libpurple/protocols/bonjour/parser.c

/*
 * purple - Bonjour Jabber XML parser stuff
 *
 * Purple is the legal property of its developers, whose names are too numerous
 * to list here.  Please refer to the COPYRIGHT file distributed with this
 * source distribution.
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
 *
 */
#include "internal.h"

#include <libxml/parser.h>

#include "connection.h"
#include "debug.h"
#include "jabber.h"
#include "parser.h"
#include "util.h"
#include "xmlnode.h"

static gboolean
parse_from_attrib_and_find_buddy(BonjourJabberConversation *bconv, int nb_attributes, const xmlChar **attributes) {
	int i;

	/* If the "from" attribute is specified, attach it to the conversation. */
	for(i=0; i < nb_attributes * 5; i+=5) {
		if(!xmlStrcmp(attributes[i], (xmlChar*) "from")) {
			int len = attributes[i+4] - attributes[i+3];
			bconv->buddy_name = g_strndup((char *)attributes[i+3], len);
			bonjour_jabber_conv_match_by_name(bconv);

			return (bconv->pb != NULL);
		}
	}

	return FALSE;
}

static char *purple_unescape_text(const char *in)
{
    GString *ret;
    const char *c = in;

    if (in == NULL)
        return NULL;

    ret = g_string_new("");
    while (*c) {
        int len;
        const char *ent;

        if ((ent = purple_markup_unescape_entity(c, &len)) != NULL) {
            g_string_append(ret, ent);
            c += len;
        } else {
            g_string_append_c(ret, *c);
            c++;
        }
    }

    return g_string_free(ret, FALSE);
}

static void
bonjour_parser_element_start_libxml(void *user_data,
				   const xmlChar *element_name, const xmlChar *prefix, const xmlChar *namespace,
				   int nb_namespaces, const xmlChar **namespaces,
				   int nb_attributes, int nb_defaulted, const xmlChar **attributes)
{
	BonjourJabberConversation *bconv = user_data;

	xmlnode *node;
	int i;

	g_return_if_fail(element_name != NULL);

	if(!xmlStrcmp(element_name, (xmlChar*) "stream")) {
		if(!bconv->recv_stream_start) {
			bconv->recv_stream_start = TRUE;

			if (bconv->pb == NULL)
				parse_from_attrib_and_find_buddy(bconv, nb_attributes, attributes);

			bonjour_jabber_stream_started(bconv);
		}
	} else {

		/* If we haven't yet attached a buddy and this isn't "<stream:features />",
		 * try to get a "from" attribute as a last resort to match our buddy. */
		if(bconv->pb == NULL
				&& !(prefix && !xmlStrcmp(prefix, (xmlChar*) "stream")
					&& !xmlStrcmp(element_name, (xmlChar*) "features"))
				&& !parse_from_attrib_and_find_buddy(bconv, nb_attributes, attributes))
			/* We've run out of options for finding who the conversation is from
			   using explicitly specified stuff; see if we can make a good match
			   by using the IP */
			bonjour_jabber_conv_match_by_ip(bconv);

		if(bconv->current)
			node = xmlnode_new_child(bconv->current, (const char*) element_name);
		else
			node = xmlnode_new((const char*) element_name);
		xmlnode_set_namespace(node, (const char*) namespace);

		for(i=0; i < nb_attributes * 5; i+=5) {
			const char *name = (const char *)attributes[i];
			const char *prefix = (const char *)attributes[i+1];
			const char *attrib_ns = (const char *)attributes[i+2];
			char *txt;
			int attrib_len = attributes[i+4] - attributes[i+3];
			char *attrib = g_malloc(attrib_len + 1);

			memcpy(attrib, attributes[i+3], attrib_len);
			attrib[attrib_len] = '\0';

			txt = attrib;
			attrib = purple_unescape_text(txt);
			g_free(txt);
			xmlnode_set_attrib_full(node, name, attrib_ns, prefix, attrib);
			g_free(attrib);
		}

		bconv->current = node;
	}
}

static void
bonjour_parser_element_end_libxml(void *user_data, const xmlChar *element_name,
				 const xmlChar *prefix, const xmlChar *namespace)
{
	BonjourJabberConversation *bconv = user_data;

	if(!bconv->current) {
		/* We don't keep a reference to the start stream xmlnode,
		 * so we have to check for it here to close the conversation */
		if(!xmlStrcmp(element_name, (xmlChar*) "stream"))
			/* Asynchronously close the conversation to prevent bonjour_parser_setup()
			 * being called from within this context */
			async_bonjour_jabber_close_conversation(bconv);
		return;
	}

	if(bconv->current->parent) {
		if(!xmlStrcmp((xmlChar*) bconv->current->name, element_name))
			bconv->current = bconv->current->parent;
	} else {
		xmlnode *packet = bconv->current;
		bconv->current = NULL;
		bonjour_jabber_process_packet(bconv->pb, packet);
		xmlnode_free(packet);
	}
}

static void
bonjour_parser_element_text_libxml(void *user_data, const xmlChar *text, int text_len)
{
	BonjourJabberConversation *bconv = user_data;

	if(!bconv->current)
		return;

	if(!text || !text_len)
		return;

	xmlnode_insert_data(bconv->current, (const char*) text, text_len);
}

static void
bonjour_parser_structured_error_handler(void *user_data, xmlErrorPtr error)
{
	BonjourJabberConversation *bconv = user_data;

	purple_debug_error("jabber", "XML parser error for BonjourJabberConversation %p: "
	                             "Domain %i, code %i, level %i: %s",
	                   bconv,
	                   error->domain, error->code, error->level,
	                   (error->message ? error->message : "(null)\n"));
}

static xmlSAXHandler bonjour_parser_libxml = {
	NULL,									/*internalSubset*/
	NULL,									/*isStandalone*/
	NULL,									/*hasInternalSubset*/
	NULL,									/*hasExternalSubset*/
	NULL,									/*resolveEntity*/
	NULL,									/*getEntity*/
	NULL,									/*entityDecl*/
	NULL,									/*notationDecl*/
	NULL,									/*attributeDecl*/
	NULL,									/*elementDecl*/
	NULL,									/*unparsedEntityDecl*/
	NULL,									/*setDocumentLocator*/
	NULL,									/*startDocument*/
	NULL,									/*endDocument*/
	NULL,									/*startElement*/
	NULL,									/*endElement*/
	NULL,									/*reference*/
	bonjour_parser_element_text_libxml,		/*characters*/
	NULL,									/*ignorableWhitespace*/
	NULL,									/*processingInstruction*/
	NULL,									/*comment*/
	NULL,									/*warning*/
	NULL,									/*error*/
	NULL,									/*fatalError*/
	NULL,									/*getParameterEntity*/
	NULL,									/*cdataBlock*/
	NULL,									/*externalSubset*/
	XML_SAX2_MAGIC,							/*initialized*/
	NULL,									/*_private*/
	bonjour_parser_element_start_libxml,	/*startElementNs*/
	bonjour_parser_element_end_libxml,		/*endElementNs*/
	bonjour_parser_structured_error_handler /*serror*/
};

void
bonjour_parser_setup(BonjourJabberConversation *bconv)
{

	/* This seems backwards, but it makes sense. The libxml code creates
	 * the parser context when you try to use it (this way, it can figure
	 * out the encoding at creation time. So, setting up the parser is
	 * just a matter of destroying any current parser. */
	if (bconv->context) {
		xmlParseChunk(bconv->context, NULL,0,1);
		xmlFreeParserCtxt(bconv->context);
		bconv->context = NULL;
	}
}


void bonjour_parser_process(BonjourJabberConversation *bconv, const char *buf, int len)
{

	if (bconv->context == NULL) {
		/* libxml inconsistently starts parsing on creating the
		 * parser, so do a ParseChunk right afterwards to force it. */
		bconv->context = xmlCreatePushParserCtxt(&bonjour_parser_libxml, bconv, buf, len, NULL);
		xmlParseChunk(bconv->context, "", 0, 0);
	} else if (xmlParseChunk(bconv->context, buf, len, 0) < 0)
		/* TODO: What should we do here - I assume we should display an error or something (maybe just print something to the conv?) */
		purple_debug_error("bonjour", "Error parsing xml.\n");

}