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/**
* @file xpath.h
* @author Rastislav Szabo <raszabo@cisco.com>, Lukas Macko <lmacko@cisco.com>
* @brief Sysrepo helpers for node's address manipulation.
*
* @copyright
* Copyright 2015 Cisco Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SYSREPO_XPATH_H_
#define SYSREPO_XPATH_H_
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup xpath_utils XPath Processing Utilities
* @{
*
* @brief Set of helpers working on a subset of xpath expressions used of node identification
* Functions modify inputs arguments by placing termination zero at appropriate places to save up
* string duplication. The state of processing is stored in ::sr_xpath_ctx_t opaque for user.
* It allows to continue in processing where the processing stopped or recover processed input.
*
* Similarly to strtok function in all subsequent calls that is supposed to work with the same
* input xpath must be NULL.
*/
/**
* @brief State of xpath parsing. User must not modify nor rely on the content
* of the structure.
*/
typedef struct sr_xpath_ctx_s {
char *begining; /**< Pointer to the begining of the processed string */
char *current_node; /**< Pointer to the currently processed node, used as a context for key search */
char *replaced_position; /**< Pointer to the posistion where the last terminating 0 by was written */
char replaced_char; /**< Character that was overwritten by the last termination 0 */
} sr_xpath_ctx_t;
/**
* @brief The function returns a pointer to the following node. If xpath is
* not NULL returns the first node name, otherwise returns the subsequent node
* according to the state.
*
* The state is modified upon function successful return from function, so the subsequent
* calls can continue in processing or xpath can be recovered by calling ::sr_xpath_recover.
*
* @note It writes terminating zero at the and of the node name.
*
* @note Skips the namespace if it is present to get node name qualified by namespace use ::sr_xpath_next_node_with_ns
*
* @param [in] xpath - xpath to be processed, can be NULL
* @param [in] state
* @return Pointer to the node name, NULL if there are no more node names
*/
char *sr_xpath_next_node(char *xpath, sr_xpath_ctx_t *state);
/**
* @brief Returns pointer to the last node.
* @param [in] xpath
* @param [in] state
* @return Pointer to the last node
*/
char *sr_xpath_last_node(char *xpath, sr_xpath_ctx_t *state);
/**
* @brief Same as ::sr_xpath_next_node with the difference that namespace is included in result if present in xpath
*
* @param [in] xpath - xpath to be processed, can be NULL if the user wants to continue in processing of previous input
* @param [in] state
* @return Pointer to the node name including namespace, NULL if there are no more node names
*/
char *sr_xpath_next_node_with_ns(char *xpath, sr_xpath_ctx_t *state);
/**
* @brief Returns the name of the next key at the current level in processed xpath.
*
* @param [in] xpath
* @param [in] state
* @return Pointer to the key name, NULL if there are no more keys at the current level
*/
char *sr_xpath_next_key_name(char *xpath, sr_xpath_ctx_t *state);
/**
* @brief Returns the value of the next key at the current level in processed xpath.
*
* @param [in] xpath
* @param [in] state
* @return Pointer to the key value, NULL if there are no more keys at the current level
*/
char *sr_xpath_next_key_value(char *xpath, sr_xpath_ctx_t *state);
/**
* @brief Returns a pointer to the node specified by name. It searches from the beginning of the xpath, returns first match.
* Can be used to jump at the desired node xpath and subsequent analysis of key values.
*
* @param [in] xpath
* @param [in] node_name
* @param [in] state
* @return Pointer to the node, NULL if the node with the specified name is not found
*/
char *sr_xpath_node(char *xpath, const char *node_name, sr_xpath_ctx_t *state);
/**
* @brief Similar to ::sr_xpath_node. The difference is that search start at current node
* according to the state.
*
* @param [in] xpath
* @param [in] node_name
* @param [in] state
* @return Pointer to the node, NULL if the node with the specified name is not found
*/
char *sr_xpath_node_rel(char *xpath, const char *node_name, sr_xpath_ctx_t *state);
/**
* @brief Returns node specified by index starting at the begin of expression.
* First node has index 0.
*
* @param [in] xpath
* @param [in] index
* @param [in] state
* @return Pointer to the specified node, NULL if the index is out of bounds
*/
char *sr_xpath_node_idx(char *xpath, size_t index, sr_xpath_ctx_t *state);
/**
* @brief Return node specified by index. Following node has index zero.
*
* @param [in] xpath
* @param [in] index
* @param [in] state
* @return Pointer to the specified node, NULL if the index is out of bounds
*/
char *sr_xpath_node_idx_rel(char *xpath, size_t index, sr_xpath_ctx_t *state);
/**
* @brief Looks up the value for the key at the current level in xpath.
*
* @param [in] xpath
* @param [in] key - key name to be looked up
* @param [in] state
* @return Key value, NULL if the key with the specified name is not found
*/
char *sr_xpath_node_key_value(char *xpath, const char *key, sr_xpath_ctx_t *state);
/**
* @brief Looks up the value for the key at the current level in xpath specified by index.
* First key has index zero.
*
* @param [in] xpath
* @param [in] index
* @param [in] state
* @return Key value, NULL if the index is out of bound
*/
char *sr_xpath_node_key_value_idx(char *xpath, size_t index, sr_xpath_ctx_t *state);
/**
* @brief Looks up the value of the key in a node specified by name.
*
* @param [in] xpath
* @param [in] node_name
* @param [in] key_name
* @param [in] state
* @return Pointer to the key value, NULL if not found
*/
char *sr_xpath_key_value(char *xpath, const char *node_name, const char *key_name, sr_xpath_ctx_t *state);
/**
* @brief Looks up the value of the key in a node specified by index. First node has index zero.
*
* @param [in] xpath
* @param [in] node_index
* @param [in] key_index
* @param [in] state
* @return Pointer to the key value, NULL if not found or index out of bound
*/
char *sr_xpath_key_value_idx(char *xpath, size_t node_index, size_t key_index, sr_xpath_ctx_t *state);
/**
* @brief Returns pointer to the string after the last slash in xpath (node name).
*
* @note The returned string can also contain namespace and/or key values
* if they were specified for the last node in xpath.
*
* @param [in] xpath
* @return Result, NULL in case of the slash was not found
*/
char *sr_xpath_node_name(const char *xpath);
/**
* @brief Compares string after the last slash in xpath (node name) with provided string.
*
* @note The returned string can also contain namespace and/or key values
* if they were specified for the last node in xpath.
*
* @param [in] xpath
* @param [in] node_str String to test for equality.
* @return true in case that the Node names are equal, false otherwise
*/
bool sr_xpath_node_name_eq(const char *xpath, const char *node_str);
/**
* @brief Recovers the xpath string to the original state (puts back the character
* that was replaced by termination zero).
*
* @param [in] state
*/
void sr_xpath_recover(sr_xpath_ctx_t *state);
/**@} xpath_utils */
#ifdef __cplusplus
}
#endif
#endif /* SYSREPO_XPATH_H_ */
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