MarkupParseContext#
- class MarkupParseContext(**kwargs)#
A parse context is used to parse a stream of bytes that you expect to contain marked-up text.
See new()
, MarkupParser
, and so
on for more details.
Constructors#
- class MarkupParseContext
- classmethod new(parser: MarkupParser, flags: MarkupParseFlags, user_data: None, user_data_dnotify: Callable[[None], None]) 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).
- Parameters:
parser – a
MarkupParser
flags – one or more
MarkupParseFlags
user_data – user data to pass to
MarkupParser
functionsuser_data_dnotify – user data destroy notifier called when the parse context is freed
Methods#
- class MarkupParseContext
- end_parse() bool #
Signals to the
MarkupParseContext
that all data has been fed into the parse context withparse()
.This function reports an error if the document isn’t complete, for example if elements are still open.
- free() None #
Frees a
MarkupParseContext
.This function can’t be called from inside one of the
MarkupParser
functions or while a subparser is pushed.
- get_element() 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
get_element_stack()
.Added in version 2.2.
- get_element_stack() list[str] #
Retrieves the element stack from the internal state of the parser.
The returned
GSList
is a list of strings where the first item is the currently open tag (as would be returned byget_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
get_element()
would merely return the name of the element that is being processed.Added in version 2.16.
- get_position() tuple[int, 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() None #
Returns the user_data associated with
context
.This will either be the user_data that was provided to
new()
or to the most recent call ofpush()
.Added in version 2.18.
- parse(text: str, text_len: int) bool #
Feed some data to the
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
MarkupParseContext
; all errors are fatal.- Parameters:
text – chunk of text to parse
text_len – length of
text
in bytes
- pop() None #
Completes the process of a temporary sub-parser redirection.
This function exists to collect the user_data allocated by a matching call to
push()
. It must be called in the end_element handler corresponding to the start_element handler during whichpush()
was called. You must not call this function from the error callback – theuser_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.
Added in version 2.18.
- push(parser: MarkupParser, user_data: None) None #
Temporarily redirects markup data to a sub-parser.
This function may only be called from the start_element handler of a
MarkupParser
. It must be matched with a corresponding call topop()
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
pop()
is provided to allow “one last access” to theuser_data
provided to this function. In the case of error, theuser_data
provided here is passed directly to the error callback of the subparser andpop()
should not be called. In either case, ifuser_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... }
Added in version 2.18.
- Parameters:
parser – a
MarkupParser
user_data – user data to pass to
MarkupParser
functions