * False otherwise (looks like a string).
 *
 * Since 2.15
 */
static gboolean
string_is_empty_or_a_number (const gchar *string)
{
  int fractional = 0;
  int exponent = 0;
  int hexadecimal = 0;
  int octal = 0;

  if (string == NULL)
    return TRUE;
  if (string[0] == '\0')
    return TRUE;

  if (!g_strcmp0 (string, ".nan"))
    return TRUE; /* not a number symbol */
  if (string[0] == '+' || string[0] == '-')
    string++; /* accept a leading sign */
  if (!g_strcmp0 (string, ".inf"))
    return TRUE; /* infinity symbol */
  if (string[0] == '.')
    {
      fractional = 1; /* accept a leading decimal point */
      string++;
    }
  else if (string[0] == '0' && string[1] == 'x')
    {
      hexadecimal = 1;
      string += 2;
    }
  else if (string[0] == '0' && string[1] == 'o')
    {
      octal = 1;
      string += 2;
    }
  if (string[0] == '\0')
    return FALSE; /* incomplete notation */

  for (const gchar *character = string; *character != '\0'; character++)
    {
      if (hexadecimal)
        {
          if (!((*character >= '0' && *character <= '9') ||
                (*character >= 'a' && *character <= 'f') ||
                (*character >= 'A' && *character <= 'F')))
            return FALSE;
          continue;
        }
      else if (octal)
        {
          if (!(*character >= '0' && *character <= '7'))
            return FALSE;
          continue;
        }
      else /* decimal */
        {
          if (*character == '.')
            {
              if (fractional)
                return FALSE; /* multiple decimal points */
              else
                {
                  fractional = 1;
                  continue;
                }
            }
          if (fractional && (*character == 'e' || *character == 'E'))
            {
              if (exponent)
                return FALSE; /* multiple franctional exponents */
              else
                {
                  exponent = 1;
                  continue;
                }
            }
          if (exponent == 1 && (*character == '+' || *character == '-'))
            {
              exponent = 2; /* a sign of the exponent */
              continue;
            }
          if (*character < '0' || *character > '9')
            return FALSE;
        }
    }

  return TRUE;
}


gboolean
mmd_emitter_scalar_string (yaml_emitter_t *emitter,
                           const gchar *scalar,
                           GError **error)
{
  return mmd_emitter_scalar (emitter,
                             scalar,
                             string_is_empty_or_a_number (scalar) ?
                               YAML_DOUBLE_QUOTED_SCALAR_STYLE :
                               YAML_PLAIN_SCALAR_STYLE,
                             error);
}


gboolean
mmd_emitter_strv (yaml_emitter_t *emitter,
                  yaml_sequence_style_t seq_style,
                  const GStrv list,
                  GError **error)
{
  int ret;
  g_autoptr (GError) nested_error = NULL;
  MMD_INIT_YAML_EVENT (event);
  int numentries = g_strv_length (list);

  ret = mmd_emitter_start_sequence (emitter, seq_style, &nested_error);
  if (!ret)
    {
      g_propagate_prefixed_error (
        error, nested_error, "Failed to emit list start: ");
      return FALSE;
    }

  for (int i = 0; i < numentries; i++)
    {
      ret = mmd_emitter_scalar (emitter,
                                list[i],
                                string_is_empty_or_a_number (list[i]) ?
                                  YAML_DOUBLE_QUOTED_SCALAR_STYLE :
                                  YAML_PLAIN_SCALAR_STYLE,
                                &nested_error);
      if (!ret)
        {
          g_propagate_prefixed_error (
            error, nested_error, "Failed to emit list entry: ");
          return FALSE;
        }
    }

  ret = mmd_emitter_end_sequence (emitter, &nested_error);
  if (!ret)
    {
      g_propagate_prefixed_error (
        error, nested_error, "Failed to emit list end: ");
      return FALSE;
    }
  return TRUE;
}


GDate *
modulemd_yaml_parse_date (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  g_auto (GStrv) strv = NULL;

  YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);
  if (event.type != YAML_SCALAR_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT (error, event, "Date was not a scalar");
    }

  g_debug ("Parsing scalar: %s", (const gchar *)event.data.scalar.value);

  strv = g_strsplit ((const gchar *)event.data.scalar.value, "-", 4);

  if (!strv[0] || !strv[1] || !strv[2])
    {
      MMD_YAML_ERROR_EVENT_EXIT (
        error, event, "Date not in the form YYYY-MM-DD");
    }

  return g_date_new_dmy (g_ascii_strtoull (strv[2], NULL, 10), /* Day */
                         g_ascii_strtoull (strv[1], NULL, 10), /* Month */
                         g_ascii_strtoull (strv[0], NULL, 10)); /* Year */
}

gchar *
modulemd_yaml_parse_string (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);

  YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);
  if (event.type != YAML_SCALAR_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT (error, event, "String was not a scalar");
    }

  g_debug ("Parsing scalar: %s", (const gchar *)event.data.scalar.value);

  return g_strdup ((const gchar *)event.data.scalar.value);
}


gboolean
modulemd_yaml_parse_bool (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);

  YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);
  if (event.type != YAML_SCALAR_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT_INT (
        error, event, "Expected a scalar boolean");
    }

  if (g_str_equal ((const gchar *)event.data.scalar.value, "false"))
    {
      return FALSE;
    }
  if (g_str_equal ((const gchar *)event.data.scalar.value, "true"))
    {
      return TRUE;
    }

  MMD_YAML_ERROR_EVENT_EXIT_INT (
    error,
    event,
    "Boolean value was neither \"true\" nor \"false\": %s",
    (const gchar *)event.data.scalar.value);
}


gint64
modulemd_yaml_parse_int64 (yaml_parser_t *parser, GError **error)
{
  gint64 value;
  gchar *endptr;
  MMD_INIT_YAML_EVENT (event);

  YAML_PARSER_PARSE_WITH_EXIT_INT (parser, &event, error);
  if (event.type != YAML_SCALAR_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT_INT (error, event, "String was not a scalar");
    }

  value =
    g_ascii_strtoll ((const gchar *)event.data.scalar.value, &endptr, 10);

  if ((value == G_MAXINT64 && errno == ERANGE))
    {
#ifdef HAVE_OVERFLOWED_BUILDORDER
      /* A temporary hack. Remove when RHEL 8 goes end of life. */
      if (g_str_equal ((const gchar *)event.data.scalar.value,
                       "18446744073709551615"))
        {
          g_debug ("Coercing an invalid signed 64-bit integer to -1: %s",
                   (const gchar *)event.data.scalar.value);
          return -1;
        }
#endif
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MODULEMD_ERROR_VALIDATE,
                   "%s: The integer value is larger than %" G_GINT64_FORMAT,
                   (const gchar *)event.data.scalar.value,
                   G_MAXINT64);
      return 0;
    }

  if ((value == G_MININT64 && errno == ERANGE))
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MODULEMD_ERROR_VALIDATE,
                   "%s: The integer value is samller than %" G_GINT64_FORMAT,
                   (const gchar *)event.data.scalar.value,
                   G_MININT64);
      return 0;
    }

  if (value == 0 && errno == EINVAL)
    {
      g_set_error_literal (
        error,
        MODULEMD_YAML_ERROR,
        MODULEMD_ERROR_NOT_IMPLEMENTED,
        "Your GLib library does not support parsing integers in 10 base");
      return 0;
    }

  if ((value == 0 && endptr == (gchar *)event.data.scalar.value) ||
      *endptr != '\0')
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_ERROR_VALIDATE,
                   "%s: The string is not a valid integer",
                   (const gchar *)event.data.scalar.value);
      return 0;
    }

  return value;
}


guint64
modulemd_yaml_parse_uint64 (yaml_parser_t *parser, GError **error)
{
  guint64 value;
  gchar *endptr;
  MMD_INIT_YAML_EVENT (event);

  YAML_PARSER_PARSE_WITH_EXIT_INT (parser, &event, error);
  if (event.type != YAML_SCALAR_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT_INT (error, event, "String was not a scalar");
    }

  g_debug ("Parsing scalar: %s", (const gchar *)event.data.scalar.value);

  /* g_ascii_strtoull() accepts negative values by definition. */
  if (event.data.scalar.value[0] == '-')
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MODULEMD_ERROR_VALIDATE,
                   "%s: The integer value is negative",
                   (const gchar *)event.data.scalar.value);
      return 0u;
    }

  value =
    g_ascii_strtoull ((const gchar *)event.data.scalar.value, &endptr, 10);

  if (value == G_MAXUINT64 && errno == ERANGE)
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MODULEMD_ERROR_VALIDATE,
                   "%s: The integer value is larger than %" G_GUINT64_FORMAT,
                   (const gchar *)event.data.scalar.value,
                   G_MAXUINT64);
      return 0u;
    }

  if (value == 0u && errno == EINVAL)
    {
      g_set_error_literal (
        error,
        MODULEMD_YAML_ERROR,
        MODULEMD_ERROR_NOT_IMPLEMENTED,
        "Your GLib library does not support parsing integers in 10 base");
      return 0u;
    }

  if ((value == 0u && endptr == (gchar *)event.data.scalar.value) ||
      *endptr != '\0')
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_ERROR_VALIDATE,
                   "%s: The string is not a valid integer",
                   (const gchar *)event.data.scalar.value);
      return 0u;
    }

  return value;
}


GHashTable *
modulemd_yaml_parse_string_set (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  gboolean done = FALSE;
  gboolean in_list = FALSE;
  g_autoptr (GHashTable) result =
    g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_SEQUENCE_START_EVENT: in_list = TRUE; break;

        case YAML_SEQUENCE_END_EVENT:
          if (!in_list)
            {
              MMD_YAML_ERROR_EVENT_EXIT (
                error, event, "Unexpected end of list");
            }
          in_list = FALSE;
          done = TRUE;
          break;

        case YAML_SCALAR_EVENT:
          g_debug ("Parsing scalar: %s",
                   (const gchar *)event.data.scalar.value);

          if (in_list)
            {
              g_hash_table_add (
                result, g_strdup ((const gchar *)event.data.scalar.value));
            }
          else
            {
              /* We got a scalar instead of a sequence. */
              if (event.data.scalar.value && event.data.scalar.value[0])
                {
                  /* Treat it as a list with a single entry
                   * if it's nonempty. */
                  g_hash_table_add (
                    result, g_strdup ((const gchar *)event.data.scalar.value));
                  done = TRUE;
                }
              else
                {
                  /* Otherwise, it's an empty value node ("foo:") or an empty
                   * string value node ("foo:''"), both which libyaml reports
                   * as an empty string. Then keep the result hash table empty
                   * as it's more helpful than a list with an empty string
                   * which would be nevertheless invalid. */
                  done = TRUE;
                }
            }
          break;

        default:
          MMD_YAML_ERROR_EVENT_EXIT (
            error, event, "Unexpected YAML event in list");
          break;
        }
      yaml_event_delete (&event);
    }

  /* Work around false-positive in clang static analysis which thinks it's
   * possible for this function to return NULL and not set error.
   */
  if (G_UNLIKELY (result == NULL))
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EMIT,
                   "Somehow got a NULL hash table here.");
    }

  return g_steal_pointer (&result);
}


GHashTable *
modulemd_yaml_parse_string_set_from_map (yaml_parser_t *parser,
                                         const gchar *key,
                                         gboolean strict,
                                         GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  gboolean done = FALSE;
  gboolean in_map = FALSE;
  g_autoptr (GHashTable) set = NULL;
  g_autoptr (GError) nested_error = NULL;

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_MAPPING_START_EVENT: in_map = TRUE; break;

        case YAML_MAPPING_END_EVENT:
          if (!in_map)
            {
              MMD_YAML_ERROR_EVENT_EXIT (
                error, event, "Unexpected end of map");
            }
          in_map = FALSE;
          done = TRUE;
          break;

        case YAML_SCALAR_EVENT:
          if (!in_map)
            {
              MMD_YAML_ERROR_EVENT_EXIT (
                error, event, "Unexpected scalar outside of map.");
            }

          if (g_str_equal ((const gchar *)event.data.scalar.value, key))
            {
              set = modulemd_yaml_parse_string_set (parser, &nested_error);
              if (!set)
                {
                  g_propagate_error (error, g_steal_pointer (&nested_error));
                  return NULL;
                }
            }
          else
            {
              /* Encountered a key other than the expected one. */
              SKIP_UNKNOWN (parser,
                            NULL,
                            "Unexpected key in map: %s",
                            (const gchar *)event.data.scalar.value);
            }
          break;

        default:
          MMD_YAML_ERROR_EVENT_EXIT (
            error, event, "Unexpected YAML event in map");
          break;
        }
      yaml_event_delete (&event);
    }
  return g_steal_pointer (&set);
}


GHashTable *
modulemd_yaml_parse_string_string_map (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  gboolean done = FALSE;
  g_autoptr (GHashTable) table = NULL;
  g_autoptr (GError) nested_error = NULL;
  const gchar *key = NULL;
  g_autofree gchar *value = NULL;

  table = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);

  YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);
  if (event.type != YAML_MAPPING_START_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT (error,
                                 event,
                                 "Got %s instead of MAPPING_START.",
                                 mmd_yaml_get_event_name (event.type));
    }

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_MAPPING_END_EVENT: done = TRUE; break;

        case YAML_SCALAR_EVENT:
          /* Parse the value */
          key = (const gchar *)event.data.scalar.value;

          value = modulemd_yaml_parse_string (parser, &nested_error);
          if (!value)
            {
              g_propagate_error (error, g_steal_pointer (&nested_error));
              return NULL;
            }

          g_hash_table_replace (
            table, g_strdup (key), g_steal_pointer (&value));

          break;

        default:
          MMD_YAML_ERROR_EVENT_EXIT (
            error, event, "Unexpected YAML event in map");
          break;
        }
      yaml_event_delete (&event);
    }
  return g_steal_pointer (&table);
}


GHashTable *
modulemd_yaml_parse_nested_set (yaml_parser_t *parser, GError **error)
{
  MODULEMD_INIT_TRACE ();
  MMD_INIT_YAML_EVENT (event);
  gboolean done = FALSE;
  g_autofree gchar *key = NULL;
  g_autoptr (GHashTable) value = NULL;
  g_autoptr (GHashTable) t = NULL;
  g_autoptr (GError) nested_error = NULL;

  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  t = g_hash_table_new_full (
    g_str_hash, g_str_equal, g_free, (GDestroyNotify)g_hash_table_unref);

  /* The first event must be a MAPPING_START */
  YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);
  if (event.type != YAML_MAPPING_START_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT (
        error, event, "Missing mapping in nested set");
    }

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_MAPPING_END_EVENT: done = TRUE; break;

        case YAML_SCALAR_EVENT:
          key = g_strdup ((const gchar *)event.data.scalar.value);
          if (g_hash_table_contains (t,
                                     (const gchar *)event.data.scalar.value))
            {
              MMD_YAML_ERROR_EVENT_EXIT (
                error,
                event,
                "Key %s encountered twice in nested set",
                (const gchar *)event.data.scalar.value);
            }

          value = modulemd_yaml_parse_string_set (parser, &nested_error);
          if (value == NULL)
            {
              MMD_YAML_ERROR_EVENT_EXIT (error,
                                         event,
                                         "Failed to parse nested set: %s",
                                         nested_error->message);
            }

          g_hash_table_insert (
            t, g_steal_pointer (&key), g_steal_pointer (&value));
          break;

        default:
          MMD_YAML_ERROR_EVENT_EXIT (error,
                                     event,
                                     "Unexpected YAML event in nested set: %d",
                                     event.type);
          break;
        }
      yaml_event_delete (&event);
    }

  /* Work around false-positive in clang static analysis which thinks it's
   * possible for this function to return NULL and not set error.
   */
  if (G_UNLIKELY (t == NULL))
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EMIT,
                   "Somehow got a NULL hash table here.");
    }

  return g_steal_pointer (&t);
}

gboolean
modulemd_yaml_emit_nested_set (yaml_emitter_t *emitter,
                               GHashTable *table,
                               GError **error)
{
  MODULEMD_INIT_TRACE ();
  int ret;
  g_autoptr (GError) nested_error = NULL;
  MMD_INIT_YAML_EVENT (event);
  g_autoptr (GPtrArray) keys = NULL;
  GHashTable *dep = NULL;
  gchar *key = NULL;

  ret = mmd_emitter_start_mapping (
    emitter, YAML_BLOCK_MAPPING_STYLE, &nested_error);
  if (!ret)
    {
      g_propagate_prefixed_error (
        error,
        g_steal_pointer (&nested_error),
        "Failed to start dependencies nested mapping: ");
      return FALSE;
    }

  keys = modulemd_ordered_str_keys (table, modulemd_strcmp_sort);
  for (guint i = 0; i < keys->len; i++)
    {
      key = g_ptr_array_index (keys, i);
      dep = g_hash_table_lookup (table, key);

      EMIT_STRING_SET_FULL (
        emitter, error, key, dep, YAML_FLOW_SEQUENCE_STYLE);
    }

  ret = mmd_emitter_end_mapping (emitter, &nested_error);
  if (!ret)
    {
      g_propagate_prefixed_error (error,
                                  g_steal_pointer (&nested_error),
                                  "Failed to end nested mapping");
      return FALSE;
    }

  return TRUE;
}


static gboolean
modulemd_yaml_parse_document_type_internal (
  yaml_parser_t *parser,
  ModulemdYamlDocumentTypeEnum *_doctype,
  guint64 *_mdversion,
  yaml_emitter_t *emitter,
  GError **error)
{
  MODULEMD_INIT_TRACE ();
  MMD_INIT_YAML_EVENT (event);
  gboolean done = FALSE;
  gboolean had_data = FALSE;
  ModulemdYamlDocumentTypeEnum doctype = MODULEMD_YAML_DOC_UNKNOWN;
  guint64 mdversion = 0;
  g_autofree gchar *doctype_scalar = NULL;
  g_autofree gchar *mdversion_string = NULL;
  g_autoptr (GError) nested_error = NULL;
  int depth = 0;

  if (!mmd_emitter_start_stream (emitter, &nested_error))
    {
      g_propagate_prefixed_error (
        error, nested_error, "Error emitting stream: ");
      return FALSE;
    }

  /*
   * We should assume the initial document start is consumed by the Index.
   * But we still emit it.
   */
  if (!mmd_emitter_start_document (emitter, error))
    {
      return FALSE;
    }

  /* The second event must be the mapping start */
  YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);
  if (event.type != YAML_MAPPING_START_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT_BOOL (
        error, event, "Document did not start with a mapping");
    }
  MMD_EMIT_WITH_EXIT_FULL (
    emitter, FALSE, &event, error, "Error starting mapping");
  yaml_event_delete (&event);
  depth++;

  /* Now process through the document top-level */
  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);

      switch (event.type)
        {
        case YAML_MAPPING_END_EVENT:
          if (!mmd_emitter_end_mapping (emitter, error))
            {
              return FALSE;
            }
          depth--;
          if (depth == 0)
            {
              done = TRUE;
            }
          break;

        case YAML_MAPPING_START_EVENT:
          if (!mmd_emitter_start_mapping (
                emitter, event.data.mapping_start.style, error))
            {
              return FALSE;
            }
          depth++;
          break;

        case YAML_SCALAR_EVENT:
          if (!mmd_emitter_scalar (emitter,
                                   (const gchar *)event.data.scalar.value,
                                   event.data.scalar.style,
                                   error))
            {
              return FALSE;
            }

          if (depth == 1 &&
              g_str_equal ((const gchar *)event.data.scalar.value, "document"))
            {
              if (doctype != MODULEMD_YAML_DOC_UNKNOWN)
                {
                  MMD_YAML_ERROR_EVENT_EXIT_BOOL (
                    error, event, "Document type encountered twice.");
                }

              doctype_scalar =
                modulemd_yaml_parse_string (parser, &nested_error);
              if (!doctype_scalar)
                {
                  g_propagate_error (error, g_steal_pointer (&nested_error));
                  return FALSE;
                }
              if (!mmd_emitter_scalar (emitter,
                                       (const gchar *)doctype_scalar,
                                       YAML_PLAIN_SCALAR_STYLE,
                                       error))
                {
                  return FALSE;
                }

              if (g_str_equal (doctype_scalar, "modulemd") ||
                  g_str_equal (doctype_scalar, "modulemd-stream"))
                {
                  doctype = MODULEMD_YAML_DOC_MODULESTREAM;
                }
              else if (g_str_equal (doctype_scalar, "modulemd-defaults"))
                {
                  doctype = MODULEMD_YAML_DOC_DEFAULTS;
                }
              else if (g_str_equal (doctype_scalar, "modulemd-translations"))
                {
                  doctype = MODULEMD_YAML_DOC_TRANSLATIONS;
                }
              else if (g_str_equal (doctype_scalar, "modulemd-packager"))
                {
                  doctype = MODULEMD_YAML_DOC_PACKAGER;
                }
              else if (g_str_equal (doctype_scalar, "modulemd-obsoletes"))
                {
                  doctype = MODULEMD_YAML_DOC_OBSOLETES;
                }
              else
                {
                  MMD_YAML_ERROR_EVENT_EXIT_BOOL (
                    error, event, "Document type %s unknown.", doctype_scalar);
                }

              g_clear_pointer (&doctype_scalar, g_free);
            }
          else if (depth == 1 &&
                   g_str_equal ((const gchar *)event.data.scalar.value,
                                "version"))
            {
              if (mdversion != 0)
                {
                  MMD_YAML_ERROR_EVENT_EXIT_BOOL (
                    error, event, "Metadata version encountered twice.");
                }

              mdversion = modulemd_yaml_parse_uint64 (parser, &nested_error);
              if (nested_error)
                {
                  /* If we got a parsing error, report it. Otherwise, continue
                   * and we'll catch the invalid mdversion further on
                   */
                  g_propagate_error (error, g_steal_pointer (&nested_error));
                  return FALSE;
                }
              mdversion_string = g_strdup_printf ("%" PRIu64, mdversion);
              if (!mmd_emitter_scalar (
                    emitter, mdversion_string, YAML_PLAIN_SCALAR_STYLE, error))
                {
                  return FALSE;
                }
            }
          else if (depth == 1 &&
                   g_str_equal ((const gchar *)event.data.scalar.value,
                                "data"))
            {
              had_data = TRUE;
            }

          break;

        default:
          /* Anything else, we just re-emit into the subdocument */
          MMD_EMIT_WITH_EXIT_FULL (
            emitter, FALSE, &event, error, "Error re-emiting event");
          ;
          break;
        }

      yaml_event_delete (&event);
    }

  /* The final event must be the document end */
  YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);
  if (event.type != YAML_DOCUMENT_END_EVENT)
    {
      MMD_YAML_ERROR_EVENT_EXIT_BOOL (
        error, event, "Document did not end. It just goes on forever...");
    }
  MMD_EMIT_WITH_EXIT_FULL (
    emitter, FALSE, &event, error, "Error ending document");
  yaml_event_delete (&event);

  if (!mmd_emitter_end_stream (emitter, error))
    {
      return FALSE;
    }

  if (doctype == MODULEMD_YAML_DOC_UNKNOWN)
    {
      g_set_error_literal (error,
                           MODULEMD_YAML_ERROR,
                           MMD_YAML_ERROR_MISSING_REQUIRED,
                           "No document type specified");
      return FALSE;
    }

  if (!mdversion)
    {
      g_set_error_literal (error,
                           MODULEMD_YAML_ERROR,
                           MMD_YAML_ERROR_MISSING_REQUIRED,
                           "No metadata version specified");
      return FALSE;
    }

  if (doctype == MODULEMD_YAML_DOC_PACKAGER && mdversion < 2)
    {
      g_set_error_literal (error,
                           MODULEMD_YAML_ERROR,
                           MMD_YAML_ERROR_INCONSISTENT,
                           "Document type 'modulemd-packager' is permissible "
                           "only for module stream version 2 or higher.");
      return FALSE;
    }

  if (!had_data)
    {
      g_set_error_literal (error,
                           MODULEMD_YAML_ERROR,
                           MMD_YAML_ERROR_MISSING_REQUIRED,
                           "No data section provided");
      return FALSE;
    }

  *_doctype = doctype;
  *_mdversion = mdversion;

  return TRUE;
}


ModulemdSubdocumentInfo *
modulemd_yaml_parse_document_type (yaml_parser_t *parser)
{
  MMD_INIT_YAML_EMITTER (emitter);
  MMD_INIT_YAML_STRING (&emitter, yaml_string);
  g_autoptr (ModulemdSubdocumentInfo) s = modulemd_subdocument_info_new ();
  ModulemdYamlDocumentTypeEnum doctype = MODULEMD_YAML_DOC_UNKNOWN;
  guint64 mdversion = 0;
  g_autoptr (GError) error = NULL;

  if (!modulemd_yaml_parse_document_type_internal (
        parser, &doctype, &mdversion, &emitter, &error))
    {
      modulemd_subdocument_info_set_gerror (s, error);
    }

  modulemd_subdocument_info_set_doctype (s, doctype);
  modulemd_subdocument_info_set_mdversion (s, mdversion);
  modulemd_subdocument_info_set_yaml (s, yaml_string->str);

  return g_steal_pointer (&s);
}


static const gchar *
modulemd_yaml_get_doctype_string (ModulemdYamlDocumentTypeEnum doctype,
                                  guint64 mdversion)
{
  switch (doctype)
    {
    case MODULEMD_YAML_DOC_MODULESTREAM:
      if (mdversion <= 2)
        {
          return "modulemd";
        }
      return "modulemd-stream";

    case MODULEMD_YAML_DOC_DEFAULTS: return "modulemd-defaults";

    case MODULEMD_YAML_DOC_TRANSLATIONS: return "modulemd-translations";

    case MODULEMD_YAML_DOC_OBSOLETES: return "modulemd-obsoletes";

    case MODULEMD_YAML_DOC_PACKAGER: return "modulemd-packager";

    default: return NULL;
    }
}


gboolean
modulemd_yaml_emit_document_headers (yaml_emitter_t *emitter,
                                     ModulemdYamlDocumentTypeEnum doctype,
                                     guint64 mdversion,
                                     GError **error)
{
  MODULEMD_INIT_TRACE ();
  const gchar *doctype_string =
    modulemd_yaml_get_doctype_string (doctype, mdversion);
  g_autofree gchar *mdversion_string = g_strdup_printf ("%" PRIu64, mdversion);

  if (!mmd_emitter_start_document (emitter, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_start_mapping (emitter, YAML_BLOCK_MAPPING_STYLE, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_scalar (
        emitter, "document", YAML_PLAIN_SCALAR_STYLE, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_scalar (
        emitter, doctype_string, YAML_PLAIN_SCALAR_STYLE, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_scalar (emitter, "version", YAML_PLAIN_SCALAR_STYLE, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_scalar (
        emitter, mdversion_string, YAML_PLAIN_SCALAR_STYLE, error))
    {
      return FALSE;
    }

  if (!mmd_emitter_scalar (emitter, "data", YAML_PLAIN_SCALAR_STYLE, error))
    {
      return FALSE;
    }

  return TRUE;
}


gboolean
modulemd_yaml_emit_variant (yaml_emitter_t *emitter,
                            GVariant *variant,
                            GError **error)
{
  GVariantIter iter;
  g_autofree gchar *key = NULL;
  g_autoptr (GVariant) value = NULL;
  g_autoptr (GPtrArray) keys = NULL;
  g_autoptr (GVariantDict) dict = NULL;

  if (g_variant_is_of_type (variant, G_VARIANT_TYPE_STRING))
    {
      EMIT_SCALAR_STRING (
        emitter, error, g_variant_get_string (variant, NULL));
    }
  else if (g_variant_is_of_type (variant, G_VARIANT_TYPE_BOOLEAN))
    {
      if (g_variant_get_boolean (variant))
        {
          EMIT_SCALAR (emitter, error, "TRUE");
        }
      else
        {
          EMIT_SCALAR (emitter, error, "FALSE");
        }
    }
  else if (g_variant_is_of_type (variant, G_VARIANT_TYPE_DICTIONARY))
    {
      EMIT_MAPPING_START (emitter, error);
      keys = g_ptr_array_new_with_free_func (g_free);

      dict = g_variant_dict_new (variant);
      g_variant_iter_init (&iter, variant);

      /* Get a list of the keys to sort */
      while (g_variant_iter_next (&iter, "{sv}", &key, &value))
        {
          g_ptr_array_add (keys, g_steal_pointer (&key));
          g_clear_pointer (&value, g_variant_unref);
        }

      /* Sort the keys alphabetically */
      g_ptr_array_sort (keys, modulemd_strcmp_sort);

      /* Write out the keys and recurse into their values */
      for (guint i = 0; i < keys->len; i++)
        {
          value = g_variant_dict_lookup_value (
            dict, g_ptr_array_index (keys, i), NULL);
          if (!value)
            {
              g_set_error (
                error,
                MODULEMD_YAML_ERROR,
                MMD_YAML_ERROR_EMIT,
                "Got unexpected type while processing XMD dictionary.");
              return FALSE;
            }
          EMIT_SCALAR_STRING (emitter, error, g_ptr_array_index (keys, i));
          if (!modulemd_yaml_emit_variant (emitter, value, error))
            {
              return FALSE;
            }

          g_clear_pointer (&value, g_variant_unref);
        }

      g_clear_pointer (&keys, g_ptr_array_unref);
      EMIT_MAPPING_END (emitter, error);
    }
  else if (g_variant_is_of_type (variant, G_VARIANT_TYPE_ARRAY))
    {
      EMIT_SEQUENCE_START (emitter, error);
      g_variant_iter_init (&iter, variant);
      while ((value = g_variant_iter_next_value (&iter)))
        {
          if (!modulemd_yaml_emit_variant (emitter, value, error))
            {
              return FALSE;
            }
          g_clear_pointer (&value, g_variant_unref);
        }
      EMIT_SEQUENCE_END (emitter, error);
    }
  else
    {
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_EMIT,
                   "Unhandled variant type: \"%s\": %s",
                   g_variant_get_type_string (variant),
                   g_variant_print (variant, TRUE));
      return FALSE;
    }
  return TRUE;
}

GVariant *
mmd_variant_from_scalar (const gchar *scalar)
{
  MODULEMD_INIT_TRACE ();
  GVariant *variant = NULL;

  g_debug ("Variant from scalar: %s", scalar);

  g_return_val_if_fail (scalar, NULL);

  /* Treat "TRUE" and "FALSE" as boolean values */
  if (g_str_equal (scalar, "TRUE"))
    {
      variant = g_variant_new_boolean (TRUE);
    }
  else if (g_str_equal (scalar, "FALSE"))
    {
      variant = g_variant_new_boolean (FALSE);
    }

  else if (scalar)
    {
      /* Any value we don't handle specifically becomes a string */
      variant = g_variant_new_string (scalar);
    }

  return variant;
}


GVariant *
mmd_variant_from_mapping (yaml_parser_t *parser, GError **error)
{
  MODULEMD_INIT_TRACE ();
  gboolean done = FALSE;
  MMD_INIT_YAML_EVENT (event);
  MMD_INIT_YAML_EVENT (value_event);

  g_autoptr (GVariantDict) dict = NULL;
  g_autoptr (GVariant) value = NULL;
  g_autofree gchar *key = NULL;
  g_autoptr (GError) nested_error = NULL;

  dict = g_variant_dict_new (NULL);

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_MAPPING_END_EVENT:
          /* We've processed the whole dictionary */
          done = TRUE;
          break;

        case YAML_SCALAR_EVENT:
          /* All mapping keys must be scalars */
          key = g_strdup ((const gchar *)event.data.scalar.value);

          YAML_PARSER_PARSE_WITH_EXIT (parser, &value_event, error);

          switch (value_event.type)
            {
            case YAML_SCALAR_EVENT:
              value = mmd_variant_from_scalar (
                (const gchar *)value_event.data.scalar.value);
              if (!value)
                {
                  MMD_YAML_ERROR_EVENT_EXIT (
                    error, event, "Error parsing scalar");
                }
              break;

            case YAML_MAPPING_START_EVENT:
              value = mmd_variant_from_mapping (parser, &nested_error);
              if (!value)
                {
                  g_propagate_error (error, g_steal_pointer (&nested_error));
                  return NULL;
                }
              break;

            case YAML_SEQUENCE_START_EVENT:
              value = mmd_variant_from_sequence (parser, &nested_error);
              if (!value)
                {
                  g_propagate_error (error, g_steal_pointer (&nested_error));
                  return NULL;
                }
              break;

            default:
              /* We received a YAML event we shouldn't expect at this level */
              MMD_YAML_ERROR_EVENT_EXIT (
                error,
                event,
                "Unexpected YAML event in inner raw mapping: %s",
                mmd_yaml_get_event_name (value_event.type));
              break;
            }

          yaml_event_delete (&value_event);
          g_variant_dict_insert_value (dict, key, g_steal_pointer (&value));
          g_clear_pointer (&key, g_free);
          break;

        default:
          /* We received a YAML event we shouldn't expect at this level */
          MMD_YAML_ERROR_EVENT_EXIT (
            error,
            event,
            "Unexpected YAML event in raw mapping: %s",
            mmd_yaml_get_event_name (event.type));
          break;
        }

      yaml_event_delete (&event);
    }

  return g_variant_dict_end (dict);
}


GVariant *
mmd_variant_from_sequence (yaml_parser_t *parser, GError **error)
{
  MODULEMD_INIT_TRACE ();
  gboolean done = FALSE;
  MMD_INIT_YAML_EVENT (event);

  g_auto (GVariantBuilder) builder;
  g_autoptr (GVariant) value = NULL;
  g_autoptr (GError) nested_error = NULL;
  gboolean empty_array = TRUE;
  GVariant *result = NULL;

  g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

      switch (event.type)
        {
        case YAML_SEQUENCE_END_EVENT:
          /* We've processed the whole sequence */
          done = TRUE;
          break;

        case YAML_SCALAR_EVENT:
          value =
            mmd_variant_from_scalar ((const gchar *)event.data.scalar.value);
          if (!value)
            {
              MMD_YAML_ERROR_EVENT_EXIT (error, event, "Error parsing scalar");
            }
          break;

        case YAML_MAPPING_START_EVENT:
          value = mmd_variant_from_mapping (parser, &nested_error);
          if (!value)
            {
              g_propagate_error (error, g_steal_pointer (&nested_error));
              return NULL;
            }
          break;

        case YAML_SEQUENCE_START_EVENT:
          value = mmd_variant_from_sequence (parser, &nested_error);
          if (!value)
            {
              g_propagate_error (error, g_steal_pointer (&nested_error));
              return NULL;
            }
          break;

        default:
          /* We received a YAML event we shouldn't expect at this level */
          MMD_YAML_ERROR_EVENT_EXIT (
            error,
            event,
            "Unexpected YAML event in raw sequence: %s",
            mmd_yaml_get_event_name (event.type));
          break;
        }

      if (value)
        {
          g_variant_builder_add_value (&builder, g_steal_pointer (&value));
          empty_array = FALSE;
        }

      yaml_event_delete (&event);
    }

  if (empty_array)
    {
      /* If we got an empty array, treat it as a zero-length array of
       * GVariants
       */
      result = g_variant_new ("av", NULL);
    }
  else
    {
      /* Otherwise, finish it up */
      result = g_variant_builder_end (&builder);
    }

  return result;
}


GVariant *
mmd_parse_xmd (yaml_parser_t *parser, GError **error)
{
  MODULEMD_INIT_TRACE ();
  MMD_INIT_YAML_EVENT (event);
  GVariant *variant = NULL;
  g_autoptr (GError) nested_error = NULL;

  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  YAML_PARSER_PARSE_WITH_EXIT (parser, &event, error);

  switch (event.type)
    {
    case YAML_SCALAR_EVENT:
      variant =
        mmd_variant_from_scalar ((const gchar *)event.data.scalar.value);
      if (!variant)
        {
          MMD_YAML_ERROR_EVENT_EXIT (error, event, "Error parsing scalar");
        }
      break;

    case YAML_MAPPING_START_EVENT:
      variant = mmd_variant_from_mapping (parser, &nested_error);
      break;

    default:
      MMD_YAML_ERROR_EVENT_EXIT (error,
                                 event,
                                 "Unexpected YAML event in raw parsing: %s",
                                 mmd_yaml_get_event_name (event.type));
      break;
    }

  return g_variant_ref_sink (variant);
}


static gboolean
skip_unknown_yaml_mapping (yaml_parser_t *parser, GError **error);
static gboolean
skip_unknown_yaml_sequence (yaml_parser_t *parser, GError **error);


gboolean
skip_unknown_yaml (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  MODULEMD_INIT_TRACE ();

  /* This function is called when an unknown key appears in a mapping.
   * Read the next event and then skip to the end of it.
   */

  YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);

  switch (event.type)
    {
    case YAML_SCALAR_EVENT:
      /* If we get a scalar key, we can just return here */
      break;

    case YAML_MAPPING_START_EVENT:
      return skip_unknown_yaml_mapping (parser, error);

    case YAML_SEQUENCE_START_EVENT:
      return skip_unknown_yaml_sequence (parser, error);

    default:
      /* We received a YAML event we shouldn't expect at this level */
      g_set_error (error,
                   MODULEMD_YAML_ERROR,
                   MMD_YAML_ERROR_PARSE,
                   "Unexpected YAML event %s in skip_unknown_yaml()",
                   mmd_yaml_get_event_name (event.type));
      return FALSE;
    }

  return TRUE;
}


static gboolean
skip_unknown_yaml_sequence (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  gsize depth = 0;
  gboolean done = FALSE;

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);

      switch (event.type)
        {
        case YAML_SCALAR_EVENT: break;

        case YAML_MAPPING_START_EVENT:
        case YAML_SEQUENCE_START_EVENT: depth++; break;

        case YAML_MAPPING_END_EVENT: depth--; break;

        case YAML_SEQUENCE_END_EVENT:
          if (depth == 0)
            {
              done = TRUE;
              break;
            }

          depth--;
          break;


        default:
          /* We received a YAML event we shouldn't expect at this level */
          g_set_error (
            error,
            MODULEMD_YAML_ERROR,
            MMD_YAML_ERROR_PARSE,
            "Unexpected YAML event %s in skip_unknown_yaml_sequence()",
            mmd_yaml_get_event_name (event.type));
          return FALSE;
        }

      yaml_event_delete (&event);
    }

  return TRUE;
}


static gboolean
skip_unknown_yaml_mapping (yaml_parser_t *parser, GError **error)
{
  MMD_INIT_YAML_EVENT (event);
  gsize depth = 0;
  gboolean done = FALSE;

  while (!done)
    {
      YAML_PARSER_PARSE_WITH_EXIT_BOOL (parser, &event, error);

      switch (event.type)
        {
        case YAML_SCALAR_EVENT: break;

        case YAML_MAPPING_START_EVENT:
        case YAML_SEQUENCE_START_EVENT: depth++; break;

        case YAML_SEQUENCE_END_EVENT: depth--; break;

        case YAML_MAPPING_END_EVENT:
          if (depth == 0)
            {
              done = TRUE;
              break;
            }

          depth--;
          break;


        default:
          /* We received a YAML event we shouldn't expect at this level */
          g_set_error (
            error,
            MODULEMD_YAML_ERROR,
            MMD_YAML_ERROR_PARSE,
            "Unexpected YAML event %s in skip_unknown_yaml_sequence()",
            mmd_yaml_get_event_name (event.type));
          return FALSE;
        }

      yaml_event_delete (&event);
    }

  return TRUE;
}