gstreamer/gst/gstxml.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstxml.c: XML save/restore of pipelines
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "gst_private.h"
#include "gstxml.h"
#include "gstmarshal.h"
#include "gstinfo.h"
#include "gstbin.h"
enum
{
OBJECT_LOADED,
LAST_SIGNAL
};
static void gst_xml_class_init (GstXMLClass * klass);
static void gst_xml_init (GstXML * xml);
static void gst_xml_object_loaded (GstObject * private, GstObject * object,
xmlNodePtr self, gpointer data);
static GstObjectClass *parent_class = NULL;
static guint gst_xml_signals[LAST_SIGNAL] = { 0 };
GType
gst_xml_get_type (void)
{
static GType xml_type = 0;
if (!xml_type) {
static const GTypeInfo xml_info = {
sizeof (GstXMLClass),
NULL,
NULL,
(GClassInitFunc) gst_xml_class_init,
NULL,
NULL,
sizeof (GstXML),
0,
(GInstanceInitFunc) gst_xml_init,
NULL
};
xml_type = g_type_register_static (GST_TYPE_OBJECT, "GstXML", &xml_info, 0);
}
return xml_type;
}
static void
gst_xml_class_init (GstXMLClass * klass)
{
GObjectClass *gobject_class;
gobject_class = (GObjectClass *) klass;
parent_class = g_type_class_ref (GST_TYPE_OBJECT);
/* FIXME G_TYPE_POINTER should be GType of xmlNodePtr */
gst_xml_signals[OBJECT_LOADED] =
g_signal_new ("object-loaded", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstXMLClass, object_loaded), NULL,
NULL, gst_marshal_VOID__OBJECT_POINTER, G_TYPE_NONE, 2, GST_TYPE_OBJECT,
G_TYPE_POINTER);
}
static void
gst_xml_init (GstXML * xml)
{
xml->topelements = NULL;
}
/**
* gst_xml_new:
*
* Create a new GstXML parser object.
*
* Returns: a pointer to a new GstXML object.
*/
GstXML *
gst_xml_new (void)
{
return GST_XML (g_object_new (GST_TYPE_XML, NULL));
}
/**
* gst_xml_write:
* @element: The element to write out
*
* Converts the given element into an XML presentation.
*
* Returns: a pointer to an XML document
*/
xmlDocPtr
gst_xml_write (GstElement * element)
{
xmlDocPtr doc;
xmlNodePtr elementnode;
xmlNsPtr gst_ns;
doc = xmlNewDoc ((guchar *) "1.0");
doc->xmlRootNode = xmlNewDocNode (doc, NULL, (guchar *) "gstreamer", NULL);
gst_ns =
xmlNewNs (doc->xmlRootNode,
(guchar *) "http://gstreamer.net/gst-core/1.0/", (guchar *) "gst");
elementnode =
xmlNewChild (doc->xmlRootNode, gst_ns, (guchar *) "element", NULL);
gst_object_save_thyself (GST_OBJECT (element), elementnode);
return doc;
}
/**
* gst_xml_write_file:
* @element: The element to write out
* @out: an open file, like stdout
*
* Converts the given element into XML and writes the formatted XML to an open
* file.
*
* Returns: number of bytes written on success, -1 otherwise.
*/
gint
gst_xml_write_file (GstElement * element, FILE * out)
{
xmlDocPtr cur;
#ifdef HAVE_LIBXML2
xmlOutputBufferPtr buf;
#endif
const char *encoding;
xmlCharEncodingHandlerPtr handler = NULL;
int indent;
gboolean ret;
cur = gst_xml_write (element);
if (!cur)
return -1;
#ifdef HAVE_LIBXML2
encoding = (const char *) cur->encoding;
if (encoding != NULL) {
xmlCharEncoding enc;
enc = xmlParseCharEncoding (encoding);
if (cur->charset != XML_CHAR_ENCODING_UTF8) {
xmlGenericError (xmlGenericErrorContext,
"xmlDocDump: document not in UTF8\n");
return -1;
}
if (enc != XML_CHAR_ENCODING_UTF8) {
handler = xmlFindCharEncodingHandler (encoding);
if (handler == NULL) {
xmlFree ((char *) cur->encoding);
cur->encoding = NULL;
}
}
}
buf = xmlOutputBufferCreateFile (out, handler);
indent = xmlIndentTreeOutput;
xmlIndentTreeOutput = 1;
ret = xmlSaveFormatFileTo (buf, cur, NULL, 1);
xmlIndentTreeOutput = indent;
#else
/* apparently this doesn't return anything in libxml1 */
xmlDocDump (out, cur);
ret = 1;
#endif
return ret;
}
/**
* gst_xml_parse_doc:
* @xml: a pointer to a GstXML object
* @doc: a pointer to an xml document to parse
* @root: The name of the root object to build
*
* Fills the GstXML object with the elements from the
* xmlDocPtr.
*
* Returns: TRUE on success, FALSE otherwise
*/
gboolean
gst_xml_parse_doc (GstXML * xml, xmlDocPtr doc, const guchar * root)
{
xmlNodePtr field, cur;
xmlNsPtr ns;
cur = xmlDocGetRootElement (doc);
if (cur == NULL) {
g_warning ("gstxml: empty document\n");
return FALSE;
}
ns = xmlSearchNsByHref (doc, cur,
(guchar *) "http://gstreamer.net/gst-core/1.0/");
if (ns == NULL) {
g_warning ("gstxml: document of wrong type, core namespace not found\n");
return FALSE;
}
if (strcmp ((char *) cur->name, "gstreamer")) {
g_warning ("gstxml: XML file is in wrong format\n");
return FALSE;
}
gst_class_signal_connect (GST_OBJECT_CLASS (G_OBJECT_GET_CLASS (xml)),
"object_loaded", gst_xml_object_loaded, xml);
xml->ns = ns;
field = cur->xmlChildrenNode;
while (field) {
if (!strcmp ((char *) field->name, "element") && (field->ns == xml->ns)) {
GstElement *element;
element = gst_xml_make_element (field, NULL);
xml->topelements = g_list_prepend (xml->topelements, element);
}
field = field->next;
}
xml->topelements = g_list_reverse (xml->topelements);
return TRUE;
}
/**
* gst_xml_parse_file:
* @xml: a pointer to a GstXML object
* @fname: The filename with the xml description
* @root: The name of the root object to build
*
* Fills the GstXML object with the corresponding elements from
* the XML file fname. Optionally it will only build the element from
* the element node root (if it is not NULL). This feature is useful
* if you only want to build a specific element from an XML file
* but not the pipeline it is embedded in.
*
* Pass "-" as fname to read from stdin. You can also pass a URI
* of any format that libxml supports, including http.
*
* Returns: TRUE on success, FALSE otherwise
*/
gboolean
gst_xml_parse_file (GstXML * xml, const guchar * fname, const guchar * root)
{
xmlDocPtr doc;
g_return_val_if_fail (fname != NULL, FALSE);
doc = xmlParseFile ((char *) fname);
if (!doc) {
g_warning ("gstxml: XML file \"%s\" could not be read\n", fname);
return FALSE;
}
return gst_xml_parse_doc (xml, doc, root);
}
/**
* gst_xml_parse_memory:
* @xml: a pointer to a GstXML object
* @buffer: a pointer to the in memory XML buffer
* @size: the size of the buffer
* @root: the name of the root objects to build
*
* Fills the GstXML object with the corresponding elements from
* an in memory XML buffer.
*
* Returns: TRUE on success
*/
gboolean
gst_xml_parse_memory (GstXML * xml, guchar * buffer, guint size,
const gchar * root)
{
xmlDocPtr doc;
g_return_val_if_fail (buffer != NULL, FALSE);
doc = xmlParseMemory ((char *) buffer, size);
return gst_xml_parse_doc (xml, doc, (const guchar *) root);
}
static void
gst_xml_object_loaded (GstObject * private, GstObject * object, xmlNodePtr self,
gpointer data)
{
GstXML *xml = GST_XML (data);
/* FIXME check that this element was created from the same xmlDocPtr... */
g_signal_emit (G_OBJECT (xml), gst_xml_signals[OBJECT_LOADED], 0, object,
self);
}
/**
* gst_xml_get_topelements:
* @xml: The GstXML to get the elements from
*
* Retrive a list of toplevel elements.
*
* Returns: a GList of elements
*/
GList *
gst_xml_get_topelements (GstXML * xml)
{
g_return_val_if_fail (xml != NULL, NULL);
return xml->topelements;
}
/**
* gst_xml_get_element:
* @xml: The GstXML to get the element from
* @name: The name of element to retreive
*
* This function is used to get a pointer to the GstElement corresponding
* to name in the pipeline description. You would use this if you have
* to do anything to the element after loading.
*
* Returns: a pointer to a new GstElement
*/
GstElement *
gst_xml_get_element (GstXML * xml, const guchar * name)
{
GstElement *element;
GList *topelements;
g_return_val_if_fail (xml != NULL, NULL);
g_return_val_if_fail (name != NULL, NULL);
GST_DEBUG ("gstxml: getting element \"%s\"", name);
topelements = gst_xml_get_topelements (xml);
while (topelements) {
GstElement *top = GST_ELEMENT (topelements->data);
GST_DEBUG ("gstxml: getting element \"%s\"", name);
if (!strcmp ((char *) GST_ELEMENT_NAME (top), (char *) name)) {
return top;
} else {
if (GST_IS_BIN (top)) {
element = gst_bin_get_by_name (GST_BIN (top), (char *) name);
if (element)
return element;
}
}
topelements = g_list_next (topelements);
}
return NULL;
}
/**
* gst_xml_make_element:
* @cur: the xml node
* @parent: the parent of this object when it's loaded
*
* Load the element from the XML description
*
* Returns: the new element
*/
GstElement *
gst_xml_make_element (xmlNodePtr cur, GstObject * parent)
{
xmlNodePtr children = cur->xmlChildrenNode;
GstElement *element;
guchar *name = NULL;
guchar *type = NULL;
/* first get the needed tags to construct the element */
while (children) {
if (!strcmp ((char *) children->name, "name")) {
name = xmlNodeGetContent (children);
} else if (!strcmp ((char *) children->name, "type")) {
type = xmlNodeGetContent (children);
}
children = children->next;
}
g_return_val_if_fail (name != NULL, NULL);
g_return_val_if_fail (type != NULL, NULL);
GST_CAT_INFO (GST_CAT_XML, "loading \"%s\" of type \"%s\"", name, type);
element = gst_element_factory_make ((char *) type, (char *) name);
g_return_val_if_fail (element != NULL, NULL);
g_free (type);
g_free (name);
/* ne need to set the parent on this object bacause the pads */
/* will go through the hierarchy to link to their peers */
if (parent)
gst_object_set_parent (GST_OBJECT (element), parent);
gst_object_restore_thyself (GST_OBJECT (element), cur);
return element;
}