/*
 *  SPL - The SPL Programming Language
 *  Copyright (C) 2004, 2005  Clifford Wolf <clifford@clifford.at>
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  mod_xml.c: The SPL XML modules
 */

/**
 * A module for accessing XML data
 *
 * This module currently implements XML, XPath, XSLT (including some EXSLT
 * extensions), XML Namespaces and a simple interface for modifying XML data.
 */

#ifdef _WIN32
#define LIBXML_DLL_IMPORT __declspec(dllimport)
#else
extern int xmlLoadExtDtdDefaultValue;
#endif

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>

#ifndef MAKEDEPS

#  include <libxml/parser.h>
#  include <libxml/xpath.h>
#  include <libxml/xpathInternals.h>

#  ifdef ENABLE_LIBXSLT_SUPPORT
#    include <libxslt/xslt.h>
#    include <libxslt/xsltInternals.h>
#    include <libxslt/transform.h>
#    include <libxslt/xsltutils.h>
#    include <libexslt/exslt.h>
#  endif

#endif

#include "spl.h"
#include "compat.h"

extern void SPL_ABI(spl_mod_xml_init)(struct spl_vm *vm, struct spl_module *mod, int restore);
extern void SPL_ABI(spl_mod_xml_done)(struct spl_vm *vm, struct spl_module *mod);

struct xml_hnode_data {
	xmlDocPtr doc;
#ifdef ENABLE_LIBXSLT_SUPPORT
	xsltStylesheetPtr xsl;
#endif

	xmlNodePtr *node_id_list;
	int node_id_list_size;
	int node_id_counter;
};

struct xml_node_private {
	struct xml_hnode_data *hnd;
	char seq_text[32];
	int node_id;
};

/**
 * This function parses the XML text passed as parameter and returns an XML
 * document handler. This document handler can then be used to access the
 * data in the XML file using XPATH queries. The XPATH queries are used like
 * array indexes:
 *
 *	var xmldoc = xml_parse(file_read("demo.xml"));
 *
 *	foreach[] i (xmldoc["//@*"].nodes)
 *		debug "Attribute '$i' has the value '${xmldoc[i].data}'.";
 *
 * Virtual member variables (.nodes and .data in the example above) are used
 * to specify what kind of data should be accessed. The following virtual
 * member variables are defined for read accesses:
 *
 *	.nodes
 *		Returns an array with references to all nodes in the XML
 *		tree which do match the XPATH query. This references are
 *		auto-generated unique identifiers for the nodes which are
 *		accepted as array indexes just like xpath queries.
 *		(The 'i' variable in the example above.)
 *
 *	.node
 *		Only the first matching node.
 *
 *	.type
 *		The type of the XML node (e.g. "element", "attribute",
 *		"text", "cdata", etc).
 *
 *	.name
 *		The name of the XML node (for element and attribute nodes).
 *
 *	.path
 *		An auto-generated xpath query to this XML node.
 *
 *	.data
 *		The data associated with the first matching XML node. This
 *		is the content if the match is an element node or text node
 *		and the value if the match is an attribute node.
 *
 *	.xml
 *		The XML text of the first matching XML node and its child
 *		nodes.
 *
 *	.innerxml
 *		The XML text of the child nodes of the first matching XML
 *		node.
 *
 * This member variables (except the .nodes variable) do only use the first
 * match. It is possible to specify a seperator using an additional virtual
 * index. Then all matches are included in the result set, seperated by the
 * specified seperator:
 *
 *	debug "All attributes: ${xmldoc["//@*"].data.[", "]}";
 *
 * The following virtual memeber variables are supported for writing:
 *
 *	.data
 *	.xml
 *	.innerxml
 *		This variables are also available for writing and have
 *		the same meaning as for read accesses.
 *
 *	.add_xml_before
 *	.add_xml_after
 *		This adds new XML text before or after the found matches.
 *
 *	.add_xml_top
 *	.add_xml_bottom
 *		This adds new XML text as new child nodes before of after
 *		the child nodes of the found matches.
 *
 * All write queries modify each found match. In cases such as the following
 * example you need to use an iterator because it contains a combined
 * read/write access. Without the iterator, the regex would read the first
 * match, do the substitution once and write the result to all matches:
 *
 *	foreach[] i (xmldoc["//@year"].nodes)
 *		xmldoc[i] =~ s/2004/2005/;
 *
 * The default behavior - if no virtual member varable is specified - is the
 * behavior of the .data variable.
 *
 * It is also possible to remove XML nodes using the 'delete' SPL keyword:
 *
 *	delete xmldoc["//record[@year < 2005]"];
 *
 * The 'node handlers' returned by the .nodes and .node variables can also
 * be used directly to make relative xpath queries. So the following two
 * code snippets are identical:
 *
 *	foreach[] n (xmldoc["//data"].nodes)
 *		debug xmldoc["$n/@value"];
 *
 *	foreach[] n (xmldoc["//data"].nodes)
 *		debug n["@value"];
 *
 * Check out the documents on www.w3.org for a detailed description of XML
 * and the XPath query language.
 *
 * The optional parameters load_dtd and substitute_entities can be set
 * to 1 if entity substitution should be performed. This is usually required
 * when transforming a complete document with xslt.
 *
 * If you parse a document that uses entities from the DTD but substitution
 * of the entities is not desired (i.e. the original document should be kept
 * as is), then you should set load_dtd to 1 and substitute_entities to 0.
 * This way the parser knows about the entities, but does not substitute
 * them. This also avoids parsing errors due to unknown entities.
 */
// builtin xml_parse(xml_text,load_dtd,substitute_entities);
static struct spl_node *handler_xml_parse(struct spl_task *task, void UNUSED(*data))
{
	char *text = spl_clib_get_string(task);
	int load_external_dtd = spl_clib_get_int(task);
	int substitute_entities = spl_clib_get_int(task);

	xmlSubstituteEntitiesDefault(substitute_entities);
	xmlLoadExtDtdDefaultValue = load_external_dtd;

	struct spl_node *n = SPL_NEW_STRING_DUP("XML DATA");
	struct xml_hnode_data *hnd = calloc(1, sizeof(struct xml_hnode_data));

	n->hnode_name = strdup("xml_doc");
	n->hnode_data = hnd;

	hnd->doc = xmlParseMemory(text, strlen(text));

	if (!hnd->doc) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("XML Parser Error"),
			NULL);
		spl_put(task->vm, n);
		return 0;
	} else
		hnd->doc->_private = hnd;

	return n;
}

static void xml_tree_genseqtab(xmlNodePtr cur, xmlNodePtr *tab, int *seq)
{
	while (cur) {
		tab[(*seq)++] = cur;
		if (cur->type == XML_ELEMENT_NODE)
			xml_tree_genseqtab((xmlNodePtr)cur->properties, tab, seq);
		if (cur->children)
			xml_tree_genseqtab(cur->children, tab, seq);
		cur = cur->next;
	}
}

static struct xml_hnode_data *get_xml_hnd(struct spl_node *node)
{
	if (!node->hnode_data)
		node->hnode_data = calloc(1, sizeof(struct xml_hnode_data));

	struct xml_hnode_data *hnd = node->hnode_data;

	if (!hnd->doc) {
		char *seq_list = strstr(node->hnode_dump, "<>");

		if (seq_list) {
			*seq_list = 0;
			seq_list += 2;
		}

		hnd->doc = xmlParseMemory(node->hnode_dump, strlen(node->hnode_dump));
		hnd->doc->_private = hnd;

		if (seq_list) {
			int seq_max = atoi(seq_list), seq = 0;
			seq_list += strspn(seq_list, "0123456789");

			xmlNodePtr *seq_table = calloc(seq_max, sizeof(xmlNodePtr));
			xml_tree_genseqtab(hnd->doc->children, seq_table, &seq);

			while (*seq_list == ',') {
				int inner_seq = atoi(++seq_list);

				seq_list += strspn(seq_list, "0123456789");
				if (*seq_list != '=') break;

				int id = atoi(++seq_list);

				seq_list += strspn(seq_list, "0123456789");
				if (*seq_list != ',' && *seq_list != '<') break;

				xmlNodePtr cur = seq_table[inner_seq-1];

				cur->_private = calloc(1, sizeof(struct xml_node_private));
				struct xml_node_private *p = cur->_private;

				p->hnd = hnd;
				p->node_id = id;

				if (id > hnd->node_id_counter)
					hnd->node_id_counter = id;

				if (hnd->node_id_counter > hnd->node_id_list_size) {
					hnd->node_id_list_size = hnd->node_id_counter * 2;
					hnd->node_id_list = realloc(hnd->node_id_list,
							hnd->node_id_list_size * sizeof(xmlNodePtr));
				}

				hnd->node_id_list[p->node_id-1] = cur;
			}

			free(seq_table);
		}

		free(node->hnode_dump);
		node->hnode_dump = 0;
	}

	return hnd;
}

/**
 * This function expects an XML document handler (as returned by [[xml_parse]])
 * as parameter and creates XML text from it.
 *
 * The xml is dumped with indenting spaces if the named parameter 'format'
 * is passed and has a 'true' (non-zero) value.
 *
 */
// builtin xml_dump(xmldoc);
static struct spl_node *handler_xml_dump(struct spl_task *task, void UNUSED(*data))
{
	struct spl_node *hargs = spl_cleanup(task, spl_clib_get_hargs(task));
	struct spl_node *hnode;

	struct spl_node *n = spl_cleanup(task, spl_clib_get_node(task));

	int format = 0;

	hnode = spl_lookup(task, hargs, "format", SPL_LOOKUP_TEST);
	if (hnode && spl_get_int(hnode)) format = 1;

	if (!n->hnode_name || strcmp(n->hnode_name, "xml_doc")) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Called xml_dump() with something not an XML document handler"),
			NULL);
		spl_put(task->vm, n);
		return 0;
	}

	struct xml_hnode_data *hnd = get_xml_hnd(n);
	int xmltext_size;
	xmlChar *xmltext;

	xmlDocDumpFormatMemory(hnd->doc, &xmltext, &xmltext_size, format);
	return SPL_NEW_STRING((char*)xmltext);
}

static void xml_tree_genseq(xmlNodePtr cur, int *seq, int *seq_len)
{
	while (cur) {
		(*seq)++;
		if (cur->_private) {
			struct xml_node_private *p = cur->_private;
			snprintf(p->seq_text, 32, "%d=%d", *seq, p->node_id);
			*seq_len += strlen(p->seq_text) + 1;
		}
		if (cur->type == XML_ELEMENT_NODE)
			xml_tree_genseq((xmlNodePtr)cur->properties, seq, seq_len);
		if (cur->children)
			xml_tree_genseq(cur->children, seq, seq_len);
		cur = cur->next;
	}
}

static int xml_node_process_lookup(const char *xtype, const char *xarg1,
		xmlNodePtr cur, struct spl_string **n_string_p,
		struct spl_node *n, struct spl_task *task,
		struct xml_hnode_data *hnd, struct spl_node *doc_node)
{
	if (!xtype || !strcmp(xtype, "data")) {
		char *raw_data = (char*)xmlNodeGetContent(cur);
		struct spl_string *data = spl_string_new(0, 0, 0, raw_data, 0);
		struct spl_string *old_str = *n_string_p;
		*n_string_p = spl_string_new(0, *n_string_p, data,
				*n_string_p && xarg1 ? strdup(xarg1) : 0, 0);
		spl_string_put(old_str);
		spl_string_put(data);
		if (!xarg1) return 0;
	}
	else
	if (!strcmp(xtype, "type")) {
		char *raw_data = "unknown";

#define XET(e, t) case e: raw_data = t; break;
		switch (cur->type) {
			XET(	XML_ELEMENT_NODE,	"element"	)
			XET(	XML_ATTRIBUTE_NODE,	"attribute"	)
			XET(	XML_TEXT_NODE,		"text"		)
			XET(	XML_CDATA_SECTION_NODE,	"cdata"		)
			XET(	XML_ENTITY_REF_NODE,	"entity_ref"	)
			XET(	XML_ENTITY_NODE,	"entity"	)
			XET(	XML_PI_NODE,		"pi"		)
			XET(	XML_COMMENT_NODE,	"comment"	)
			XET(	XML_DOCUMENT_NODE,	"document"	)
			XET(	XML_DOCUMENT_TYPE_NODE,	"document_type"	)
			XET(	XML_DOCUMENT_FRAG_NODE,	"document_frag"	)
			XET(	XML_NOTATION_NODE,	"notation"	)
			XET(	XML_HTML_DOCUMENT_NODE,	"html_document"	)
			XET(	XML_DTD_NODE,		"dtd"		)
			XET(	XML_ELEMENT_DECL,	"element_decl"	)
			XET(	XML_ATTRIBUTE_DECL,	"attribute_decl")
			XET(	XML_ENTITY_DECL,	"entity_decl"	)
			XET(	XML_NAMESPACE_DECL,	"namespace_decl")
			XET(	XML_XINCLUDE_START,	"xinclude_start")
			XET(	XML_XINCLUDE_END,	"xinclude_end"	)
			XET(	XML_DOCB_DOCUMENT_NODE,	"docb_document"	)
		}
#undef XET

		struct spl_string *data = spl_string_new(SPL_STRING_STATIC, 0, 0, raw_data, 0);
		struct spl_string *old_str = *n_string_p;
		*n_string_p = spl_string_new(0, *n_string_p, data,
				*n_string_p && xarg1 ? strdup(xarg1) : 0, 0);
		spl_string_put(old_str);
		spl_string_put(data);
		if (!xarg1) return 0;
	}
	else
	if (!strcmp(xtype, "name")) {
		char *raw_data = cur->name ? strdup((char*)cur->name) : "";
		struct spl_string *data = spl_string_new(0, 0, 0, raw_data, 0);
		struct spl_string *old_str = *n_string_p;
		*n_string_p = spl_string_new(0, *n_string_p, data,
				*n_string_p && xarg1 ? strdup(xarg1) : 0, 0);
		spl_string_put(old_str);
		spl_string_put(data);
		if (!xarg1) return 0;
	}
	else
	if (!strcmp(xtype, "path")) {
		char *raw_data = (char*)xmlGetNodePath(cur);
		struct spl_string *data = spl_string_new(0, 0, 0, raw_data, 0);
		struct spl_string *old_str = *n_string_p;
		*n_string_p = spl_string_new(0, *n_string_p, data,
				*n_string_p && xarg1 ? strdup(xarg1) : 0, 0);
		spl_string_put(old_str);
		spl_string_put(data);
		if (!xarg1) return 0;
	}
	else
	if (!strcmp(xtype, "node") || !strcmp(xtype, "nodes")) {
		if (!cur->_private) {
			cur->_private = calloc(1, sizeof(struct xml_node_private));
			struct xml_node_private *p = cur->_private;

			p->hnd = hnd;
			p->node_id = ++hnd->node_id_counter;

			if (hnd->node_id_counter > hnd->node_id_list_size) {
				hnd->node_id_list_size = hnd->node_id_counter * 2;
				hnd->node_id_list = realloc(hnd->node_id_list,
						hnd->node_id_list_size * sizeof(xmlNodePtr));
			}

			hnd->node_id_list[p->node_id-1] = cur;
		}

		struct xml_node_private *p = cur->_private;

		if (!strcmp(xtype, "node")) {
			struct spl_string *data = spl_string_printf(0, 0, 0, "_NodeBySplId_(%d)", p->node_id);
			struct spl_string *old_str = *n_string_p;
			*n_string_p = spl_string_new(0, *n_string_p, data,
					*n_string_p && xarg1 ? strdup(xarg1) : 0, 0);
			spl_string_put(old_str);
			spl_string_put(data);
			if (!xarg1) {
				if (!n->hnode_name && !n->cls) {
					n->hnode_name = strdup("xml_node");
					n->cls = spl_get(doc_node);
				}
				return 0;
			}
		} else {
			struct spl_node *n1 = SPL_NEW_PRINTF("_NodeBySplId_(%d)", p->node_id);
			if (!n1->hnode_name && !n1->cls) {
				n1->hnode_name = strdup("xml_node");
				n1->cls = spl_get(doc_node);
			}
			spl_create(task, n, NULL, n1, SPL_CREATE_LOCAL);
		}
	}
	else
	if (!strcmp(xtype, "xml") || !strcmp(xtype, "innerxml")) {
		xmlBufferPtr buf = xmlBufferCreate();
		xmlNodeDump(buf, hnd->doc, cur, 0, 0);
		if (xarg1 && *n_string_p) {
			struct spl_string *old_str = *n_string_p;
			*n_string_p = spl_string_new(0, *n_string_p, 0, strdup(xarg1), 0);
			spl_string_put(old_str);
		}

		const char *xmltext_buffer = (const char*)xmlBufferContent(buf);
		int innerxml = !strcmp(xtype, "innerxml") && *xmltext_buffer == '<';

		if (innerxml) {
			xmltext_buffer += strcspn(xmltext_buffer, ">");
			if (*xmltext_buffer == '>') xmltext_buffer++;
		}

		char *xmltext = strdup(xmltext_buffer);

		if (innerxml) {
			char *p = strrchr(xmltext, '<');
			if (p) *p = 0;
		}

		struct spl_string *old_str = *n_string_p;
		*n_string_p = spl_string_new(0, *n_string_p, 0, xmltext, 0);
		spl_string_put(old_str);
		xmlBufferFree(buf);
		if (!xarg1) return 0;
	}
	else {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Unknown XML query type (read): %s", xtype),
			NULL);
		return 0;
	}

	return 1;
}

static int xml_node_process_create(const char *xtype, xmlNodePtr cur,
		struct spl_node *value, struct spl_task *task)
{
	if (!xtype || !strcmp(xtype, "data")) {
		xmlNodeSetContent(cur, (xmlChar*)spl_get_string(value));
	}
	else
	if (!strcmp(xtype, "xml") || !strcmp(xtype, "innerxml") ||
	    !strcmp(xtype, "add_xml_before") || !strcmp(xtype, "add_xml_after") ||
	    !strcmp(xtype, "add_xml_top") || !strcmp(xtype, "add_xml_bottom")) {
		char *xmltext = spl_get_string(value);
		xmlNodePtr elem, last=cur, list=0;

		if (xmlParseInNodeContext(cur, xmltext, strlen(xmltext), 0, &list) != XML_ERR_OK) {
			spl_clib_exception(task, "XmlEx", "description",
				SPL_NEW_PRINTF("XML Parser Error"),
				NULL);
			return 0;
		}

		if (!strcmp(xtype, "xml"))
		{
			while (list) {
				list = (elem=list)->next;
				xmlAddNextSibling(last, elem);
				last = elem;
			}

			xmlUnlinkNode(cur);
			xmlFreeNode(cur);
		}

		if (!strcmp(xtype, "innerxml"))
		{
			while ((elem=xmlGetLastChild(cur)) != NULL) {
				xmlUnlinkNode(elem);
				xmlFreeNode(elem);
			}
			xmlAddChildList(cur, list);
		}

		if (!strcmp(xtype, "add_xml_before"))
		{
			while (list) {
				list = (elem=list)->next;
				xmlAddPrevSibling(cur, elem);
			}
		}

		if (!strcmp(xtype, "add_xml_after"))
		{
			while (list) {
				list = (elem=list)->next;
				xmlAddNextSibling(last, elem);
				last = elem;
			}
		}

		if (!strcmp(xtype, "add_xml_top"))
		{
			if ((last=last->children) != NULL)
				while (list) {
					list = (elem=list)->next;
					xmlAddPrevSibling(last, elem);
				}
			else
				xmlAddChildList(cur, list);
		}

		if (!strcmp(xtype, "add_xml_bottom"))
		{
			xmlAddChildList(cur, list);
		}
	}
	else {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Unknown XML query type (write): %s", xtype),
			NULL);
		return 0;
	}

	return 1;
}

static xmlNodePtr nodebysplid(struct xml_hnode_data *hnd, int id)
{
	if (id >= 1 && id <= hnd->node_id_counter && hnd->node_id_list[id-1])
		return hnd->node_id_list[id-1];
	return 0;
}

static void xmlxpfunc_nodebysplid(xmlXPathParserContextPtr ctxt, int nargs)
{
	if (ctxt && nargs == 1) {
		int id = xmlXPathPopNumber(ctxt);
		struct xml_hnode_data *hnd = ctxt->context->doc->_private;
		xmlNodePtr cur = nodebysplid(hnd, id);
		if (cur) valuePush(ctxt, xmlXPathNewNodeSet(cur));
	}
}

static void handler_xml_node(struct spl_task *task, struct spl_vm UNUSED(*vm),
	struct spl_node *node, struct spl_hnode_args *args, void UNUSED(*data))
{
	int node_id = 0;

	if (!strcmp(node->hnode_name, "xml_node")) {
		sscanf(spl_get_string(node),
				"_NodeBySplId_(%d)", &node_id);
		if ((node = node->cls) == 0) return;
		goto redir_from_xml_node_hnode;
	}

	if (args->action == SPL_HNODE_ACTION_PUT)
	{
		struct xml_hnode_data *hnd = node->hnode_data;
		if (hnd) {
#ifdef ENABLE_LIBXSLT_SUPPORT
			if (hnd->xsl) {
				xsltFreeStylesheet(hnd->xsl);
				hnd->doc = 0;
			}
#endif
			if (hnd->doc)
				xmlFreeDoc(hnd->doc);
			if (hnd->node_id_list)
				free(hnd->node_id_list);
			free(hnd);
		}
		return;
	}

	if (args->action == SPL_HNODE_ACTION_DUMP)
	{
		struct xml_hnode_data *hnd = node->hnode_data;
		if (hnd && hnd->doc) {
			int xmltext_size, seq = 0, seq_len = 0;
			char max_seq_text[32];
			xmlChar *xmltext;

			if (node->hnode_dump) {
				free(node->hnode_dump);
				node->hnode_dump = 0;
			}

			xmlDocDumpMemory(hnd->doc, &xmltext, &xmltext_size);

			xml_tree_genseq(hnd->doc->children, &seq, &seq_len);
			snprintf(max_seq_text, 32, "%d", seq);

			int new_xmltext_size = xmltext_size +
				seq_len + strlen(max_seq_text) + 5;
			xmltext = realloc(xmltext, new_xmltext_size);
			xmltext[xmltext_size++] = '<';
			xmltext[xmltext_size++] = '>';

			strcpy((char*)xmltext+xmltext_size, max_seq_text);
			xmltext_size += strlen(max_seq_text);
			xmltext[xmltext_size++] = ',';

			for (int i=0; i<hnd->node_id_counter; i++)
				if (hnd->node_id_list[i]) {
					struct xml_node_private *p = hnd->node_id_list[i]->_private;

					strcpy((char*)xmltext+xmltext_size, p->seq_text);
					xmltext_size += strlen(p->seq_text);
					xmltext[xmltext_size++] = ',';
				}

			xmltext[xmltext_size-1] = '<';
			xmltext[xmltext_size++] = '>';
			xmltext[xmltext_size++] = 0;

			assert(new_xmltext_size == xmltext_size);

			node->hnode_dump = (char*)xmltext;
		}
		return;
	}

redir_from_xml_node_hnode:;
	struct xml_hnode_data *hnd = get_xml_hnd(node);
	if (!hnd->doc) return;

	if (args->action == SPL_HNODE_ACTION_LOOKUP ||
	    args->action == SPL_HNODE_ACTION_CREATE ||
	    args->action == SPL_HNODE_ACTION_DELETE)
	{
		char *key_dup = strdup(args->key);

#ifndef USEWIN32API
		char *strtokptr = 0;
		char *xpath = strtok_r(key_dup, ".", &strtokptr);
		char *xtype = strtok_r(0, ".", &strtokptr);
		char *xarg1 = strtok_r(0, ".", &strtokptr);
#else
		// No strtok_r on windows
		char *xpath = strtok(key_dup, ".");
		char *xtype = strtok(0, ".");
		char *xarg1 = strtok(0, ".");
#endif

		if (xpath) xpath = spl_hash_decode(xpath);
		else xpath = "NULL";

		if (xtype) xtype = spl_hash_decode(xtype);
		if (xarg1) xarg1 = spl_hash_decode(xarg1);

		xmlXPathContextPtr xpathCtx = xmlXPathNewContext(hnd->doc);

		/* copy namespace declarations from root element */
		xmlNsPtr *nsList = xmlGetNsList(hnd->doc, xmlDocGetRootElement(hnd->doc));
		if (nsList) {
			for (xmlNsPtr *i = nsList; *i; i++)
				xmlXPathRegisterNs(xpathCtx, (*i)->prefix, (*i)->href);
			free(nsList);
		}

		xmlXPathRegisterFunc(xpathCtx, (xmlChar*)"_NodeBySplId_", xmlxpfunc_nodebysplid);

		if (node_id)
			xpathCtx->node = nodebysplid(hnd, node_id);

		xmlXPathObjectPtr xpathObj = xmlXPathEvalExpression((xmlChar*)xpath, xpathCtx);

		if (!xpathObj) {
			spl_clib_exception(task, "XmlEx", "description",
				SPL_NEW_PRINTF("XPath Error"),
				NULL);

			xmlXPathFreeContext(xpathCtx);
		} else
		if (xpathObj->nodesetval)
		{
			int list_size = xpathObj->nodesetval->nodeNr;
			xmlNodePtr list[list_size];

			for(int i = 0; i < list_size; i++)
				list[i] = xpathObj->nodesetval->nodeTab[i];

			xmlXPathFreeObject(xpathObj);
			xmlXPathFreeContext(xpathCtx);

			if (args->action == SPL_HNODE_ACTION_LOOKUP) {
				struct spl_node *n = spl_get(0);
				struct spl_string *n_string = 0;

				for(int i = 0; i < list_size; i++) {
					xmlNodePtr cur = list[i];
					if (!xml_node_process_lookup(xtype, xarg1, cur, &n_string, n, task, hnd, node))
						break;
				}

				if (n_string)
					spl_set_spl_string(n, n_string);
				args->value = n;
			}

			if (args->action == SPL_HNODE_ACTION_CREATE) {
				// process in inverse order, so we can't try modifying a child node
				// after removing it by replacing the parrent...
				for(int i = list_size-1; i >= 0; i--) {
					xmlNodePtr cur = list[i];
					if (!xml_node_process_create(xtype, cur, args->value, task))
						break;
				}
			}

			if (args->action == SPL_HNODE_ACTION_DELETE) {
				// process in inverse order, so we can't try modifying a child node
				// after removing it by removing the parrent...
				for(int i = list_size-1; i >= 0; i--) {
					xmlNodePtr cur = list[i];
					xmlUnlinkNode(cur);
					xmlFreeNode(cur);
				}
			}
		} else {
			xmlXPathFreeObject(xpathObj);
			xmlXPathFreeContext(xpathCtx);
		}

		free(key_dup);
		free(xpath);
		free(xtype);
		free(xarg1);

		return;
	}
}

/**
 * This function performs an XSLT transformation:
 *
 *	var xmldoc = xml_parse(file_read("demo.xml"));
 *	var stylesheet = xml_parse(file_read("demo.xsl"));
 *
 *	debug xml_xslt_text(xmldoc, stylesheet, foo: "'bar'");
 *
 * The first parameter is the handler of XML document to be transformed, as
 * returned by [[xml_parse()]]. The 2nd parameter is the XML document
 * handler for the XSLT stylesheet.
 *
 * Parameters for the stylesheet are passed as named function parameters. Note
 * that the parameters are XPath expressions. I.e. a string constant needs to
 * be passed with quotes.
 *
 * The return value is the XML text after the transformation.
 */
// builtin xml_xslt_text(xmldoc, stylesheet, %params);

/**
 * This function works exactly like [[.xml_xslt_text]], but it returns a new
 * XML document handler.
 */
// builtin xml_xslt_xml(xmldoc, stylesheet, %params);


#ifdef ENABLE_LIBXSLT_SUPPORT
static struct spl_node *handler_xml_xslt(struct spl_task *task, void *data)
{
	struct spl_node *xml_node = spl_cleanup(task, spl_clib_get_node(task));
	struct spl_node *xsl_node = spl_cleanup(task, spl_clib_get_node(task));

	if (strcmp(xml_node->hnode_name, "xml_doc")) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("First parameter to xml_xslt() is not an XML document handler!"),
			NULL);
		return 0;
	}

	if (strcmp(xsl_node->hnode_name, "xml_doc")) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Second parameter to xml_xslt() is not an XML document handler!"),
			NULL);
		return 0;
	}

	struct xml_hnode_data *xml_hnd = get_xml_hnd(xml_node);
	if (!xml_hnd->doc) return 0;

	struct xml_hnode_data *xsl_hnd = get_xml_hnd(xsl_node);
	if (!xsl_hnd->doc) return 0;

	if (!xsl_hnd->xsl)
		xsl_hnd->xsl = xsltParseStylesheetDoc(xsl_hnd->doc);

	if (!xsl_hnd->xsl) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Got an XSLT parser error!"),
			NULL);
		return 0;
	}

	char **params = 0;

	{
		struct spl_node *params_node = spl_clib_get_hargs(task);
		int params_len = 1;

		struct spl_node_sub *s = params_node->subs_begin;
		while (s) { params_len += 2; s = s->next; }

		params = calloc(params_len, sizeof(char *));

		s = params_node->subs_begin;
		for (int i=0; s; i+=2, s=s->next) {
			params[i+0] = spl_hash_decode(s->key);
			params[i+1] = strdup(spl_get_string(s->node));
		}

		spl_put(task->vm, params_node);
	}

	xmlDocPtr res = xsltApplyStylesheet(xsl_hnd->xsl, xml_hnd->doc, (const char **)params);

	for (int i=0; params[i]; i++)
		free(params[i]);
	free(params);
	params = 0;

	if (!res) {
		spl_clib_exception(task, "XmlEx", "description",
			SPL_NEW_PRINTF("Got an XSLT processor error!"),
			NULL);
		goto got_error;
	}

	if (!strcmp((char*)data, "text")) {
		xmlChar *res_text;
		int res_len;

		xsltSaveResultToString(&res_text, &res_len, res, xsl_hnd->xsl);
		xmlFreeDoc(res);

		return SPL_NEW_STRING((char*)res_text);
	}

	if (!strcmp((char*)data, "xml")) {
		struct spl_node *n = SPL_NEW_STRING_DUP("XML DATA");
		struct xml_hnode_data *hnd = calloc(1, sizeof(struct xml_hnode_data));

		n->hnode_name = strdup("xml");
		n->hnode_data = hnd;

		hnd->doc = res;
		return n;
	}

got_error:
	if (res)
		xmlFreeDoc(res);

	return 0;
}
#else
static struct spl_node *handler_xml_xslt(struct spl_task *task, void *data)
{
	spl_clib_exception(task, "XmlEx", "description",
		SPL_NEW_PRINTF("The XML module has been built without XSLT support!"),
		NULL);
	return 0;
}
#endif

static void deregister_node(xmlNodePtr node)
{
	if (node->type == XML_DOCUMENT_NODE) return;
	if (node->_private) {
		struct xml_node_private *p = node->_private;
		p->hnd->node_id_list[p->node_id-1] = 0;
		free(node->_private);
		node->_private = 0;
	}
}

/**
 * An instance of this object is thrown on XML parser errors.
 */
//object XmlEx

/**
 * A description text describing the error.
 */
// var description;

static int xml_module_loader_count = 0;

void SPL_ABI(spl_mod_xml_init)(struct spl_vm *vm, struct spl_module *mod, int restore)
{
	if (!restore) {
		spl_module_load(vm, "encode_xml", 0);
		spl_eval(vm, 0, strdup(mod->name), "object XmlEx { }");
	}

	spl_clib_reg(vm, "xml_parse", handler_xml_parse, 0);
	spl_clib_reg(vm, "xml_dump",  handler_xml_dump,  0);

	spl_hnode_reg(vm, "xml_doc",  handler_xml_node,  0);
	spl_hnode_reg(vm, "xml_node", handler_xml_node,  0);

	spl_clib_reg(vm, "xml_xslt_text", handler_xml_xslt, "text");
	spl_clib_reg(vm, "xml_xslt_xml",  handler_xml_xslt, "xml");

	if (!xml_module_loader_count) {
		xmlInitParser();
		xmlDeregisterNodeDefault(deregister_node);
		//xmlSetExternalEntityLoader(xmlNoNetExternalEntityLoader);
#ifdef ENABLE_LIBXSLT_SUPPORT
		exsltRegisterAll();
#endif
	}
	xml_module_loader_count++;
}

void SPL_ABI(spl_mod_xml_done)(struct spl_vm UNUSED(*vm), struct spl_module UNUSED(*mod))
{
	xml_module_loader_count--;
	if (!xml_module_loader_count) {
#ifdef ENABLE_LIBXSLT_SUPPORT
		xsltCleanupGlobals();
#endif
		xmlCleanupParser();
	}
	return;
}