MongoDB C++ Driver  mongocxx-3.0.3
sub_document.hpp
1 // Copyright 2014 MongoDB Inc.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 #include <bsoncxx/builder/basic/helpers.hpp>
18 #include <bsoncxx/builder/concatenate.hpp>
19 #include <bsoncxx/builder/core.hpp>
20 #include <bsoncxx/stdx/string_view.hpp>
21 
22 #include <bsoncxx/config/prelude.hpp>
23 
24 namespace bsoncxx {
25 BSONCXX_INLINE_NAMESPACE_BEGIN
26 namespace builder {
27 namespace basic {
28 
29 namespace impl {
30 template <typename T>
31 void value_append(core* core, T&& t);
32 } // namespace impl
33 
38 class sub_document {
39  public:
40  BSONCXX_INLINE sub_document(core* core) : _core(core) {
41  }
42 
46  template <typename Arg, typename... Args>
47  BSONCXX_INLINE void append(Arg&& a, Args&&... args) {
48  append_(std::forward<Arg>(a));
49  append(std::forward<Args>(args)...);
50  }
51 
55  BSONCXX_INLINE
56  void append() {
57  }
58 
59  private:
60  //
61  // Appends a basic::kvp where the key is a non-owning string view.
62  //
63  template <typename K, typename V>
64  BSONCXX_INLINE typename std::enable_if<
65  std::is_same<typename std::decay<K>::type, stdx::string_view>::value>::type
66  append_(std::tuple<K, V>&& t) {
67  _core->key_view(std::forward<K>(std::get<0>(t)));
68  impl::value_append(_core, std::forward<V>(std::get<1>(t)));
69  }
70 
71  //
72  // Appends a basic::kvp where the key is an owning STL string.
73  //
74  template <typename K, typename V>
75  BSONCXX_INLINE typename std::enable_if<
76  std::is_same<typename std::decay<K>::type, std::string>::value>::type
77  append_(std::tuple<K, V>&& t) {
78  _core->key_owned(std::forward<K>(std::get<0>(t)));
79  impl::value_append(_core, std::forward<V>(std::get<1>(t)));
80  }
81 
82  //
83  // Appends a basic::kvp where the key is a string literal
84  //
85  template <std::size_t n, typename V>
86  BSONCXX_INLINE void append_(std::tuple<const char(&)[n], V>&& t) {
87  _core->key_view(stdx::string_view{std::get<0>(t), n - 1});
88  impl::value_append(_core, std::forward<V>(std::get<1>(t)));
89  }
90 
91  //
92  // Concatenates another bson document directly.
93  //
94  BSONCXX_INLINE
95  void append_(concatenate_doc doc) {
96  _core->concatenate(doc);
97  }
98 
99  core* _core;
100 };
101 
102 } // namespace basic
103 } // namespace builder
104 BSONCXX_INLINE_NAMESPACE_END
105 } // namespace bsoncxx
106 
107 #include <bsoncxx/config/postlude.hpp>
A low-level interface for constructing BSON documents and arrays.
Definition: core.hpp:42
void append(Arg &&a, Args &&...args)
Appends multiple basic::kvp key-value pairs.
Definition: sub_document.hpp:47
An internal class of builder::basic.
Definition: sub_document.hpp:38
void key_owned(std::string key)
Appends a key passed as a STL string.
void key_view(stdx::string_view key)
Appends a key passed as a non-owning stdx::string_view.
void append()
Inductive base-case for the variadic append(...)
Definition: sub_document.hpp:56
void concatenate(const document::view &view)
Appends the keys from a BSON document into this BSON datum.
Definition: element.hpp:24