njs_xml_module.c

/*
 * Copyright (C) Dmitry Volyntsev
 * Copyright (C) NGINX, Inc.
 */


#include <njs.h>
#include <string.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/c14n.h>
#include <libxml/xpathInternals.h>


typedef struct {
    xmlDoc         *doc;
    xmlParserCtxt  *ctx;
} njs_xml_doc_t;


typedef enum {
    XML_NSET_TREE = 0,
    XML_NSET_TREE_NO_COMMENTS,
    XML_NSET_TREE_INVERT,
} njs_xml_nset_type_t;


typedef struct njs_xml_nset_s  njs_xml_nset_t;

struct njs_xml_nset_s {
    xmlNodeSet           *nodes;
    xmlDoc               *doc;
    njs_xml_nset_type_t  type;
    njs_xml_nset_t       *next;
    njs_xml_nset_t       *prev;
};

static njs_int_t njs_xml_ext_parse(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval);
static njs_int_t njs_xml_ext_canonicalization(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t magic, njs_value_t *retval);
static njs_int_t njs_xml_doc_ext_prop_keys(njs_vm_t *vm, njs_value_t *value,
    njs_value_t *keys);
static njs_int_t njs_xml_doc_ext_root(njs_vm_t *vm, njs_object_prop_t *prop,
     njs_value_t *value, njs_value_t *unused, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_prop_keys(njs_vm_t *vm, njs_value_t *value,
    njs_value_t *keys);
static njs_int_t njs_xml_node_ext_prop_handler(njs_vm_t *vm,
    njs_object_prop_t *prop, njs_value_t *value, njs_value_t *unused,
    njs_value_t *retval);
static njs_int_t njs_xml_attr_ext_prop_keys(njs_vm_t *vm, njs_value_t *value,
    njs_value_t *keys);
static njs_int_t njs_xml_attr_ext_prop_handler(njs_vm_t *vm,
    njs_object_prop_t *prop, njs_value_t *value, njs_value_t *unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_add_child(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_attrs(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_name(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_ns(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_parent(njs_vm_t *vm, njs_object_prop_t *prop,
     njs_value_t *value, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_remove_all_attributes(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_remove_attribute(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_remove_children(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_remove_text(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_set_attribute(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_set_text(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused,
    njs_value_t *retval);
static njs_int_t njs_xml_node_ext_tags(njs_vm_t *vm, njs_object_prop_t *prop,
     njs_value_t *value, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_ext_text(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval);

static njs_int_t njs_xml_node_attr_handler(njs_vm_t *vm, xmlNode *current,
    njs_str_t *name, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_tag_remove(njs_vm_t *vm, xmlNode *current,
    njs_str_t *name);
static njs_int_t njs_xml_node_tag_handler(njs_vm_t *vm, xmlNode *current,
    njs_str_t *name, njs_value_t *setval, njs_value_t *retval);
static njs_int_t njs_xml_node_tags_handler(njs_vm_t *vm, xmlNode *current,
    njs_str_t *name, njs_value_t *setval, njs_value_t *retval);

static xmlNode *njs_xml_external_node(njs_vm_t *vm, njs_value_t *value);
static njs_int_t njs_xml_str_to_c_string(njs_vm_t *vm, njs_str_t *str,
    u_char *dst, size_t size);
static const u_char *njs_xml_value_to_c_string(njs_vm_t *vm, njs_value_t *value,
    u_char *dst, size_t size);
static njs_int_t njs_xml_encode_special_chars(njs_vm_t *vm, njs_str_t *src,
    njs_str_t *out);
static njs_int_t njs_xml_replace_node(njs_vm_t *vm, xmlNode *old,
    xmlNode *current);
static void njs_xml_node_cleanup(void *data);
static void njs_xml_doc_cleanup(void *data);

static njs_xml_nset_t *njs_xml_nset_create(njs_vm_t *vm, xmlDoc *doc,
    xmlNode *current, njs_xml_nset_type_t type);
static njs_xml_nset_t *njs_xml_nset_add(njs_xml_nset_t *nset,
    njs_xml_nset_t *add);
static void njs_xml_nset_cleanup(void *data);
static void njs_xml_error(njs_vm_t *vm, njs_xml_doc_t *tree, const char *fmt,
    ...);
static njs_int_t njs_xml_init(njs_vm_t *vm);


static njs_external_t  njs_ext_xml[] = {

    {
        .flags = NJS_EXTERN_PROPERTY | NJS_EXTERN_SYMBOL,
        .name.symbol = NJS_SYMBOL_TO_STRING_TAG,
        .u.property = {
            .value = "xml",
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("parse"),
        .writable = 1,
        .configurable = 1,
        .u.method = {
            .native = njs_xml_ext_parse,
            .magic8 = 0,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("c14n"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_ext_canonicalization,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("exclusiveC14n"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_ext_canonicalization,
            .magic8 = 1,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("serialize"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_ext_canonicalization,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("serializeToString"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_ext_canonicalization,
            .magic8 = 3,
        }
    },

};


static njs_external_t  njs_ext_xml_doc[] = {

    {
        .flags = NJS_EXTERN_PROPERTY | NJS_EXTERN_SYMBOL,
        .name.symbol = NJS_SYMBOL_TO_STRING_TAG,
        .u.property = {
            .value = "XMLDoc",
        }
    },

    {
        .flags = NJS_EXTERN_SELF,
        .u.object = {
            .enumerable = 1,
            .prop_handler = njs_xml_doc_ext_root,
            .keys = njs_xml_doc_ext_prop_keys,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$root"),
        .enumerable = 1,
        .u.property = {
            .handler = njs_xml_doc_ext_root,
            .magic32 = 1,
        }
    },

};


static njs_external_t  njs_ext_xml_node[] = {

    {
        .flags = NJS_EXTERN_PROPERTY | NJS_EXTERN_SYMBOL,
        .name.symbol = NJS_SYMBOL_TO_STRING_TAG,
        .u.property = {
            .value = "XMLNode",
        }
    },

    {
        .flags = NJS_EXTERN_SELF,
        .u.object = {
            .enumerable = 1,
            .writable = 1,
            .configurable = 1,
            .prop_handler = njs_xml_node_ext_prop_handler,
            .keys = njs_xml_node_ext_prop_keys,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("addChild"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_add_child,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$attrs"),
        .enumerable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_attrs,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$name"),
        .enumerable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_name,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$ns"),
        .enumerable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_ns,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$parent"),
        .enumerable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_parent,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("removeAllAttributes"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_remove_all_attributes,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("removeAttribute"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_remove_attribute,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("removeChildren"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_remove_children,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("removeText"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_remove_text,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("setAttribute"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_set_attribute,
        }
    },

    {
        .flags = NJS_EXTERN_METHOD,
        .name.string = njs_str("setText"),
        .writable = 1,
        .configurable = 1,
        .enumerable = 1,
        .u.method = {
            .native = njs_xml_node_ext_set_text,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$tags"),
        .enumerable = 1,
        .writable = 1,
        .configurable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_tags,
        }
    },

    {
        .flags = NJS_EXTERN_PROPERTY,
        .name.string = njs_str("$text"),
        .enumerable = 1,
        .writable = 1,
        .u.property = {
            .handler = njs_xml_node_ext_text,
        }
    },

};


static njs_external_t  njs_ext_xml_attr[] = {

    {
        .flags = NJS_EXTERN_PROPERTY | NJS_EXTERN_SYMBOL,
        .name.symbol = NJS_SYMBOL_TO_STRING_TAG,
        .u.property = {
            .value = "XMLAttr",
        }
    },

    {
        .flags = NJS_EXTERN_SELF,
        .u.object = {
            .enumerable = 1,
            .prop_handler = njs_xml_attr_ext_prop_handler,
            .keys = njs_xml_attr_ext_prop_keys,
        }
    },

};


njs_module_t  njs_xml_module = {
    .name = njs_str("xml"),
    .preinit = NULL,
    .init = njs_xml_init,
};


static njs_int_t    njs_xml_doc_proto_id;
static njs_int_t    njs_xml_node_proto_id;
static njs_int_t    njs_xml_attr_proto_id;


static njs_int_t
njs_xml_ext_parse(njs_vm_t *vm, njs_value_t *args, njs_uint_t nargs,
    njs_index_t unused, njs_value_t *retval)
{
    njs_int_t         ret;
    njs_str_t         data;
    njs_xml_doc_t     *tree;
    njs_mp_cleanup_t  *cln;

    ret = njs_vm_value_to_bytes(vm, &data, njs_arg(args, nargs, 1));
    if (njs_slow_path(ret != NJS_OK)) {
        return NJS_ERROR;
    }

    tree = njs_mp_zalloc(njs_vm_memory_pool(vm), sizeof(njs_xml_doc_t));
    if (njs_slow_path(tree == NULL)) {
        njs_vm_memory_error(vm);
        return NJS_ERROR;
    }

    tree->ctx = xmlNewParserCtxt();
    if (njs_slow_path(tree->ctx == NULL)) {
        njs_vm_internal_error(vm, "xmlNewParserCtxt() failed");
        return NJS_ERROR;
    }

    tree->doc = xmlCtxtReadMemory(tree->ctx, (char *) data.start, data.length,
                                  NULL, NULL, XML_PARSE_NOWARNING
                                              | XML_PARSE_NOERROR);
    if (njs_slow_path(tree->doc == NULL)) {
        njs_xml_error(vm, tree, "failed to parse XML");
        return NJS_ERROR;
    }

    cln = njs_mp_cleanup_add(njs_vm_memory_pool(vm), 0);
    if (njs_slow_path(cln == NULL)) {
        njs_vm_memory_error(vm);
        return NJS_ERROR;
    }

    cln->handler = njs_xml_doc_cleanup;
    cln->data = tree;

    return njs_vm_external_create(vm, retval, njs_xml_doc_proto_id,
                                  tree, 0);
}


static njs_int_t
njs_xml_doc_ext_prop_keys(njs_vm_t *vm, njs_value_t *value, njs_value_t *keys)
{
    xmlNode        *node;
    njs_int_t      ret;
    njs_value_t    *push;
    njs_xml_doc_t  *tree;

    tree = njs_vm_external(vm, njs_xml_doc_proto_id, value);
    if (njs_slow_path(tree == NULL)) {
        njs_value_undefined_set(keys);
        return NJS_DECLINED;
    }

    ret = njs_vm_array_alloc(vm, keys, 2);
    if (njs_slow_path(ret != NJS_OK)) {
        return NJS_ERROR;
    }

    for (node = xmlDocGetRootElement(tree->doc);
         node != NULL;
         node = node->next)
    {
        if (node->type != XML_ELEMENT_NODE) {
            continue;
        }

        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, node->name,
                                         njs_strlen(node->name));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }
    }

    return NJS_OK;
}


static njs_int_t
njs_xml_doc_ext_root(njs_vm_t *vm, njs_object_prop_t *prop, njs_value_t *value,
     njs_value_t *unused, njs_value_t *retval)
{
    xmlNode        *node;
    njs_int_t      ret;
    njs_str_t      name;
    njs_bool_t     any;
    njs_xml_doc_t  *tree;

    tree = njs_vm_external(vm, njs_xml_doc_proto_id, value);
    if (njs_slow_path(tree == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    any = njs_vm_prop_magic32(prop);

    if (!any) {
        ret = njs_vm_prop_name(vm, prop, &name);
        if (njs_slow_path(ret != NJS_OK)) {
            njs_value_undefined_set(retval);
            return NJS_DECLINED;
        }

    } else {
        /* To suppress warning. */
        name.length = 0;
        name.start = NULL;
    }

    for (node = xmlDocGetRootElement(tree->doc);
         node != NULL;
         node = node->next)
    {
        if (node->type != XML_ELEMENT_NODE) {
            continue;
        }

        if (!any) {
            if (name.length != njs_strlen(node->name)
                || njs_strncmp(name.start, node->name, name.length) != 0)
            {
                continue;
            }
        }

        return njs_vm_external_create(vm, retval, njs_xml_node_proto_id, node,
                                      0);
    }

    njs_value_undefined_set(retval);

    return NJS_DECLINED;
}


static njs_int_t
njs_xml_node_ext_prop_keys(njs_vm_t *vm, njs_value_t *value, njs_value_t *keys)
{
    xmlNode      *node, *current;
    njs_int_t    ret;
    njs_value_t  *push;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL)) {
        njs_value_undefined_set(keys);
        return NJS_DECLINED;
    }

    ret = njs_vm_array_alloc(vm, keys, 2);
    if (njs_slow_path(ret != NJS_OK)) {
        return NJS_ERROR;
    }

    if (current->name != NULL && current->type == XML_ELEMENT_NODE) {
        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, (u_char *) "$name",
                                         njs_length("$name"));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }
    }

    if (current->ns != NULL) {
        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, (u_char *) "$ns",
                                         njs_length("$ns"));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }
    }

    if (current->properties != NULL) {
        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, (u_char *) "$attrs",
                                         njs_length("$attrs"));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }
    }

    if (current->children != NULL && current->children->content != NULL) {
        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, (u_char *) "$text",
                                         njs_length("$text"));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }
    }

    for (node = current->children; node != NULL; node = node->next) {
        if (node->type != XML_ELEMENT_NODE) {
            continue;
        }

        push = njs_vm_array_push(vm, keys);
        if (njs_slow_path(push == NULL)) {
            return NJS_ERROR;
        }

        ret = njs_vm_value_string_create(vm, push, (u_char *) "$tags",
                                         njs_length("$tags"));
        if (njs_slow_path(ret != NJS_OK)) {
            return NJS_ERROR;
        }

        break;
    }

    return NJS_OK;
}


static njs_int_t
njs_xml_node_ext_prop_handler(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
{
    xmlNode    *current;
    njs_int_t  ret;
    njs_str_t  name;

    /*
     * $tag$foo - the first tag child with the name "foo"
     * $tags$foo - the all children with the name "foo" as an array
     * $attr$foo - the attribute with the name "foo"
     * foo - the same as $tag$foo
     */

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    ret = njs_vm_prop_name(vm, prop, &name);
    if (njs_slow_path(ret != NJS_OK)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    if (name.length > 1 && name.start[0] == '$') {
        if (name.length > njs_length("$attr$")
            && njs_strncmp(&name.start[1], "attr$", njs_length("attr$")) == 0)
        {
            name.length -= njs_length("$attr$");
            name.start += njs_length("$attr$");

            return njs_xml_node_attr_handler(vm, current, &name, setval,
                                             retval);
        }

        if (name.length > njs_length("$tag$")
            && njs_strncmp(&name.start[1], "tag$", njs_length("tag$")) == 0)
        {
            name.length -= njs_length("$tag$");
            name.start += njs_length("$tag$");

            return njs_xml_node_tag_handler(vm, current, &name, setval, retval);
        }

        if (name.length >= njs_length("$tags$")
            && njs_strncmp(&name.start[1], "tags$", njs_length("tags$")) == 0)
        {
            name.length -= njs_length("$tags$");
            name.start += njs_length("$tags$");

            return njs_xml_node_tags_handler(vm, current, &name, setval,
                                             retval);
        }
    }

    return njs_xml_node_tag_handler(vm, current, &name, setval, retval);
}


static njs_int_t
njs_xml_node_ext_add_child(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval)
{
    xmlNode    *current, *node, *copy, *rnode;
    njs_int_t  ret;

    current = njs_vm_external(vm, njs_xml_node_proto_id, njs_argument(args, 0));
    if (njs_slow_path(current == NULL)) {
        njs_vm_type_error(vm, "\"this\" is not a XMLNode object");
        return NJS_ERROR;
    }

    node = njs_xml_external_node(vm, njs_arg(args, nargs, 1));
    if (njs_slow_path(node == NULL)) {
        njs_vm_type_error(vm, "node is not a XMLNode object");
        return NJS_ERROR;
    }

    copy = xmlDocCopyNode(current, current->doc, 1);
    if (njs_slow_path(copy == NULL)) {
        njs_vm_internal_error(vm, "xmlDocCopyNode() failed");
        return NJS_ERROR;
    }

    node = xmlDocCopyNode(node, current->doc, 1);
    if (njs_slow_path(node == NULL)) {
        njs_vm_internal_error(vm, "xmlDocCopyNode() failed");
        goto error;
    }

    rnode = xmlAddChild(copy, node);
    if (njs_slow_path(rnode == NULL)) {
        xmlFreeNode(node);
        njs_vm_internal_error(vm, "xmlAddChild() failed");
        goto error;
    }

    ret = xmlReconciliateNs(current->doc, copy);
    if (njs_slow_path(ret == -1)) {
        njs_vm_internal_error(vm, "xmlReconciliateNs() failed");
        goto error;
    }

    njs_value_undefined_set(retval);

    return njs_xml_replace_node(vm, current, copy);

error:

    xmlFreeNode(copy);

    return NJS_ERROR;
}


static njs_int_t
njs_xml_node_ext_attrs(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
{
    xmlNode  *current;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL || current->properties == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    return njs_vm_external_create(vm, retval, njs_xml_attr_proto_id,
                                  current->properties, 0);
}


static njs_int_t
njs_xml_node_ext_name(njs_vm_t *vm, njs_object_prop_t *prop, njs_value_t *value,
     njs_value_t *setval, njs_value_t *retval)
{
    xmlNode  *current;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (current == NULL || current->type != XML_ELEMENT_NODE) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    return njs_vm_value_string_create(vm, retval, current->name,
                                      njs_strlen(current->name));
}


static njs_int_t
njs_xml_node_ext_ns(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
{
    xmlNode  *current;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL || current->ns == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    return njs_vm_value_string_create(vm, retval, current->ns->href,
                                      njs_strlen(current->ns->href));
}


static njs_int_t
njs_xml_node_ext_parent(njs_vm_t *vm, njs_object_prop_t *prop,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
{
    xmlNode  *current;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL
                      || current->parent == NULL
                      || current->parent->type != XML_ELEMENT_NODE))
    {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    return njs_vm_external_create(vm, retval, njs_xml_node_proto_id,
                                  current->parent, 0);
}


static njs_int_t
njs_xml_node_ext_remove_attribute(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval)
{
    return njs_xml_node_ext_set_attribute(vm, args, nargs, 1, retval);
}


static njs_int_t
njs_xml_node_ext_remove_all_attributes(njs_vm_t *vm,
    njs_value_t *args, njs_uint_t nargs, njs_index_t unused, njs_value_t *retval)
{
    xmlNode  *current;

    current = njs_vm_external(vm, njs_xml_node_proto_id, njs_argument(args, 0));
    if (njs_slow_path(current == NULL)) {
        njs_vm_type_error(vm, "\"this\" is not a XMLNode object");
        return NJS_ERROR;
    }

    if (current->properties != NULL) {
        xmlFreePropList(current->properties);
        current->properties = NULL;
    }

    njs_value_undefined_set(retval);

    return NJS_OK;
}


static njs_int_t
njs_xml_node_ext_remove_children(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval)
{
    xmlNode      *current, *copy;
    njs_str_t    name;
    njs_value_t  *selector;

    current = njs_vm_external(vm, njs_xml_node_proto_id, njs_argument(args, 0));
    if (njs_slow_path(current == NULL)) {
        njs_vm_type_error(vm, "\"this\" is not a XMLNode object");
        return NJS_ERROR;
    }

    selector = njs_arg(args, nargs, 1);

    njs_value_undefined_set(retval);

    if (!njs_value_is_null_or_undefined(selector)) {
        if (njs_slow_path(!njs_value_is_string(selector))) {
            njs_vm_type_error(vm, "selector is not a string");
            return NJS_ERROR;
        }

        njs_value_string_get(selector, &name);

        return njs_xml_node_tag_remove(vm, current, &name);
    }

    /* all. */

    copy = xmlDocCopyNode(current, current->doc, 1);
    if (njs_slow_path(copy == NULL)) {
        njs_vm_internal_error(vm, "xmlDocCopyNode() failed");
        return NJS_ERROR;
    }

    if (copy->children != NULL) {
        xmlFreeNodeList(copy->children);
        copy->children = NULL;
    }

    return njs_xml_replace_node(vm, current, copy);
}


static njs_int_t
njs_xml_node_ext_remove_text(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t unused, njs_value_t *retval)
{
    return njs_xml_node_ext_text(vm, NULL, njs_argument(args, 0), NULL, NULL);
}


static njs_int_t
njs_xml_node_ext_set_attribute(njs_vm_t *vm, njs_value_t *args,
    njs_uint_t nargs, njs_index_t remove, njs_value_t *retval)
{
    xmlNode      *current;
    njs_str_t    str;
    njs_value_t  *name;

    current = njs_vm_external(vm, njs_xml_node_proto_id, njs_argument(args, 0));
    if (njs_slow_path(current == NULL)) {
        njs_vm_type_error(vm, "\"this\" is not a XMLNode object");
        return NJS_ERROR;
    }

    name = njs_arg(args, nargs, 1);

    if (njs_slow_path(!njs_value_is_string(name))) {
        njs_vm_type_error(vm, "name is not a string");
        return NJS_ERROR;
    }

    njs_value_string_get(name, &str);

    return njs_xml_node_attr_handler(vm, current, &str, njs_arg(args, nargs, 2),
                                     !remove ? retval : NULL);
}


static njs_int_t
njs_xml_node_ext_set_text(njs_vm_t *vm, njs_value_t *args, njs_uint_t nargs,
    njs_index_t unused, njs_value_t *retval)
{
    return njs_xml_node_ext_text(vm, NULL, njs_argument(args, 0),
                                 njs_arg(args, nargs, 1), retval);
}


static njs_int_t
njs_xml_node_ext_tags(njs_vm_t *vm, njs_object_prop_t *prop, njs_value_t *value,
     njs_value_t *setval, njs_value_t *retval)
{
    xmlNode    *current;
    njs_str_t  name;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL || current->children == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }

    name.start = NULL;
    name.length = 0;

    return njs_xml_node_tags_handler(vm, current, &name, setval, retval);
}


static njs_int_t
njs_xml_node_ext_text(njs_vm_t *vm, njs_object_prop_t *unused,
    njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
{
    u_char     *text;
    xmlNode    *current, *copy;
    njs_int_t  ret;
    njs_str_t  content, enc;

    current = njs_vm_external(vm, njs_xml_node_proto_id, value);
    if (njs_slow_path(current == NULL)) {
        njs_value_undefined_set(retval);
        return NJS_DECLINED;
    }