GLib Reference Manual | ||||
---|---|---|---|---|
#include <glib.h> enum GMarkupError; #define G_MARKUP_ERROR enum GMarkupParseFlags; GMarkupParseContext; GMarkupParser; gchar* g_markup_escape_text (const gchar *text, gssize length); gchar* g_markup_printf_escaped (const char *format, ...); gchar* g_markup_vprintf_escaped (const char *format, va_list args); gboolean g_markup_parse_context_end_parse (GMarkupParseContext *context, GError **error); void g_markup_parse_context_free (GMarkupParseContext *context); void g_markup_parse_context_get_position (GMarkupParseContext *context, gint *line_number, gint *char_number); const gchar* g_markup_parse_context_get_element (GMarkupParseContext *context); GMarkupParseContext* g_markup_parse_context_new (const GMarkupParser *parser, GMarkupParseFlags flags, gpointer user_data, GDestroyNotify user_data_dnotify); gboolean g_markup_parse_context_parse (GMarkupParseContext *context, const gchar *text, gssize text_len, GError **error);
The "GMarkup" parser is intended to parse a simple markup format that's a subset of XML. This is a small, efficient, easy-to-use parser. It should not be used if you expect to interoperate with other applications generating full-scale XML. However, it's very useful for application data files, config files, etc. where you know your application will be the only one writing the file. Full-scale XML parsers should be able to parse the subset used by GMarkup, so you can easily migrate to full-scale XML at a later time if the need arises.
GMarkup is not guaranteed to signal an error on all invalid XML; the parser may accept documents that an XML parser would not. However, XML documents which are not well-formed[4] are not considered valid GMarkup documents.
Simplifications to XML include:
Only UTF-8 encoding is allowed.
No user-defined entities.
Processing instructions, comments and the doctype declaration are "passed through" but are not interpreted in any way.
No DTD or validation.
The markup format does support:
Elements
Attributes
5 standard entities: & < > " '
Character references
Sections marked as CDATA
typedef enum { G_MARKUP_ERROR_BAD_UTF8, G_MARKUP_ERROR_EMPTY, G_MARKUP_ERROR_PARSE, /* These three are primarily intended for specific GMarkupParser * implementations to set. */ G_MARKUP_ERROR_UNKNOWN_ELEMENT, G_MARKUP_ERROR_UNKNOWN_ATTRIBUTE, G_MARKUP_ERROR_INVALID_CONTENT } GMarkupError;
Error codes returned by markup parsing.
G_MARKUP_ERROR_BAD_UTF8 |
text being parsed was not valid UTF-8 |
G_MARKUP_ERROR_EMPTY |
document contained nothing, or only whitespace |
G_MARKUP_ERROR_PARSE |
document was ill-formed |
G_MARKUP_ERROR_UNKNOWN_ELEMENT |
error should be set by GMarkupParser functions; element wasn't known |
G_MARKUP_ERROR_UNKNOWN_ATTRIBUTE |
error should be set by GMarkupParser functions; attribute wasn't known |
G_MARKUP_ERROR_INVALID_CONTENT |
error should be set by GMarkupParser functions; something was wrong with contents of the document, e.g. invalid attribute value |
#define G_MARKUP_ERROR g_markup_error_quark ()
Error domain for markup parsing. Errors in this domain will be from the GMarkupError enumeration. See GError for information on error domains.
typedef enum { G_MARKUP_DO_NOT_USE_THIS_UNSUPPORTED_FLAG = 1 << 0, G_MARKUP_TREAT_CDATA_AS_TEXT = 1 << 1 } GMarkupParseFlags;
Flags that affect the behaviour of the parser.
typedef struct _GMarkupParseContext GMarkupParseContext;
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()
,
GMarkupParser, and so on for more details.
typedef struct { /* Called for open tags <foo bar="baz"> */ void (*start_element) (GMarkupParseContext *context, const gchar *element_name, const gchar **attribute_names, const gchar **attribute_values, gpointer user_data, GError **error); /* Called for close tags </foo> */ void (*end_element) (GMarkupParseContext *context, const gchar *element_name, gpointer user_data, GError **error); /* Called for character data */ /* text is not nul-terminated */ void (*text) (GMarkupParseContext *context, const gchar *text, gsize text_len, gpointer user_data, GError **error); /* Called for strings that should be re-saved verbatim in this same * position, but are not otherwise interpretable. At the moment * this includes comments and processing instructions. */ /* text is not nul-terminated. */ void (*passthrough) (GMarkupParseContext *context, const gchar *passthrough_text, gsize text_len, gpointer user_data, GError **error); /* Called on error, including one set by other * methods in the vtable. The GError should not be freed. */ void (*error) (GMarkupParseContext *context, GError *error, gpointer user_data); } GMarkupParser;
Any of the fields in GMarkupParser can be NULL
, in which case they
will be ignored. Except for the error
function, any of these
callbacks can set an error; in particular the
G_MARKUP_ERROR_UNKNOWN_ELEMENT
, G_MARKUP_ERROR_UNKNOWN_ATTRIBUTE
,
and G_MARKUP_ERROR_INVALID_CONTENT
errors are intended to be set
from these callbacks. If you set an error from a callback,
g_markup_parse_context_parse()
will report that error back to its caller.
start_element () |
Callback to invoke when the opening tag of an element is seen. |
end_element () |
Callback to invoke when the closing tag of an element is seen.
Note that this is also called for empty tags like
<empty/> .
|
text () |
Callback to invoke when some text is seen (text is always
inside an element). Note that the text of an element may be spread
over multiple calls of this function. If the G_MARKUP_TREAT_CDATA_AS_TEXT
flag is set, this function is also called for the content of CDATA marked
sections.
|
passthrough () |
Callback to invoke for comments, processing instructions
and doctype declarations; if you're re-writing the parsed document,
write the passthrough text back out in the same position. If the
G_MARKUP_TREAT_CDATA_AS_TEXT flag is not set, this function is also
called for CDATA marked sections.
|
error () |
Callback to invoke when an error occurs. |
gchar* g_markup_escape_text (const gchar *text, gssize length);
Escapes text so that the markup parser will parse it verbatim. Less than, greater than, ampersand, etc. are replaced with the corresponding entities. This function would typically be used when writing out a file to be parsed with the markup parser.
Note that this function doesn't protect whitespace and line endings from being processed according to the XML rules for normalization of line endings and attribute values.
text : |
some valid UTF-8 text |
length : |
length of text in bytes, or -1 if the text is nul-terminated
|
Returns : | a newly allocated string with the escaped text |
gchar* g_markup_printf_escaped (const char *format, ...);
Formats arguments according to format
, escaping
all string and character arguments in the fashion
of g_markup_escape_text()
. This is useful when you
want to insert literal strings into XML-style markup
output, without having to worry that the strings
might themselves contain markup.
const char *store = "Fortnum & Mason"; const char *item = "Tea"; char *output; output = g_markup_printf_escaped ("<purchase>" "<store>%s</store>" "<item>%s</item>" "</purchase>", store, item);
format : |
printf() style format string
|
... : |
the arguments to insert in the format string |
Returns : | newly allocated result from formatting
operation. Free with g_free() .
|
Since 2.4
gchar* g_markup_vprintf_escaped (const char *format, va_list args);
Formats the data in args
according to format
, escaping
all string and character arguments in the fashion
of g_markup_escape_text()
. See g_markup_printf_escaped()
.
format : |
printf() style format string
|
args : |
variable argument list, similar to vprintf()
|
Returns : | newly allocated result from formatting
operation. Free with g_free() .
|
Since 2.4
gboolean g_markup_parse_context_end_parse (GMarkupParseContext *context, GError **error);
Signals to the GMarkupParseContext 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.
context : |
a GMarkupParseContext |
error : |
return location for a GError |
Returns : | TRUE on success, FALSE if an error was set
|
void g_markup_parse_context_free (GMarkupParseContext *context);
Frees a GMarkupParseContext. Can't be called from inside one of the GMarkupParser functions.
context : |
a GMarkupParseContext |
void g_markup_parse_context_get_position (GMarkupParseContext *context, gint *line_number, gint *char_number);
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."
context : |
a GMarkupParseContext |
line_number : |
return location for a line number, or NULL
|
char_number : |
return location for a char-on-line number, or NULL
|
const gchar* g_markup_parse_context_get_element (GMarkupParseContext *context);
Retrieves the name of the currently open element.
context : |
a GMarkupParseContext |
Returns : | the name of the currently open element, or NULL
|
Since 2.2
GMarkupParseContext* g_markup_parse_context_new (const GMarkupParser *parser, GMarkupParseFlags flags, gpointer user_data, GDestroyNotify user_data_dnotify);
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).
parser : |
a GMarkupParser |
flags : |
one or more GMarkupParseFlags |
user_data : |
user data to pass to GMarkupParser functions |
user_data_dnotify : |
user data destroy notifier called when the parse context is freed |
Returns : | a new GMarkupParseContext |
gboolean g_markup_parse_context_parse (GMarkupParseContext *context, const gchar *text, gssize text_len, GError **error);
Feed some data to the GMarkupParseContext. 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 GMarkupParseContext; all errors are fatal.
context : |
a GMarkupParseContext |
text : |
chunk of text to parse |
text_len : |
length of text in bytes
|
error : |
return location for a GError |
Returns : | FALSE if an error occurred, TRUE on success
|