ceph/src/seastar/include/seastar/util/program-options.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18 /*
  19  * Copyright (C) 2017 ScyllaDB
  20  */
  21
  22 #pragma once
  23
  24 #include <seastar/core/sstring.hh>
  25
  26 #include <boost/any.hpp>
  27 #include <boost/program_options.hpp>
  28
  29 #include <string>
  30 #include <unordered_map>
  31 #include <vector>
  32
  33 namespace seastar {
  34
  35 namespace program_options {
  36
  37 ///
  38 /// \brief Wrapper for command-line options with arbitrary string associations.
  39 ///
  40 /// This type, to be used with Boost.Program_options, will result in an option that stores an arbitrary number of
  41 /// string associations.
  42 ///
  43 /// Values are specified in the form "key0=value0:[key1=value1:...]". Options of this type can be specified multiple
  44 /// times, and the values will be merged (with the last-provided value for a key taking precedence).
  45 ///
  46 /// \note We need a distinct type (rather than a simple type alias) for overload resolution in the implementation, but
  47 /// advertizing our inheritance of \c std::unordered_map would introduce the possibility of memory leaks since STL
  48 /// containers do not declare virtual destructors.
  49 ///
  50 class string_map final : private std::unordered_map<sstring, sstring> {
  51 private:
  52     using base = std::unordered_map<sstring, sstring>;
  53 public:
  54     using base::value_type;
  55     using base::key_type;
  56     using base::mapped_type;
  57
  58     using base::base;
  59     using base::at;
  60     using base::find;
  61     using base::count;
  62     using base::emplace;
  63     using base::clear;
  64     using base::operator[];
  65     using base::begin;
  66     using base::end;
  67
  68     friend bool operator==(const string_map&, const string_map&);
  69     friend bool operator!=(const string_map&, const string_map&);
  70 };
  71
  72 inline bool operator==(const string_map& lhs, const string_map& rhs) {
  73     return static_cast<const string_map::base&>(lhs) == static_cast<const string_map::base&>(rhs);
  74 }
  75
  76 inline bool operator!=(const string_map& lhs, const string_map& rhs) {
  77     return !(lhs == rhs);
  78 }
  79
  80 ///
  81 /// \brief Query the value of a key in a \c string_map, or a default value if the key doesn't exist.
  82 ///
  83 sstring get_or_default(const string_map&, const sstring& key, const sstring& def = sstring());
  84
  85 std::istream& operator>>(std::istream& is, string_map&);
  86 std::ostream& operator<<(std::ostream& os, const string_map&);
  87
  88 /// \cond internal
  89
  90 //
  91 // Required implementation hook for Boost.Program_options.
  92 //
  93 void validate(boost::any& out, const std::vector<std::string>& in, string_map*, int);
  94
  95 /// \endcond
  96
  97 }
  98
  99 }