get_xlink_node()

static xmlNodePtr get_xlink_node ( xmlNodePtr  xnode )

static

Return a xmlNodePtr on a node referenced by a XLink or NULL otherwise.

Definition at line 227 of file lwgeom_in_gml.c.

References gml_lwpgerror(), gmlGetProp(), lwalloc(), lwfree(), and XLINK_NS.

Referenced by parse_gml_coll(), parse_gml_curve(), parse_gml_data(), parse_gml_line(), parse_gml_linearring(), parse_gml_mcurve(), parse_gml_mline(), parse_gml_mpoint(), parse_gml_mpoly(), parse_gml_msurface(), parse_gml_point(), parse_gml_polygon(), parse_gml_psurface(), parse_gml_surface(), parse_gml_tin(), and parse_gml_triangle().

{
        char *id;
        xmlNsPtr *ns, *n;
        xmlXPathContext *ctx;
        xmlXPathObject *xpath;
        xmlNodePtr node, ret_node;
        xmlChar *href, *p, *node_id;

        href = xmlGetNsProp(xnode, (xmlChar *)"href", (xmlChar *) XLINK_NS);
        id = lwalloc((xmlStrlen(xnode->ns->prefix) * 2 + xmlStrlen(xnode->name)
                      + xmlStrlen(href) + sizeof("//:[@:id='']") + 1));
        p = href;
        p++; /* ignore '#' first char */

        /* XPath pattern look like: //gml:point[@gml:id='p1'] */
        sprintf(id, "//%s:%s[@%s:id='%s']",     (char *) xnode->ns->prefix,
                (char *) xnode->name,
                (char *) xnode->ns->prefix,
                (char *) p);

        ctx = xmlXPathNewContext(xnode->doc);
        if (ctx == NULL)
        {
                xmlFree(href);
                lwfree(id);
                return NULL;
        }

        /* Handle namespaces */
        ns = xmlGetNsList(xnode->doc, xnode);
        for (n=ns ; *n; n++) xmlXPathRegisterNs(ctx, (*n)->prefix, (*n)->href);
        xmlFree(ns);

        /* Execute XPath expression */
        xpath = xmlXPathEvalExpression((xmlChar *) id, ctx);
        lwfree(id);
        if (xpath == NULL || xpath->nodesetval == NULL || xpath->nodesetval->nodeNr != 1)
        {
                xmlFree(href);
                xmlXPathFreeObject(xpath);
                xmlXPathFreeContext(ctx);
                return NULL;
        }
        ret_node = xpath->nodesetval->nodeTab[0];
        xmlXPathFreeObject(xpath);
        xmlXPathFreeContext(ctx);

        /* Protection against circular calls */
        for (node = xnode ; node != NULL ; node = node->parent)
        {
                if (node->type != XML_ELEMENT_NODE) continue;
                node_id = gmlGetProp(node, (xmlChar *) "id");
                if (node_id != NULL)
                {
                        if (!xmlStrcmp(node_id, p))
                                gml_lwpgerror("invalid GML representation", 2);
                        xmlFree(node_id);
                }
        }

        xmlFree(href);
        return ret_node;
}

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