--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/gst/gstxml.c	Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,490 @@
+/* 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.
+ */
+
+/**
+ * SECTION:gstxml
+ * @short_description: XML save/restore operations of pipelines
+ *
+ * GStreamer pipelines can be saved to xml files using gst_xml_write_file().
+ * They can be loaded back using gst_xml_parse_doc() / gst_xml_parse_file() / 
+ * gst_xml_parse_memory().
+ * Additionally one can load saved pipelines into the gst-editor to inspect the
+ * graph.
+ *
+ * #GstElement implementations need to override gst_object_save_thyself() and
+ * gst_object_restore_thyself().
+ */
+
+#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_dispose (GObject * object);
+
+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 (G_UNLIKELY (xml_type == 0)) {
+    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_peek_parent (klass);
+
+  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_xml_dispose);
+
+  /* FIXME G_TYPE_POINTER should be GType of xmlNodePtr
+   * (ensonic) can't be fixed, as libxml does not use GObject (unfortunately)
+   */
+  /**
+   * GstXML::object-loaded:
+   * @xml: the xml persistence instance
+   * @object: the object that has been loaded
+   * @xml_node: the related xml_node pointer to the document tree
+   *
+   * Signals that a new object has been deserialized.
+   */
+  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;
+}
+
+static void
+gst_xml_dispose (GObject * object)
+{
+  GstXML *xml = GST_XML (object);
+
+  g_list_foreach (xml->topelements, (GFunc) gst_object_unref, NULL);
+  g_list_free (xml->topelements);
+  xml->topelements = NULL;
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+/**
+ * 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 ((xmlChar *) "1.0");
+
+  doc->xmlRootNode = xmlNewDocNode (doc, NULL, (xmlChar *) "gstreamer", NULL);
+
+  gst_ns =
+      xmlNewNs (doc->xmlRootNode,
+      (xmlChar *) "http://gstreamer.net/gst-core/1.0/", (xmlChar *) "gst");
+
+  elementnode = xmlNewChild (doc->xmlRootNode, gst_ns, (xmlChar *) "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,
+      (xmlChar *) "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", (gpointer) 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;
+}
+
+/* FIXME 0.9: Why guchar*? */
+/**
+ * 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;
+  gboolean ret;
+
+  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;
+  }
+
+  ret = gst_xml_parse_doc (xml, doc, root);
+
+  xmlFreeDoc (doc);
+  return ret;
+}
+
+/* FIXME 0.9: guchar* */
+/**
+ * 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;
+  gboolean ret;
+
+  g_return_val_if_fail (buffer != NULL, FALSE);
+
+  doc = xmlParseMemory ((char *) buffer, size);
+
+  ret = gst_xml_parse_doc (xml, doc, (const xmlChar *) root);
+
+  xmlFreeDoc (doc);
+  return ret;
+}
+
+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
+ *
+ * Retrieve a list of toplevel elements.
+ *
+ * Returns: a GList of top-level elements. The caller does not own a copy
+ * of the list and must not free or modify the list. The caller also does not
+ * own a reference to any of the elements in the list and should obtain its own
+ * reference using gst_object_ref() if necessary.
+ */
+GList *
+gst_xml_get_topelements (GstXML * xml)
+{
+  g_return_val_if_fail (xml != NULL, NULL);
+
+  return xml->topelements;
+}
+
+/* FIXME 0.11: why is the arg guchar* instead of gchar*? */
+/**
+ * gst_xml_get_element:
+ * @xml: The GstXML to get the element from
+ * @name: The name of element to retrieve
+ *
+ * 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, caller owns returned reference.
+ */
+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 (GST_ELEMENT_NAME (top), (char *) name)) {
+      return GST_ELEMENT_CAST (gst_object_ref (top));
+    } else {
+      if (GST_IS_BIN (top)) {
+        element = gst_bin_get_by_name (GST_BIN (top), (gchar *) 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;
+  gchar *name = NULL;
+  gchar *type = NULL;
+
+  /* first get the needed tags to construct the element */
+  while (children) {
+    if (!strcmp ((char *) children->name, "name")) {
+      name = (gchar *) xmlNodeGetContent (children);
+    } else if (!strcmp ((char *) children->name, "type")) {
+      type = (gchar *) 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 (type, 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) {
+    if (GST_IS_BIN (parent)) {
+      gst_bin_add (GST_BIN (parent), element);
+    } else {
+      gst_object_set_parent (GST_OBJECT (element), parent);
+    }
+  }
+
+  gst_object_restore_thyself (GST_OBJECT (element), cur);
+
+  return element;
+}