GLib.MarkupParseContext¶

Fields¶

None

Methods¶

class	`new` (parser, flags, user_data, user_data_dnotify)
	`end_parse` ()
	`free` ()
	`get_element` ()
	`get_element_stack` ()
	`get_position` ()
	`get_user_data` ()
	`parse` (text, text_len)
	`pop` ()
	`push` (parser, user_data)
	`ref` ()
	`unref` ()

Details¶

class GLib.MarkupParseContext¶

A parse context is used to parse a stream of bytes that you expect to contain marked-up text.

See GLib.MarkupParseContext.new(), GLib.MarkupParser, and so on for more details.

classmethod new(parser, flags, user_data, user_data_dnotify)[source]¶

Parameters:

parser (GLib.MarkupParser) – a GLib.MarkupParser
flags (GLib.MarkupParseFlags) – one or more GLib.MarkupParseFlags
user_data (object or None) – user data to pass to GLib.MarkupParser functions
user_data_dnotify (GLib.DestroyNotify) – user data destroy notifier called when the parse context is freed

Returns:

a new GLib.MarkupParseContext

Return type:

GLib.MarkupParseContext

Creates a new parse context. A parse context is used to parse marked-up documents. You can feed any number of documents into a context, as long as no errors occur; once an error occurs, the parse context can’t continue to parse text (you have to free it and create a new parse context).

end_parse()[source]¶

Raises:: GLib.Error
Returns:: True on success, False if an error was set
Return type:: bool

Signals to the GLib.MarkupParseContext that all data has been fed into the parse context with GLib.MarkupParseContext.parse().

This function reports an error if the document isn’t complete, for example if elements are still open.

free()[source]¶

Frees a GLib.MarkupParseContext.

This function can’t be called from inside one of the GLib.MarkupParser functions or while a subparser is pushed.

get_element()[source]¶

Returns:: the name of the currently open element, or None
Return type:: str

Retrieves the name of the currently open element.

If called from the start_element or end_element handlers this will give the element_name as passed to those functions. For the parent elements, see GLib.MarkupParseContext.get_element_stack().

New in version 2.2.

get_element_stack()[source]¶

Returns:: the element stack, which must not be modified
Return type:: [str]

Retrieves the element stack from the internal state of the parser.

The returned GLib.SList is a list of strings where the first item is the currently open tag (as would be returned by GLib.MarkupParseContext.get_element()) and the next item is its immediate parent.

This function is intended to be used in the start_element and end_element handlers where GLib.MarkupParseContext.get_element() would merely return the name of the element that is being processed.

New in version 2.16.

get_position()[source]¶

Returns:

line_number:: return location for a line number, or None
char_number:: return location for a str-on-line number, or None

Return type:

(line_number: int, char_number: int)

Retrieves the current line number and the number of the character on that line. Intended for use in error messages; there are no strict semantics for what constitutes the “current” line number other than “the best number we could come up with for error messages.”

get_user_data()[source]¶

Returns:: the provided user_data. The returned data belongs to the markup context and will be freed when GLib.MarkupParseContext.free() is called.
Return type:: object or None

Returns the user_data associated with self.

This will either be the user_data that was provided to GLib.MarkupParseContext.new() or to the most recent call of GLib.MarkupParseContext.push().

New in version 2.18.

parse(text, text_len)[source]¶

Parameters:

text (str) – chunk of text to parse
text_len (int) – length of text in bytes

Raises:

GLib.Error

Returns:

False if an error occurred, True on success

Return type:

bool

Feed some data to the GLib.MarkupParseContext.

The data need not be valid UTF-8; an error will be signaled if it’s invalid. The data need not be an entire document; you can feed a document into the parser incrementally, via multiple calls to this function. Typically, as you receive data from a network connection or file, you feed each received chunk of data into this function, aborting the process if an error occurs. Once an error is reported, no further data may be fed to the GLib.MarkupParseContext; all errors are fatal.

pop()[source]¶

Returns:: the user data passed to GLib.MarkupParseContext.push()
Return type:: object or None

Completes the process of a temporary sub-parser redirection.

This function exists to collect the user_data allocated by a matching call to GLib.MarkupParseContext.push(). It must be called in the end_element handler corresponding to the start_element handler during which GLib.MarkupParseContext.push() was called. You must not call this function from the error callback – the user_data is provided directly to the callback in that case.

This function is not intended to be directly called by users interested in invoking subparsers. Instead, it is intended to be used by the subparsers themselves to implement a higher-level interface.

New in version 2.18.

push(parser, user_data)[source]¶

Parameters:

parser (GLib.MarkupParser) – a GLib.MarkupParser
user_data (object or None) – user data to pass to GLib.MarkupParser functions

Temporarily redirects markup data to a sub-parser.

This function may only be called from the start_element handler of a GLib.MarkupParser. It must be matched with a corresponding call to GLib.MarkupParseContext.pop() in the matching end_element handler (except in the case that the parser aborts due to an error).

All tags, text and other data between the matching tags is redirected to the subparser given by parser. user_data is used as the user_data for that parser. user_data is also passed to the error callback in the event that an error occurs. This includes errors that occur in subparsers of the subparser.

The end tag matching the start tag for which this call was made is handled by the previous parser (which is given its own user_data) which is why GLib.MarkupParseContext.pop() is provided to allow “one last access” to the user_data provided to this function. In the case of error, the user_data provided here is passed directly to the error callback of the subparser and GLib.MarkupParseContext.pop() should not be called. In either case, if user_data was allocated then it ought to be freed from both of these locations.

This function is not intended to be directly called by users interested in invoking subparsers. Instead, it is intended to be used by the subparsers themselves to implement a higher-level interface.

As an example, see the following implementation of a simple parser that counts the number of tags encountered.

typedef struct
{
  gint tag_count;
} CounterData;

static void
counter_start_element (GMarkupParseContext  *context,
                       const gchar          *element_name,
                       const gchar         **attribute_names,
                       const gchar         **attribute_values,
                       gpointer              user_data,
                       GError              **error)
{
  CounterData *data = user_data;

  data->tag_count++;
}

static void
counter_error (GMarkupParseContext *context,
               GError              *error,
               gpointer             user_data)
{
  CounterData *data = user_data;

  g_slice_free (CounterData, data);
}

static GMarkupParser counter_subparser =
{
  counter_start_element,
  NULL,
  NULL,
  NULL,
  counter_error
};

In order to allow this parser to be easily used as a subparser, the following interface is provided:

void
start_counting (GMarkupParseContext *context)
{
  CounterData *data = g_slice_new (CounterData);

  data->tag_count = 0;
  g_markup_parse_context_push (context, &counter_subparser, data);
}

gint
end_counting (GMarkupParseContext *context)
{
  CounterData *data = g_markup_parse_context_pop (context);
  int result;

  result = data->tag_count;
  g_slice_free (CounterData, data);

  return result;
}

The subparser would then be used as follows:

static void start_element (context, element_name, ...)
{
  if (strcmp (element_name, "count-these") == 0)
    start_counting (context);

  // else, handle other tags...
}

static void end_element (context, element_name, ...)
{
  if (strcmp (element_name, "count-these") == 0)
    g_print ("Counted %d tags\n", end_counting (context));

  // else, handle other tags...
}

New in version 2.18.

ref()[source]¶

Returns:: the same self
Return type:: GLib.MarkupParseContext

Increases the reference count of self.

New in version 2.36.

unref()[source]¶: Decreases the reference count of self. When its reference count drops to 0, it is freed.

New in version 2.36.