blob: a79ea82b716f29f9b6165c8a411413b5dbf30e9a [file] [log] [blame]
Radek Krejcib1646a92018-11-02 16:08:26 +01001/**
2 * @file xpath.h
3 * @author Michal Vasko <mvasko@cesnet.cz>
4 * @brief YANG XPath evaluation functions header
5 *
Michal Vasko519fd602020-05-26 12:17:39 +02006 * Copyright (c) 2015 - 2020 CESNET, z.s.p.o.
Radek Krejcib1646a92018-11-02 16:08:26 +01007 *
8 * This source code is licensed under BSD 3-Clause License (the "License").
9 * You may not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
11 *
12 * https://opensource.org/licenses/BSD-3-Clause
13 */
14
Michal Vasko14676352020-05-29 11:35:55 +020015#ifndef LY_XPATH_H
16#define LY_XPATH_H
Radek Krejcib1646a92018-11-02 16:08:26 +010017
18#include <stdint.h>
Radek Krejciad97c5f2020-06-30 09:19:28 +020019#include <stddef.h>
Radek Krejcib1646a92018-11-02 16:08:26 +010020
Radek Krejci535ea9f2020-05-29 16:01:05 +020021#include "config.h"
Radek Krejcie7b95092019-05-15 11:03:07 +020022#include "log.h"
Radek Krejci535ea9f2020-05-29 16:01:05 +020023#include "tree_schema.h"
Radek Krejcie7b95092019-05-15 11:03:07 +020024
25struct ly_ctx;
Radek Krejcie7b95092019-05-15 11:03:07 +020026
Radek Krejcib1646a92018-11-02 16:08:26 +010027/*
28 * XPath evaluator fully compliant with http://www.w3.org/TR/1999/REC-xpath-19991116/
29 * except the following restrictions in the grammar.
30 *
31 * PARSED GRAMMAR
32 *
33 * Full axes are not supported, abbreviated forms must be used,
34 * variables are not supported, "id()" function is not supported,
35 * and processing instruction and comment nodes are not supported,
36 * which is also reflected in the grammar. Undefined rules and
37 * constants are tokens.
38 *
39 * Modified full grammar:
40 *
41 * [1] Expr ::= OrExpr // just an alias
42 *
43 * [2] LocationPath ::= RelativeLocationPath | AbsoluteLocationPath
44 * [3] AbsoluteLocationPath ::= '/' RelativeLocationPath? | '//' RelativeLocationPath
45 * [4] RelativeLocationPath ::= Step | RelativeLocationPath '/' Step | RelativeLocationPath '//' Step
46 * [5] Step ::= '@'? NodeTest Predicate* | '.' | '..'
47 * [6] NodeTest ::= NameTest | NodeType '(' ')'
Michal Vaskod3678892020-05-21 10:06:58 +020048 * [7] NameTest ::= '*' | NCName ':' '*' | QName
49 * [8] NodeType ::= 'text' | 'node'
50 * [9] Predicate ::= '[' Expr ']'
51 * [10] PrimaryExpr ::= '(' Expr ')' | Literal | Number | FunctionCall
52 * [11] FunctionCall ::= FunctionName '(' ( Expr ( ',' Expr )* )? ')'
53 * [12] PathExpr ::= LocationPath | PrimaryExpr Predicate*
Radek Krejcib1646a92018-11-02 16:08:26 +010054 * | PrimaryExpr Predicate* '/' RelativeLocationPath
55 * | PrimaryExpr Predicate* '//' RelativeLocationPath
Michal Vaskod3678892020-05-21 10:06:58 +020056 * [13] OrExpr ::= AndExpr | OrExpr 'or' AndExpr
57 * [14] AndExpr ::= EqualityExpr | AndExpr 'and' EqualityExpr
58 * [15] EqualityExpr ::= RelationalExpr | EqualityExpr '=' RelationalExpr
Radek Krejcib1646a92018-11-02 16:08:26 +010059 * | EqualityExpr '!=' RelationalExpr
Michal Vaskod3678892020-05-21 10:06:58 +020060 * [16] RelationalExpr ::= AdditiveExpr
Radek Krejcib1646a92018-11-02 16:08:26 +010061 * | RelationalExpr '<' AdditiveExpr
62 * | RelationalExpr '>' AdditiveExpr
63 * | RelationalExpr '<=' AdditiveExpr
64 * | RelationalExpr '>=' AdditiveExpr
Michal Vaskod3678892020-05-21 10:06:58 +020065 * [17] AdditiveExpr ::= MultiplicativeExpr
Radek Krejcib1646a92018-11-02 16:08:26 +010066 * | AdditiveExpr '+' MultiplicativeExpr
67 * | AdditiveExpr '-' MultiplicativeExpr
Michal Vaskod3678892020-05-21 10:06:58 +020068 * [18] MultiplicativeExpr ::= UnaryExpr
Radek Krejcib1646a92018-11-02 16:08:26 +010069 * | MultiplicativeExpr '*' UnaryExpr
70 * | MultiplicativeExpr 'div' UnaryExpr
71 * | MultiplicativeExpr 'mod' UnaryExpr
Michal Vaskod3678892020-05-21 10:06:58 +020072 * [19] UnaryExpr ::= UnionExpr | '-' UnaryExpr
73 * [20] UnionExpr ::= PathExpr | UnionExpr '|' PathExpr
Radek Krejcib1646a92018-11-02 16:08:26 +010074 */
75
76/* expression tokens allocation */
77#define LYXP_EXPR_SIZE_START 10
78#define LYXP_EXPR_SIZE_STEP 5
79
80/* XPath matches allocation */
81#define LYXP_SET_SIZE_START 2
82#define LYXP_SET_SIZE_STEP 2
83
84/* building string when casting */
85#define LYXP_STRING_CAST_SIZE_START 64
86#define LYXP_STRING_CAST_SIZE_STEP 16
87
88/**
89 * @brief Tokens that can be in an XPath expression.
90 */
91enum lyxp_token {
92 LYXP_TOKEN_NONE = 0,
93 LYXP_TOKEN_PAR1, /* '(' */
94 LYXP_TOKEN_PAR2, /* ')' */
95 LYXP_TOKEN_BRACK1, /* '[' */
96 LYXP_TOKEN_BRACK2, /* ']' */
97 LYXP_TOKEN_DOT, /* '.' */
98 LYXP_TOKEN_DDOT, /* '..' */
99 LYXP_TOKEN_AT, /* '@' */
100 LYXP_TOKEN_COMMA, /* ',' */
101 /* LYXP_TOKEN_DCOLON, * '::' * axes not supported */
102 LYXP_TOKEN_NAMETEST, /* NameTest */
103 LYXP_TOKEN_NODETYPE, /* NodeType */
104 LYXP_TOKEN_FUNCNAME, /* FunctionName */
Michal Vasko3e48bf32020-06-01 08:39:07 +0200105 LYXP_TOKEN_OPER_LOG, /* Operator 'and', 'or' */
106 LYXP_TOKEN_OPER_EQUAL, /* Operator '=' */
107 LYXP_TOKEN_OPER_NEQUAL, /* Operator '!=' */
108 LYXP_TOKEN_OPER_COMP, /* Operator '<', '<=', '>', '>=' */
109 LYXP_TOKEN_OPER_MATH, /* Operator '+', '-', '*', 'div', 'mod', '-' (unary) */
110 LYXP_TOKEN_OPER_UNI, /* Operator '|' */
111 LYXP_TOKEN_OPER_PATH, /* Operator '/' */
112 LYXP_TOKEN_OPER_RPATH, /* Operator '//' (recursive path) */
Radek Krejcib1646a92018-11-02 16:08:26 +0100113 /* LYXP_TOKEN_AXISNAME, * AxisName * axes not supported */
114 LYXP_TOKEN_LITERAL, /* Literal - with either single or double quote */
115 LYXP_TOKEN_NUMBER /* Number */
116};
117
118/**
119 * @brief XPath (sub)expressions that can be repeated.
120 */
121enum lyxp_expr_type {
122 LYXP_EXPR_NONE = 0,
123 LYXP_EXPR_OR,
124 LYXP_EXPR_AND,
125 LYXP_EXPR_EQUALITY,
126 LYXP_EXPR_RELATIONAL,
127 LYXP_EXPR_ADDITIVE,
128 LYXP_EXPR_MULTIPLICATIVE,
129 LYXP_EXPR_UNARY,
130 LYXP_EXPR_UNION,
131};
132
133/**
Michal Vasko03ff5a72019-09-11 13:49:33 +0200134 * @brief Types of context nodes, #LYXP_NODE_ROOT_CONFIG used only in when or must conditions.
135 */
136enum lyxp_node_type {
Michal Vasko2caefc12019-11-14 16:07:56 +0100137 LYXP_NODE_NONE, /* invalid node type */
138
Michal Vasko03ff5a72019-09-11 13:49:33 +0200139 /* XML document roots */
140 LYXP_NODE_ROOT, /* access to all the data (node value first top-level node) */
141 LYXP_NODE_ROOT_CONFIG, /* <running> data context, no state data (node value first top-level node) */
142
143 /* XML elements */
Michal Vasko9f96a052020-03-10 09:41:45 +0100144 LYXP_NODE_ELEM, /* YANG data element (most common) */
145 LYXP_NODE_TEXT, /* YANG data text element (extremely specific use, unlikely to be ever needed) */
146 LYXP_NODE_META /* YANG metadata (do not use for the context node) */
Michal Vasko03ff5a72019-09-11 13:49:33 +0200147};
148
149/**
Radek Krejcib1646a92018-11-02 16:08:26 +0100150 * @brief Structure holding a parsed XPath expression.
151 */
152struct lyxp_expr {
153 enum lyxp_token *tokens; /* array of tokens */
154 uint16_t *tok_pos; /* array of the token offsets in expr */
155 uint16_t *tok_len; /* array of token lengths in expr */
156 enum lyxp_expr_type **repeat; /* array of expression types that this token begins and is repeated ended with 0,
157 more in the comment after this declaration */
158 uint16_t used; /* used array items */
159 uint16_t size; /* allocated array items */
160
161 const char *expr; /* the original XPath expression */
162};
163
164/*
165 * lyxp_expr repeat
166 *
167 * This value is NULL for all the tokens that do not begin an
168 * expression which can be repeated. Otherwise it is an array
169 * of expression types that this token begins. These values
170 * are used during evaluation to know whether we need to
171 * duplicate the current context or not and to decide what
172 * the current expression is (for example, if we are only
173 * starting the parsing and the first token has no repeat,
174 * we do not parse it as an OrExpr but directly as PathExpr).
175 * Examples:
176 *
177 * Expression: "/ *[key1 and key2 or key1 < key2]"
178 * Tokens: '/', '*', '[', NameTest, 'and', NameTest, 'or', NameTest, '<', NameTest, ']'
179 * Repeat: NULL, NULL, NULL, [AndExpr, NULL, NULL, NULL, [RelationalExpr, NULL, NULL, NULL
180 * OrExpr, 0],
181 * 0],
182 *
183 * Expression: "//node[key and node2]/key | /cont"
184 * Tokens: '//', 'NameTest', '[', 'NameTest', 'and', 'NameTest', ']', '/', 'NameTest', '|', '/', 'NameTest'
185 * Repeat: [UnionExpr, NULL, NULL, [AndExpr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
186 * 0], 0],
187 *
188 * Operators between expressions which this concerns:
189 * 'or', 'and', '=', '!=', '<', '>', '<=', '>=', '+', '-', '*', 'div', 'mod', '|'
190 */
191
192/**
193 * @brief Supported types of (partial) XPath results.
194 */
195enum lyxp_set_type {
Michal Vaskod3678892020-05-21 10:06:58 +0200196 LYXP_SET_NODE_SET = 0,
Michal Vasko03ff5a72019-09-11 13:49:33 +0200197 LYXP_SET_SCNODE_SET,
Radek Krejcib1646a92018-11-02 16:08:26 +0100198 LYXP_SET_BOOLEAN,
199 LYXP_SET_NUMBER,
200 LYXP_SET_STRING
201};
Radek Krejcib1646a92018-11-02 16:08:26 +0100202
203/**
204 * @brief Item stored in an XPath set hash table.
205 */
206struct lyxp_set_hash_node {
207 struct lyd_node *node;
208 enum lyxp_node_type type;
209} _PACKED;
210
Radek Krejcib1646a92018-11-02 16:08:26 +0100211/**
212 * @brief XPath set - (partial) result.
213 */
214struct lyxp_set {
215 enum lyxp_set_type type;
216 union {
217 struct lyxp_set_node {
218 struct lyd_node *node;
219 enum lyxp_node_type type;
220 uint32_t pos;
221 } *nodes;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200222 struct lyxp_set_scnode {
223 struct lysc_node *scnode;
Radek Krejcib1646a92018-11-02 16:08:26 +0100224 enum lyxp_node_type type;
Michal Vasko5c4e5892019-11-14 12:31:38 +0100225 /* -2 - scnode not traversed, currently (the only node) in context;
226 * -1 - scnode not traversed except for the eval start, not currently in the context;
227 * 0 - scnode was traversed, but not currently in the context;
228 * 1 - scnode currently in context;
229 * 2 - scnode in context and just added, so skip it for the current operation;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200230 * >=3 - scnode is not in context because we are in a predicate and this scnode was used/will be used later */
Michal Vasko5c4e5892019-11-14 12:31:38 +0100231 int32_t in_ctx;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200232 } *scnodes;
Michal Vasko9f96a052020-03-10 09:41:45 +0100233 struct lyxp_set_meta {
234 struct lyd_meta *meta;
Radek Krejcib1646a92018-11-02 16:08:26 +0100235 enum lyxp_node_type type;
Michal Vasko9f96a052020-03-10 09:41:45 +0100236 uint32_t pos; /* if node_type is LYXP_SET_NODE_META, it is the parent node position */
237 } *meta;
Radek Krejcib1646a92018-11-02 16:08:26 +0100238 char *str;
239 long double num;
Michal Vasko004d3152020-06-11 19:59:22 +0200240 int bln;
Radek Krejcib1646a92018-11-02 16:08:26 +0100241 } val;
242
Michal Vasko03ff5a72019-09-11 13:49:33 +0200243 /* this is valid only for type LYXP_SET_NODE_SET and LYXP_SET_SCNODE_SET */
Radek Krejcib1646a92018-11-02 16:08:26 +0100244 uint32_t used;
245 uint32_t size;
Radek Krejcib1646a92018-11-02 16:08:26 +0100246 struct hash_table *ht;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200247
248 /* XPath context information, this is valid only for type LYXP_SET_NODE_SET */
Radek Krejcib1646a92018-11-02 16:08:26 +0100249 uint32_t ctx_pos;
250 uint32_t ctx_size;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200251
252 /* general context */
253 struct ly_ctx *ctx;
254 union {
255 const struct lyd_node *ctx_node;
256 const struct lysc_node *ctx_scnode;
257 };
Michal Vasko5e0e6eb2019-11-06 15:47:50 +0100258 enum lyxp_node_type root_type;
Michal Vasko6b26e742020-07-17 15:02:10 +0200259 const struct lysc_node *context_op;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200260 const struct lys_module *local_mod;
Michal Vaskof03ed032020-03-04 13:31:44 +0100261 const struct lyd_node *tree;
Michal Vasko03ff5a72019-09-11 13:49:33 +0200262 LYD_FORMAT format;
Radek Krejcib1646a92018-11-02 16:08:26 +0100263};
264
265/**
Michal Vasko24cddf82020-06-01 08:17:01 +0200266 * @brief Print an XPath token \p tok type.
267 *
268 * @param[in] tok Token to print.
269 * @return Token type string.
270 */
271const char *lyxp_print_token(enum lyxp_token tok);
272
273/**
Michal Vasko03ff5a72019-09-11 13:49:33 +0200274 * @brief Evaluate an XPath expression on data. Be careful when using this function, the result can often
275 * be confusing without thorough understanding of XPath evaluation rules defined in RFC 7950.
Radek Krejcib1646a92018-11-02 16:08:26 +0100276 *
Michal Vaskoecd62de2019-11-13 12:35:11 +0100277 * @param[in] exp Parsed XPath expression to be evaluated.
Michal Vasko03ff5a72019-09-11 13:49:33 +0200278 * @param[in] format Format of the XPath expression (more specifcally, of any used prefixes).
279 * @param[in] local_mod Local module relative to the @p expr.
Michal Vasko004d3152020-06-11 19:59:22 +0200280 * @param[in] ctx_node Current (context) data node. In case of a root node, set @p ctx_node_type correctly,
281 * but @p ctx_node must also be set to any node from the root node module - it will be used for resolving
282 * unqualified names.
283 * @param[in] ctx_node_type Current (context) data node type.
Michal Vaskof03ed032020-03-04 13:31:44 +0100284 * @param[in] tree Data tree on which to perform the evaluation, it must include all the available data (including
Michal Vaskod0aa1a82019-11-07 08:58:42 +0100285 * the tree of @p ctx_node).
Michal Vasko004d3152020-06-11 19:59:22 +0200286 * @param[out] set Result set.
Radek Krejcib1646a92018-11-02 16:08:26 +0100287 * @param[in] options Whether to apply some evaluation restrictions.
Michal Vasko004d3152020-06-11 19:59:22 +0200288 * @return LY_EVALID for invalid argument types/count,
289 * @return LY_EINCOMPLETE for unresolved when,
290 * @return LY_EINVAL, LY_EMEM, LY_EINT for other errors.
Radek Krejcib1646a92018-11-02 16:08:26 +0100291 */
Michal Vaskoecd62de2019-11-13 12:35:11 +0100292LY_ERR lyxp_eval(struct lyxp_expr *exp, LYD_FORMAT format, const struct lys_module *local_mod, const struct lyd_node *ctx_node,
Michal Vaskof03ed032020-03-04 13:31:44 +0100293 enum lyxp_node_type ctx_node_type, const struct lyd_node *tree, struct lyxp_set *set, int options);
Michal Vasko03ff5a72019-09-11 13:49:33 +0200294
Michal Vasko004d3152020-06-11 19:59:22 +0200295#define LYXP_SCHEMA 0x01 /**< Apply data node access restrictions defined for 'when' and 'must' evaluation. */
Radek Krejcib1646a92018-11-02 16:08:26 +0100296
297/**
Michal Vasko03ff5a72019-09-11 13:49:33 +0200298 * @brief Get all the partial XPath nodes (atoms) that are required for @p exp to be evaluated.
Radek Krejcib1646a92018-11-02 16:08:26 +0100299 *
Michal Vasko03ff5a72019-09-11 13:49:33 +0200300 * @param[in] exp Parsed XPath expression to be evaluated.
301 * @param[in] format Format of the XPath expression (more specifcally, of any used prefixes).
302 * @param[in] local_mod Local module relative to the @p exp.
Michal Vasko004d3152020-06-11 19:59:22 +0200303 * @param[in] ctx_scnode Current (context) schema node. In case of a root node, set @p ctx_scnode_type correctly,
304 * but @p ctx_scnode must also be set to any node from the root node module - it will be used for resolving
305 * unqualified names.
Michal Vasko03ff5a72019-09-11 13:49:33 +0200306 * @param[in] ctx_scnode_type Current (context) schema node type.
Michal Vasko004d3152020-06-11 19:59:22 +0200307 * @param[out] set Result set.
Radek Krejcib1646a92018-11-02 16:08:26 +0100308 * @param[in] options Whether to apply some evaluation restrictions, one flag must always be used.
Michal Vaskoecd62de2019-11-13 12:35:11 +0100309 * @return LY_ERR (same as lyxp_eval()).
Radek Krejcib1646a92018-11-02 16:08:26 +0100310 */
Michal Vasko03ff5a72019-09-11 13:49:33 +0200311LY_ERR lyxp_atomize(struct lyxp_expr *exp, LYD_FORMAT format, const struct lys_module *local_mod, const struct lysc_node *ctx_scnode,
312 enum lyxp_node_type ctx_scnode_type, struct lyxp_set *set, int options);
Radek Krejcib1646a92018-11-02 16:08:26 +0100313
Michal Vasko519fd602020-05-26 12:17:39 +0200314/* used only internally */
Michal Vasko03ff5a72019-09-11 13:49:33 +0200315#define LYXP_SCNODE_ALL 0x0E
Radek Krejcib1646a92018-11-02 16:08:26 +0100316
317/**
Radek Krejcib1646a92018-11-02 16:08:26 +0100318 * @brief Cast XPath set to another type.
319 * Indirectly context position aware.
320 *
321 * @param[in] set Set to cast.
322 * @param[in] target Target type to cast \p set into.
Michal Vasko03ff5a72019-09-11 13:49:33 +0200323 * @return LY_ERR
Radek Krejcib1646a92018-11-02 16:08:26 +0100324 */
Michal Vasko5e0e6eb2019-11-06 15:47:50 +0100325LY_ERR lyxp_set_cast(struct lyxp_set *set, enum lyxp_set_type target);
Michal Vasko03ff5a72019-09-11 13:49:33 +0200326
Radek Krejcib1646a92018-11-02 16:08:26 +0100327/**
Michal Vaskod3678892020-05-21 10:06:58 +0200328 * @brief Free dynamic content of a set.
329 *
330 * @param[in] set Set to modify.
331 */
332void lyxp_set_free_content(struct lyxp_set *set);
333
334/**
Michal Vaskoecd62de2019-11-13 12:35:11 +0100335 * @brief Insert schema node into set.
336 *
337 * @param[in] set Set to insert into.
338 * @param[in] node Node to insert.
339 * @param[in] node_type Node type of @p node.
340 * @return Index of the inserted node in set.
341 */
342int lyxp_set_scnode_insert_node(struct lyxp_set *set, const struct lysc_node *node, enum lyxp_node_type node_type);
343
344/**
345 * @brief Check for duplicates in a schema node set.
346 *
347 * @param[in] set Set to check.
348 * @param[in] node Node to look for in @p set.
349 * @param[in] node_type Type of @p node.
350 * @param[in] skip_idx Index from @p set to skip.
351 * @return Index of the found node, -1 if not found.
352 */
353int lyxp_set_scnode_dup_node_check(struct lyxp_set *set, const struct lysc_node *node, enum lyxp_node_type node_type,
354 int skip_idx);
355
356/**
357 * @brief Merge 2 schema node sets.
358 *
359 * @param[in] set1 Set to merge into.
360 * @param[in] set2 Set to merge. Its content is freed.
361 */
362void lyxp_set_scnode_merge(struct lyxp_set *set1, struct lyxp_set *set2);
363
364/**
Radek Krejcib1646a92018-11-02 16:08:26 +0100365 * @brief Parse an XPath expression into a structure of tokens.
366 * Logs directly.
367 *
Michal Vasko03ff5a72019-09-11 13:49:33 +0200368 * https://www.w3.org/TR/1999/REC-xpath-19991116/#exprlex
Radek Krejcib1646a92018-11-02 16:08:26 +0100369 *
370 * @param[in] ctx Context for errors.
371 * @param[in] expr XPath expression to parse. It is duplicated.
Michal Vasko004d3152020-06-11 19:59:22 +0200372 * @param[in] expr_len Length of @p expr, can be 0 if @p expr is 0-terminated.
373 * @param[in] reparse Whether to re-parse the expression to finalize full XPath parsing and fill
374 * information about expressions and their operators (fill repeat).
Radek Krejcib1646a92018-11-02 16:08:26 +0100375 * @return Filled expression structure or NULL on error.
376 */
Michal Vasko004d3152020-06-11 19:59:22 +0200377struct lyxp_expr *lyxp_expr_parse(const struct ly_ctx *ctx, const char *expr, size_t expr_len, int reparse);
378
379/**
380 * @brief Duplicate parsed XPath expression.
381 *
382 * @param[in] ctx Context with a dictionary.
383 * @param[in] exp Parsed expression.
384 * @return Duplicated structure, NULL on error.
385 */
386struct lyxp_expr *lyxp_expr_dup(const struct ly_ctx *ctx, const struct lyxp_expr *exp);
Michal Vasko14676352020-05-29 11:35:55 +0200387
388/**
389 * @brief Look at the next token and check its kind.
390 *
391 * @param[in] ctx Context for logging, not logged if NULL.
392 * @param[in] exp Expression to use.
Michal Vasko004d3152020-06-11 19:59:22 +0200393 * @param[in] tok_idx Token index in the expression \p exp.
Michal Vasko14676352020-05-29 11:35:55 +0200394 * @param[in] want_tok Expected token.
395 * @return LY_EINCOMPLETE on EOF,
396 * @return LY_ENOT on non-matching token,
397 * @return LY_SUCCESS on success.
398 */
Michal Vasko004d3152020-06-11 19:59:22 +0200399LY_ERR lyxp_check_token(const struct ly_ctx *ctx, const struct lyxp_expr *exp, uint16_t tok_idx, enum lyxp_token want_tok);
400
401/**
402 * @brief Look at the next token and skip it if it matches the expected one.
403 *
404 * @param[in] ctx Context for logging, not logged if NULL.
405 * @param[in] exp Expression to use.
406 * @param[in,out] tok_idx Token index in the expression \p exp, is updated.
407 * @param[in] want_tok Expected token.
408 * @return LY_EINCOMPLETE on EOF,
409 * @return LY_ENOT on non-matching token,
410 * @return LY_SUCCESS on success.
411 */
412LY_ERR lyxp_next_token(const struct ly_ctx *ctx, const struct lyxp_expr *exp, uint16_t *tok_idx, enum lyxp_token want_tok);
Radek Krejcib1646a92018-11-02 16:08:26 +0100413
414/**
Michal Vasko03ff5a72019-09-11 13:49:33 +0200415 * @brief Frees a parsed XPath expression. @p expr should not be used afterwards.
Radek Krejcib1646a92018-11-02 16:08:26 +0100416 *
417 * @param[in] ctx libyang context of the expression.
418 * @param[in] expr Expression to free.
419 */
Michal Vasko14676352020-05-29 11:35:55 +0200420void lyxp_expr_free(const struct ly_ctx *ctx, struct lyxp_expr *expr);
Radek Krejcib1646a92018-11-02 16:08:26 +0100421
Michal Vasko14676352020-05-29 11:35:55 +0200422#endif /* LY_XPATH_H */