Class (GI Struct)

GLib-2.0 ▶ GLib ▶ MarkupParseContext

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

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

Index

Constructors

constructor

Properties

$gtype

Methods

end_parse free get_element get_element_stack get_position get_user_data parse pop push ref unref new

Constructors

Properties

$gtype: GType<GLib.MarkupParseContext>

Methods

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

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

    Returns boolean

    true on success, false if an error was set

  • 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 g_markup_parse_context_get_element_stack().

    Returns string

    the name of the currently open element, or null

  • 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 g_markup_parse_context_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 g_markup_parse_context_get_element() would merely return the name of the element that is being processed.

    Returns string[]

    the element stack, which must not be modified

  • 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."

    Returns [number, number]

  • Returns the user_data associated with context.

    This will either be the user_data that was provided to g_markup_parse_context_new() or to the most recent call of g_markup_parse_context_push().

    Returns any

    the provided user_data. The returned data belongs to the markup context and will be freed when g_markup_parse_context_free() is called.

  • 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.

    Parameters

    • text: string

      chunk of text to parse

    • text_len: number

      length of text in bytes

    Returns boolean

    false if an error occurred, true on success

  • Completes the process of a temporary sub-parser redirection.

    This function exists to collect the user_data allocated by a matching call to g_markup_parse_context_push(). It must be called in the end_element handler corresponding to the start_element handler during which g_markup_parse_context_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.

    Returns any

    the user data passed to g_markup_parse_context_push()

  • 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 g_markup_parse_context_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 g_markup_parse_context_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 g_markup_parse_context_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...
    }

    Parameters

    Returns void

  • Decreases the reference count of context. When its reference count drops to 0, it is freed.

    Returns void