1 files changed, 277 insertions, 0 deletions
diff --git a/src/plugins_exts/yangdata.c b/src/plugins_exts/yangdata.c
new file mode 100644
index 0000000..c9c5dd8
--- /dev/null
+++ b/src/plugins_exts/yangdata.c
@@ -0,0 +1,277 @@
+/**
+ * @file yangdata.c
+ * @author Radek Krejci <rkrejci@cesnet.cz>
+ * @author Michal Vasko <mvasko@cesnet.cz>
+ * @brief libyang extension plugin - yang-data (RFC 8040)
+ *
+ * Copyright (c) 2021 - 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 <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "compat.h"
+#include "libyang.h"
+#include "plugins_exts.h"
+
+static void yangdata_cfree(const struct ly_ctx *ctx, struct lysc_ext_instance *ext);
+
+/**
+ * @brief Parse yang-data extension instances.
+ *
+ * Implementation of ::lyplg_ext_parse_clb callback set as lyext_plugin::parse.
+ */
+static LY_ERR
+yangdata_parse(struct lysp_ctx *pctx, struct lysp_ext_instance *ext)
+{
+    LY_ERR ret;
+    LY_ARRAY_COUNT_TYPE u;
+    struct lysp_module *pmod;
+
+    /* yang-data can appear only at the top level of a YANG module or submodule */
+    if ((ext->parent_stmt != LY_STMT_MODULE) && (ext->parent_stmt != LY_STMT_SUBMODULE)) {
+        lyplg_ext_parse_log(pctx, ext, LY_LLWRN, 0, "Extension %s is ignored since it appears as a non top-level statement "
+                "in \"%s\" statement.", ext->name, lyplg_ext_stmt2str(ext->parent_stmt));
+        return LY_ENOT;
+    }
+
+    pmod = ext->parent;
+
+    /* check for duplication */
+    LY_ARRAY_FOR(pmod->exts, u) {
+        if ((&pmod->exts[u] != ext) && (pmod->exts[u].name == ext->name) && !strcmp(pmod->exts[u].argument, ext->argument)) {
+            /* duplication of the same yang-data extension in a single module */
+            lyplg_ext_parse_log(pctx, ext, LY_LLERR, LY_EVALID, "Extension %s is instantiated multiple times.", ext->name);
+            return LY_EVALID;
+        }
+    }
+
+    /* parse yang-data substatements */
+    LY_ARRAY_CREATE_GOTO(lyplg_ext_parse_get_cur_pmod(pctx)->mod->ctx, ext->substmts, 3, ret, emem);
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[0].stmt = LY_STMT_CONTAINER;
+    ext->substmts[0].storage = (uint64_t)(uintptr_t)&ext->parsed;
+
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[1].stmt = LY_STMT_CHOICE;
+    ext->substmts[1].storage = (uint64_t)(uintptr_t)&ext->parsed;
+
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[2].stmt = LY_STMT_USES;
+    ext->substmts[2].storage = (uint64_t)(uintptr_t)&ext->parsed;
+
+    if ((ret = lyplg_ext_parse_extension_instance(pctx, ext))) {
+        return ret;
+    }
+
+    return LY_SUCCESS;
+
+emem:
+    lyplg_ext_parse_log(pctx, ext, LY_LLERR, LY_EMEM, "Memory allocation failed (%s()).", __func__);
+    return LY_EMEM;
+}
+
+/**
+ * @brief Compile yang-data extension instances.
+ *
+ * Implementation of ::lyplg_ext_compile_clb callback set as lyext_plugin::compile.
+ */
+static LY_ERR
+yangdata_compile(struct lysc_ctx *cctx, const struct lysp_ext_instance *extp, struct lysc_ext_instance *ext)
+{
+    LY_ERR ret;
+    const struct lysc_node *child;
+    ly_bool valid = 1;
+    uint32_t prev_options = *lyplg_ext_compile_get_options(cctx);
+
+    /* compile yangg-data substatements */
+    LY_ARRAY_CREATE_GOTO(cctx->ctx, ext->substmts, 3, ret, emem);
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[0].stmt = LY_STMT_CONTAINER;
+    ext->substmts[0].storage = (uint64_t)(uintptr_t)&ext->compiled;
+
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[1].stmt = LY_STMT_CHOICE;
+    ext->substmts[1].storage = (uint64_t)(uintptr_t)&ext->compiled;
+
+    LY_ARRAY_INCREMENT(ext->substmts);
+    ext->substmts[2].stmt = LY_STMT_USES;
+    ext->substmts[2].storage = (uint64_t)(uintptr_t)&ext->compiled;
+
+    *lyplg_ext_compile_get_options(cctx) |= LYS_COMPILE_NO_CONFIG | LYS_COMPILE_NO_DISABLED;
+    ret = lyplg_ext_compile_extension_instance(cctx, extp, ext);
+    *lyplg_ext_compile_get_options(cctx) = prev_options;
+    if (ret) {
+        return ret;
+    }
+
+    /* check that we have really just a single container data definition in the top */
+    child = ext->compiled;
+    if (!child) {
+        valid = 0;
+        lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EVALID,
+                "Extension %s is instantiated without any top level data node, but exactly one container data node is expected.",
+                extp->name);
+    } else if (child->next) {
+        valid = 0;
+        lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EVALID,
+                "Extension %s is instantiated with multiple top level data nodes, but only a single container data node is allowed.",
+                extp->name);
+    } else if (child->nodetype == LYS_CHOICE) {
+        /* all the choice's case are expected to result to a single container node */
+        struct lysc_module *mod_c = ext->parent;
+        const struct lysc_node *snode = NULL;
+
+        while ((snode = lys_getnext(snode, child, mod_c, 0))) {
+            if (snode->next) {
+                valid = 0;
+                lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EVALID,
+                        "Extension %s is instantiated with multiple top level data nodes (inside a single choice's case), "
+                        "but only a single container data node is allowed.", extp->name);
+                break;
+            } else if (snode->nodetype != LYS_CONTAINER) {
+                valid = 0;
+                lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EVALID,
+                        "Extension %s is instantiated with %s top level data node (inside a choice), "
+                        "but only a single container data node is allowed.", extp->name, lys_nodetype2str(snode->nodetype));
+                break;
+            }
+        }
+    } else if (child->nodetype != LYS_CONTAINER) {
+        /* via uses */
+        valid = 0;
+        lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EVALID,
+                "Extension %s is instantiated with %s top level data node, but only a single container data node is allowed.",
+                extp->name, lys_nodetype2str(child->nodetype));
+    }
+
+    if (!valid) {
+        yangdata_cfree(lyplg_ext_compile_get_ctx(cctx), ext);
+        ext->compiled = ext->substmts = NULL;
+        return LY_EVALID;
+    }
+
+    return LY_SUCCESS;
+
+emem:
+    lyplg_ext_compile_log(cctx, ext, LY_LLERR, LY_EMEM, "Memory allocation failed (%s()).", __func__);
+    return LY_EMEM;
+}
+
+/**
+ * @brief INFO printer
+ *
+ * Implementation of ::lyplg_ext_sprinter_info_clb set as ::lyext_plugin::printer_info
+ */
+static LY_ERR
+yangdata_printer_info(struct lyspr_ctx *ctx, struct lysc_ext_instance *ext, ly_bool *flag)
+{
+    lyplg_ext_print_info_extension_instance(ctx, ext, flag);
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Free parsed yang-data extension instance data.
+ *
+ * Implementation of ::lyplg_clb_parse_free_clb callback set as lyext_plugin::pfree.
+ */
+static void
+yangdata_pfree(const struct ly_ctx *ctx, struct lysp_ext_instance *ext)
+{
+    lyplg_ext_pfree_instance_substatements(ctx, ext->substmts);
+}
+
+/**
+ * @brief Free compiled yang-data extension instance data.
+ *
+ * Implementation of ::lyplg_clb_compile_free_clb callback set as lyext_plugin::cfree.
+ */
+static void
+yangdata_cfree(const struct ly_ctx *ctx, struct lysc_ext_instance *ext)
+{
+    lyplg_ext_cfree_instance_substatements(ctx, ext->substmts);
+}
+
+static void
+yangdata_sprinter_node(uint16_t nodetype, const char **flags)
+{
+    if (nodetype & LYS_USES) {
+        *flags = "-u";
+    } else {
+        *flags = "--";
+    }
+}
+
+static LY_ERR
+yangdata_sprinter_cnode(const struct lysc_node *node, const void *UNUSED(plugin_priv), ly_bool *UNUSED(skip),
+        const char **flags, const char **UNUSED(add_opts))
+{
+    yangdata_sprinter_node(node->nodetype, flags);
+    return LY_SUCCESS;
+}
+
+static LY_ERR
+yangdata_sprinter_pnode(const struct lysp_node *node, const void *UNUSED(plugin_priv), ly_bool *UNUSED(skip),
+        const char **flags, const char **UNUSED(add_opts))
+{
+    yangdata_sprinter_node(node->nodetype, flags);
+    return LY_SUCCESS;
+}
+
+static LY_ERR
+yangdata_sprinter_ctree(struct lysc_ext_instance *ext, const struct lyspr_tree_ctx *ctx,
+        const char **UNUSED(flags), const char **UNUSED(add_opts))
+{
+    LY_ERR rc = LY_SUCCESS;
+
+    assert(ctx);
+    rc = lyplg_ext_sprinter_ctree_add_ext_nodes(ctx, ext, yangdata_sprinter_cnode);
+    return rc;
+}
+
+static LY_ERR
+yangdata_sprinter_ptree(struct lysp_ext_instance *ext, const struct lyspr_tree_ctx *ctx,
+        const char **UNUSED(flags), const char **UNUSED(add_opts))
+{
+    LY_ERR rc = LY_SUCCESS;
+
+    assert(ctx);
+    rc = lyplg_ext_sprinter_ptree_add_ext_nodes(ctx, ext, yangdata_sprinter_pnode);
+    return rc;
+}
+
+/**
+ * @brief Plugin descriptions for the yang-data extension
+ *
+ * Note that external plugins are supposed to use:
+ *
+ *   LYPLG_EXTENSIONS = {
+ */
+const struct lyplg_ext_record plugins_yangdata[] = {
+    {
+        .module = "ietf-restconf",
+        .revision = "2017-01-26",
+        .name = "yang-data",
+
+        .plugin.id = "ly2 yang-data v1",
+        .plugin.parse = yangdata_parse,
+        .plugin.compile = yangdata_compile,
+        .plugin.printer_info = yangdata_printer_info,
+        .plugin.printer_ctree = yangdata_sprinter_ctree,
+        .plugin.printer_ptree = yangdata_sprinter_ptree,
+        .plugin.node = NULL,
+        .plugin.snode = NULL,
+        .plugin.validate = NULL,
+        .plugin.pfree = yangdata_pfree,
+        .plugin.cfree = yangdata_cfree
+    },
+    {0}     /* terminating zeroed record */
+};