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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2013 Cloudwatt <libre.licensing@cloudwatt.com>
*
* Author: Loic Dachary <loic@dachary.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
*/
#ifndef CEPH_STRMAP_H
#define CEPH_STRMAP_H
#define CONST_DELIMS ",;\t\n "
#include <map>
#include <string>
#include <sstream>
template <typename Func>
void for_each_pair(std::string_view s, const char* delims, Func&& f)
{
auto pos = s.find_first_not_of(delims);
while (pos != s.npos) {
s.remove_prefix(pos); // trim delims from the front
auto end = s.find_first_of(delims);
auto kv = s.substr(0, end);
if (auto equal = kv.find('='); equal != kv.npos) {
f(kv.substr(0, equal), kv.substr(equal + 1));
} else {
f(kv.substr(0, equal), std::string_view());
}
pos = s.find_first_not_of(delims, end);
}
}
using str_map_t = std::map<std::string,std::string>;
/**
* Parse **str** and set **str_map** with the key/value pairs read
* from it. The format of **str** is either a well formed JSON object
* or a custom key[=value] plain text format.
*
* JSON is tried first. If successfully parsed into a JSON object, it
* is copied into **str_map** verbatim. If it is not a JSON object ( a
* string, integer etc. ), -EINVAL is returned and **ss** is set to
* a human readable error message.
*
* If **str** is no valid JSON and if **fallback_to_plain** is set to true
* (default: true) it is assumed to be a string containing white space
* separated key=value pairs. A white space is either space, tab or newline.
* Function **get_str_map** will be leveraged to parse the plain-text
* key/value pairs.
*
* @param [in] str JSON or plain text key/value pairs
* @param [out] ss human readable message on error
* @param [out] str_map key/value pairs read from str
* @param [in] fallback_to_plain attempt parsing as plain-text if json fails
* @return **0** on success or a -EINVAL on error.
*/
int get_json_str_map(
const std::string &str,
std::ostream &ss,
str_map_t* str_map,
bool fallback_to_plain = true);
/**
* Parse **str** and set **str_map** with the key/value pairs read from
* it. The format of **str** is a number of custom key[=value] pairs in
* plain text format.
*
* The string will be parsed taking **delims** as field delimiters for
* key/values. The value is optional resulting in an empty string when
* not provided. For example, using white space as delimiters:
*
* insert your own=political/ideological statement=here
*
* will be parsed into:
*
* { "insert": "",
* "your": "",
* "own": "political/ideological",
* "statement": "here" }
*
* Alternative delimiters may be provided. For instance, specifying
* "white space and slash", for the above statement, would be parsed
* into:
*
* { "insert": "",
* "your": "",
* "own": "political",
* "ideological": "",
* "statement": "here" }
*
* See how adding '/' to the delimiters field will spawn a new key without
* a set value.
*
* Always returns 0, as there is no condition for failure.
*
* @param [in] str plain text key/value pairs
* @param [in] delims field delimiters to be used for parsing str
* @param [out] str_map key/value pairs parsed from str
* @return **0**
*/
int get_str_map(
const std::string &str,
str_map_t* str_map,
const char *delims = CONST_DELIMS);
// an alternate form (as we never fail):
str_map_t get_str_map(
const std::string& str,
const char* delim = CONST_DELIMS);
/**
* Returns the value of **key** in **str_map** if available.
*
* If **key** is not available in **str_map**, and if **def_val** is
* not-NULL then returns **def_val**. Otherwise checks if the value of
* **key** is an empty string and if so will return **key**.
* If the map contains **key**, the function returns the value of **key**.
*
* @param[in] str_map Map to obtain **key** from
* @param[in] key The key to search for in the map
* @param[in] def_val The value to return in case **key** is not present
*/
std::string get_str_map_value(
const str_map_t& str_map,
const std::string &key,
const std::string *def_val = nullptr);
/**
* Returns the value of **key** in **str_map** if available.
*
* If **key** is available in **str_map** returns the value of **key**.
*
* If **key** is not available in **str_map**, and if **def_key**
* is not-NULL and available in **str_map**, then returns the value
* of **def_key**.
*
* Otherwise returns an empty string.
*
* @param[in] str_map Map to obtain **key** or **def_key** from
* @param[in] key Key to obtain the value of from **str_map**
* @param[in] def_key Key to fallback to if **key** is not present
* in **str_map**
*/
std::string get_str_map_key(
const str_map_t& str_map,
const std::string &key,
const std::string *fallback_key = nullptr);
// This function's only purpose is to check whether a given map has only
// ONE key with an empty value (which would mean that 'get_str_map()' read
// a map in the form of 'VALUE', without any KEY/VALUE pairs) and, in such
// event, to assign said 'VALUE' to a given 'def_key', such that we end up
// with a map of the form "m = { 'def_key' : 'VALUE' }" instead of the
// original "m = { 'VALUE' : '' }".
int get_conf_str_map_helper(
const std::string &str,
std::ostringstream &oss,
str_map_t* str_map,
const std::string &default_key);
std::string get_value_via_strmap(
const std::string& conf_string,
std::string_view default_key);
std::string get_value_via_strmap(
const std::string& conf_string,
const std::string& key,
std::string_view default_key);
#endif
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