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| -rw-r--r-- | src/path.h | 265 |
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diff --git a/src/path.h b/src/path.h new file mode 100644 index 0000000..9a9e342 --- /dev/null +++ b/src/path.h @@ -0,0 +1,265 @@ +/** + * @file path.h + * @author Michal Vasko <mvasko@cesnet.cz> + * @brief Path structure and manipulation routines. + * + * Copyright (c) 2020 - 2023 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 + */ + +#ifndef LY_PATH_H_ +#define LY_PATH_H_ + +#include <stddef.h> +#include <stdint.h> + +#include "log.h" +#include "tree.h" +#include "tree_data.h" + +struct ly_ctx; +struct lys_module; +struct lysc_ext_instance; +struct lysc_node; +struct lyxp_expr; + +enum ly_path_pred_type { + LY_PATH_PREDTYPE_POSITION, /**< position predicate - [2] */ + LY_PATH_PREDTYPE_LIST, /**< keys predicate - [key1='val1'][key2='val2']... */ + LY_PATH_PREDTYPE_LEAFLIST, /**< leaflist value predicate - [.='value'] */ + LY_PATH_PREDTYPE_LIST_VAR /**< keys predicate with variable instead of value - [key1=$USER]... */ +}; + +/** + * @brief Structure for simple path predicate. + */ +struct ly_path_predicate { + enum ly_path_pred_type type; /**< Predicate type (see YANG ABNF) */ + union { + uint64_t position; /**< position value for the position-predicate */ + struct { + const struct lysc_node *key; /**< key node of the predicate, NULL in case of a leaf-list predicate */ + union { + struct lyd_value value; /**< stored value representation according to the key's type (realtype ref) */ + char *variable; /**< XPath variable used instead of the value */ + }; + }; + }; +}; + +/** + * @brief Structure for holding one segment of resolved path on schema including + * simple predicates. Is used as a [sized array](@ref sizedarrays). + */ +struct ly_path { + const struct lysc_node *node; /**< Schema node representing the path segment, first node has special meaning: + - is a top-level node - path is absolute, + - is inner node - path is relative */ + const struct lysc_ext_instance *ext; /**< Extension instance of @p node, if any */ + struct ly_path_predicate *predicates; /**< [Sized array](@ref sizedarrays) of the path segment's predicates */ +}; + +/** + * @defgroup path_begin_options Path begin options. + * @{ + */ +#define LY_PATH_BEGIN_ABSOLUTE 0x01 /**< path must be absolute */ +#define LY_PATH_BEGIN_EITHER 0x02 /**< path be be either absolute or relative */ +/** @} */ + +/** + * @defgroup path_prefix_options Path prefix options. + * @{ + */ +#define LY_PATH_PREFIX_OPTIONAL 0x10 /**< prefixes in the path are optional (XML path) */ +#define LY_PATH_PREFIX_MANDATORY 0x20 /**< prefixes in the path are mandatory (XML instance-identifier) */ +#define LY_PATH_PREFIX_FIRST 0x40 /**< prefixes in the path are mandatory only in the first node of absolute path (JSON path) */ +#define LY_PATH_PREFIX_STRICT_INHERIT 0x80 /**< prefixes in the path are mandatory in case they differ from the + previous prefixes, otherwise they are prohibited (JSON instance-identifier) */ +/** @} */ + +/** + * @defgroup path_pred_options Path predicate options. + * @{ + */ +#define LY_PATH_PRED_KEYS 0x0100 /** expected predicate only - [node='value']* */ +#define LY_PATH_PRED_SIMPLE 0x0200 /** expected predicates - ( [node='value'] | [node=$VAR] )*; [.='value']; [1] */ +#define LY_PATH_PRED_LEAFREF 0x0400 /** expected predicates only leafref - [node=current()/../../../node/node]; + at least 1 ".." and 1 "node" after */ +/** @} */ + +/** + * @brief Parse path into XPath token structure and perform all additional checks. + * + * @param[in] ctx libyang context. + * @param[in] ctx_node Optional context node, used for logging. + * @param[in] str_path Path to parse. + * @param[in] path_len Length of @p str_path. + * @param[in] lref Whether leafref is being parsed or not. + * @param[in] begin Begin option (@ref path_begin_options). + * @param[in] prefix Prefix option (@ref path_prefix_options). + * @param[in] pred Predicate option (@ref path_pred_options). + * @param[out] expr Parsed path. + * @return LY_ERR value. + */ +LY_ERR ly_path_parse(const struct ly_ctx *ctx, const struct lysc_node *ctx_node, const char *str_path, size_t path_len, + ly_bool lref, uint16_t begin, uint16_t prefix, uint16_t pred, struct lyxp_expr **expr); + +/** + * @brief Parse predicate into XPath token structure and perform all additional checks. + * + * @param[in] ctx libyang context. + * @param[in] cur_node Optional current (original context) node, used for logging. + * @param[in] str_path Path to parse. + * @param[in] path_len Length of @p str_path. + * @param[in] prefix Prefix option (@ref path_prefix_options). + * @param[in] pred Predicate option (@ref path_pred_options). + * @param[out] expr Parsed path. + * @return LY_ERR value. + */ +LY_ERR ly_path_parse_predicate(const struct ly_ctx *ctx, const struct lysc_node *cur_node, const char *str_path, + size_t path_len, uint16_t prefix, uint16_t pred, struct lyxp_expr **expr); + +/** + * @defgroup path_oper_options Path operation options. + * @{ + */ +#define LY_PATH_OPER_INPUT 0x01 /**< if any RPC/action is traversed, its input nodes are used */ +#define LY_PATH_OPER_OUTPUT 0x02 /**< if any RPC/action is traversed, its output nodes are used */ +/** @} */ + +/* lref */ + +/** + * @defgroup path_target_options Path target options. + * @{ + */ +#define LY_PATH_TARGET_SINGLE 0x10 /**< last (target) node must identify an exact instance */ +#define LY_PATH_TARGET_MANY 0x20 /**< last (target) node may identify all instances (of leaf-list/list) */ +/** @} */ + +/** + * @brief Compile path into ly_path structure. + * + * @param[in] ctx libyang context. + * @param[in] cur_mod Current module of the path (where it was "instantiated"). Used for nodes in schema-nodeid + * without a prefix for ::LY_VALUE_SCHEMA and ::LY_VALUE_SCHEMA_RESOLVED format. + * @param[in] ctx_node Optional context node. + * @param[in] top_ext Extension instance containing the definition of the data being created. It is used to find the top-level + * node inside the extension instance instead of a module. Note that this is the case not only if the @p ctx_node is NULL, + * but also if the relative path starting in @p ctx_node reaches the document root via double dots. + * @param[in] expr Parsed path. + * @param[in] oper Oper option (@ref path_oper_options). + * @param[in] target Target option (@ref path_target_options). + * @param[in] limit_access_tree Whether to limit accessible tree. + * @param[in] format Format of the path. + * @param[in] prefix_data Format-specific data for resolving any prefixes (see ::ly_resolve_prefix). + * @param[out] path Compiled path. + * @return LY_ERR value. + */ +LY_ERR ly_path_compile(const struct ly_ctx *ctx, const struct lys_module *cur_mod, const struct lysc_node *ctx_node, + const struct lysc_ext_instance *top_ext, const struct lyxp_expr *expr, uint16_t oper, uint16_t target, + ly_bool limit_access_tree, LY_VALUE_FORMAT format, void *prefix_data, struct ly_path **path); + +/** + * @brief Compile path into ly_path structure. Any predicates of a leafref are only checked, not compiled. + * + * @param[in] ctx libyang context. + * @param[in] ctx_node Context node. + * @param[in] top_ext Extension instance containing the definition of the data being created. It is used to find the top-level + * node inside the extension instance instead of a module. Note that this is the case not only if the @p ctx_node is NULL, + * but also if the relative path starting in @p ctx_node reaches the document root via double dots. + * @param[in] expr Parsed path. + * @param[in] oper Oper option (@ref path_oper_options). + * @param[in] target Target option (@ref path_target_options). + * @param[in] format Format of the path. + * @param[in] prefix_data Format-specific data for resolving any prefixes (see ::ly_resolve_prefix). + * @param[out] path Compiled path. + * @return LY_ERR value. + */ +LY_ERR ly_path_compile_leafref(const struct ly_ctx *ctx, const struct lysc_node *ctx_node, + const struct lysc_ext_instance *top_ext, const struct lyxp_expr *expr, uint16_t oper, uint16_t target, + LY_VALUE_FORMAT format, void *prefix_data, struct ly_path **path); + +/** + * @brief Compile predicate into ly_path_predicate structure. Only simple predicates (not leafref) are supported. + * + * @param[in] ctx libyang context. + * @param[in] cur_node Optional current (original context) node. + * @param[in] cur_mod Current module of the path (where it was "instantiated"). Used for nodes without a prefix + * for ::LY_VALUE_SCHEMA and ::LY_VALUE_SCHEMA_RESOLVED format. + * @param[in] ctx_node Context node, node for which the predicate is defined. + * @param[in] expr Parsed path. + * @param[in,out] tok_idx Index in @p expr, is adjusted for parsed tokens. + * @param[in] format Format of the path. + * @param[in] prefix_data Format-specific data for resolving any prefixes (see ::ly_resolve_prefix). + * @param[out] predicates Compiled predicates. + * @return LY_ERR value. + */ +LY_ERR ly_path_compile_predicate(const struct ly_ctx *ctx, const struct lysc_node *cur_node, const struct lys_module *cur_mod, + const struct lysc_node *ctx_node, const struct lyxp_expr *expr, uint32_t *tok_idx, LY_VALUE_FORMAT format, + void *prefix_data, struct ly_path_predicate **predicates); + +/** + * @brief Resolve at least partially the target defined by ly_path structure. Not supported for leafref! + * + * @param[in] path Path structure specifying the target. + * @param[in] start Starting node for relative paths, can be any for absolute paths. + * @param[in] vars Array of defined variables to use in predicates, may be NULL. + * @param[in] with_opaq Whether to consider opaque nodes or not. + * @param[out] path_idx Last found path segment index, can be NULL, set to 0 if not found. + * @param[out] match Last found matching node, can be NULL, set to NULL if not found. + * @return LY_ENOTFOUND if no nodes were found, + * @return LY_EINCOMPLETE if some node was found but not the last one, + * @return LY_SUCCESS when the last node in the path was found, + * @return LY_ERR on another error. + */ +LY_ERR ly_path_eval_partial(const struct ly_path *path, const struct lyd_node *start, const struct lyxp_var *vars, + ly_bool with_opaq, LY_ARRAY_COUNT_TYPE *path_idx, struct lyd_node **match); + +/** + * @brief Resolve the target defined by ly_path structure. Not supported for leafref! + * + * @param[in] path Path structure specifying the target. + * @param[in] start Starting node for relative paths, can be any for absolute paths. + * @param[in] vars Array of defined variables to use in predicates, may be NULL. + * @param[out] match Found matching node, can be NULL, set to NULL if not found. + * @return LY_ENOTFOUND if no nodes were found, + * @return LY_SUCCESS when the last node in the path was found, + * @return LY_ERR on another error. + */ +LY_ERR ly_path_eval(const struct ly_path *path, const struct lyd_node *start, const struct lyxp_var *vars, + struct lyd_node **match); + +/** + * @brief Duplicate ly_path structure. + * + * @param[in] ctx libyang context. + * @param[in] path Path to duplicate. + * @param[out] dup Duplicated path. + * @return LY_ERR value. + */ +LY_ERR ly_path_dup(const struct ly_ctx *ctx, const struct ly_path *path, struct ly_path **dup); + +/** + * @brief Free ly_path_predicate structure. + * + * @param[in] ctx libyang context. + * @param[in] predicates Predicates ([sized array](@ref sizedarrays)) to free. + */ +void ly_path_predicates_free(const struct ly_ctx *ctx, struct ly_path_predicate *predicates); + +/** + * @brief Free ly_path structure. + * + * @param[in] ctx libyang context. + * @param[in] path The structure ([sized array](@ref sizedarrays)) to free. + */ +void ly_path_free(const struct ly_ctx *ctx, struct ly_path *path); + +#endif /* LY_PATH_H_ */ |