asterisk/main/xml.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008, Eliel C. Sardanons (LU1ALY) <eliels@gmail.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief XML abstraction layer
 *
 * \author Eliel C. Sardanons (LU1ALY) <eliels@gmail.com>
 */

/*** MODULEINFO
	<support_level>core</support_level>
 ***/

#include "asterisk.h"
#include "asterisk/xml.h"
#include "asterisk/logger.h"
#include "asterisk/utils.h"
#include "asterisk/autoconfig.h"

#if defined(HAVE_LIBXML2)
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xinclude.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
/* libxml2 ast_xml implementation. */
#ifdef HAVE_LIBXSLT
	#include <libxslt/xsltInternals.h>
	#include <libxslt/transform.h>
	#include <libxslt/xsltutils.h>
#endif /* HAVE_LIBXSLT */


int ast_xml_init(void)
{
	LIBXML_TEST_VERSION
#ifdef HAVE_LIBXSLT
	xsltInit();
#endif
	return 0;
}

int ast_xml_finish(void)
{
	xmlCleanupParser();
#ifdef HAVE_LIBXSLT
#ifdef HAVE_LIBXSLT_CLEANUP
	xsltCleanupGlobals();
#else
	xsltUninit();
#endif
#endif

	return 0;
}

/*!
 * \internal
 * \brief Process XML Inclusions (XInclude).
 *
 * XIncludes can result in new includes being inserted, so we need to reprocess
 * until no changes are made or we encounter an error.
 *
 * \param doc the document to process
 *
 * \retval 0 if XInclude processing concluded successfully
 * \retval -1 if an error occurred during XInclude processing
 */
static int process_xincludes(xmlDoc *doc)
{
	int res;

	do {
		res = xmlXIncludeProcess(doc);
	} while (res > 0);

	return res;
}

struct ast_xml_doc *ast_xml_open(char *filename)
{
	xmlDoc *doc;

	if (!filename) {
		return NULL;
	}

	xmlSubstituteEntitiesDefault(1);

	doc = xmlReadFile(filename, NULL, XML_PARSE_RECOVER);
	if (!doc) {
		return NULL;
	}

	/* process xinclude elements. */
	if (process_xincludes(doc) < 0) {
		xmlFreeDoc(doc);
		return NULL;
	}

#ifdef HAVE_LIBXSLT
	{
		xsltStylesheetPtr xslt = xsltLoadStylesheetPI(doc);
		if (xslt) {
			xmlDocPtr tmpdoc = xsltApplyStylesheet(xslt, doc, NULL);
			xsltFreeStylesheet(xslt);
			xmlFreeDoc(doc);
			if (!tmpdoc) {
				return NULL;
			}
			doc = tmpdoc;
		}
	}
#else /* no HAVE_LIBXSLT */
	ast_log(LOG_NOTICE, "XSLT support not found. XML documentation may be incomplete.\n");
#endif /* HAVE_LIBXSLT */

	/* Optimize for XPath */
	xmlXPathOrderDocElems(doc);

	return (struct ast_xml_doc *) doc;
}

struct ast_xml_doc *ast_xml_new(void)
{
	xmlDoc *doc;

	doc = xmlNewDoc((const xmlChar *) "1.0");
	return (struct ast_xml_doc *) doc;
}

struct ast_xml_node *ast_xml_new_node(const char *name)
{
	xmlNode *node;
	if (!name) {
		return NULL;
	}

	node = xmlNewNode(NULL, (const xmlChar *) name);

	return (struct ast_xml_node *) node;
}

struct ast_xml_node *ast_xml_new_child(struct ast_xml_node *parent, const char *child_name)
{
	xmlNode *child;

	if (!parent || !child_name) {
		return NULL;
	}

	child = xmlNewChild((xmlNode *) parent, NULL, (const xmlChar *) child_name, NULL);
	return (struct ast_xml_node *) child;
}

struct ast_xml_node *ast_xml_add_child(struct ast_xml_node *parent, struct ast_xml_node *child)
{
	if (!parent || !child) {
		return NULL;
	}
	return (struct ast_xml_node *) xmlAddChild((xmlNode *) parent, (xmlNode *) child);
}

struct ast_xml_node *ast_xml_add_child_list(struct ast_xml_node *parent, struct ast_xml_node *child)
{
	if (!parent || !child) {
		return NULL;
	}
	return (struct ast_xml_node *) xmlAddChildList((xmlNode *) parent, (xmlNode *) child);
}

struct ast_xml_node *ast_xml_copy_node_list(struct ast_xml_node *list)
{
	if (!list) {
		return NULL;
	}
	return (struct ast_xml_node *) xmlCopyNodeList((xmlNode *) list);
}

struct ast_xml_doc *ast_xml_read_memory(char *buffer, size_t size)
{
	xmlDoc *doc;

	if (!buffer) {
		return NULL;
	}

	if (!(doc = xmlParseMemory(buffer, (int) size))) {
		/* process xinclude elements. */
		if (process_xincludes(doc) < 0) {
			xmlFreeDoc(doc);
			return NULL;
		}
	}

	return (struct ast_xml_doc *) doc;
}

void ast_xml_close(struct ast_xml_doc *doc)
{
	if (!doc) {
		return;
	}

	xmlFreeDoc((xmlDoc *) doc);
	doc = NULL;
}

void ast_xml_set_root(struct ast_xml_doc *doc, struct ast_xml_node *node)
{
	if (!doc || !node) {
		return;
	}

	xmlDocSetRootElement((xmlDoc *) doc, (xmlNode *) node);
}

struct ast_xml_node *ast_xml_get_root(struct ast_xml_doc *doc)
{
	xmlNode *root_node;

	if (!doc) {
		return NULL;
	}

	root_node = xmlDocGetRootElement((xmlDoc *) doc);

	return (struct ast_xml_node *) root_node;
}

void ast_xml_free_node(struct ast_xml_node *node)
{
	if (!node) {
		return;
	}

	xmlFreeNode((xmlNode *) node);
	node = NULL;
}

void ast_xml_free_attr(const char *attribute)
{
	if (attribute) {
		xmlFree((char *) attribute);
	}
}

void ast_xml_free_text(const char *text)
{
	if (text) {
		xmlFree((char *) text);
	}
}

const char *ast_xml_get_attribute(struct ast_xml_node *node, const char *attrname)
{
	xmlChar *attrvalue;

	if (!node) {
		return NULL;
	}

	if (!attrname) {
		return NULL;
	}

	attrvalue = xmlGetProp((xmlNode *) node, (xmlChar *) attrname);

	return (const char *) attrvalue;
}

int ast_xml_set_attribute(struct ast_xml_node *node, const char *name, const char *value)
{
	if (!name || !value) {
		return -1;
	}

	if (!xmlSetProp((xmlNode *) node, (xmlChar *) name, (xmlChar *) value)) {
		return -1;
	}

	return 0;
}

struct ast_xml_node *ast_xml_find_element(struct ast_xml_node *root_node, const char *name, const char *attrname, const char *attrvalue)
{
	struct ast_xml_node *cur;
	const char *attr;

	if (!root_node) {
		return NULL;
	}

	for (cur = root_node; cur; cur = ast_xml_node_get_next(cur)) {
		/* Check if the name matchs */
		if (strcmp(ast_xml_node_get_name(cur), name)) {
			continue;
		}
		/* We need to check for a specific attribute name? */
		if (!attrname || !attrvalue) {
			return cur;
		}
		/* Get the attribute, we need to compare it. */
		if ((attr = ast_xml_get_attribute(cur, attrname))) {
			/* does attribute name/value matches? */
			if (!strcmp(attr, attrvalue)) {
				ast_xml_free_attr(attr);
				return cur;
			}
			ast_xml_free_attr(attr);
		}
	}

	return NULL;
}

struct ast_xml_doc *ast_xml_get_doc(struct ast_xml_node *node)
{
	if (!node) {
		return NULL;
	}

	return (struct ast_xml_doc *) ((xmlNode *)node)->doc;
}

struct ast_xml_ns *ast_xml_find_namespace(struct ast_xml_doc *doc, struct ast_xml_node *node, const char *ns_name) {
	xmlNsPtr ns = xmlSearchNs((xmlDocPtr) doc, (xmlNodePtr) node, (xmlChar *) ns_name);
	return (struct ast_xml_ns *) ns;
}

const char *ast_xml_get_ns_prefix(struct ast_xml_ns *ns)
{
	return (const char *) ((xmlNsPtr) ns)->prefix;
}

const char *ast_xml_get_ns_href(struct ast_xml_ns *ns)
{
	return (const char *) ((xmlNsPtr) ns)->href;
}

const char *ast_xml_get_text(struct ast_xml_node *node)
{
	if (!node) {
		return NULL;
	}

	return (const char *) xmlNodeGetContent((xmlNode *) node);
}

void ast_xml_set_text(struct ast_xml_node *node, const char *content)
{
	if (!node || !content) {
		return;
	}

	xmlNodeSetContent((xmlNode *) node, (const xmlChar *) content);
}

void ast_xml_set_name(struct ast_xml_node *node, const char *name)
{
	if (!node || !name) {
		return;
	}

	xmlNodeSetName((xmlNode *) node, (const xmlChar *) name);
}

int ast_xml_doc_dump_file(FILE *output, struct ast_xml_doc *doc)
{
	return xmlDocDump(output, (xmlDocPtr)doc);
}

void ast_xml_doc_dump_memory(struct ast_xml_doc *doc, char **buffer, int *length)
{
	xmlDocDumpFormatMemory((xmlDocPtr)doc, (xmlChar **)buffer, length, 1);
}

const char *ast_xml_node_get_name(struct ast_xml_node *node)
{
	return (const char *) ((xmlNode *) node)->name;
}

struct ast_xml_node *ast_xml_node_get_children(struct ast_xml_node *node)
{
	return (struct ast_xml_node *) ((xmlNode *) node)->children;
}

struct ast_xml_node *ast_xml_node_get_next(struct ast_xml_node *node)
{
	return (struct ast_xml_node *) ((xmlNode *) node)->next;
}

struct ast_xml_node *ast_xml_node_get_prev(struct ast_xml_node *node)
{
	return (struct ast_xml_node *) ((xmlNode *) node)->prev;
}

struct ast_xml_node *ast_xml_node_get_parent(struct ast_xml_node *node)
{
	return (struct ast_xml_node *) ((xmlNode *) node)->parent;
}

struct ast_xml_node *ast_xml_xpath_get_first_result(struct ast_xml_xpath_results *results)
{
	return (struct ast_xml_node *) ((xmlXPathObjectPtr) results)->nodesetval->nodeTab[0];
}

struct ast_xml_node *ast_xml_xpath_get_result(struct ast_xml_xpath_results *results, int i)
{
	return (struct ast_xml_node *) ((xmlXPathObjectPtr) results)->nodesetval->nodeTab[i];
}

void ast_xml_xpath_results_free(struct ast_xml_xpath_results *results)
{
	if (!results) {
		return;
	}
	xmlXPathFreeObject((xmlXPathObjectPtr) results);
}

int ast_xml_xpath_num_results(struct ast_xml_xpath_results *results)
{
	if (!results) {
		return 0;
	}
	return ((xmlXPathObjectPtr) results)->nodesetval->nodeNr;
}

struct ast_xml_xpath_results *ast_xml_query(struct ast_xml_doc *doc, const char *xpath_str)
{
	xmlXPathContextPtr context;
	xmlXPathObjectPtr result;
	if (!(context = xmlXPathNewContext((xmlDoc *) doc))) {
		ast_log(LOG_ERROR, "Could not create XPath context!\n");
		return NULL;
	}
	result = xmlXPathEvalExpression((xmlChar *) xpath_str, context);
	xmlXPathFreeContext(context);
	if (!result) {
		ast_log(LOG_WARNING, "Error for query: %s\n", xpath_str);
		return NULL;
	}
	if (xmlXPathNodeSetIsEmpty(result->nodesetval)) {
		xmlXPathFreeObject(result);
		ast_debug(5, "No results for query: %s\n", xpath_str);
		return NULL;
	}
	return (struct ast_xml_xpath_results *) result;
}

struct ast_xml_xpath_results *ast_xml_query_with_namespaces(struct ast_xml_doc *doc, const char *xpath_str,
	struct ast_xml_namespace_def_vector *namespaces)
{
	xmlXPathContextPtr context;
	xmlXPathObjectPtr result;
	int i;

	if (!(context = xmlXPathNewContext((xmlDoc *) doc))) {
		ast_log(LOG_ERROR, "Could not create XPath context!\n");
		return NULL;
	}

	for (i = 0; i < AST_VECTOR_SIZE(namespaces); i++) {
		struct ast_xml_namespace_def ns = AST_VECTOR_GET(namespaces, i);
		if (xmlXPathRegisterNs(context, (xmlChar *)ns.prefix,
			(xmlChar *)ns.href) != 0) {
			xmlXPathFreeContext(context);
			ast_log(LOG_ERROR, "Could not register namespace %s:%s\n",
				ns.prefix, ns.href);
			return NULL;
		}
	}

	result = xmlXPathEvalExpression((xmlChar *) xpath_str, context);
	xmlXPathFreeContext(context);
	if (!result) {
		ast_log(LOG_WARNING, "Error for query: %s\n", xpath_str);
		return NULL;
	}
	if (xmlXPathNodeSetIsEmpty(result->nodesetval)) {
		xmlXPathFreeObject(result);
		ast_debug(5, "No results for query: %s\n", xpath_str);
		return NULL;
	}
	return (struct ast_xml_xpath_results *) result;
}

#ifdef HAVE_LIBXSLT
struct ast_xslt_doc *ast_xslt_open(char *filename)
{
	xsltStylesheet *xslt;
	xmlDoc *xml;

	xmlSubstituteEntitiesDefault(1);

	xml = xmlReadFile(filename, NULL, XML_PARSE_RECOVER);
	if (!xml) {
		return NULL;
	}

	if (process_xincludes(xml) < 0) {
		xmlFreeDoc(xml);
		return NULL;
	}
	xmlXPathOrderDocElems(xml);

	if (!(xslt = xsltParseStylesheetDoc(xml))) {
		xmlFreeDoc(xml);
		return NULL;
	}

	return (struct ast_xslt_doc *) xslt;
}

struct ast_xslt_doc *ast_xslt_read_memory(char *buffer, size_t size)
{
	xsltStylesheet *xslt;
	xmlDoc *doc;

	if (!buffer) {
		return NULL;
	}

	xmlSubstituteEntitiesDefault(1);

	if (!(doc = xmlParseMemory(buffer, (int) size))) {
		return NULL;
	}

	if (process_xincludes(doc) < 0) {
		xmlFreeDoc(doc);
		return NULL;
	}

	if (!(xslt = xsltParseStylesheetDoc(doc))) {
		xmlFreeDoc(doc);
		return NULL;
	}

	return (struct ast_xslt_doc *) xslt;
}

void ast_xslt_close(struct ast_xslt_doc *axslt)
{
	if (!axslt) {
		return;
	}

	xsltFreeStylesheet((xsltStylesheet *) axslt);
}

struct ast_xml_doc *ast_xslt_apply(struct ast_xslt_doc *axslt, struct ast_xml_doc *axml, const char **params)
{
	xsltStylesheet *xslt = (xsltStylesheet *)axslt;
	xmlDoc *xml = (xmlDoc *)axml;
	xmlDoc *res;
	xsltTransformContextPtr ctxt;
	xmlNs *ns;
	int options = XSLT_PARSE_OPTIONS;

	/*
	 * Normally we could just call xsltApplyStylesheet() without creating
	 * our own transform context but passing parameters to it that have
	 * namespace prefixes isn't supported. Instead we have to create a
	 * transform context, iterate over the namespace declarations in the
	 * stylesheet (not the incoming xml document), add them to the
	 * transform context's xpath context, and call xsltApplyStylesheetUser.
	 *
	 * Since this is a bit involved and libxslt apparently doesn't completely
	 * clean up after itself in this situation,  we'll only do that dance
	 * if there are parameters passed in.  Otherwise we just call the simpler
	 * xsltApplyStylesheet.
	 *
	 */

	if (!params) {
		res = xsltApplyStylesheet(xslt, xml, params);
		return (struct ast_xml_doc *)res;
	}

	ctxt = xsltNewTransformContext(xslt, xml);
	xsltSetCtxtParseOptions(ctxt, options);

	for (ns = xslt->doc->children->nsDef; ns; ns = ns->next) {
		if (xmlXPathRegisterNs(ctxt->xpathCtxt, ns->prefix, ns->href) != 0) {
			xsltFreeTransformContext(ctxt);
			return NULL;
		}
	}

	res = xsltApplyStylesheetUser(xslt, xml, params, NULL, NULL, ctxt);
	xmlXPathFreeContext(ctxt->xpathCtxt);
	ctxt->xpathCtxt = NULL;
	xsltFreeTransformContext(ctxt);

	return (struct ast_xml_doc *)res;
}

int ast_xslt_save_result_to_string(char **buffer, int *length, struct ast_xml_doc *result,
	struct ast_xslt_doc *axslt)
{
	return xsltSaveResultToString((xmlChar **)buffer, length, (xmlDoc *)result, (xsltStylesheet *)axslt);
}

#endif /* defined(HAVE_LIBXSLT) */
#endif /* defined(HAVE_LIBXML2) */