src/tree_schema.c

/**
 * @file tree_schema.c
 * @author Radek Krejci <rkrejci@cesnet.cz>
 * @brief Manipulation with libyang schema data structures
 *
 * Copyright (c) 2015 CESNET, z.s.p.o.
 *
 * This source code is licensed under BSD 3-Clause License (the "License").
 * You may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://opensource.org/licenses/BSD-3-Clause
 */

#define _GNU_SOURCE

#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include "common.h"
#include "context.h"
#include "parser.h"
#include "resolve.h"
#include "xml.h"
#include "xpath.h"
#include "xml_internal.h"
#include "tree_internal.h"
#include "validation.h"
#include "parser_yang.h"

static int
lys_type_dup(struct lys_module *mod, struct lys_node *parent, struct lys_type *new, struct lys_type *old,
             int tpdftype, struct unres_schema *unres);

API const struct lys_node *
lys_is_disabled(const struct lys_node *node, int recursive)
{
    int i;

    if (!node) {
        return NULL;
    }

check:
    if (node->nodetype != LYS_INPUT && node->nodetype != LYS_OUTPUT) {
        /* input/output does not have if-feature, so skip them */

        /* check local if-features */
        for (i = 0; i < node->iffeature_size; i++) {
            if (!resolve_iffeature(&node->iffeature[i])) {
                return node;
            }
        }
    }

    if (!recursive) {
        return NULL;
    }

    /* go through parents */
    if (node->nodetype == LYS_AUGMENT) {
        /* go to parent actually means go to the target node */
        node = ((struct lys_node_augment *)node)->target;
    } else if (node->parent) {
        node = node->parent;
    } else {
        return NULL;
    }

    if (recursive == 2) {
        /* continue only if the node cannot have a data instance */
        if (node->nodetype & (LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST)) {
            return NULL;
        }
    }
    goto check;
}

int
lys_get_sibling(const struct lys_node *siblings, const char *mod_name, int mod_name_len, const char *name,
                int nam_len, LYS_NODE type, const struct lys_node **ret)
{
    const struct lys_node *node, *parent = NULL;
    const struct lys_module *mod = NULL;
    const char *node_mod_name;

    assert(siblings && mod_name && name);
    assert(!(type & (LYS_USES | LYS_GROUPING)));

    /* fill the lengths in case the caller is so indifferent */
    if (!mod_name_len) {
        mod_name_len = strlen(mod_name);
    }
    if (!nam_len) {
        nam_len = strlen(name);
    }

    while (siblings && (siblings->nodetype == LYS_USES)) {
        siblings = siblings->child;
    }
    if (!siblings) {
        /* unresolved uses */
        return EXIT_FAILURE;
    }

    if (siblings->nodetype == LYS_GROUPING) {
        for (node = siblings; (node->nodetype == LYS_GROUPING) && (node->prev != siblings); node = node->prev);
        if (node->nodetype == LYS_GROUPING) {
            /* we went through all the siblings, only groupings there - no valid sibling */
            return EXIT_FAILURE;
        }
        /* update siblings to be valid */
        siblings = node;
    }

    /* set parent correctly */
    parent = lys_parent(siblings);

    /* go up all uses */
    while (parent && (parent->nodetype == LYS_USES)) {
        parent = lys_parent(parent);
    }

    if (!parent) {
        /* handle situation when there is a top-level uses referencing a foreign grouping */
        for (node = siblings; lys_parent(node) && (node->nodetype == LYS_USES); node = lys_parent(node));
        mod = lys_node_module(node);
    }

    /* try to find the node */
    node = NULL;
    while ((node = lys_getnext(node, parent, mod, LYS_GETNEXT_WITHCHOICE | LYS_GETNEXT_WITHCASE | LYS_GETNEXT_WITHINOUT))) {
        if (!type || (node->nodetype & type)) {
            /* module name comparison */
            node_mod_name = lys_node_module(node)->name;
            if (!ly_strequal(node_mod_name, mod_name, 1) && (strncmp(node_mod_name, mod_name, mod_name_len) || node_mod_name[mod_name_len])) {
                continue;
            }

            /* direct name check */
            if (ly_strequal(node->name, name, 1) || (!strncmp(node->name, name, nam_len) && !node->name[nam_len])) {
                if (ret) {
                    *ret = node;
                }
                return EXIT_SUCCESS;
            }
        }
    }

    return EXIT_FAILURE;
}

int
lys_get_data_sibling(const struct lys_module *mod, const struct lys_node *siblings, const char *name, int nam_len,
                     LYS_NODE type, const struct lys_node **ret)
{
    const struct lys_node *node;

    assert(siblings && name);
    assert(!(type & (LYS_AUGMENT | LYS_USES | LYS_GROUPING | LYS_CHOICE | LYS_CASE | LYS_INPUT | LYS_OUTPUT)));

    /* find the beginning */
    while (siblings->prev->next) {
        siblings = siblings->prev;
    }

    if (!mod) {
        mod = siblings->module;
    }

    /* try to find the node */
    node = NULL;
    while ((node = lys_getnext(node, lys_parent(siblings), mod, 0))) {
        if (!type || (node->nodetype & type)) {
            /* module check */
            if (lys_node_module(node) != lys_main_module(mod)) {
                continue;
            }

            /* direct name check */
            if (!strncmp(node->name, name, nam_len) && !node->name[nam_len]) {
                if (ret) {
                    *ret = node;
                }
                return EXIT_SUCCESS;
            }
        }
    }

    return EXIT_FAILURE;
}

API const struct lys_node *
lys_getnext(const struct lys_node *last, const struct lys_node *parent, const struct lys_module *module, int options)
{
    const struct lys_node *next;

    if (!last) {
        /* first call */

        /* get know where to start */
        if (parent) {
            /* schema subtree */
            next = last = parent->child;
        } else {
            /* top level data */
            assert(module);
            next = last = module->data;
        }
    } else if ((last->nodetype == LYS_USES) && (options & LYS_GETNEXT_INTOUSES) && last->child) {
        /* continue with uses content */
        next = last->child;
    } else {
        /* continue after the last returned value */
        next = last->next;
    }

repeat:
    while (next && (next->nodetype == LYS_GROUPING)) {
        if (options & LYS_GETNEXT_WITHGROUPING) {
            return next;
        }
        next = next->next;
    }

    if (!next) {     /* cover case when parent is augment */
        if (!last || last->parent == parent || lys_parent(last) == parent) {
            /* no next element */
            return NULL;
        }
        last = lys_parent(last);
        next = last->next;
        goto repeat;
    } else {
        last = next;
    }

    switch (next->nodetype) {
    case LYS_INPUT:
    case LYS_OUTPUT:
        if (options & LYS_GETNEXT_WITHINOUT) {
            return next;
        } else if (next->child) {
            next = next->child;
        } else {
            next = next->next;
        }
        goto repeat;

    case LYS_CASE:
        if (options & LYS_GETNEXT_WITHCASE) {
            return next;
        } else if (next->child) {
            next = next->child;
        } else {
            next = next->next;
        }
        goto repeat;

    case LYS_USES:
        /* go into */
        if (options & LYS_GETNEXT_WITHUSES) {
            return next;
        } else if (next->child) {
            next = next->child;
        } else {
            next = next->next;
        }
        goto repeat;

    case LYS_RPC:
    case LYS_ACTION:
    case LYS_NOTIF:
    case LYS_LEAF:
    case LYS_ANYXML:
    case LYS_ANYDATA:
    case LYS_LIST:
    case LYS_LEAFLIST:
        return next;

    case LYS_CONTAINER:
        if (!((struct lys_node_container *)next)->presence && (options & LYS_GETNEXT_INTONPCONT)) {
            if (next->child) {
                /* go into */
                next = next->child;
            } else {
                next = next->next;
            }
            goto repeat;
        } else {
            return next;
        }

    case LYS_CHOICE:
        if (options & LYS_GETNEXT_WITHCHOICE) {
            return next;
        } else if (next->child) {
            /* go into */
            next = next->child;
        } else {
            next = next->next;
        }
        goto repeat;

    default:
        /* we should not be here */
        return NULL;
    }


}

void
lys_node_unlink(struct lys_node *node)
{
    struct lys_node *parent, *first;
    struct lys_module *main_module;

    if (!node) {
        return;
    }

    /* unlink from data model if necessary */
    if (node->module) {
        /* get main module with data tree */
        main_module = lys_node_module(node);
        if (main_module->data == node) {
            main_module->data = node->next;
        }
    }

    /* store pointers to important nodes */
    parent = node->parent;
    if (parent && (parent->nodetype == LYS_AUGMENT)) {
        /* handle augments - first, unlink it from the augment parent ... */
        if (parent->child == node) {
            parent->child = node->next;
        }

        if (parent->flags & LYS_NOTAPPLIED) {
            /* data are not connected in the target, so we cannot continue with the target as a parent */
            parent = NULL;
        } else {
            /* data are connected in target, so we will continue with the target as a parent */
            parent = ((struct lys_node_augment *)parent)->target;
        }
    }

    /* unlink from parent */
    if (parent) {
        if (parent->child == node) {
            parent->child = node->next;
        }
        node->parent = NULL;
    }

    /* unlink from siblings */
    if (node->prev == node) {
        /* there are no more siblings */
        return;
    }
    if (node->next) {
        node->next->prev = node->prev;
    } else {
        /* unlinking the last element */
        if (parent) {
            first = parent->child;
        } else {
            first = node;
            while (first->prev->next) {
                first = first->prev;
            }
        }
        first->prev = node->prev;
    }
    if (node->prev->next) {
        node->prev->next = node->next;
    }

    /* clean up the unlinked element */
    node->next = NULL;
    node->prev = node;
}

struct lys_node_grp *
lys_find_grouping_up(const char *name, struct lys_node *start)
{
    struct lys_node *par_iter, *iter, *stop;

    for (par_iter = start; par_iter; par_iter = par_iter->parent) {
        /* top-level augment, look into module (uses augment is handled correctly below) */
        if (par_iter->parent && !par_iter->parent->parent && (par_iter->parent->nodetype == LYS_AUGMENT)) {
            par_iter = par_iter->parent->module->data;
            if (!par_iter) {
                break;
            }
        }

        if (par_iter->parent && (par_iter->parent->nodetype & (LYS_CHOICE | LYS_CASE | LYS_AUGMENT | LYS_USES))) {
            continue;
        }

        for (iter = par_iter, stop = NULL; iter; iter = iter->prev) {
            if (!stop) {
                stop = par_iter;
            } else if (iter == stop) {
                break;
            }
            if (iter->nodetype != LYS_GROUPING) {
                continue;
            }

            if (!strcmp(name, iter->name)) {
                return (struct lys_node_grp *)iter;
            }
        }
    }

    return NULL;
}

/*
 * get next grouping in the root's subtree, in the
 * first call, tha last is NULL
 */
static struct lys_node_grp *
lys_get_next_grouping(struct lys_node_grp *lastgrp, struct lys_node *root)
{
    struct lys_node *last = (struct lys_node *)lastgrp;
    struct lys_node *next;

    assert(root);

    if (!last) {
        last = root;
    }

    while (1) {
        if ((last->nodetype & (LYS_CONTAINER | LYS_CHOICE | LYS_LIST | LYS_GROUPING | LYS_INPUT | LYS_OUTPUT))) {
            next = last->child;
        } else {
            next = NULL;
        }
        if (!next) {
            if (last == root) {
                /* we are done */
                return NULL;
            }

            /* no children, go to siblings */
            next = last->next;
        }
        while (!next) {
            /* go back through parents */
            if (lys_parent(last) == root) {
                /* we are done */
                return NULL;
            }
            next = last->next;
            last = lys_parent(last);
        }

        if (next->nodetype == LYS_GROUPING) {
            return (struct lys_node_grp *)next;
        }

        last = next;
    }
}

/* logs directly */
int
lys_check_id(struct lys_node *node, struct lys_node *parent, struct lys_module *module)
{
    struct lys_node *start, *stop, *iter;
    struct lys_node_grp *grp;
    int down;

    assert(node);

    if (!parent) {
        assert(module);
    } else {
        module = parent->module;
    }

    switch (node->nodetype) {
    case LYS_GROUPING:
        /* 6.2.1, rule 6 */
        if (parent) {
            if (parent->child) {
                down = 1;
                start = parent->child;
            } else {
                down = 0;
                start = parent;
            }
        } else {
            down = 1;
            start = module->data;
        }
        /* go up */
        if (lys_find_grouping_up(node->name, start)) {
            LOGVAL(LYE_DUPID, LY_VLOG_LYS, node, "grouping", node->name);
            return EXIT_FAILURE;
        }
        /* go down, because grouping can be defined after e.g. container in which is collision */
        if (down) {
            for (iter = start, stop = NULL; iter; iter = iter->prev) {
                if (!stop) {
                    stop = start;
                } else if (iter == stop) {
                    break;
                }
                if (!(iter->nodetype & (LYS_CONTAINER | LYS_CHOICE | LYS_LIST | LYS_GROUPING | LYS_INPUT | LYS_OUTPUT))) {
                    continue;
                }

                grp = NULL;
                while ((grp = lys_get_next_grouping(grp, iter))) {
                    if (ly_strequal(node->name, grp->name, 1)) {
                        LOGVAL(LYE_DUPID,LY_VLOG_LYS, node, "grouping", node->name);
                        return EXIT_FAILURE;
                    }
                }
            }
        }
        break;
    case LYS_LEAF:
    case LYS_LEAFLIST:
    case LYS_LIST:
    case LYS_CONTAINER:
    case LYS_CHOICE:
    case LYS_ANYDATA:
        /* 6.2.1, rule 7 */
        if (parent) {
            iter = parent;
            while (iter && (iter->nodetype & (LYS_USES | LYS_CASE | LYS_CHOICE | LYS_AUGMENT))) {
                if (iter->nodetype == LYS_AUGMENT) {
                    if (((struct lys_node_augment *)iter)->target) {
                        /* augment is resolved, go up */
                        iter = ((struct lys_node_augment *)iter)->target;
                        continue;
                    }
                    /* augment is not resolved, this is the final parent */
                    break;
                }
                iter = iter->parent;
            }

            if (!iter) {
                stop = NULL;
                iter = module->data;
            } else {
                stop = iter;
                iter = iter->child;
            }
        } else {
            stop = NULL;
            iter = module->data;
        }
        while (iter) {
            if (iter->nodetype & (LYS_USES | LYS_CASE)) {
                iter = iter->child;
                continue;
            }

            if (iter->nodetype & (LYS_LEAF | LYS_LEAFLIST | LYS_LIST | LYS_CONTAINER | LYS_CHOICE | LYS_ANYDATA)) {
                if (iter->module == node->module && ly_strequal(iter->name, node->name, 1)) {
                    LOGVAL(LYE_DUPID, LY_VLOG_LYS, node, strnodetype(node->nodetype), node->name);
                    return EXIT_FAILURE;
                }
            }

            /* special case for choice - we must check the choice's name as
             * well as the names of nodes under the choice
             */
            if (iter->nodetype == LYS_CHOICE) {
                iter = iter->child;
                continue;
            }

            /* go to siblings */
            if (!iter->next) {
                /* no sibling, go to parent's sibling */
                do {
                    /* for parent LYS_AUGMENT */
                    if (iter->parent == stop) {
                        iter = stop;
                        break;
                    }
                    iter = lys_parent(iter);
                    if (iter && iter->next) {
                        break;
                    }
                } while (iter != stop);

                if (iter == stop) {
                    break;
                }
            }
            iter = iter->next;
        }
        break;
    case LYS_CASE:
        /* 6.2.1, rule 8 */
        if (parent) {
            start = parent->child;
        } else {
            start = module->data;
        }

        LY_TREE_FOR(start, iter) {
            if (!(iter->nodetype & (LYS_ANYDATA | LYS_CASE | LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST))) {
                continue;
            }

            if (iter->module == node->module && ly_strequal(iter->name, node->name, 1)) {
                LOGVAL(LYE_DUPID, LY_VLOG_LYS, node, "case", node->name);
                return EXIT_FAILURE;
            }
        }
        break;
    default:
        /* no check needed */
        break;
    }

    return EXIT_SUCCESS;
}

/* logs directly */
int
lys_node_addchild(struct lys_node *parent, struct lys_module *module, struct lys_node *child)
{
    struct lys_node *iter;
    struct lys_node_inout *in, *out, *inout;
    int type;

    assert(child);

    if (parent) {
        type = parent->nodetype;
        module = parent->module;
    } else {
        assert(module);
        assert(!(child->nodetype & (LYS_INPUT | LYS_OUTPUT)));
        type = 0;
    }

    /* checks */
    switch (type) {
    case LYS_CONTAINER:
    case LYS_LIST:
    case LYS_GROUPING:
    case LYS_USES:
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CHOICE | LYS_CONTAINER | LYS_GROUPING | LYS_LEAF |
                 LYS_LEAFLIST | LYS_LIST | LYS_USES | LYS_ACTION | LYS_NOTIF))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), strnodetype(parent->nodetype));
            return EXIT_FAILURE;
        }
        break;
    case LYS_INPUT:
    case LYS_OUTPUT:
    case LYS_NOTIF:
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CHOICE | LYS_CONTAINER | LYS_GROUPING | LYS_LEAF |
                 LYS_LEAFLIST | LYS_LIST | LYS_USES))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), strnodetype(parent->nodetype));
            return EXIT_FAILURE;
        }
        break;
    case LYS_CHOICE:
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CASE | LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST | LYS_CHOICE))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), "choice");
            return EXIT_FAILURE;
        }
        break;
    case LYS_CASE:
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CHOICE | LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST | LYS_USES))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), "case");
            return EXIT_FAILURE;
        }
        break;
    case LYS_RPC:
    case LYS_ACTION:
        if (!(child->nodetype & (LYS_INPUT | LYS_OUTPUT | LYS_GROUPING))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), "rpc");
            return EXIT_FAILURE;
        }
        break;
    case LYS_LEAF:
    case LYS_LEAFLIST:
    case LYS_ANYXML:
    case LYS_ANYDATA:
        LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), strnodetype(parent->nodetype));
        LOGVAL(LYE_SPEC, LY_VLOG_PREV, NULL, "The \"%s\" statement cannot have any data substatement.",
               strnodetype(parent->nodetype));
        return EXIT_FAILURE;
    case LYS_AUGMENT:
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CASE | LYS_CHOICE | LYS_CONTAINER | LYS_LEAF
                | LYS_LEAFLIST | LYS_LIST | LYS_USES | LYS_ACTION))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), strnodetype(parent->nodetype));
            return EXIT_FAILURE;
        }
        break;
    case LYS_UNKNOWN:
        /* top level */
        if (!(child->nodetype &
                (LYS_ANYDATA | LYS_CHOICE | LYS_CONTAINER | LYS_LEAF | LYS_GROUPING
                | LYS_LEAFLIST | LYS_LIST | LYS_USES | LYS_RPC | LYS_NOTIF | LYS_AUGMENT))) {
            LOGVAL(LYE_INCHILDSTMT, LY_VLOG_LYS, parent, strnodetype(child->nodetype), "(sub)module");
            return EXIT_FAILURE;
        }

        break;
    }

    /* check identifier uniqueness */
    if (lys_check_id(child, parent, module)) {
        return EXIT_FAILURE;
    }

    if (child->parent) {
        lys_node_unlink(child);
    }

    if (child->nodetype & (LYS_INPUT | LYS_OUTPUT)) {
        /* replace the implicit input/output node */
        if (child->nodetype == LYS_OUTPUT) {
            inout = (struct lys_node_inout *)parent->child->next;
        } else { /* LYS_INPUT */
            inout = (struct lys_node_inout *)parent->child;
            parent->child = child;
        }
        if (inout->next) {
            child->next = inout->next;
            inout->next->prev = child;
            inout->next = NULL;
        } else {
            parent->child->prev = child;
        }
        child->prev = inout->prev;
        if (inout->prev->next) {
            inout->prev->next = child;
        }
        inout->prev = (struct lys_node *)inout;
        child->parent = parent;
        inout->parent = NULL;
        lys_node_free((struct lys_node *)inout, NULL, 0);
    } else {
        /* connect the child correctly */
        if (!parent) {
            if (module->data) {
                module->data->prev->next = child;
                child->prev = module->data->prev;
                module->data->prev = child;
            } else {
                module->data = child;
            }
        } else {
            if (!parent->child) {
                /* the only/first child of the parent */
                parent->child = child;
                child->parent = parent;
                iter = child;
            } else {
                /* add a new child at the end of parent's child list */
                iter = parent->child->prev;
                iter->next = child;
                child->prev = iter;
            }
            while (iter->next) {
                iter = iter->next;
                iter->parent = parent;
            }
            parent->child->prev = iter;
        }
    }

    /* check config value (but ignore them in groupings and augments) */
    for (iter = parent; iter && !(iter->nodetype & (LYS_GROUPING | LYS_AUGMENT)); iter = iter->parent);
    if (parent && !iter) {
        for (iter = child; iter && !(iter->nodetype & (LYS_NOTIF | LYS_INPUT | LYS_OUTPUT | LYS_RPC)); iter = iter->parent);
        if (!iter && (parent->flags & LYS_CONFIG_R) && (child->flags & LYS_CONFIG_W)) {
            LOGVAL(LYE_INARG, LY_VLOG_LYS, child, "true", "config");
            LOGVAL(LYE_SPEC, LY_VLOG_PREV, NULL, "State nodes cannot have configuration nodes as children.");
            return EXIT_FAILURE;
        }
    }

    /* propagate information about status data presence */
    if ((child->nodetype & (LYS_CONTAINER | LYS_CHOICE | LYS_LEAF | LYS_LEAFLIST | LYS_LIST | LYS_ANYDATA)) &&
            (child->flags & LYS_INCL_STATUS)) {
        for(iter = parent; iter; iter = lys_parent(iter)) {
            /* store it only into container or list - the only data inner nodes */
            if (iter->nodetype & (LYS_CONTAINER | LYS_LIST)) {
                if (iter->flags & LYS_INCL_STATUS) {
                    /* done, someone else set it already from here */
                    break;
                }
                /* set flag about including status data */
                iter->flags |= LYS_INCL_STATUS;
            }
        }
    }

    /* create implicit input/output nodes to have available them as possible target for augment */
    if (child->nodetype & (LYS_RPC | LYS_ACTION)) {
        in = calloc(1, sizeof *in);
        in->nodetype = LYS_INPUT;
        in->name = lydict_insert(child->module->ctx, "input", 5);
        out = calloc(1, sizeof *out);
        out->name = lydict_insert(child->module->ctx, "output", 6);
        out->nodetype = LYS_OUTPUT;
        in->module = out->module = child->module;
        in->parent = out->parent = child;
        in->flags = out->flags = LYS_IMPLICIT;
        in->next = (struct lys_node *)out;
        in->prev = (struct lys_node *)out;
        out->prev = (struct lys_node *)in;
        child->child = (struct lys_node *)in;
    }
    return EXIT_SUCCESS;
}

static const struct lys_module *
lys_parse_mem_(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, int internal)
{
    char *enlarged_data = NULL;
    struct lys_module *mod = NULL;
    unsigned int len;

    ly_err_clean(1);

    if (!ctx || !data) {
        LOGERR(LY_EINVAL, "%s: Invalid parameter.", __func__);
        return NULL;
    }

    if (!internal && format == LYS_IN_YANG) {
        /* enlarge data by 2 bytes for flex */
        len = strlen(data);
        enlarged_data = malloc((len + 2) * sizeof *enlarged_data);
        if (!enlarged_data) {
            LOGMEM;
            return NULL;
        }
        memcpy(enlarged_data, data, len);
        enlarged_data[len] = enlarged_data[len + 1] = '\0';
        data = enlarged_data;
    }

    switch (format) {
    case LYS_IN_YIN:
        mod = yin_read_module(ctx, data, NULL, 1);
        break;
    case LYS_IN_YANG:
        mod = yang_read_module(ctx, data, 0, NULL, 1);
        break;
    default:
        LOGERR(LY_EINVAL, "Invalid schema input format.");
        break;
    }

    free(enlarged_data);
    return mod;
}

API const struct lys_module *
lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format)
{
    return lys_parse_mem_(ctx, data, format, 0);
}

struct lys_submodule *
lys_submodule_parse(struct lys_module *module, const char *data, LYS_INFORMAT format, struct unres_schema *unres)
{
    struct lys_submodule *submod = NULL;

    assert(module);
    assert(data);

    /* get the main module */
    module = lys_main_module(module);

    switch (format) {
    case LYS_IN_YIN:
        submod = yin_read_submodule(module, data, unres);
        break;
    case LYS_IN_YANG:
        submod = yang_read_submodule(module, data, 0, unres);
        break;
    default:
        assert(0);
        break;
    }

    return submod;
}

API const struct lys_module *
lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format)
{
    int fd;
    const struct lys_module *ret;
    const char *rev, *dot, *filename;
    size_t len;

    if (!ctx || !path) {
        LOGERR(LY_EINVAL, "%s: Invalid parameter.", __func__);
        return NULL;
    }

    fd = open(path, O_RDONLY);
    if (fd == -1) {
        LOGERR(LY_ESYS, "Opening file \"%s\" failed (%s).", path, strerror(errno));
        return NULL;
    }

    ret = lys_parse_fd(ctx, fd, format);
    close(fd);

    if (!ret) {
        /* error */
        return NULL;
    }

    /* check that name and revision match filename */
    filename = strrchr(path, '/');
    if (!filename) {
        filename = path;
    } else {
        filename++;
    }
    rev = strchr(filename, '@');
    dot = strrchr(filename, '.');

    /* name */
    len = strlen(ret->name);
    if (strncmp(filename, ret->name, len) ||
            ((rev && rev != &filename[len]) || (!rev && dot != &filename[len]))) {
        LOGWRN("File name \"%s\" does not match module name \"%s\".", filename, ret->name);
    }
    if (rev) {
        len = dot - ++rev;
        if (!ret->rev_size || len != 10 || strncmp(ret->rev[0].date, rev, len)) {
            LOGWRN("File name \"%s\" does not match module revision \"%s\".", filename,
                   ret->rev_size ? ret->rev[0].date : "none");
        }
    }

    if (!ret->filepath) {
        /* store URI */
        ((struct lys_module *)ret)->filepath = lydict_insert(ctx, path, 0);
    }

    return ret;
}

API const struct lys_module *
lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format)
{
    const struct lys_module *module;
    struct stat sb;
    char *addr;
    char buf[PATH_MAX];
    int len;

    if (!ctx || fd < 0) {
        LOGERR(LY_EINVAL, "%s: Invalid parameter.", __func__);
        return NULL;
    }

    if (fstat(fd, &sb) == -1) {
        LOGERR(LY_ESYS, "Failed to stat the file descriptor (%s).", strerror(errno));
        return NULL;
    }
    if (!S_ISREG(sb.st_mode)) {
        LOGERR(LY_EINVAL, "Invalid parameter, input file is not a regular file");
        return NULL;
    }

    if (!sb.st_size) {
        LOGERR(LY_EINVAL, "File empty.");
        return NULL;
    }

    addr = mmap(NULL, sb.st_size + 2, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
    if (addr == MAP_FAILED) {
        LOGERR(LY_EMEM, "Map file into memory failed (%s()).",__func__);
        return NULL;
    }
    module = lys_parse_mem_(ctx, addr, format, 1);
    munmap(addr, sb.st_size + 2);

    if (module && !module->filepath) {
        /* get URI if there is /proc */
        addr = NULL;
        if (asprintf(&addr, "/proc/self/fd/%d", fd) != -1) {
            if ((len = readlink(addr, buf, PATH_MAX - 1)) > 0) {
                ((struct lys_module *)module)->filepath = lydict_insert(ctx, buf, len);
            }
            free(addr);
        }
    }

    return module;
}

struct lys_submodule *
lys_submodule_read(struct lys_module *module, int fd, LYS_INFORMAT format, struct unres_schema *unres)
{
    struct lys_submodule *submodule;
    struct stat sb;
    char *addr;

    assert(module);
    assert(fd >= 0);

    if (fstat(fd, &sb) == -1) {
        LOGERR(LY_ESYS, "Failed to stat the file descriptor (%s).", strerror(errno));
        return NULL;
    }

    if (!sb.st_size) {
        LOGERR(LY_EINVAL, "File empty.");
        return NULL;
    }

    addr = mmap(NULL, sb.st_size + 2, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
    if (addr == MAP_FAILED) {
        LOGERR(LY_EMEM,"Map file into memory failed (%s()).",__func__);
        return NULL;
    }
    submodule = lys_submodule_parse(module, addr, format, unres);
    munmap(addr, sb.st_size + 2);

    return submodule;

}

static struct lys_restr *
lys_restr_dup(struct ly_ctx *ctx, struct lys_restr *old, int size)
{
    struct lys_restr *result;
    int i;

    if (!size) {
        return NULL;
    }

    result = calloc(size, sizeof *result);
    if (!result) {
        LOGMEM;
        return NULL;
    }
    for (i = 0; i < size; i++) {
        result[i].expr = lydict_insert(ctx, old[i].expr, 0);
        result[i].dsc = lydict_insert(ctx, old[i].dsc, 0);
        result[i].ref = lydict_insert(ctx, old[i].ref, 0);
        result[i].eapptag = lydict_insert(ctx, old[i].eapptag, 0);
        result[i].emsg = lydict_insert(ctx, old[i].emsg, 0);
    }

    return result;
}

void
lys_restr_free(struct ly_ctx *ctx, struct lys_restr *restr)
{
    assert(ctx);
    if (!restr) {
        return;
    }

    lydict_remove(ctx, restr->expr);
    lydict_remove(ctx, restr->dsc);
    lydict_remove(ctx, restr->ref);
    lydict_remove(ctx, restr->eapptag);
    lydict_remove(ctx, restr->emsg);
}

static void
lys_iffeature_free(struct lys_iffeature *iffeature, uint8_t iffeature_size)
{
    uint8_t i;

    for (i = 0; i < iffeature_size; ++i) {
        free(iffeature[i].expr);
        free(iffeature[i].features);
    }
    free(iffeature);
}

static int
type_dup(struct lys_module *mod, struct lys_node *parent, struct lys_type *new, struct lys_type *old,
              LY_DATA_TYPE base, int tpdftype, struct unres_schema *unres)
{
    int i;

    switch (base) {
        case LY_TYPE_BINARY:
            if (old->info.binary.length) {
                new->info.binary.length = lys_restr_dup(mod->ctx, old->info.binary.length, 1);
            }
            break;

        case LY_TYPE_BITS:
            new->info.bits.count = old->info.bits.count;
            if (new->info.bits.count) {
                new->info.bits.bit = calloc(new->info.bits.count, sizeof *new->info.bits.bit);
                if (!new->info.bits.bit) {
                    LOGMEM;
                    return -1;
                }
                for (i = 0; i < new->info.bits.count; i++) {
                    new->info.bits.bit[i].name = lydict_insert(mod->ctx, old->info.bits.bit[i].name, 0);
                    new->info.bits.bit[i].dsc = lydict_insert(mod->ctx, old->info.bits.bit[i].dsc, 0);
                    new->info.bits.bit[i].ref = lydict_insert(mod->ctx, old->info.bits.bit[i].ref, 0);
                    new->info.bits.bit[i].flags = old->info.bits.bit[i].flags;
                    new->info.bits.bit[i].pos = old->info.bits.bit[i].pos;
                }
            }
            break;

        case LY_TYPE_DEC64:
            new->info.dec64.dig = old->info.dec64.dig;
            new->info.dec64.div = old->info.dec64.div;
            if (old->info.dec64.range) {
                new->info.dec64.range = lys_restr_dup(mod->ctx, old->info.dec64.range, 1);
            }
            break;

        case LY_TYPE_ENUM:
            new->info.enums.count = old->info.enums.count;
            if (new->info.enums.count) {
                new->info.enums.enm = calloc(new->info.enums.count, sizeof *new->info.enums.enm);
                if (!new->info.enums.enm) {
                    LOGMEM;
                    return -1;
                }
                for (i = 0; i < new->info.enums.count; i++) {
                    new->info.enums.enm[i].name = lydict_insert(mod->ctx, old->info.enums.enm[i].name, 0);
                    new->info.enums.enm[i].dsc = lydict_insert(mod->ctx, old->info.enums.enm[i].dsc, 0);
                    new->info.enums.enm[i].ref = lydict_insert(mod->ctx, old->info.enums.enm[i].ref, 0);
                    new->info.enums.enm[i].flags = old->info.enums.enm[i].flags;
                    new->info.enums.enm[i].value = old->info.enums.enm[i].value;
                }
            }
            break;

        case LY_TYPE_IDENT:
            new->info.ident.count = old->info.ident.count;
            if (old->info.ident.count) {
                new->info.ident.ref = malloc(old->info.ident.count * sizeof *new->info.ident.ref);
                if (!new->info.ident.ref) {
                    LOGMEM;
                    return -1;
                }
                memcpy(new->info.ident.ref, old->info.ident.ref, old->info.ident.count * sizeof *new->info.ident.ref);
            } else {
                /* there can be several unresolved base identities, duplicate them all */
                i = -1;
                while ((i = unres_schema_find(unres, i, old, UNRES_TYPE_IDENTREF)) != -1) {
                    if (unres_schema_add_str(mod, unres, new, UNRES_TYPE_IDENTREF, unres->str_snode[i]) == -1) {
                        return -1;
                    }
                    --i;
                }
            }
            break;

        case LY_TYPE_INST:
            new->info.inst.req = old->info.inst.req;
            break;

        case LY_TYPE_INT8:
        case LY_TYPE_INT16:
        case LY_TYPE_INT32:
        case LY_TYPE_INT64:
        case LY_TYPE_UINT8:
        case LY_TYPE_UINT16:
        case LY_TYPE_UINT32:
        case LY_TYPE_UINT64:
            if (old->info.num.range) {
                new->info.num.range = lys_restr_dup(mod->ctx, old->info.num.range, 1);
            }
            break;

        case LY_TYPE_LEAFREF:
            if (old->info.lref.path) {
                new->info.lref.path = lydict_insert(mod->ctx, old->info.lref.path, 0);
                if (!tpdftype && unres_schema_add_node(mod, unres, new, UNRES_TYPE_LEAFREF, parent) == -1) {
                    return -1;
                }
            }
            break;

        case LY_TYPE_STRING:
            if (old->info.str.length) {
                new->info.str.length = lys_restr_dup(mod->ctx, old->info.str.length, 1);
            }
            new->info.str.patterns = lys_restr_dup(mod->ctx, old->info.str.patterns, old->info.str.pat_count);
            new->info.str.pat_count = old->info.str.pat_count;
            break;

        case LY_TYPE_UNION:
            new->info.uni.count = old->info.uni.count;
            if (new->info.uni.count) {
                new->info.uni.types = calloc(new->info.uni.count, sizeof *new->info.uni.types);
                if (!new->info.uni.types) {
                    LOGMEM;
                    return -1;
                }
                for (i = 0; i < new->info.uni.count; i++) {
                    if (lys_type_dup(mod, parent, &(new->info.uni.types[i]), &(old->info.uni.types[i]), tpdftype, unres)) {
                        return -1;
                    }
                }
            }
            break;

        default:
            /* nothing to do for LY_TYPE_BOOL, LY_TYPE_EMPTY */
            break;
    }
    return EXIT_SUCCESS;
}

struct yang_type *
lys_yang_type_dup(struct lys_module *module, struct lys_node *parent, struct yang_type *old, struct lys_type *type,
                  int tpdftype, struct unres_schema *unres)
{
    struct yang_type *new;

    new = calloc(1, sizeof *new);
    if (!new) {
        LOGMEM;
        return NULL;
    }
    new->flags = old->flags;
    new->base = old->base;
    new->name = lydict_insert(module->ctx, old->name, 0);
    new->type = type;
    if (!new->name) {
        LOGMEM;
        goto error;
    }
    if (type_dup(module, parent, type, old->type, new->base, tpdftype, unres)) {
        new->type->base = new->base;
        lys_type_free(module->ctx, new->type);
        memset(&new->type->info, 0, sizeof new->type->info);
        goto error;
    }
    return new;

    error:
    free(new);
    return NULL;
}

static int
lys_type_dup(struct lys_module *mod, struct lys_node *parent, struct lys_type *new, struct lys_type *old,
            int tpdftype, struct unres_schema *unres)
{
    int i;

    new->module_name = lydict_insert(mod->ctx, old->module_name, 0);
    new->base = old->base;
    new->der = old->der;
    new->parent = (struct lys_tpdf *)parent;

    i = unres_schema_find(unres, -1, old, tpdftype ? UNRES_TYPE_DER_TPDF : UNRES_TYPE_DER);
    if (i != -1) {
        /* HACK (serious one) for unres */
        /* nothing else we can do but duplicate it immediately */
        if (((struct lyxml_elem *)old->der)->flags & LY_YANG_STRUCTURE_FLAG) {
            new->der = (struct lys_tpdf *)lys_yang_type_dup(mod, parent, (struct yang_type *)old->der, new, tpdftype, unres);
        } else {
            new->der = (struct lys_tpdf *)lyxml_dup_elem(mod->ctx, (struct lyxml_elem *)old->der, NULL, 1);
        }
        /* all these unres additions can fail even though they did not before */
        if (!new->der || unres_schema_add_node(mod, unres, new,
                                               tpdftype ? UNRES_TYPE_DER_TPDF : UNRES_TYPE_DER, parent) == -1) {
            return -1;
        }
        return EXIT_SUCCESS;
    }

    return type_dup(mod, parent, new, old, new->base, tpdftype, unres);
}

void
lys_type_free(struct ly_ctx *ctx, struct lys_type *type)
{
    int i;

    assert(ctx);
    if (!type) {
        return;
    }

    lydict_remove(ctx, type->module_name);

    switch (type->base) {
    case LY_TYPE_BINARY:
        lys_restr_free(ctx, type->info.binary.length);
        free(type->info.binary.length);
        break;
    case LY_TYPE_BITS:
        for (i = 0; i < type->info.bits.count; i++) {
            lydict_remove(ctx, type->info.bits.bit[i].name);
            lydict_remove(ctx, type->info.bits.bit[i].dsc);
            lydict_remove(ctx, type->info.bits.bit[i].ref);
            lys_iffeature_free(type->info.bits.bit[i].iffeature, type->info.bits.bit[i].iffeature_size);
        }
        free(type->info.bits.bit);
        break;

    case LY_TYPE_DEC64:
        lys_restr_free(ctx, type->info.dec64.range);
        free(type->info.dec64.range);
        break;

    case LY_TYPE_ENUM:
        for (i = 0; i < type->info.enums.count; i++) {
            lydict_remove(ctx, type->info.enums.enm[i].name);
            lydict_remove(ctx, type->info.enums.enm[i].dsc);
            lydict_remove(ctx, type->info.enums.enm[i].ref);
            lys_iffeature_free(type->info.enums.enm[i].iffeature, type->info.enums.enm[i].iffeature_size);
        }
        free(type->info.enums.enm);
        break;

    case LY_TYPE_INT8:
    case LY_TYPE_INT16:
    case LY_TYPE_INT32:
    case LY_TYPE_INT64:
    case LY_TYPE_UINT8:
    case LY_TYPE_UINT16:
    case LY_TYPE_UINT32:
    case LY_TYPE_UINT64:
        lys_restr_free(ctx, type->info.num.range);
        free(type->info.num.range);
        break;

    case LY_TYPE_LEAFREF:
        lydict_remove(ctx, type->info.lref.path);
        break;

    case LY_TYPE_STRING:
        lys_restr_free(ctx, type->info.str.length);
        free(type->info.str.length);
        for (i = 0; i < type->info.str.pat_count; i++) {
            lys_restr_free(ctx, &type->info.str.patterns[i]);
        }
        free(type->info.str.patterns);
        break;

    case LY_TYPE_UNION:
        for (i = 0; i < type->info.uni.count; i++) {
            lys_type_free(ctx, &type->info.uni.types[i]);
        }
        free(type->info.uni.types);
        break;

    case LY_TYPE_IDENT:
        free(type->info.ident.ref);
        break;

    default:
        /* nothing to do for LY_TYPE_INST, LY_TYPE_BOOL, LY_TYPE_EMPTY */
        break;
    }
}

static void
lys_tpdf_free(struct ly_ctx *ctx, struct lys_tpdf *tpdf)
{
    assert(ctx);
    if (!tpdf) {
        return;
    }

    lydict_remove(ctx, tpdf->name);
    lydict_remove(ctx, tpdf->dsc);
    lydict_remove(ctx, tpdf->ref);

    lys_type_free(ctx, &tpdf->type);

    lydict_remove(ctx, tpdf->units);
    lydict_remove(ctx, tpdf->dflt);
}

static struct lys_tpdf *
lys_tpdf_dup(struct lys_module *mod, struct lys_node *parent, struct lys_tpdf *old, int size, struct unres_schema *unres)
{
    struct lys_tpdf *result;
    int i, j;

    if (!size) {
        return NULL;
    }

    result = calloc(size, sizeof *result);
    if (!result) {
        LOGMEM;
        return NULL;
    }
    for (i = 0; i < size; i++) {
        result[i].name = lydict_insert(mod->ctx, old[i].name, 0);
        result[i].dsc = lydict_insert(mod->ctx, old[i].dsc, 0);
        result[i].ref = lydict_insert(mod->ctx, old[i].ref, 0);
        result[i].flags = old[i].flags;
        result[i].module = old[i].module;

        if (lys_type_dup(mod, parent, &(result[i].type), &(old[i].type), 1, unres)) {
            for (j = 0; j <= i; ++j) {
                lys_tpdf_free(mod->ctx, &result[j]);
            }
            free(result);
            return NULL;
        }

        result[i].dflt = lydict_insert(mod->ctx, old[i].dflt, 0);
        result[i].units = lydict_insert(mod->ctx, old[i].units, 0);
    }

    return result;
}

static struct lys_when *
lys_when_dup(struct ly_ctx *ctx, struct lys_when *old)
{
    struct lys_when *new;

    if (!old) {
        return NULL;
    }

    new = calloc(1, sizeof *new);
    if (!new) {
        LOGMEM;
        return NULL;
    }
    new->cond = lydict_insert(ctx, old->cond, 0);
    new->dsc = lydict_insert(ctx, old->dsc, 0);
    new->ref = lydict_insert(ctx, old->ref, 0);

    return new;
}

void
lys_when_free(struct ly_ctx *ctx, struct lys_when *w)
{
    if (!w) {
        return;
    }

    lydict_remove(ctx, w->cond);
    lydict_remove(ctx, w->dsc);
    lydict_remove(ctx, w->ref);

    free(w);
}

static void
lys_augment_free(struct ly_ctx *ctx, struct lys_node_augment *aug, void (*private_destructor)(const struct lys_node *node, void *priv))
{
    struct lys_node *next, *sub;

    /* children from a resolved augment are freed under the target node */
    if (!aug->target || (aug->flags & LYS_NOTAPPLIED)) {
        LY_TREE_FOR_SAFE(aug->child, next, sub) {
            lys_node_free(sub, private_destructor, 0);
        }
    }

    lydict_remove(ctx, aug->target_name);
    lydict_remove(ctx, aug->dsc);
    lydict_remove(ctx, aug->ref);

    lys_iffeature_free(aug->iffeature, aug->iffeature_size);

    lys_when_free(ctx, aug->when);
}

static struct lys_node_augment *
lys_augment_dup(struct lys_module *module, struct lys_node *parent, struct lys_node_augment *old, int size)
{
    struct lys_node_augment *new = NULL;
    struct lys_node *old_child, *new_child;
    int i;

    if (!size) {
        return NULL;
    }

    new = calloc(size, sizeof *new);
    if (!new) {
        LOGMEM;
        return NULL;
    }
    for (i = 0; i < size; i++) {
        new[i].target_name = lydict_insert(module->ctx, old[i].target_name, 0);
        new[i].dsc = lydict_insert(module->ctx, old[i].dsc, 0);
        new[i].ref = lydict_insert(module->ctx, old[i].ref, 0);
        new[i].flags = old[i].flags;
        new[i].module = old[i].module;
        new[i].nodetype = old[i].nodetype;

        /* this must succeed, it was already resolved once */
        if (resolve_augment_schema_nodeid(new[i].target_name, parent->child, NULL, 1,
                                          (const struct lys_node **)&new[i].target)) {
            LOGINT;
            free(new);
            return NULL;
        }
        new[i].parent = parent;

        /* Correct the augment nodes.
         * This function can only be called from lys_node_dup() with uses
         * being the node duplicated, so we must have a case of grouping
         * with a uses with augments. The augmented nodes have already been
         * copied and everything is almost fine except their parent is wrong
         * (it was set to their actual data parent, not an augment), and
         * the new augment does not have child pointer to its augment nodes,
         * so we just correct it.
         */
        LY_TREE_FOR(new[i].target->child, new_child) {
            if (ly_strequal(new_child->name, old[i].child->name, 1)) {
                break;
            }
        }
        assert(new_child);
        new[i].child = new_child;
        LY_TREE_FOR(old[i].child, old_child) {
            /* all augment nodes were connected as siblings, there can be no more after this */
            if (old_child->parent != (struct lys_node *)&old[i]) {
                break;
            }

            assert(ly_strequal(old_child->name, new_child->name, 1));

            new_child->parent = (struct lys_node *)&new[i];
            new_child = new_child->next;
        }
    }

    return new;
}

static const char **
lys_dflt_dup(struct ly_ctx *ctx, const char **old, int size)
{
    int i;
    const char **result;

    if (!size) {
        return NULL;
    }

    result = calloc(size, sizeof *result);
    if (!result) {
        LOGMEM;
        return NULL;
    }

    for (i = 0; i < size; i++) {
        result[i] = lydict_insert(ctx, old[i], 0);
    }
    return result;
}

static struct lys_refine *
lys_refine_dup(struct lys_module *mod, struct lys_refine *old, int size)
{
    struct lys_refine *result;
    int i;

    if (!size) {
        return NULL;
    }

    result = calloc(size, sizeof *result);
    if (!result) {
        LOGMEM;
        return NULL;
    }
    for (i = 0; i < size; i++) {
        result[i].target_name = lydict_insert(mod->ctx, old[i].target_name, 0);
        result[i].dsc = lydict_insert(mod->ctx, old[i].dsc, 0);
        result[i].ref = lydict_insert(mod->ctx, old[i].ref, 0);
        result[i].flags = old[i].flags;
        result[i].target_type = old[i].target_type;

        result[i].must_size = old[i].must_size;
        result[i].must = lys_restr_dup(mod->ctx, old[i].must, old[i].must_size);

        result[i].dflt_size = old[i].dflt_size;
        result[i].dflt = lys_dflt_dup(mod->ctx, old[i].dflt, old[i].dflt_size);

        if (result[i].target_type == LYS_CONTAINER) {
            result[i].mod.presence = lydict_insert(mod->ctx, old[i].mod.presence, 0);
        } else if (result[i].target_type & (LYS_LIST | LYS_LEAFLIST)) {
            result[i].mod.list = old[i].mod.list;
        }
    }

    return result;
}

static void
lys_ident_free(struct ly_ctx *ctx, struct lys_ident *ident)
{
    assert(ctx);
    if (!ident) {
        return;
    }

    free(ident->base);
    ly_set_free(ident->der);
    lydict_remove(ctx, ident->name);
    lydict_remove(ctx, ident->dsc);
    lydict_remove(ctx, ident->ref);
    lys_iffeature_free(ident->iffeature, ident->iffeature_size);

}

static void
lys_grp_free(struct ly_ctx *ctx, struct lys_node_grp *grp)
{
    int i;

    /* handle only specific parts for LYS_GROUPING */
    for (i = 0; i < grp->tpdf_size; i++) {
        lys_tpdf_free(ctx, &grp->tpdf[i]);
    }
    free(grp->tpdf);
}

static void
lys_inout_free(struct ly_ctx *ctx, struct lys_node_inout *io)
{
    int i;

    /* handle only specific parts for LYS_INPUT and LYS_OUTPUT */
    for (i = 0; i < io->tpdf_size; i++) {
        lys_tpdf_free(ctx, &io->tpdf[i]);
    }
    free(io->tpdf);

    for (i = 0; i < io->must_size; i++) {
        lys_restr_free(ctx, &io->must[i]);
    }
    free(io->must);
}

static void
lys_notif_free(struct ly_ctx *ctx, struct lys_node_notif *notif)
{
    int i;

    for (i = 0; i < notif->must_size; i++) {
        lys_restr_free(ctx, &notif->must[i]);
    }
    free(notif->must);

    for (i = 0; i < notif->tpdf_size; i++) {
        lys_tpdf_free(ctx, &notif->tpdf[i]);
    }
    free(notif->tpdf);
}
static void
lys_anydata_free(struct ly_ctx *ctx, struct lys_node_anydata *anyxml)
{
    int i;

    for (i = 0; i < anyxml->must_size; i++) {
        lys_restr_free(ctx, &anyxml->must[i]);
    }
    free(anyxml->must);

    lys_when_free(ctx, anyxml->when);
}

static void
lys_leaf_free(struct ly_ctx *ctx, struct lys_node_leaf *leaf)
{
    int i;

    /* leafref backlinks */
    ly_set_free((struct ly_set *)leaf->backlinks);

    for (i = 0; i < leaf->must_size; i++) {
        lys_restr_free(ctx, &leaf->must[i]);
    }
    free(leaf->must);

    lys_when_free(ctx, leaf->when);

    lys_type_free(ctx, &leaf->type);
    lydict_remove(ctx, leaf->units);
    lydict_remove(ctx, leaf->dflt);
}

static void
lys_leaflist_free(struct ly_ctx *ctx, struct lys_node_leaflist *llist)
{
    int i;

    if (llist->backlinks) {
        /* leafref backlinks */
        ly_set_free(llist->backlinks);
    }

    for (i = 0; i < llist->must_size; i++) {
        lys_restr_free(ctx, &llist->must[i]);
    }
    free(llist->must);

    for (i = 0; i < llist->dflt_size; i++) {
        lydict_remove(ctx, llist->dflt[i]);
    }
    free(llist->dflt);

    lys_when_free(ctx, llist->when);

    lys_type_free(ctx, &llist->type);
    lydict_remove(ctx, llist->units);
}

static void
lys_list_free(struct ly_ctx *ctx, struct lys_node_list *list)
{
    int i, j;

    /* handle only specific parts for LY_NODE_LIST */
    for (i = 0; i < list->tpdf_size; i++) {
        lys_tpdf_free(ctx, &list->tpdf[i]);
    }
    free(list->tpdf);

    for (i = 0; i < list->must_size; i++) {
        lys_restr_free(ctx, &list->must[i]);
    }
    free(list->must);

    lys_when_free(ctx, list->when);

    for (i = 0; i < list->unique_size; i++) {
        for (j = 0; j < list->unique[i].expr_size; j++) {
            lydict_remove(ctx, list->unique[i].expr[j]);
        }
        free(list->unique[i].expr);
    }
    free(list->unique);

    free(list->keys);
}

static void
lys_container_free(struct ly_ctx *ctx, struct lys_node_container *cont)
{
    int i;

    /* handle only specific parts for LY_NODE_CONTAINER */
    lydict_remove(ctx, cont->presence);

    for (i = 0; i < cont->tpdf_size; i++) {
        lys_tpdf_free(ctx, &cont->tpdf[i]);
    }
    free(cont->tpdf);

    for (i = 0; i < cont->must_size; i++) {
        lys_restr_free(ctx, &cont->must[i]);
    }
    free(cont->must);

    lys_when_free(ctx, cont->when);
}

static void
lys_feature_free(struct ly_ctx *ctx, struct lys_feature *f)
{
    lydict_remove(ctx, f->name);
    lydict_remove(ctx, f->dsc);
    lydict_remove(ctx, f->ref);
    lys_iffeature_free(f->iffeature, f->iffeature_size);
    ly_set_free(f->depfeatures);
}

static void
lys_deviation_free(struct lys_module *module, struct lys_deviation *dev)
{
    int i, j, k;
    struct ly_ctx *ctx;
    struct lys_node *next, *elem;

    ctx = module->ctx;

    lydict_remove(ctx, dev->target_name);
    lydict_remove(ctx, dev->dsc);
    lydict_remove(ctx, dev->ref);

    if (!dev->deviate) {
        return ;
    }

    /* the module was freed, but we only need the context from orig_node, use ours */
    if (dev->deviate[0].mod == LY_DEVIATE_NO) {
        /* it's actually a node subtree, we need to update modules on all the nodes :-/ */
        LY_TREE_DFS_BEGIN(dev->orig_node, next, elem) {
            elem->module = module;

            LY_TREE_DFS_END(dev->orig_node, next, elem);
        }
        lys_node_free(dev->orig_node, NULL, 0);
    } else {
        /* it's just a shallow copy, freeing one node */
        dev->orig_node->module = module;
        lys_node_free(dev->orig_node, NULL, 1);
    }

    for (i = 0; i < dev->deviate_size; i++) {
        for (j = 0; j < dev->deviate[i].dflt_size; j++) {
            lydict_remove(ctx, dev->deviate[i].dflt[j]);
        }
        free(dev->deviate[i].dflt);

        lydict_remove(ctx, dev->deviate[i].units);

        if (dev->deviate[i].mod == LY_DEVIATE_DEL) {
            for (j = 0; j < dev->deviate[i].must_size; j++) {
                lys_restr_free(ctx, &dev->deviate[i].must[j]);
            }
            free(dev->deviate[i].must);

            for (j = 0; j < dev->deviate[i].unique_size; j++) {
                for (k = 0; k < dev->deviate[i].unique[j].expr_size; k++) {
                    lydict_remove(ctx, dev->deviate[i].unique[j].expr[k]);
                }
                free(dev->deviate[i].unique[j].expr);
            }
            free(dev->deviate[i].unique);
        }
    }
    free(dev->deviate);
}

static void
lys_uses_free(struct ly_ctx *ctx, struct lys_node_uses *uses, void (*private_destructor)(const struct lys_node *node, void *priv))
{
    int i, j;

    for (i = 0; i < uses->refine_size; i++) {
        lydict_remove(ctx, uses->refine[i].target_name);
        lydict_remove(ctx, uses->refine[i].dsc);
        lydict_remove(ctx, uses->refine[i].ref);

        for (j = 0; j < uses->refine[i].must_size; j++) {
            lys_restr_free(ctx, &uses->refine[i].must[j]);
        }
        free(uses->refine[i].must);

        for (j = 0; j < uses->refine[i].dflt_size; j++) {
            lydict_remove(ctx, uses->refine[i].dflt[j]);
        }
        free(uses->refine[i].dflt);

        if (uses->refine[i].target_type & LYS_CONTAINER) {
            lydict_remove(ctx, uses->refine[i].mod.presence);
        }
    }
    free(uses->refine);

    for (i = 0; i < uses->augment_size; i++) {
        lys_augment_free(ctx, &uses->augment[i], private_destructor);
    }
    free(uses->augment);

    lys_when_free(ctx, uses->when);
}

void
lys_node_free(struct lys_node *node, void (*private_destructor)(const struct lys_node *node, void *priv), int shallow)
{
    struct ly_ctx *ctx;
    struct lys_node *sub, *next;

    if (!node) {
        return;
    }

    assert(node->module);
    assert(node->module->ctx);

    ctx = node->module->ctx;

    /* remove private object */
    if (node->priv && private_destructor) {
        private_destructor(node, node->priv);
    }

    /* common part */
    lydict_remove(ctx, node->name);
    if (!(node->nodetype & (LYS_INPUT | LYS_OUTPUT))) {
        lys_iffeature_free(node->iffeature, node->iffeature_size);
        lydict_remove(ctx, node->dsc);
        lydict_remove(ctx, node->ref);
    }

    if (!shallow && !(node->nodetype & (LYS_LEAF | LYS_LEAFLIST))) {
        LY_TREE_FOR_SAFE(node->child, next, sub) {
            lys_node_free(sub, private_destructor, 0);
        }
    }

    /* specific part */
    switch (node->nodetype) {
    case LYS_CONTAINER:
        lys_container_free(ctx, (struct lys_node_container *)node);
        break;
    case LYS_CHOICE:
        lys_when_free(ctx, ((struct lys_node_choice *)node)->when);
        break;
    case LYS_LEAF:
        lys_leaf_free(ctx, (struct lys_node_leaf *)node);
        break;
    case LYS_LEAFLIST:
        lys_leaflist_free(ctx, (struct lys_node_leaflist *)node);
        break;
    case LYS_LIST:
        lys_list_free(ctx, (struct lys_node_list *)node);
        break;
    case LYS_ANYXML:
    case LYS_ANYDATA:
        lys_anydata_free(ctx, (struct lys_node_anydata *)node);
        break;
    case LYS_USES:
        lys_uses_free(ctx, (struct lys_node_uses *)node, private_destructor);
        break;
    case LYS_CASE:
        lys_when_free(ctx, ((struct lys_node_case *)node)->when);
        break;
    case LYS_AUGMENT:
        /* do nothing */
        break;
    case LYS_GROUPING:
    case LYS_RPC:
    case LYS_ACTION:
        lys_grp_free(ctx, (struct lys_node_grp *)node);
        break;
    case LYS_NOTIF:
        lys_notif_free(ctx, (struct lys_node_notif *)node);
        break;
    case LYS_INPUT:
    case LYS_OUTPUT:
        lys_inout_free(ctx, (struct lys_node_inout *)node);
        break;
    case LYS_UNKNOWN:
        LOGINT;
        break;
    }

    /* again common part */
    lys_node_unlink(node);
    free(node);
}

API struct lys_module *
lys_implemented_module(const struct lys_module *mod)
{
    struct ly_ctx *ctx;
    int i;

    if (!mod || mod->implemented) {
        /* invalid argument or the module itself is implemented */
        return (struct lys_module *)mod;
    }

    ctx = mod->ctx;
    for (i = 0; i < ctx->models.used; i++) {
        if (!ctx->models.list[i]->implemented) {
            continue;
        }

        if (ly_strequal(mod->name, ctx->models.list[i]->name, 1)) {
            /* we have some revision of the module implemented */
            return ctx->models.list[i];
        }
    }

    /* we have no revision of the module implemented, return the module itself,
     * it is up to the caller to set the module implemented when needed */
    return (struct lys_module *)mod;
}

const struct lys_module *
lys_get_import_module(const struct lys_module *module, const char *prefix, int pref_len, const char *name, int name_len)
{
    const struct lys_module *main_module;
    char *str;
    int i;

    assert(!prefix || !name);

    if (prefix && !pref_len) {
        pref_len = strlen(prefix);
    }
    if (name && !name_len) {
        name_len = strlen(name);
    }

    main_module = lys_main_module(module);

    /* module own prefix, submodule own prefix, (sub)module own name */
    if ((!prefix || (!module->type && !strncmp(main_module->prefix, prefix, pref_len) && !main_module->prefix[pref_len])
                 || (module->type && !strncmp(module->prefix, prefix, pref_len) && !module->prefix[pref_len]))
            && (!name || (!strncmp(main_module->name, name, name_len) && !main_module->name[name_len]))) {
        return main_module;
    }

    /* standard import */
    for (i = 0; i < module->imp_size; ++i) {
        if ((!prefix || (!strncmp(module->imp[i].prefix, prefix, pref_len) && !module->imp[i].prefix[pref_len]))
                && (!name || (!strncmp(module->imp[i].module->name, name, name_len) && !module->imp[i].module->name[name_len]))) {
            return module->imp[i].module;
        }
    }

    /* module required by a foreign grouping, deviation, or submodule */
    if (name) {
        str = strndup(name, name_len);
        if (!str) {
            LOGMEM;
            return NULL;
        }
        main_module = ly_ctx_get_module(module->ctx, str, NULL);
        free(str);
        return main_module;
    }

    return NULL;
}

/* free_int_mods - flag whether to free the internal modules as well */
static void
module_free_common(struct lys_module *module, void (*private_destructor)(const struct lys_node *node, void *priv))
{
    struct ly_ctx *ctx;
    struct lys_node *next, *iter;
    unsigned int i;

    assert(module->ctx);
    ctx = module->ctx;

    /* just free the import array, imported modules will stay in the context */
    for (i = 0; i < module->imp_size; i++) {
        lydict_remove(ctx, module->imp[i].prefix);
        lydict_remove(ctx, module->imp[i].dsc);
        lydict_remove(ctx, module->imp[i].ref);
    }
    free(module->imp);

    /* submodules don't have data tree, the data nodes
     * are placed in the main module altogether */
    if (!module->type) {
        LY_TREE_FOR_SAFE(module->data, next, iter) {
            lys_node_free(iter, private_destructor, 0);
        }
    }

    lydict_remove(ctx, module->dsc);
    lydict_remove(ctx, module->ref);
    lydict_remove(ctx, module->org);
    lydict_remove(ctx, module->contact);
    lydict_remove(ctx, module->filepath);

    /* revisions */
    for (i = 0; i < module->rev_size; i++) {
        lydict_remove(ctx, module->rev[i].dsc);
        lydict_remove(ctx, module->rev[i].ref);
    }
    free(module->rev);

    /* identities */
    for (i = 0; i < module->ident_size; i++) {
        lys_ident_free(ctx, &module->ident[i]);
    }
    module->ident_size = 0;
    free(module->ident);

    /* typedefs */
    for (i = 0; i < module->tpdf_size; i++) {
        lys_tpdf_free(ctx, &module->tpdf[i]);
    }
    free(module->tpdf);

    /* include */
    for (i = 0; i < module->inc_size; i++) {
        lydict_remove(ctx, module->inc[i].dsc);
        lydict_remove(ctx, module->inc[i].ref);
        /* complete submodule free is done only from main module since
         * submodules propagate their includes to the main module */
        if (!module->type) {
            lys_submodule_free(module->inc[i].submodule, private_destructor);
        }
    }
    free(module->inc);

    /* augment */
    for (i = 0; i < module->augment_size; i++) {
        lys_augment_free(ctx, &module->augment[i], private_destructor);
    }
    free(module->augment);

    /* features */
    for (i = 0; i < module->features_size; i++) {
        lys_feature_free(ctx, &module->features[i]);
    }
    free(module->features);

    /* deviations */
    for (i = 0; i < module->deviation_size; i++) {
        lys_deviation_free(module, &module->deviation[i]);
    }
    free(module->deviation);

    lydict_remove(ctx, module->name);
    lydict_remove(ctx, module->prefix);
}

void
lys_submodule_free(struct lys_submodule *submodule, void (*private_destructor)(const struct lys_node *node, void *priv))
{
    if (!submodule) {
        return;
    }

    /* common part with struct ly_module */
    module_free_common((struct lys_module *)submodule, private_destructor);

    /* no specific items to free */

    free(submodule);
}

static int
ingrouping(const struct lys_node *node)
{
    const struct lys_node *iter = node;
    assert(node);

    for(iter = node; iter && iter->nodetype != LYS_GROUPING; iter = lys_parent(iter));
    if (!iter) {
        return 0;
    } else {
        return 1;
    }
}

/*
 * final: 0 - do not change config flags; 1 - inherit config flags from the parent; 2 - remove config flags
 */
static struct lys_node *
lys_node_dup_recursion(struct lys_module *module, struct lys_node *parent, const struct lys_node *node, uint8_t nacm,
                       struct unres_schema *unres, int shallow, int finalize)
{
    struct lys_node *retval = NULL, *iter, *p;
    struct ly_ctx *ctx = module->ctx;
    int i, j, rc;
    unsigned int size, size1, size2;
    struct unres_list_uniq *unique_info;
    uint16_t flags;

    struct lys_node_container *cont = NULL;
    struct lys_node_container *cont_orig = (struct lys_node_container *)node;
    struct lys_node_choice *choice = NULL;
    struct lys_node_choice *choice_orig = (struct lys_node_choice *)node;
    struct lys_node_leaf *leaf = NULL;
    struct lys_node_leaf *leaf_orig = (struct lys_node_leaf *)node;
    struct lys_node_leaflist *llist = NULL;
    struct lys_node_leaflist *llist_orig = (struct lys_node_leaflist *)node;
    struct lys_node_list *list = NULL;
    struct lys_node_list *list_orig = (struct lys_node_list *)node;
    struct lys_node_anydata *any = NULL;
    struct lys_node_anydata *any_orig = (struct lys_node_anydata *)node;
    struct lys_node_uses *uses = NULL;
    struct lys_node_uses *uses_orig = (struct lys_node_uses *)node;
    struct lys_node_grp *grp = NULL;
    struct lys_node_grp *grp_orig = (struct lys_node_grp *)node;
    struct lys_node_rpc_action *rpc = NULL;
    struct lys_node_rpc_action *rpc_orig = (struct lys_node_rpc_action *)node;
    struct lys_node_inout *io = NULL;
    struct lys_node_inout *io_orig = (struct lys_node_inout *)node;
    struct lys_node_rpc_action *ntf = NULL;
    struct lys_node_rpc_action *ntf_orig = (struct lys_node_rpc_action *)node;
    struct lys_node_case *cs = NULL;
    struct lys_node_case *cs_orig = (struct lys_node_case *)node;

    /* we cannot just duplicate memory since the strings are stored in
     * dictionary and we need to update dictionary counters.
     */

    switch (node->nodetype) {
    case LYS_CONTAINER:
        cont = calloc(1, sizeof *cont);
        retval = (struct lys_node *)cont;
        break;

    case LYS_CHOICE:
        choice = calloc(1, sizeof *choice);
        retval = (struct lys_node *)choice;
        break;

    case LYS_LEAF:
        leaf = calloc(1, sizeof *leaf);
        retval = (struct lys_node *)leaf;
        break;

    case LYS_LEAFLIST:
        llist = calloc(1, sizeof *llist);
        retval = (struct lys_node *)llist;
        break;

    case LYS_LIST:
        list = calloc(1, sizeof *list);
        retval = (struct lys_node *)list;
        break;

    case LYS_ANYXML:
    case LYS_ANYDATA:
        any = calloc(1, sizeof *any);
        retval = (struct lys_node *)any;
        break;

    case LYS_USES:
        uses = calloc(1, sizeof *uses);
        retval = (struct lys_node *)uses;
        break;

    case LYS_CASE:
        cs = calloc(1, sizeof *cs);
        retval = (struct lys_node *)cs;
        break;

    case LYS_GROUPING:
        grp = calloc(1, sizeof *grp);
        retval = (struct lys_node *)grp;
        break;

    case LYS_RPC:
    case LYS_ACTION:
        rpc = calloc(1, sizeof *rpc);
        retval = (struct lys_node *)rpc;
        break;

    case LYS_INPUT:
    case LYS_OUTPUT:
        io = calloc(1, sizeof *io);
        retval = (struct lys_node *)io;
        break;

    case LYS_NOTIF:
        ntf = calloc(1, sizeof *ntf);
        retval = (struct lys_node *)ntf;
        break;

    default:
        LOGINT;
        goto error;
    }

    if (!retval) {
        LOGMEM;
        return NULL;
    }

    /*
     * duplicate generic part of the structure
     */
    retval->name = lydict_insert(ctx, node->name, 0);
    retval->dsc = lydict_insert(ctx, node->dsc, 0);
    retval->ref = lydict_insert(ctx, node->ref, 0);
    retval->nacm = nacm;
    retval->flags = node->flags;

    retval->module = module;
    retval->nodetype = node->nodetype;

    retval->prev = retval;

    if (node->iffeature_size) {
        retval->iffeature_size = node->iffeature_size;
        retval->iffeature = calloc(retval->iffeature_size, sizeof *retval->iffeature);
        if (!retval->iffeature) {
            LOGMEM;
            goto error;
        }
    }

    if (!shallow) {
        for (i = 0; i < node->iffeature_size; ++i) {
            resolve_iffeature_getsizes(&node->iffeature[i], &size1, &size2);
            if (size1) {
                /* there is something to duplicate */

                /* duplicate compiled expression */
                size = (size1 / 4) + (size1 % 4) ? 1 : 0;
                retval->iffeature[i].expr = malloc(size * sizeof *retval->iffeature[i].expr);
                memcpy(retval->iffeature[i].expr, node->iffeature[i].expr, size * sizeof *retval->iffeature[i].expr);

                /* list of feature pointer must be updated to point to the resulting tree */
                retval->iffeature[i].features = calloc(size2, sizeof *retval->iffeature[i].features);
                for (j = 0; (unsigned int)j < size2; j++) {
                    rc = unres_schema_dup(module, unres, &node->iffeature[i].features[j], UNRES_IFFEAT,
                                          &retval->iffeature[i].features[j]);
                    if (rc == EXIT_FAILURE) {
                        /* feature is resolved in origin, so copy it
                         * - duplication is used for instantiating groupings
                         * and if-feature inside grouping is supposed to be
                         * resolved inside the original grouping, so we want
                         * to keep pointers to features from the grouping
                         * context */
                        retval->iffeature[i].features[j] = node->iffeature[i].features[j];
                    } else if (rc == -1) {
                        goto error;
                    } /* else unres was duplicated */
                }
            }
        }

        /* inherit config flags */
        p = parent;
        do {
            for (iter = p; iter && (iter->nodetype == LYS_USES); iter = iter->parent);
        } while (iter && iter->nodetype == LYS_AUGMENT && (p = lys_parent(iter)));
        if (iter) {
            flags = iter->flags & LYS_CONFIG_MASK;
        } else {
            /* default */
            flags = LYS_CONFIG_W;
        }

        switch (finalize) {
        case 1:
            /* inherit config flags */
            if (retval->flags & LYS_CONFIG_SET) {
                /* skip nodes with an explicit config value */
                if ((flags & LYS_CONFIG_R) && (retval->flags & LYS_CONFIG_W)) {
                    LOGVAL(LYE_INARG, LY_VLOG_LYS, retval, "true", "config");
                    LOGVAL(LYE_SPEC, LY_VLOG_PREV, NULL, "State nodes cannot have configuration nodes as children.");
                    goto error;
                }
                break;
            }

            if (retval->nodetype != LYS_USES) {
                retval->flags = (retval->flags & ~LYS_CONFIG_MASK) | flags;
            }
            break;
        case 2:
            /* erase config flags */
            retval->flags &= ~LYS_CONFIG_MASK;
            retval->flags &= ~LYS_CONFIG_SET;
            break;
        }

        /* connect it to the parent */
        if (lys_node_addchild(parent, retval->module, retval)) {
            goto error;
        }

        /* go recursively */
        if (!(node->nodetype & (LYS_LEAF | LYS_LEAFLIST))) {
            LY_TREE_FOR(node->child, iter) {
                if (!lys_node_dup_recursion(module, retval, iter, retval->nacm, unres, 0, finalize)) {
                    goto error;
                }
            }
        }

        if (finalize == 1) {
            /* check that configuration lists have keys
             * - we really want to check keys_size in original node, because the keys are
             * not yet resolved here, it is done below in nodetype specific part */
            if ((retval->nodetype == LYS_LIST) && (retval->flags & LYS_CONFIG_W)
                    && !((struct lys_node_list *)node)->keys_size) {
                LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_LYS, retval, "key", "list");
                goto error;
            }
        }
    } else {
        memcpy(retval->iffeature, node->iffeature, retval->iffeature_size * sizeof *retval->iffeature);
    }

    /*
     * duplicate specific part of the structure
     */
    switch (node->nodetype) {
    case LYS_CONTAINER:
        if (cont_orig->when) {
            cont->when = lys_when_dup(ctx, cont_orig->when);
        }
        cont->presence = lydict_insert(ctx, cont_orig->presence, 0);

        cont->must_size = cont_orig->must_size;
        cont->tpdf_size = cont_orig->tpdf_size;

        cont->must = lys_restr_dup(ctx, cont_orig->must, cont->must_size);
        cont->tpdf = lys_tpdf_dup(module, lys_parent(node), cont_orig->tpdf, cont->tpdf_size, unres);
        break;

    case LYS_CHOICE:
        if (choice_orig->when) {
            choice->when = lys_when_dup(ctx, choice_orig->when);
        }

        if (!shallow) {
            if (choice_orig->dflt) {
                rc = lys_get_sibling(choice->child, lys_node_module(retval)->name, 0, choice_orig->dflt->name, 0,
                                            LYS_ANYDATA | LYS_CASE | LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST,
                                            (const struct lys_node **)&choice->dflt);
                if (rc) {
                    if (rc == EXIT_FAILURE) {
                        LOGINT;
                    }
                    goto error;
                }
            } else {
                /* useless to check return value, we don't know whether
                * there really wasn't any default defined or it just hasn't
                * been resolved, we just hope for the best :)
                */
                unres_schema_dup(module, unres, choice_orig, UNRES_CHOICE_DFLT, choice);
            }
        } else {
            choice->dflt = choice_orig->dflt;
        }
        break;

    case LYS_LEAF:
        if (lys_type_dup(module, retval, &(leaf->type), &(leaf_orig->type), ingrouping(retval), unres)) {
            goto error;
        }
        leaf->units = lydict_insert(module->ctx, leaf_orig->units, 0);

        if (leaf_orig->dflt) {
            leaf->dflt = lydict_insert(ctx, leaf_orig->dflt, 0);
            if (unres_schema_add_node(module, unres, &leaf->type, UNRES_TYPE_DFLT,
                                      (struct lys_node *)(&leaf->dflt)) == -1) {
                goto error;
            }
        }

        leaf->must_size = leaf_orig->must_size;
        leaf->must = lys_restr_dup(ctx, leaf_orig->must, leaf->must_size);

        if (leaf_orig->when) {
            leaf->when = lys_when_dup(ctx, leaf_orig->when);
        }
        break;

    case LYS_LEAFLIST:
        if (lys_type_dup(module, retval, &(llist->type), &(llist_orig->type), ingrouping(retval), unres)) {
            goto error;
        }
        llist->units = lydict_insert(module->ctx, llist_orig->units, 0);

        llist->min = llist_orig->min;
        llist->max = llist_orig->max;

        llist->must_size = llist_orig->must_size;
        llist->must = lys_restr_dup(ctx, llist_orig->must, llist->must_size);

        llist->dflt_size = llist_orig->dflt_size;
        llist->dflt = malloc(llist->dflt_size * sizeof *llist->dflt);
        for (i = 0; i < llist->dflt_size; i++) {
            llist->dflt[i] = lydict_insert(ctx, llist_orig->dflt[i], 0);
            if (unres_schema_add_node(module, unres, &llist->type, UNRES_TYPE_DFLT,
                                      (struct lys_node *)(&llist->dflt[i])) == -1) {
                goto error;
            }
        }

        if (llist_orig->when) {
            llist->when = lys_when_dup(ctx, llist_orig->when);
        }
        break;

    case LYS_LIST:
        list->min = list_orig->min;
        list->max = list_orig->max;

        list->must_size = list_orig->must_size;
        list->must = lys_restr_dup(ctx, list_orig->must, list->must_size);

        list->tpdf_size = list_orig->tpdf_size;
        list->tpdf = lys_tpdf_dup(module, lys_parent(node), list_orig->tpdf, list->tpdf_size, unres);

        list->keys_size = list_orig->keys_size;
        if (list->keys_size) {
            list->keys = calloc(list->keys_size, sizeof *list->keys);
            list->keys_str = lydict_insert(ctx, list_orig->keys_str, 0);
            if (!list->keys) {
                LOGMEM;
                goto error;
            }

            if (!shallow) {
                /* the keys are going to be resolved only if the list is instantiated in data tree, not just
                 * in another grouping */
                for (iter = parent; iter && iter->nodetype != LYS_GROUPING; iter = iter->parent);
                if (!iter && unres_schema_add_node(module, unres, list, UNRES_LIST_KEYS, NULL) == -1) {
                    goto error;
                }
            } else {
                memcpy(list->keys, list_orig->keys, list->keys_size * sizeof *list->keys);
            }
        }

        list->unique_size = list_orig->unique_size;
        list->unique = malloc(list->unique_size * sizeof *list->unique);
        if (!list->unique) {
            LOGMEM;
            goto error;
        }
        for (i = 0; i < list->unique_size; ++i) {
            list->unique[i].expr_size = list_orig->unique[i].expr_size;
            list->unique[i].expr = malloc(list->unique[i].expr_size * sizeof *list->unique[i].expr);
            if (!list->unique[i].expr) {
                LOGMEM;
                goto error;
            }
            for (j = 0; j < list->unique[i].expr_size; j++) {
                list->unique[i].expr[j] = lydict_insert(ctx, list_orig->unique[i].expr[j], 0);

                /* if it stays in unres list, duplicate it also there */
                unique_info = malloc(sizeof *unique_info);
                unique_info->list = (struct lys_node *)list;
                unique_info->expr = list->unique[i].expr[j];
                unique_info->trg_type = &list->unique[i].trg_type;
                unres_schema_dup(module, unres, &list_orig, UNRES_LIST_UNIQ, unique_info);
            }
        }

        if (list_orig->when) {
            list->when = lys_when_dup(ctx, list_orig->when);
        }
        break;

    case LYS_ANYXML:
    case LYS_ANYDATA:
        any->must_size = any_orig->must_size;
        any->must = lys_restr_dup(ctx, any_orig->must, any->must_size);

        if (any_orig->when) {
            any->when = lys_when_dup(ctx, any_orig->when);
        }
        break;

    case LYS_USES:
        uses->grp = uses_orig->grp;

        if (uses_orig->when) {
            uses->when = lys_when_dup(ctx, uses_orig->when);
        }

        uses->refine_size = uses_orig->refine_size;
        uses->refine = lys_refine_dup(module, uses_orig->refine, uses_orig->refine_size);
        uses->augment_size = uses_orig->augment_size;
        if (!shallow) {
            uses->augment = lys_augment_dup(module, (struct lys_node *)uses, uses_orig->augment, uses_orig->augment_size);
            if (!uses->grp || uses->grp->nacm) {
                assert(!uses->child);
                if (unres_schema_add_node(module, unres, uses, UNRES_USES, NULL) == -1) {
                    goto error;
                }
            }
        } else {
            memcpy(uses->augment, uses_orig->augment, uses->augment_size * sizeof *uses->augment);
        }
        break;

    case LYS_CASE:
        if (cs_orig->when) {
            cs->when = lys_when_dup(ctx, cs_orig->when);
        }
        break;

    case LYS_GROUPING:
        grp->tpdf_size = grp_orig->tpdf_size;
        grp->tpdf = lys_tpdf_dup(module, lys_parent(node), grp_orig->tpdf, grp->tpdf_size, unres);
        break;

    case LYS_ACTION:
    case LYS_RPC:
        rpc->tpdf_size = rpc_orig->tpdf_size;
        rpc->tpdf = lys_tpdf_dup(module, lys_parent(node), rpc_orig->tpdf, rpc->tpdf_size, unres);
        break;

    case LYS_INPUT:
    case LYS_OUTPUT:
        io->tpdf_size = io_orig->tpdf_size;
        io->tpdf = lys_tpdf_dup(module, lys_parent(node), io_orig->tpdf, io->tpdf_size, unres);
        break;

    case LYS_NOTIF:
        ntf->tpdf_size = ntf_orig->tpdf_size;
        ntf->tpdf = lys_tpdf_dup(module, lys_parent(node), ntf_orig->tpdf, ntf->tpdf_size, unres);
        break;


    default:
        /* LY_NODE_AUGMENT */
        LOGINT;
        goto error;
    }

    return retval;

error:

    lys_node_free(retval, NULL, 0);
    return NULL;
}

int
lys_has_xpath(const struct lys_node *node)
{
    assert(node);

    switch (node->nodetype) {
    case LYS_AUGMENT:
        if (((struct lys_node_augment *)node)->when) {
            return 1;
        }
        break;
    case LYS_CASE:
        if (((struct lys_node_case *)node)->when) {
            return 1;
        }
        break;
    case LYS_CHOICE:
        if (((struct lys_node_choice *)node)->when) {
            return 1;
        }
        break;
    case LYS_ANYDATA:
        if (((struct lys_node_anydata *)node)->when || ((struct lys_node_anydata *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_LEAF:
        if (((struct lys_node_leaf *)node)->when || ((struct lys_node_leaf *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_LEAFLIST:
        if (((struct lys_node_leaflist *)node)->when || ((struct lys_node_leaflist *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_LIST:
        if (((struct lys_node_list *)node)->when || ((struct lys_node_list *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_CONTAINER:
        if (((struct lys_node_container *)node)->when || ((struct lys_node_container *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_INPUT:
    case LYS_OUTPUT:
        if (((struct lys_node_inout *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_NOTIF:
        if (((struct lys_node_notif *)node)->must_size) {
            return 1;
        }
        break;
    case LYS_USES:
        if (((struct lys_node_uses *)node)->when) {
            return 1;
        }
        break;
    default:
        /* does not have XPath */
        break;
    }

    return 0;
}

struct lys_node *
lys_node_dup(struct lys_module *module, struct lys_node *parent, const struct lys_node *node, uint8_t nacm,
             struct unres_schema *unres, int shallow)
{
    struct lys_node *p = NULL;
    int finalize = 0;
    struct lys_node *result, *iter, *next;

    if (!shallow) {
        /* get know where in schema tre we are to know what should be done during instantiation of the grouping */
        for (p = parent;
             p && !(p->nodetype & (LYS_NOTIF | LYS_INPUT | LYS_OUTPUT | LYS_RPC | LYS_ACTION | LYS_GROUPING));
             p = lys_parent(p));
        finalize = p ? ((p->nodetype == LYS_GROUPING) ? 0 : 2) : 1;
    }

    result = lys_node_dup_recursion(module, parent, node, nacm, unres, shallow, finalize);
    if (finalize) {
        /* check xpath expressions in the instantiated tree */
        for (iter = next = parent->child; iter; iter = next) {
            if (lys_has_xpath(iter) && unres_schema_add_node(module, unres, iter, UNRES_XPATH, NULL) == -1) {
                /* invalid xpath */
                return NULL;
            }

            /* select next item */
            if (iter->nodetype & (LYS_LEAF | LYS_LEAFLIST | LYS_ANYDATA | LYS_GROUPING)) {
                /* child exception for leafs, leaflists and anyxml without children, ignore groupings */
                next = NULL;
            } else {
                next = iter->child;
            }
            if (!next) {
                /* no children, try siblings */
                next = iter->next;
            }
            while (!next) {
                /* parent is already processed, go to its sibling */
                iter = lys_parent(iter);
                if (iter == parent) {
                    /* we are done, no next element to process */
                    break;
                }
                next = iter->next;
            }
        }
    }

    return result;
}

void
lys_node_switch(struct lys_node *dst, struct lys_node *src)
{
    struct lys_node *child;

    assert((dst->module == src->module) && ly_strequal(dst->name, src->name, 1) && (dst->nodetype == src->nodetype));

    /* sibling next */
    if (dst->prev->next) {
        dst->prev->next = src;
    }

    /* sibling prev */
    if (dst->next) {
        dst->next->prev = src;
    } else {
        for (child = dst->prev; child->prev->next; child = child->prev);
        child->prev = src;
    }

    /* next */
    src->next = dst->next;
    dst->next = NULL;

    /* prev */
    if (dst->prev != dst) {
        src->prev = dst->prev;
    }
    dst->prev = dst;

    /* parent child */
    if (dst->parent && (dst->parent->child == dst)) {
        dst->parent->child = src;
    }

    /* parent */
    src->parent = dst->parent;
    dst->parent = NULL;

    /* child parent */
    LY_TREE_FOR(dst->child, child) {
        if (child->parent == dst) {
            child->parent = src;
        }
    }

    /* child */
    src->child = dst->child;
    dst->child = NULL;
}

void
lys_free(struct lys_module *module, void (*private_destructor)(const struct lys_node *node, void *priv), int remove_from_ctx)
{
    struct ly_ctx *ctx;
    int i;

    if (!module) {
        return;
    }

    /* remove schema from the context */
    ctx = module->ctx;
    if (remove_from_ctx && ctx->models.used) {
        for (i = 0; i < ctx->models.used; i++) {
            if (ctx->models.list[i] == module) {
                /* move all the models to not change the order in the list */
                ctx->models.used--;
                memmove(&ctx->models.list[i], ctx->models.list[i + 1], (ctx->models.used - i) * sizeof *ctx->models.list);
                ctx->models.list[ctx->models.used] = NULL;
                /* we are done */
                break;
            }
        }
    }

    /* common part with struct ly_submodule */
    module_free_common(module, private_destructor);

    /* specific items to free */
    lydict_remove(ctx, module->ns);

    free(module);
}

static void
lys_features_disable_recursive(struct lys_feature *f)
{
    unsigned int i;
    struct lys_feature *depf;

    /* disable the feature */
    f->flags &= ~LYS_FENABLED;

    /* by disabling feature we have to disable also all features that depends on this feature */
    if (f->depfeatures) {
        for (i = 0; i < f->depfeatures->number; i++) {
            depf = (struct lys_feature *)f->depfeatures->set.g[i];
            if (depf->flags & LYS_FENABLED) {
                lys_features_disable_recursive(depf);
            }
        }
    }
}


/*
 * op: 1 - enable, 0 - disable
 */
static int
lys_features_change(const struct lys_module *module, const char *name, int op)
{
    int all = 0;
    int i, j, k;
    int progress, faili, failj, failk;

    uint8_t fsize;
    struct lys_feature *f;

    if (!module || !name || !strlen(name)) {
        return EXIT_FAILURE;
    }

    if (!strcmp(name, "*")) {
        /* enable all */
        all = 1;
    }

    progress = failk = 1;
    while (progress && failk) {
        for (i = -1, failk = progress = 0; i < module->inc_size; i++) {
            if (i == -1) {
                fsize = module->features_size;
                f = module->features;
            } else {
                fsize = module->inc[i].submodule->features_size;
                f = module->inc[i].submodule->features;
            }

            for (j = 0; j < fsize; j++) {
                if (all || !strcmp(f[j].name, name)) {
                    if ((op && (f[j].flags & LYS_FENABLED)) || (!op && !(f[j].flags & LYS_FENABLED))) {
                        if (all) {
                            /* skip already set features */
                            continue;
                        } else {
                            /* feature already set correctly */
                            return EXIT_SUCCESS;
                        }
                    }

                    if (op) {
                        /* check referenced features if they are enabled */
                        for (k = 0; k < f[j].iffeature_size; k++) {
                            if (!resolve_iffeature(&f[j].iffeature[k])) {
                                if (all) {
                                    faili = i;
                                    failj = j;
                                    failk = k + 1;
                                    break;
                                } else {
                                    LOGERR(LY_EINVAL, "Feature \"%s\" is disabled by its %d. if-feature condition.",
                                           f[j].name, k + 1);
                                    return EXIT_FAILURE;
                                }
                            }
                        }

                        if (k == f[j].iffeature_size) {
                            /* the last check passed, do the change */
                            f[j].flags |= LYS_FENABLED;
                            progress++;
                        }
                    } else {
                        lys_features_disable_recursive(&f[j]);
                        progress++;
                    }
                    if (!all) {
                        /* stop in case changing a single feature */
                        return EXIT_SUCCESS;
                    }
                }
            }
        }
    }
    if (failk) {
        /* print info about the last failing feature */
        LOGERR(LY_EINVAL, "Feature \"%s\" is disabled by its %d. if-feature condition.",
               faili == -1 ? module->features[failj].name : module->inc[faili].submodule->features[failj].name, failk);
        return EXIT_FAILURE;
    }

    if (all) {
        return EXIT_SUCCESS;
    } else {
        /* the specified feature not found */
        return EXIT_FAILURE;
    }
}

API int
lys_features_enable(const struct lys_module *module, const char *feature)
{
    return lys_features_change(module, feature, 1);
}

API int
lys_features_disable(const struct lys_module *module, const char *feature)
{
    return lys_features_change(module, feature, 0);
}

API int
lys_features_state(const struct lys_module *module, const char *feature)
{
    int i, j;

    if (!module || !feature) {
        return -1;
    }

    /* search for the specified feature */
    /* module itself */
    for (i = 0; i < module->features_size; i++) {
        if (!strcmp(feature, module->features[i].name)) {
            if (module->features[i].flags & LYS_FENABLED) {
                return 1;
            } else {
                return 0;
            }
        }
    }

    /* submodules */
    for (j = 0; j < module->inc_size; j++) {
        for (i = 0; i < module->inc[j].submodule->features_size; i++) {
            if (!strcmp(feature, module->inc[j].submodule->features[i].name)) {
                if (module->inc[j].submodule->features[i].flags & LYS_FENABLED) {
                    return 1;
                } else {
                    return 0;
                }
            }
        }
    }

    /* feature definition not found */
    return -1;
}

API const char **
lys_features_list(const struct lys_module *module, uint8_t **states)
{
    const char **result = NULL;
    int i, j;
    unsigned int count;

    if (!module) {
        return NULL;
    }

    count = module->features_size;
    for (i = 0; i < module->inc_size; i++) {
        count += module->inc[i].submodule->features_size;
    }
    result = malloc((count + 1) * sizeof *result);
    if (!result) {
        LOGMEM;
        return NULL;
    }
    if (states) {
        *states = malloc((count + 1) * sizeof **states);
        if (!(*states)) {
            LOGMEM;
            free(result);
            return NULL;
        }
    }
    count = 0;

    /* module itself */
    for (i = 0; i < module->features_size; i++) {
        result[count] = module->features[i].name;
        if (states) {
            if (module->features[i].flags & LYS_FENABLED) {
                (*states)[count] = 1;
            } else {
                (*states)[count] = 0;
            }
        }
        count++;
    }

    /* submodules */
    for (j = 0; j < module->inc_size; j++) {
        for (i = 0; i < module->inc[j].submodule->features_size; i++) {
            result[count] = module->inc[j].submodule->features[i].name;
            if (states) {
                if (module->inc[j].submodule->features[i].flags & LYS_FENABLED) {
                    (*states)[count] = 1;
                } else {
                    (*states)[count] = 0;
                }
            }
            count++;
        }
    }

    /* terminating NULL byte */
    result[count] = NULL;

    return result;
}

API struct lys_module *
lys_node_module(const struct lys_node *node)
{
    if (!node) {
        return NULL;
    }

    return node->module->type ? ((struct lys_submodule *)node->module)->belongsto : node->module;
}

API struct lys_module *
lys_main_module(const struct lys_module *module)
{
    if (!module) {
        return NULL;
    }

    return (module->type ? ((struct lys_submodule *)module)->belongsto : (struct lys_module *)module);
}

API struct lys_node *
lys_parent(const struct lys_node *node)
{
    if (!node || !node->parent) {
        return NULL;
    }

    if (node->parent->nodetype == LYS_AUGMENT) {
        return ((struct lys_node_augment *)node->parent)->target;
    }

    return node->parent;
}

API void *
lys_set_private(const struct lys_node *node, void *priv)
{
    void *prev;

    if (!node) {
        LOGERR(LY_EINVAL, "%s: Invalid parameter.", __func__);
        return NULL;
    }

    prev = node->priv;
    ((struct lys_node *)node)->priv = priv;

    return prev;
}

int
lys_leaf_add_leafref_target(struct lys_node_leaf *leafref_target, struct lys_node *leafref)
{
    struct lys_node_leaf *iter = leafref_target;

    if (!(leafref_target->nodetype & (LYS_LEAF | LYS_LEAFLIST))) {
        LOGINT;
        return -1;
    }

    /* check for config flag */
    if ((leafref->flags & LYS_CONFIG_W) && (leafref_target->flags & LYS_CONFIG_R)) {
        LOGVAL(LYE_SPEC, LY_VLOG_LYS, leafref,
               "The %s is config but refers to a non-config %s.",
               strnodetype(leafref->nodetype), strnodetype(leafref_target->nodetype));
        return -1;
    }
    /* check for cycles */
    while (iter && iter->type.base == LY_TYPE_LEAFREF) {
        if ((void *)iter == (void *)leafref) {
            /* cycle detected */
            LOGVAL(LYE_CIRC_LEAFREFS, LY_VLOG_LYS, leafref);
            return -1;
        }
        iter = iter->type.info.lref.target;
    }

    /* create fake child - the ly_set structure to hold the list of
     * leafrefs referencing the leaf(-list) */
    if (!leafref_target->backlinks) {
        leafref_target->backlinks = (void*)ly_set_new();
        if (!leafref_target->backlinks) {
            LOGMEM;
            return -1;
        }
    }
    ly_set_add(leafref_target->backlinks, leafref, 0);

    return 0;
}

/* not needed currently */
#if 0

static const char *
lys_data_path_reverse(const struct lys_node *node, char * const buf, uint32_t buf_len)
{
    struct lys_module *prev_mod;
    uint32_t str_len, mod_len, buf_idx;

    if (!(node->nodetype & (LYS_CONTAINER | LYS_LIST | LYS_LEAF | LYS_LEAFLIST | LYS_ANYDATA))) {
        LOGINT;
        return NULL;
    }

    buf_idx = buf_len - 1;
    buf[buf_idx] = '\0';

    while (node) {
        if (lys_parent(node)) {
            prev_mod = lys_node_module(lys_parent(node));
        } else {
            prev_mod = NULL;
        }

        if (node->nodetype & (LYS_CONTAINER | LYS_LIST | LYS_LEAF | LYS_LEAFLIST | LYS_ANYDATA)) {
            str_len = strlen(node->name);

            if (prev_mod != node->module) {
                mod_len = strlen(node->module->name);
            } else {
                mod_len = 0;
            }

            if (buf_idx < 1 + (mod_len ? mod_len + 1 : 0) + str_len) {
                LOGINT;
                return NULL;
            }

            buf_idx -= 1 + (mod_len ? mod_len + 1 : 0) + str_len;

            buf[buf_idx] = '/';
            if (mod_len) {
                memcpy(buf + buf_idx + 1, node->module->name, mod_len);
                buf[buf_idx + 1 + mod_len] = ':';
            }
            memcpy(buf + buf_idx + 1 + (mod_len ? mod_len + 1 : 0), node->name, str_len);
        }

        node = lys_parent(node);
    }

    return buf + buf_idx;
}

#endif

API struct ly_set *
lys_find_xpath(const struct lys_node *node, const char *expr, int options)
{
    struct lyxp_set set;
    struct ly_set *ret_set;
    uint32_t i;
    int opts;

    if (!node || !expr) {
        ly_errno = LY_EINVAL;
        return NULL;
    }

    memset(&set, 0, sizeof set);

    opts = LYXP_SNODE;
    if (options & LYS_FIND_OUTPUT) {
        opts |= LYXP_SNODE_OUTPUT;
    }

    /* node and nodetype won't matter at all since it is absolute */
    if (lyxp_atomize(expr, node, LYXP_NODE_ELEM, &set, opts)) {
        free(set.val.snodes);
        LOGVAL(LYE_SPEC, LY_VLOG_LYS, node, "Resolving XPath expression \"%s\" failed.", expr);
        return NULL;
    }

    ret_set = ly_set_new();

    for (i = 0; i < set.used; ++i) {
        if (!set.val.snodes[i].in_ctx) {
            continue;
        }
        assert(set.val.snodes[i].in_ctx == 1);

        switch (set.val.snodes[i].type) {
        case LYXP_NODE_ELEM:
            if (ly_set_add(ret_set, set.val.snodes[i].snode, LY_SET_OPT_USEASLIST) == -1) {
                ly_set_free(ret_set);
                free(set.val.snodes);
                return NULL;
            }
            break;
        default:
            /* ignore roots, text and attr should not ever appear */
            break;
        }
    }

    free(set.val.snodes);
    return ret_set;
}

API struct ly_set *
lys_xpath_atomize(const struct lys_node *cur_snode, enum lyxp_node_type cur_snode_type, const char *expr, int options)
{
    struct lyxp_set set;
    struct ly_set *ret_set;
    uint32_t i;

    if (!cur_snode || !expr) {
        return NULL;
    }

    /* adjust the root */
    if ((cur_snode_type == LYXP_NODE_ROOT) || (cur_snode_type == LYXP_NODE_ROOT_CONFIG)) {
        do {
            cur_snode = lys_getnext(NULL, NULL, lys_node_module(cur_snode), 0);
        } while ((cur_snode_type == LYXP_NODE_ROOT_CONFIG) && (cur_snode->flags & LYS_CONFIG_R));
    }

    memset(&set, 0, sizeof set);

    if (options & LYXP_MUST) {
        options &= ~LYXP_MUST;
        options |= LYXP_SNODE_MUST;
    } else if (options & LYXP_WHEN) {
        options &= ~LYXP_WHEN;
        options |= LYXP_SNODE_WHEN;
    } else {
        options |= LYXP_SNODE;
    }

    if (lyxp_atomize(expr, cur_snode, cur_snode_type, &set, options)) {
        free(set.val.snodes);
        LOGVAL(LYE_SPEC, LY_VLOG_LYS, cur_snode, "Resolving XPath expression \"%s\" failed.", expr);
        return NULL;
    }

    ret_set = ly_set_new();

    for (i = 0; i < set.used; ++i) {
        switch (set.val.snodes[i].type) {
        case LYXP_NODE_ELEM:
            if (ly_set_add(ret_set, set.val.snodes[i].snode, LY_SET_OPT_USEASLIST) == -1) {
                ly_set_free(ret_set);
                free(set.val.snodes);
                return NULL;
            }
            break;
        default:
            /* ignore roots, text and attr should not ever appear */
            break;
        }
    }

    free(set.val.snodes);
    return ret_set;
}

API struct ly_set *
lys_node_xpath_atomize(const struct lys_node *node, int options)
{
    const struct lys_node *next, *elem, *parent, *tmp;
    struct lyxp_set set;
    struct ly_set *ret_set;
    uint16_t i;

    if (!node) {
        return NULL;
    }

    for (parent = node; parent && !(parent->nodetype & (LYS_NOTIF | LYS_INPUT | LYS_OUTPUT)); parent = lys_parent(parent));
    if (!parent) {
        /* not in input, output, or notification */
        return NULL;
    }

    ret_set = ly_set_new();
    if (!ret_set) {
        return NULL;
    }

    LY_TREE_DFS_BEGIN(node, next, elem) {
        if ((options & LYXP_NO_LOCAL) && !(elem->flags & LYS_XPATH_DEP)) {
            /* elem has no dependencies from other subtrees and local nodes get discarded */
            goto next_iter;
        }

        if (lyxp_node_atomize(elem, &set)) {
            ly_set_free(ret_set);
            free(set.val.snodes);
            return NULL;
        }

        for (i = 0; i < set.used; ++i) {
            switch (set.val.snodes[i].type) {
            case LYXP_NODE_ELEM:
                if (options & LYXP_NO_LOCAL) {
                    for (tmp = set.val.snodes[i].snode; tmp && (tmp != parent); tmp = lys_parent(tmp));
                    if (tmp) {
                        /* in local subtree, discard */
                        break;
                    }
                }
                if (ly_set_add(ret_set, set.val.snodes[i].snode, 0) == -1) {
                    ly_set_free(ret_set);
                    free(set.val.snodes);
                    return NULL;
                }
                break;
            default:
                /* ignore roots, text and attr should not ever appear */
                break;
            }
        }

        free(set.val.snodes);
        if (!(options & LYXP_RECURSIVE)) {
            break;
        }
next_iter:
        LY_TREE_DFS_END(node, next, elem);
    }

    return ret_set;
}

static void
lys_switch_deviation(struct lys_deviation *dev, const struct lys_module *target_module)
{
    int ret;
    char *parent_path;
    struct lys_node *target;

    if (!dev->deviate) {
        return ;
    }

    if (dev->deviate[0].mod == LY_DEVIATE_NO) {
        if (dev->orig_node) {
            /* removing not-supported deviation ... */
            if (strrchr(dev->target_name, '/') != dev->target_name) {
                /* ... from a parent */
                parent_path = strndup(dev->target_name, strrchr(dev->target_name, '/') - dev->target_name);

                target = NULL;
                ret = resolve_augment_schema_nodeid(parent_path, NULL, target_module, 1,
                                                    (const struct lys_node **)&target);
                free(parent_path);
                if (ret || !target) {
                    LOGINT;
                    return;
                }

                lys_node_addchild(target, NULL, dev->orig_node);
            } else {
                /* ... from top-level data */
                lys_node_addchild(NULL, (struct lys_module *)target_module, dev->orig_node);
            }

            dev->orig_node = NULL;
        } else {
            /* adding not-supported deviation */
            target = NULL;
            ret = resolve_augment_schema_nodeid(dev->target_name, NULL, target_module, 1,
                                                (const struct lys_node **)&target);
            if (ret || !target) {
                LOGINT;
                return;
            }

            lys_node_unlink(target);
            dev->orig_node = target;
        }
    } else {
        target = NULL;
        ret = resolve_augment_schema_nodeid(dev->target_name, NULL, target_module, 1,
                                            (const struct lys_node **)&target);
        if (ret || !target) {
            LOGINT;
            return;
        }

        lys_node_switch(target, dev->orig_node);
        dev->orig_node = target;
    }
}

/* temporarily removes or applies deviations, updates module deviation flag accordingly */
void
lys_switch_deviations(struct lys_module *module)
{
    uint32_t i = 0, j;
    const struct lys_module *mod;
    const char *ptr;

    if (module->deviated) {
        while ((mod = ly_ctx_get_module_iter(module->ctx, &i))) {
            if (mod == module) {
                continue;
            }

            for (j = 0; j < mod->deviation_size; ++j) {
                ptr = strstr(mod->deviation[j].target_name, module->name);
                if (ptr && ptr[strlen(module->name)] == ':') {
                    lys_switch_deviation(&mod->deviation[j], module);
                }
            }
        }

        if (module->deviated == 2) {
            module->deviated = 1;
        } else {
            module->deviated = 2;
        }
    }
}

static void
apply_dev(struct lys_deviation *dev, const struct lys_module *module)
{
    lys_switch_deviation(dev, module);

    assert(dev->orig_node);
    lys_node_module(dev->orig_node)->deviated = 1;
}

static void
apply_aug(struct lys_node_augment *augment)
{
    struct lys_node *last;

    assert(augment->target && (augment->flags & LYS_NOTAPPLIED));

    /* reconnect augmenting data into the target - add them to the target child list */
    if (augment->target->child) {
        last = augment->target->child->prev;
        last->next = augment->child;
        augment->target->child->prev = augment->child->prev;
        augment->child->prev = last;
    } else {
        augment->target->child = augment->child;
    }

    /* remove the flag about not applicability */
    augment->flags &= ~LYS_NOTAPPLIED;
}

void
lys_sub_module_apply_devs_augs(struct lys_module *module)
{
    uint8_t u, v;

    /* remove applied deviations */
    for (u = 0; u < module->deviation_size; ++u) {
        apply_dev(&module->deviation[u], module);
    }
    /* remove applied augments */
    for (u = 0; u < module->augment_size; ++u) {
        apply_aug(&module->augment[u]);
    }

    /* remove deviation and augments defined in submodules */
    for (v = 0; v < module->inc_size; ++v) {
        for (u = 0; u < module->inc[v].submodule->deviation_size; ++u) {
            apply_dev(&module->inc[v].submodule->deviation[u], module);
        }

        for (u = 0; u < module->inc[v].submodule->augment_size; ++u) {
            apply_aug(&module->inc[v].submodule->augment[u]);
        }
    }
}

static void
remove_dev(struct lys_deviation *dev, const struct lys_module *module)
{
    uint32_t idx = 0, j;
    const struct lys_module *mod;
    struct lys_module *target_mod;
    const char *ptr;

    if (dev->orig_node) {
        target_mod = lys_node_module(dev->orig_node);
    } else {
        LOGINT;
        return;
    }
    lys_switch_deviation(dev, module);

    /* clear the deviation flag if possible */
    while ((mod = ly_ctx_get_module_iter(module->ctx, &idx))) {
        if ((mod == module) || (mod == target_mod)) {
            continue;
        }

        for (j = 0; j < mod->deviation_size; ++j) {
            ptr = strstr(mod->deviation[j].target_name, target_mod->name);
            if (ptr && (ptr[strlen(target_mod->name)] == ':')) {
                /* some other module deviation targets the inspected module, flag remains */
                break;
            }
        }

        if (j < mod->deviation_size) {
            break;
        }
    }

    if (!mod) {
        target_mod->deviated = 0;
    }
}

static void
remove_aug(struct lys_node_augment *augment)
{
    struct lys_node *last, *elem;

    if (!augment->target) {
        /* skip not resolved augments */
        return;
    }

    elem = augment->child;
    if (elem) {
        LY_TREE_FOR(elem, last) {
            if (!last->next || (last->next->parent != (struct lys_node *)augment)) {
                break;
            }
        }
        /* elem is first augment child, last is the last child */

        /* parent child ptr */
        if (augment->target->child == elem) {
            augment->target->child = last->next;
        }

        /* parent child next ptr */
        if (elem->prev->next) {
            elem->prev->next = last->next;
        }

        /* parent child prev ptr */
        if (last->next) {
            last->next->prev = elem->prev;
        } else if (augment->target->child) {
            augment->target->child->prev = elem->prev;
        }

        /* update augment children themselves */
        elem->prev = last;
        last->next = NULL;
    }

    /* augment->target still keeps the resolved target, but for lys_augment_free()
     * we have to keep information that this augment is not applied to free its data */
    augment->flags |= LYS_NOTAPPLIED;
}

void
lys_sub_module_remove_devs_augs(struct lys_module *module)
{
    uint8_t u, v;

    /* remove applied deviations */
    for (u = 0; u < module->deviation_size; ++u) {
        remove_dev(&module->deviation[u], module);
    }
    /* remove applied augments */
    for (u = 0; u < module->augment_size; ++u) {
        remove_aug(&module->augment[u]);
    }

    /* remove deviation and augments defined in submodules */
    for (v = 0; v < module->inc_size && module->inc[v].submodule; ++v) {
        for (u = 0; u < module->inc[v].submodule->deviation_size; ++u) {
            remove_dev(&module->inc[v].submodule->deviation[u], module);
        }

        for (u = 0; u < module->inc[v].submodule->augment_size; ++u) {
            remove_aug(&module->inc[v].submodule->augment[u]);
        }
    }
}

static int
lys_set_implemented_recursion(struct lys_module *module, struct unres_schema *unres)
{
    struct lys_node *root, *next, *node;
    uint8_t i;

    for (i = 0; i < module->augment_size; i++) {
        /* apply augment */
        if (!module->augment[i].target
                && (unres_schema_add_node(module, unres, &module->augment[i], UNRES_AUGMENT, NULL) == -1)) {
            return -1;
        }
    }
    LY_TREE_FOR(module->data, root) {
        /* handle leafrefs and recursively change the implemented flags in the leafref targets */
        LY_TREE_DFS_BEGIN(root, next, node) {
            if (node->nodetype == LYS_GROUPING) {
                goto nextsibling;
            }
            if (node->nodetype & (LYS_LEAF | LYS_LEAFLIST)) {
                if (((struct lys_node_leaf *)node)->type.base == LY_TYPE_LEAFREF) {
                    if (unres_schema_add_node(module, unres, &((struct lys_node_leaf *)node)->type,
                                              UNRES_TYPE_LEAFREF, node) == -1) {
                        return EXIT_FAILURE;
                    }
                }
            }

            /* modified LY_TREE_DFS_END */
            next = node->child;
            /* child exception for leafs, leaflists and anyxml without children */
            if (node->nodetype & (LYS_LEAF | LYS_LEAFLIST | LYS_ANYDATA)) {
                next = NULL;
            }
            if (!next) {
nextsibling:
                /* no children */
                if (node == root) {
                    /* we are done, root has no children */
                    break;
                }
                /* try siblings */
                next = node->next;
            }
            while (!next) {
                /* parent is already processed, go to its sibling */
                node = lys_parent(node);
                /* no siblings, go back through parents */
                if (lys_parent(node) == lys_parent(root)) {
                    /* we are done, no next element to process */
                    break;
                }
                next = node->next;
            }
        }
    }

    return EXIT_SUCCESS;
}

API int
lys_set_implemented(const struct lys_module *module)
{
    struct ly_ctx *ctx;
    struct unres_schema *unres;
    int i, j, disabled = 0;

    if (!module) {
        ly_errno = LY_EINVAL;
        return EXIT_FAILURE;
    }

    module = lys_main_module(module);

    if (module->disabled) {
        disabled = 1;
        lys_set_enabled(module);
    }

    if (module->implemented) {
        return EXIT_SUCCESS;
    }

    ctx = module->ctx;

    for (i = 0; i < ctx->models.used; ++i) {
        if (module == ctx->models.list[i]) {
            continue;
        }

        if (!strcmp(module->name, ctx->models.list[i]->name) && ctx->models.list[i]->implemented) {
            LOGERR(LY_EINVAL, "Module \"%s\" in another revision already implemented.", module->name);
            if (disabled) {
                /* set it back disabled */
                lys_set_disabled(module);
            }
            return EXIT_FAILURE;
        }
    }

    unres = calloc(1, sizeof *unres);
    if (!unres) {
        LOGMEM;
        if (disabled) {
            /* set it back disabled */
            lys_set_disabled(module);
        }
        return EXIT_FAILURE;
    }
    /* recursively make the module implemented */
    ((struct lys_module *)module)->implemented = 1;
    if (lys_set_implemented_recursion((struct lys_module *)module, unres)) {
        goto error;
    }
    /* process augments in submodules */
    for (i = 0; i < module->inc_size && module->inc[i].submodule; ++i) {
        for (j = 0; j < module->inc[i].submodule->augment_size; j++) {
            /* apply augment */
            if (!module->inc[i].submodule->augment[j].target
                    && (unres_schema_add_node((struct lys_module *)module->inc[j].submodule, unres,
                                              &module->inc[i].submodule->augment[j], UNRES_AUGMENT, NULL) == -1)) {

                goto error;
            }
        }
    }
    /* try again resolve augments in other modules possibly augmenting this one,
     * since we have just enabled it
     */
    /* resolve rest of unres items */
    if (unres->count && resolve_unres_schema((struct lys_module *)module, unres)) {
        goto error;
    }
    unres_schema_free((struct lys_module *)module, &unres);

    return EXIT_SUCCESS;

error:

    if (disabled) {
        /* set it back disabled */
        lys_set_disabled(module);
    }

    ((struct lys_module *)module)->implemented = 0;
    unres_schema_free((struct lys_module *)module, &unres);
    return EXIT_FAILURE;
}

void
lys_submodule_module_data_free(struct lys_submodule *submodule)
{
    struct lys_node *next, *elem;

    /* remove parsed data */
    LY_TREE_FOR_SAFE(submodule->belongsto->data, next, elem) {
        if (elem->module == (struct lys_module *)submodule) {
            lys_node_free(elem, NULL, 0);
        }
    }
}

int
lys_is_key(struct lys_node_list *list, struct lys_node_leaf *leaf)
{
    uint8_t i;

    for (i = 0; i < list->keys_size; i++) {
        if (list->keys[i] == leaf) {
            return i + 1;
        }
    }

    return 0;
}

API char *
lys_path(const struct lys_node *node)
{
    char *buf_backup = NULL, *buf = ly_buf(), *result = NULL;
    uint16_t index = LY_BUF_SIZE - 1;

    if (!node) {
        LOGERR(LY_EINVAL, "%s: NULL node parameter", __func__);
        return NULL;
    }

    /* backup the shared internal buffer */
    if (ly_buf_used && buf[0]) {
        buf_backup = strndup(buf, LY_BUF_SIZE - 1);
    }
    ly_buf_used++;

    /* build the path */
    buf[index] = '\0';
    ly_vlog_build_path_reverse(LY_VLOG_LYS, node, buf, &index, 0);
    result = strdup(&buf[index]);

    /* restore the shared internal buffer */
    if (buf_backup) {
        strcpy(buf, buf_backup);
        free(buf_backup);
    }
    ly_buf_used--;

    return result;
}