xml.c

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/*
 * 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) */