src/plugins_exts/structure.c - github/CESNET/libyang - Gitiles

 /**
  * @file structure.c
  * @author Michal Vasko <mvasko@cesnet.cz>
  * @brief libyang extension plugin - strcture (RFC 8791)
  *
  * Copyright (c) 2022 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
  */

 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>

 #include "compat.h"
 #include "libyang.h"
 #include "plugins_exts.h"

 struct lysc_ext_instance_structure {
     struct lysc_must *musts;
     uint16_t flags;
     const char *dsc;
     const char *ref;
     struct lysp_tpdf *typedefs;
     struct lysp_node_grp *groupings;
     struct lysc_node *child;
 };

 struct lysc_ext_instance_augment_structure {
     uint16_t flags;
     const char *dsc;
     const char *ref;
 };

 /**
  * @brief Compile structure extension instances.
  *
  * Implementation of ::lyplg_ext_compile_clb callback set as lyext_plugin::compile.
  */
 static LY_ERR
 structure_compile(struct lysc_ctx *cctx, const struct lysp_ext_instance *p_ext, struct lysc_ext_instance *c_ext)
 {
     LY_ERR rc;
     LY_ARRAY_COUNT_TYPE u;
     struct lysc_module *mod_c;
     const struct lysc_node *child;
     struct lysc_ext_instance_structure *struct_data;
     uint32_t prev_options = *lysc_ctx_get_options(cctx);

     /* structure can appear only at the top level of a YANG module or submodule */
     if ((c_ext->parent_stmt != LY_STMT_MODULE) && (c_ext->parent_stmt != LY_STMT_SUBMODULE)) {
         lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
                 "Extension %s must not be used as a non top-level statement in \"%s\" statement.",
                 p_ext->name, ly_stmt2str(c_ext->parent_stmt));
         return LY_EVALID;
     }

     mod_c = (struct lysc_module *)c_ext->parent;

     /* check identifier namespace */
     LY_ARRAY_FOR(mod_c->exts, u) {
         if ((&mod_c->exts[u] != c_ext) && (mod_c->exts[u].def == c_ext->def) && !strcmp(mod_c->exts[u].argument, c_ext->argument)) {
             /* duplication of the same structure extension in a single module */
             lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx), "Extension %s is instantiated multiple times.", p_ext->name);
             return LY_EVALID;
         }
     }
     LY_LIST_FOR(mod_c->data, child) {
         if (!strcmp(child->name, c_ext->argument)) {
             /* identifier collision */
             lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx), "Extension %s collides "
                     "with a %s with the same identifier.", p_ext->name, lys_nodetype2str(child->nodetype));
             return LY_EVALID;
         }
     }

     /* allocate the storage */
     struct_data = calloc(1, sizeof *struct_data);
     if (!struct_data) {
         goto emem;
     }
     c_ext->data = struct_data;

     /* compile substatements */
     LY_ARRAY_CREATE_GOTO(cctx->ctx, c_ext->substmts, 14, rc, emem);
     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[0].stmt = LY_STMT_MUST;
     c_ext->substmts[0].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[0].storage = &struct_data->musts;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[1].stmt = LY_STMT_STATUS;
     c_ext->substmts[1].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[1].storage = &struct_data->flags;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[2].stmt = LY_STMT_DESCRIPTION;
     c_ext->substmts[2].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[2].storage = &struct_data->dsc;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[3].stmt = LY_STMT_REFERENCE;
     c_ext->substmts[3].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[3].storage = &struct_data->ref;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[4].stmt = LY_STMT_TYPEDEF;
     c_ext->substmts[4].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[4].storage = &struct_data->typedefs;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[5].stmt = LY_STMT_GROUPING;
     c_ext->substmts[5].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[5].storage = &struct_data->groupings;

     /* data-def-stmt */
     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[6].stmt = LY_STMT_CONTAINER;
     c_ext->substmts[6].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[6].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[7].stmt = LY_STMT_LEAF;
     c_ext->substmts[7].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[7].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[8].stmt = LY_STMT_LEAF_LIST;
     c_ext->substmts[8].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[8].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[9].stmt = LY_STMT_LIST;
     c_ext->substmts[9].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[9].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[10].stmt = LY_STMT_CHOICE;
     c_ext->substmts[10].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[10].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[11].stmt = LY_STMT_ANYDATA;
     c_ext->substmts[11].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[11].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[12].stmt = LY_STMT_ANYXML;
     c_ext->substmts[12].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[12].storage = &struct_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[13].stmt = LY_STMT_USES;
     c_ext->substmts[13].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[13].storage = &struct_data->child;

     *lysc_ctx_get_options(cctx) |= LYS_COMPILE_NO_CONFIG | LYS_COMPILE_NO_DISABLED;
     rc = lys_compile_extension_instance(cctx, p_ext, c_ext);
     *lysc_ctx_get_options(cctx) = prev_options;
     if (rc) {
         return rc;
     }

     return LY_SUCCESS;

 emem:
     lyplg_ext_log(c_ext, LY_LLERR, LY_EMEM, lysc_ctx_get_path(cctx), "Memory allocation failed (%s()).", __func__);
     return LY_EMEM;
 }

 /**
  * @brief Compile augment-structure extension instances.
  *
  * Implementation of ::lyplg_ext_compile_clb callback set as lyext_plugin::compile.
  */
 static LY_ERR
 structure_aug_compile(struct lysc_ctx *cctx, const struct lysp_ext_instance *p_ext, struct lysc_ext_instance *c_ext)
 {
     LY_ERR rc;
     struct lysp_stmt *stmt;
     struct lysc_node *aug_target;
     struct lysc_ext_instance *target_ext;
     struct lysc_ext_instance_structure *target_data;
     struct lysc_ext_instance_augment_structure *aug_data;
     uint32_t prev_options = *lysc_ctx_get_options(cctx), i;

     /* augment-structure can appear only at the top level of a YANG module or submodule */
     if ((c_ext->parent_stmt != LY_STMT_MODULE) && (c_ext->parent_stmt != LY_STMT_SUBMODULE)) {
         lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
                 "Extension %s must not be used as a non top-level statement in \"%s\" statement.",
                 p_ext->name, ly_stmt2str(c_ext->parent_stmt));
         return LY_EVALID;
     }

     /* augment-structure must define some data-def-stmt */
     LY_LIST_FOR(p_ext->child, stmt) {
         if (LY_STMT_IS_DATA_NODE(stmt->kw)) {
             break;
         }
     }
     if (!stmt) {
         lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
                 "Extension %s does not define any data-def-stmt statements.", p_ext->name);
         return LY_EVALID;
     }

     /* find the target struct ext instance */
     if ((rc = lys_compile_extension_instance_find_augment_target(cctx, p_ext->argument, &target_ext, &aug_target))) {
         return rc;
     }

     /* check target_ext */
     if (strcmp(target_ext->def->name, "structure") || strcmp(target_ext->def->module->name, "ietf-yang-structure-ext")) {
         lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
                 "Extension %s can only target extension instances of \"ietf-yang-structure-ext:structure\".", p_ext->name);
         return LY_EVALID;
     }
     target_data = target_ext->data;

     /* allocate the storage */
     aug_data = calloc(1, sizeof *aug_data);
     if (!aug_data) {
         goto emem;
     }
     c_ext->data = aug_data;

     /* compile substatements */
     LY_ARRAY_CREATE_GOTO(cctx->ctx, c_ext->substmts, 12, rc, emem);
     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[0].stmt = LY_STMT_STATUS;
     c_ext->substmts[0].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[0].storage = &aug_data->flags;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[1].stmt = LY_STMT_DESCRIPTION;
     c_ext->substmts[1].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[1].storage = &aug_data->dsc;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[2].stmt = LY_STMT_REFERENCE;
     c_ext->substmts[2].cardinality = LY_STMT_CARD_OPT;
     c_ext->substmts[2].storage = &aug_data->ref;

     /* data-def-stmt */
     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[3].stmt = LY_STMT_CONTAINER;
     c_ext->substmts[3].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[3].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[4].stmt = LY_STMT_LEAF;
     c_ext->substmts[4].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[4].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[5].stmt = LY_STMT_LEAF_LIST;
     c_ext->substmts[5].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[5].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[6].stmt = LY_STMT_LIST;
     c_ext->substmts[6].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[6].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[7].stmt = LY_STMT_CHOICE;
     c_ext->substmts[7].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[7].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[8].stmt = LY_STMT_ANYDATA;
     c_ext->substmts[8].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[8].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[9].stmt = LY_STMT_ANYXML;
     c_ext->substmts[9].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[9].storage = &target_data->child;

     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[10].stmt = LY_STMT_USES;
     c_ext->substmts[10].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[10].storage = &target_data->child;

     /* case */
     LY_ARRAY_INCREMENT(c_ext->substmts);
     c_ext->substmts[11].stmt = LY_STMT_CASE;
     c_ext->substmts[11].cardinality = LY_STMT_CARD_ANY;
     c_ext->substmts[11].storage = &target_data->child;

     *lysc_ctx_get_options(cctx) |= LYS_COMPILE_NO_CONFIG | LYS_COMPILE_NO_DISABLED;
     rc = lys_compile_extension_instance_augment(cctx, p_ext, c_ext, aug_target);
     *lysc_ctx_get_options(cctx) = prev_options;
     if (rc) {
         return rc;
     }

     /* data-def-statements are now part of the target extension (do not print nor free them) */
     for (i = 0; i < 9; ++i) {
         LY_ARRAY_DECREMENT(c_ext->substmts);
     }

     return LY_SUCCESS;

 emem:
     lyplg_ext_log(c_ext, LY_LLERR, LY_EMEM, lysc_ctx_get_path(cctx), "Memory allocation failed (%s()).", __func__);
     return LY_EMEM;
 }

 /**
  * @brief INFO printer
  *
  * Implementation of ::lyplg_ext_schema_printer_clb set as ::lyext_plugin::sprinter
  */
 static LY_ERR
 structure_schema_printer(struct lyspr_ctx *ctx, struct lysc_ext_instance *ext, ly_bool *flag)
 {
     lysc_print_extension_instance(ctx, ext, flag);
     return LY_SUCCESS;
 }

 /**
  * @brief Free structure extension instances' data.
  *
  * Implementation of ::lyplg_clb_free_clb callback set as lyext_plugin::free.
  */
 static void
 structure_free(struct ly_ctx *ctx, struct lysc_ext_instance *ext)
 {
     lyplg_ext_instance_substatements_free(ctx, ext->substmts);
     free(ext->data);
 }

 /**
  * @brief Plugin descriptions for the structure extension
  *
  * Note that external plugins are supposed to use:
  *
  *   LYPLG_EXTENSIONS = {
  */
 const struct lyplg_ext_record plugins_structure[] = {
     {
         .module = "ietf-yang-structure-ext",
         .revision = "2020-06-17",
         .name = "structure",

         .plugin.id = "libyang 2 - structure, version 1",
         .plugin.compile = structure_compile,
         .plugin.sprinter = structure_schema_printer,
         .plugin.free = structure_free,
         .plugin.node = NULL,
         .plugin.snode = NULL,
         .plugin.validate = NULL
     },
     {
         .module = "ietf-yang-structure-ext",
         .revision = "2020-06-17",
         .name = "augment-structure",

         .plugin.id = "libyang 2 - structure, version 1",
         .plugin.compile = structure_aug_compile,
         .plugin.sprinter = structure_schema_printer,
         .plugin.free = structure_free,
         .plugin.node = NULL,
         .plugin.snode = NULL,
         .plugin.validate = NULL
     },
     {0}     /* terminating zeroed record */
 };
	/**
	* @file structure.c
	* @author Michal Vasko <mvasko@cesnet.cz>
	* @brief libyang extension plugin - strcture (RFC 8791)
	*
	* Copyright (c) 2022 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
	*/

	#include <stdint.h>
	#include <stdlib.h>
	#include <string.h>

	#include "compat.h"
	#include "libyang.h"
	#include "plugins_exts.h"

	struct lysc_ext_instance_structure {
	struct lysc_must *musts;
	uint16_t flags;
	const char *dsc;
	const char *ref;
	struct lysp_tpdf *typedefs;
	struct lysp_node_grp *groupings;
	struct lysc_node *child;
	};

	struct lysc_ext_instance_augment_structure {
	uint16_t flags;
	const char *dsc;
	const char *ref;
	};

	/**
	* @brief Compile structure extension instances.
	*
	* Implementation of ::lyplg_ext_compile_clb callback set as lyext_plugin::compile.
	*/
	static LY_ERR
	structure_compile(struct lysc_ctx cctx, const struct lysp_ext_instance p_ext, struct lysc_ext_instance *c_ext)
	{
	LY_ERR rc;
	LY_ARRAY_COUNT_TYPE u;
	struct lysc_module *mod_c;
	const struct lysc_node *child;
	struct lysc_ext_instance_structure *struct_data;
	uint32_t prev_options = *lysc_ctx_get_options(cctx);

	/* structure can appear only at the top level of a YANG module or submodule */
	if ((c_ext->parent_stmt != LY_STMT_MODULE) && (c_ext->parent_stmt != LY_STMT_SUBMODULE)) {
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
	"Extension %s must not be used as a non top-level statement in \"%s\" statement.",
	p_ext->name, ly_stmt2str(c_ext->parent_stmt));
	return LY_EVALID;
	}

	mod_c = (struct lysc_module *)c_ext->parent;

	/* check identifier namespace */
	LY_ARRAY_FOR(mod_c->exts, u) {
	if ((&mod_c->exts[u] != c_ext) && (mod_c->exts[u].def == c_ext->def) && !strcmp(mod_c->exts[u].argument, c_ext->argument)) {
	/* duplication of the same structure extension in a single module */
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx), "Extension %s is instantiated multiple times.", p_ext->name);
	return LY_EVALID;
	}
	}
	LY_LIST_FOR(mod_c->data, child) {
	if (!strcmp(child->name, c_ext->argument)) {
	/* identifier collision */
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx), "Extension %s collides "
	"with a %s with the same identifier.", p_ext->name, lys_nodetype2str(child->nodetype));
	return LY_EVALID;
	}
	}

	/* allocate the storage */
	struct_data = calloc(1, sizeof *struct_data);
	if (!struct_data) {
	goto emem;
	}
	c_ext->data = struct_data;

	/* compile substatements */
	LY_ARRAY_CREATE_GOTO(cctx->ctx, c_ext->substmts, 14, rc, emem);
	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[0].stmt = LY_STMT_MUST;
	c_ext->substmts[0].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[0].storage = &struct_data->musts;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[1].stmt = LY_STMT_STATUS;
	c_ext->substmts[1].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[1].storage = &struct_data->flags;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[2].stmt = LY_STMT_DESCRIPTION;
	c_ext->substmts[2].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[2].storage = &struct_data->dsc;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[3].stmt = LY_STMT_REFERENCE;
	c_ext->substmts[3].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[3].storage = &struct_data->ref;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[4].stmt = LY_STMT_TYPEDEF;
	c_ext->substmts[4].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[4].storage = &struct_data->typedefs;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[5].stmt = LY_STMT_GROUPING;
	c_ext->substmts[5].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[5].storage = &struct_data->groupings;

	/* data-def-stmt */
	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[6].stmt = LY_STMT_CONTAINER;
	c_ext->substmts[6].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[6].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[7].stmt = LY_STMT_LEAF;
	c_ext->substmts[7].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[7].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[8].stmt = LY_STMT_LEAF_LIST;
	c_ext->substmts[8].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[8].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[9].stmt = LY_STMT_LIST;
	c_ext->substmts[9].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[9].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[10].stmt = LY_STMT_CHOICE;
	c_ext->substmts[10].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[10].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[11].stmt = LY_STMT_ANYDATA;
	c_ext->substmts[11].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[11].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[12].stmt = LY_STMT_ANYXML;
	c_ext->substmts[12].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[12].storage = &struct_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[13].stmt = LY_STMT_USES;
	c_ext->substmts[13].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[13].storage = &struct_data->child;

	*lysc_ctx_get_options(cctx) \|= LYS_COMPILE_NO_CONFIG \| LYS_COMPILE_NO_DISABLED;
	rc = lys_compile_extension_instance(cctx, p_ext, c_ext);
	*lysc_ctx_get_options(cctx) = prev_options;
	if (rc) {
	return rc;
	}

	return LY_SUCCESS;

	emem:
	lyplg_ext_log(c_ext, LY_LLERR, LY_EMEM, lysc_ctx_get_path(cctx), "Memory allocation failed (%s()).", __func__);
	return LY_EMEM;
	}

	/**
	* @brief Compile augment-structure extension instances.
	*
	* Implementation of ::lyplg_ext_compile_clb callback set as lyext_plugin::compile.
	*/
	static LY_ERR
	structure_aug_compile(struct lysc_ctx cctx, const struct lysp_ext_instance p_ext, struct lysc_ext_instance *c_ext)
	{
	LY_ERR rc;
	struct lysp_stmt *stmt;
	struct lysc_node *aug_target;
	struct lysc_ext_instance *target_ext;
	struct lysc_ext_instance_structure *target_data;
	struct lysc_ext_instance_augment_structure *aug_data;
	uint32_t prev_options = *lysc_ctx_get_options(cctx), i;

	/* augment-structure can appear only at the top level of a YANG module or submodule */
	if ((c_ext->parent_stmt != LY_STMT_MODULE) && (c_ext->parent_stmt != LY_STMT_SUBMODULE)) {
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
	"Extension %s must not be used as a non top-level statement in \"%s\" statement.",
	p_ext->name, ly_stmt2str(c_ext->parent_stmt));
	return LY_EVALID;
	}

	/* augment-structure must define some data-def-stmt */
	LY_LIST_FOR(p_ext->child, stmt) {
	if (LY_STMT_IS_DATA_NODE(stmt->kw)) {
	break;
	}
	}
	if (!stmt) {
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
	"Extension %s does not define any data-def-stmt statements.", p_ext->name);
	return LY_EVALID;
	}

	/* find the target struct ext instance */
	if ((rc = lys_compile_extension_instance_find_augment_target(cctx, p_ext->argument, &target_ext, &aug_target))) {
	return rc;
	}

	/* check target_ext */
	if (strcmp(target_ext->def->name, "structure") \|\| strcmp(target_ext->def->module->name, "ietf-yang-structure-ext")) {
	lyplg_ext_log(c_ext, LY_LLERR, LY_EVALID, lysc_ctx_get_path(cctx),
	"Extension %s can only target extension instances of \"ietf-yang-structure-ext:structure\".", p_ext->name);
	return LY_EVALID;
	}
	target_data = target_ext->data;

	/* allocate the storage */
	aug_data = calloc(1, sizeof *aug_data);
	if (!aug_data) {
	goto emem;
	}
	c_ext->data = aug_data;

	/* compile substatements */
	LY_ARRAY_CREATE_GOTO(cctx->ctx, c_ext->substmts, 12, rc, emem);
	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[0].stmt = LY_STMT_STATUS;
	c_ext->substmts[0].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[0].storage = &aug_data->flags;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[1].stmt = LY_STMT_DESCRIPTION;
	c_ext->substmts[1].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[1].storage = &aug_data->dsc;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[2].stmt = LY_STMT_REFERENCE;
	c_ext->substmts[2].cardinality = LY_STMT_CARD_OPT;
	c_ext->substmts[2].storage = &aug_data->ref;

	/* data-def-stmt */
	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[3].stmt = LY_STMT_CONTAINER;
	c_ext->substmts[3].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[3].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[4].stmt = LY_STMT_LEAF;
	c_ext->substmts[4].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[4].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[5].stmt = LY_STMT_LEAF_LIST;
	c_ext->substmts[5].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[5].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[6].stmt = LY_STMT_LIST;
	c_ext->substmts[6].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[6].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[7].stmt = LY_STMT_CHOICE;
	c_ext->substmts[7].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[7].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[8].stmt = LY_STMT_ANYDATA;
	c_ext->substmts[8].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[8].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[9].stmt = LY_STMT_ANYXML;
	c_ext->substmts[9].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[9].storage = &target_data->child;

	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[10].stmt = LY_STMT_USES;
	c_ext->substmts[10].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[10].storage = &target_data->child;

	/* case */
	LY_ARRAY_INCREMENT(c_ext->substmts);
	c_ext->substmts[11].stmt = LY_STMT_CASE;
	c_ext->substmts[11].cardinality = LY_STMT_CARD_ANY;
	c_ext->substmts[11].storage = &target_data->child;

	*lysc_ctx_get_options(cctx) \|= LYS_COMPILE_NO_CONFIG \| LYS_COMPILE_NO_DISABLED;
	rc = lys_compile_extension_instance_augment(cctx, p_ext, c_ext, aug_target);
	*lysc_ctx_get_options(cctx) = prev_options;
	if (rc) {
	return rc;
	}

	/* data-def-statements are now part of the target extension (do not print nor free them) */
	for (i = 0; i < 9; ++i) {
	LY_ARRAY_DECREMENT(c_ext->substmts);
	}

	return LY_SUCCESS;

	emem:
	lyplg_ext_log(c_ext, LY_LLERR, LY_EMEM, lysc_ctx_get_path(cctx), "Memory allocation failed (%s()).", __func__);
	return LY_EMEM;
	}

	/**
	* @brief INFO printer
	*
	* Implementation of ::lyplg_ext_schema_printer_clb set as ::lyext_plugin::sprinter
	*/
	static LY_ERR
	structure_schema_printer(struct lyspr_ctx ctx, struct lysc_ext_instance ext, ly_bool *flag)
	{
	lysc_print_extension_instance(ctx, ext, flag);
	return LY_SUCCESS;
	}

	/**
	* @brief Free structure extension instances' data.
	*
	* Implementation of ::lyplg_clb_free_clb callback set as lyext_plugin::free.
	*/
	static void
	structure_free(struct ly_ctx ctx, struct lysc_ext_instance ext)
	{
	lyplg_ext_instance_substatements_free(ctx, ext->substmts);
	free(ext->data);
	}

	/**
	* @brief Plugin descriptions for the structure extension
	*
	* Note that external plugins are supposed to use:
	*
	* LYPLG_EXTENSIONS = {
	*/
	const struct lyplg_ext_record plugins_structure[] = {
	{
	.module = "ietf-yang-structure-ext",
	.revision = "2020-06-17",
	.name = "structure",

	.plugin.id = "libyang 2 - structure, version 1",
	.plugin.compile = structure_compile,
	.plugin.sprinter = structure_schema_printer,
	.plugin.free = structure_free,
	.plugin.node = NULL,
	.plugin.snode = NULL,
	.plugin.validate = NULL
	},
	{
	.module = "ietf-yang-structure-ext",
	.revision = "2020-06-17",
	.name = "augment-structure",

	.plugin.id = "libyang 2 - structure, version 1",
	.plugin.compile = structure_aug_compile,
	.plugin.sprinter = structure_schema_printer,
	.plugin.free = structure_free,
	.plugin.node = NULL,
	.plugin.snode = NULL,
	.plugin.validate = NULL
	},
	{0} /* terminating zeroed record */
	};