[core] Abstract XML parsing from GDataFeed and GDataEntry into GDataParsable

Adds a new abstract class, GDataParsable, which adds extensible XML parsing
functionality to inheriting classes. A little documentation is included, but
there is no real public API for the class.

1 files changed, 210 insertions, 0 deletions

diff --git a/gdata/gdata-parsable.c b/gdata/gdata-parsable.c
new file mode 100644
index 00000000..7d6ac479
--- /dev/null
+++ b/gdata/gdata-parsable.c
@@ -0,0 +1,210 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+/*
+ * GData Client
+ * Copyright (C) Philip Withnall 2009 <philip@tecnocode.co.uk>
+ * 
+ * GData Client is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GData Client 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GData Client.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * SECTION:gdata-parsable
+ * @short_description: GData parsable object
+ * @stability: Unstable
+ * @include: gdata/gdata-parsable.h
+ *
+ * #GDataParsable is an abstract class allowing easy implementation of an extensible parser. It is primarily extended by #GDataFeed and #GDataEntry,
+ * both of which require XML parsing which can be extended by subclassing.
+ *
+ * It allows methods to be defined for handling the root XML node, each of its child nodes, and a method to be called after parsing is complete.
+ **/
+
+#include <config.h>
+#include <glib.h>
+#include <glib/gi18n-lib.h>
+#include <string.h>
+#include <libxml/parser.h>
+
+#include "gdata-parsable.h"
+#include "gdata-private.h"
+#include "gdata-parser.h"
+
+static void gdata_parsable_finalize (GObject *object);
+static gboolean real_parse_xml (GDataParsable *parsable, xmlDoc *doc, xmlNode *node, gpointer user_data, GError **error);
+
+struct _GDataParsablePrivate {
+	GString *extra_xml;
+	GHashTable *extra_namespaces;
+};
+
+G_DEFINE_ABSTRACT_TYPE (GDataParsable, gdata_parsable, G_TYPE_OBJECT)
+#define GDATA_PARSABLE_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GDATA_TYPE_PARSABLE, GDataParsablePrivate))
+
+static void
+gdata_parsable_class_init (GDataParsableClass *klass)
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+	g_type_class_add_private (klass, sizeof (GDataParsablePrivate));
+	gobject_class->finalize = gdata_parsable_finalize;
+	klass->parse_xml = real_parse_xml;
+}
+
+static void
+gdata_parsable_init (GDataParsable *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, GDATA_TYPE_PARSABLE, GDataParsablePrivate);
+	self->priv->extra_xml = g_string_new ("");
+	self->priv->extra_namespaces = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
+}
+
+static void
+gdata_parsable_finalize (GObject *object)
+{
+	GDataParsablePrivate *priv = GDATA_PARSABLE_GET_PRIVATE (object);
+
+	g_string_free (priv->extra_xml, TRUE);
+	g_hash_table_destroy (priv->extra_namespaces);
+
+	/* Chain up to the parent class */
+	G_OBJECT_CLASS (gdata_parsable_parent_class)->finalize (object);
+}
+
+static gboolean
+real_parse_xml (GDataParsable *parsable, xmlDoc *doc, xmlNode *node, gpointer user_data, GError **error)
+{
+	xmlBuffer *buffer;
+	xmlNs **namespaces, **namespace;
+
+	/* Unhandled XML */
+	buffer = xmlBufferCreate ();
+	xmlNodeDump (buffer, doc, node, 0, 0);
+	g_string_append (parsable->priv->extra_xml, (gchar*) xmlBufferContent (buffer));
+	g_message ("Unhandled XML in %s: %s", G_OBJECT_TYPE_NAME (parsable), (gchar*) xmlBufferContent (buffer));
+	xmlBufferFree (buffer);
+
+	/* Get the namespaces */
+	namespaces = xmlGetNsList (doc, node);
+	for (namespace = namespaces; *namespace != NULL; namespace++) {
+		if ((*namespace)->prefix != NULL) {
+			g_hash_table_insert (parsable->priv->extra_namespaces,
+					     g_strdup ((gchar*) ((*namespace)->prefix)),
+					     g_strdup ((gchar*) ((*namespace)->href)));
+		}
+	}
+	xmlFree (namespaces);
+
+	return TRUE;
+}
+
+GDataParsable *
+_gdata_parsable_new_from_xml (GType parsable_type, const gchar *first_element, const gchar *xml, gint length, gpointer user_data, GError **error)
+{
+	xmlDoc *doc;
+	xmlNode *node;
+
+	g_return_val_if_fail (g_type_is_a (parsable_type, GDATA_TYPE_PARSABLE) == TRUE, FALSE);
+	g_return_val_if_fail (first_element != NULL, NULL);
+	g_return_val_if_fail (xml != NULL, NULL);
+
+	if (length == -1)
+		length = strlen (xml);
+
+	/* Parse the XML */
+	doc = xmlReadMemory (xml, length, "/dev/null", NULL, 0);
+	if (doc == NULL) {
+		xmlError *xml_error = xmlGetLastError ();
+		g_set_error (error, GDATA_PARSER_ERROR, GDATA_PARSER_ERROR_PARSING_STRING,
+			     _("Error parsing XML: %s"),
+			     xml_error->message);
+		return NULL;
+	}
+
+	/* Get the root element */
+	node = xmlDocGetRootElement (doc);
+	if (node == NULL) {
+		/* XML document's empty */
+		xmlFreeDoc (doc);
+		g_set_error (error, GDATA_PARSER_ERROR, GDATA_PARSER_ERROR_EMPTY_DOCUMENT,
+			     _("Error parsing XML: %s"),
+			     _("Empty document."));
+		return NULL;
+	}
+
+	if (xmlStrcmp (node->name, (xmlChar*) first_element) != 0) {
+		/* No <entry> element (required) */
+		xmlFreeDoc (doc);
+		gdata_parser_error_required_element_missing (first_element, "root", error);
+		return NULL;
+	}
+
+	return _gdata_parsable_new_from_xml_node (parsable_type, first_element, doc, node, user_data, error);
+}
+
+GDataParsable *
+_gdata_parsable_new_from_xml_node (GType parsable_type, const gchar *first_element, xmlDoc *doc, xmlNode *node, gpointer user_data, GError **error)
+{
+	GDataParsable *parsable;
+	GDataParsableClass *klass;
+
+	g_return_val_if_fail (g_type_is_a (parsable_type, GDATA_TYPE_PARSABLE) == TRUE, FALSE);
+	g_return_val_if_fail (doc != NULL, FALSE);
+	g_return_val_if_fail (node != NULL, FALSE);
+	g_return_val_if_fail (xmlStrcmp (node->name, (xmlChar*) first_element) == 0, FALSE);
+
+	parsable = g_object_new (parsable_type, NULL);
+
+	klass = GDATA_PARSABLE_GET_CLASS (parsable);
+	if (klass->parse_xml == NULL)
+		return FALSE;
+
+	/* Call the pre-parse function first */
+	if (klass->pre_parse_xml != NULL &&
+	    klass->pre_parse_xml (parsable, doc, node, user_data, error) == FALSE) {
+		g_object_unref (parsable);
+		return NULL;
+	}	
+
+	/* Parse each child element */
+	node = node->children;
+	while (node != NULL) {
+		if (klass->parse_xml (parsable, doc, node, user_data, error) == FALSE) {
+			g_object_unref (parsable);
+			return NULL;
+		}
+		node = node->next;
+	}
+
+	/* Call the post-parse function */
+	if (klass->post_parse_xml != NULL &&
+	    klass->post_parse_xml (parsable, user_data, error) == FALSE) {
+		g_object_unref (parsable);
+		return NULL;
+	}
+
+	return parsable;
+}
+
+const gchar *
+_gdata_parsable_get_extra_xml (GDataParsable *self)
+{
+	g_return_val_if_fail (GDATA_IS_PARSABLE (self), NULL);
+	return self->priv->extra_xml->str;
+}
+
+GHashTable *
+_gdata_parsable_get_extra_namespaces (GDataParsable *self)
+{
+	g_return_val_if_fail (GDATA_IS_PARSABLE (self), NULL);
+	return self->priv->extra_namespaces;
+}