MongoDB C++ Driver  mongocxx-3.0.1
value_context.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/core.hpp>
18 #include <bsoncxx/builder/stream/array_context.hpp>
19 #include <bsoncxx/builder/stream/closed_context.hpp>
20 #include <bsoncxx/builder/stream/helpers.hpp>
21 #include <bsoncxx/util/functor.hpp>
22 
23 #include <bsoncxx/config/prelude.hpp>
24 
25 namespace bsoncxx {
26 BSONCXX_INLINE_NAMESPACE_BEGIN
27 namespace builder {
28 namespace stream {
29 
47 template <class base>
49  public:
56  BSONCXX_INLINE value_context(core* core) : _core(core) {
57  }
58 
66  template <class T>
67  BSONCXX_INLINE
68  typename std::enable_if<!util::is_functor<T, void(single_context)>::value, base>::type
69  operator<<(T&& t) {
70  _core->append(std::forward<T>(t));
71  return unwrap();
72  }
73 
81  template <typename T>
82  BSONCXX_INLINE
83  typename std::enable_if<util::is_functor<T, void(single_context)>::value, base>::type
84  operator<<(T&& func) {
85  func(*this);
86  return unwrap();
87  }
88 
96  _core->open_document();
97  return wrap_document();
98  }
99 
107  _core->open_array();
108  return wrap_array();
109  }
110 
116  operator single_context();
117 
118 #if !defined(_MSC_VER)
119  // TODO(MSVC): Causes an ICE under VS2015U1
120  static_assert(
121  std::is_same<value_context, decltype(std::declval<value_context>() << 1 << "str")>::value,
122  "value_context must be templatized on a key_context");
123 #endif
124 
125  private:
126  BSONCXX_INLINE base unwrap() {
127  return base(_core);
128  }
129 
130  BSONCXX_INLINE array_context<base> wrap_array() {
131  return array_context<base>(_core);
132  }
133 
134  BSONCXX_INLINE key_context<base> wrap_document() {
135  return key_context<base>(_core);
136  }
137 
138  core* _core;
139 };
140 
141 } // namespace stream
142 } // namespace builder
143 BSONCXX_INLINE_NAMESPACE_END
144 } // namespace bsoncxx
145 
146 #include <bsoncxx/config/postlude.hpp>
A low-level interface for constructing BSON documents and arrays.
Definition: core.hpp:42
A stream context which expects any number of values.
Definition: array_context.hpp:52
std::enable_if<!util::is_functor< T, void(single_context)>::value, base >::type operator<<(T &&t)
<< operator for accepting a real value and appending it to the core builder.
Definition: value_context.hpp:69
A stream context which expects a key, which can later be followed by value, then more key/value pairs...
Definition: array_context.hpp:32
A stream context which appends a single value.
Definition: single_context.hpp:36
void open_array()
Opens a sub-array within this BSON datum.
void append(const types::b_double &value)
Append a BSON double.
value_context(core *core)
Create a value_context given a core builder.
Definition: value_context.hpp:56
A stream context which expects a value, which can later be followed by more key/value pairs...
Definition: value_context.hpp:48
Definition: element.hpp:24
void open_document()
Opens a sub-document within this BSON datum.