ceph/src/common/str_map.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2013 Cloudwatt <libre.licensing@cloudwatt.com>
   7  *
   8  * Author: Loic Dachary <loic@dachary.org>
   9  *
  10  *  This library is free software; you can redistribute it and/or
  11  *  modify it under the terms of the GNU Lesser General Public
  12  *  License as published by the Free Software Foundation; either
  13  *  version 2.1 of the License, or (at your option) any later version.
  14  *
  15  */
  16
  17 #include <errno.h>
  18
  19 #include "include/str_map.h"
  20 #include "include/str_list.h"
  21
  22 #include "json_spirit/json_spirit.h"
  23
  24 using namespace std;
  25
  26 int get_json_str_map(
  27     const string &str,
  28     ostream &ss,
  29     map<string,string> *str_map,
  30     bool fallback_to_plain)
  31 {
  32   json_spirit::mValue json;
  33   try {
  34     // try json parsing first
  35
  36     json_spirit::read_or_throw(str, json);
  37
  38     if (json.type() != json_spirit::obj_type) {
  39       ss << str << " must be a JSON object but is of type "
  40          << json.type() << " instead";
  41       return -EINVAL;
  42     }
  43
  44     json_spirit::mObject o = json.get_obj();
  45
  46     for (map<string, json_spirit::mValue>::iterator i = o.begin();
  47          i != o.end();
  48          ++i) {
  49       (*str_map)[i->first] = i->second.get_str();
  50     }
  51   } catch (json_spirit::Error_position &e) {
  52     if (fallback_to_plain) {
  53       // fallback to key=value format
  54       get_str_map(str, str_map, "\t\n ");
  55     } else {
  56       return -EINVAL;
  57     }
  58   }
  59   return 0;
  60 }
  61 string trim(const string& str) {
  62   size_t start = 0;
  63   size_t end = str.size() - 1;
  64   while (isspace(str[start]) != 0 && start <= end) {
  65     ++start;
  66   }
  67   while (isspace(str[end]) != 0 && start <= end) {
  68     --end;
  69   }
  70   if (start <= end) {
  71     return str.substr(start, end - start + 1);
  72   }
  73   return string();
  74 }
  75
  76 int get_str_map(
  77     const string &str,
  78     map<string,string> *str_map,
  79     const char *delims)
  80 {
  81   list<string> pairs;
  82   get_str_list(str, delims, pairs);
  83   for (list<string>::iterator i = pairs.begin(); i != pairs.end(); ++i) {
  84     size_t equal = i->find('=');
  85     if (equal == string::npos)
  86       (*str_map)[*i] = string();
  87     else {
  88       const string key = trim(i->substr(0, equal));
  89       equal++;
  90       const string value = trim(i->substr(equal));
  91       (*str_map)[key] = value;
  92     }
  93   }
  94   return 0;
  95 }
  96
  97 string get_str_map_value(
  98     const map<string,string> &str_map,
  99     const string &key,
 100     const string *def_val)
 101 {
 102   map<string,string>::const_iterator p = str_map.find(key);
 103
 104   // key exists in str_map
 105   if (p != str_map.end()) {
 106     // but value is empty
 107     if (p->second.empty())
 108       return p->first;
 109     // and value is not empty
 110     return p->second;
 111   }
 112
 113   // key DNE in str_map and def_val was specified
 114   if (def_val != NULL)
 115     return *def_val;
 116
 117   // key DNE in str_map, no def_val was specified
 118   return string();
 119 }
 120
 121 string get_str_map_key(
 122     const map<string,string> &str_map,
 123     const string &key,
 124     const string *fallback_key)
 125 {
 126   map<string,string>::const_iterator p = str_map.find(key);
 127   if (p != str_map.end())
 128     return p->second;
 129
 130   if (fallback_key != NULL) {
 131     p = str_map.find(*fallback_key);
 132     if (p != str_map.end())
 133       return p->second;
 134   }
 135   return string();
 136 }
 137
 138 // This function's only purpose is to check whether a given map has only
 139 // ONE key with an empty value (which would mean that 'get_str_map()' read
 140 // a map in the form of 'VALUE', without any KEY/VALUE pairs) and, in such
 141 // event, to assign said 'VALUE' to a given 'def_key', such that we end up
 142 // with a map of the form "m = { 'def_key' : 'VALUE' }" instead of the
 143 // original "m = { 'VALUE' : '' }".
 144 int get_conf_str_map_helper(
 145     const string &str,
 146     ostringstream &oss,
 147     map<string,string> *m,
 148     const string &def_key)
 149 {
 150   int r = get_str_map(str, m);
 151
 152   if (r < 0) {
 153     return r;
 154   }
 155
 156   if (r >= 0 && m->size() == 1) {
 157     map<string,string>::iterator p = m->begin();
 158     if (p->second.empty()) {
 159       string s = p->first;
 160       m->erase(s);
 161       (*m)[def_key] = s;
 162     }
 163   }
 164   return r;
 165 }