value_context.hpp

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// Copyright 2009-present MongoDB, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#pragma once
 
#include <bsoncxx/builder/stream/value_context-fwd.hpp>
 
#include <bsoncxx/builder/core.hpp>
#include <bsoncxx/builder/stream/array_context.hpp>
#include <bsoncxx/builder/stream/closed_context.hpp>
#include <bsoncxx/builder/stream/helpers.hpp>
#include <bsoncxx/stdx/type_traits.hpp>
 
#include <bsoncxx/config/prelude.hpp>
 
namespace bsoncxx {
namespace v_noabi {
namespace builder {
namespace stream {

template <class base>
class value_context {
   public:
    value_context(core* core) : _core(core) {}

    template <class T>
    detail::requires_not_t<base, detail::is_invocable<T, single_context>> operator<<(T&& t) {
        _core->append(std::forward<T>(t));
        return unwrap();
    }

    template <typename T>
    detail::requires_t<base, detail::is_invocable<T, single_context>> operator<<(T&& func) {
        detail::invoke(std::forward<T>(func), *this);
        return unwrap();
    }

    key_context<base> operator<<(open_document_type const) {
        _core->open_document();
        return wrap_document();
    }

    array_context<base> operator<<(open_array_type const) {
        _core->open_array();
        return wrap_array();
    }

    operator single_context();
 
#if !defined(_MSC_VER) && !defined(__INTEL_COMPILER)
    // TODO(MSVC): Causes an ICE under VS2015U1
    static_assert(
        std::is_same<value_context, decltype(std::declval<value_context>() << 1 << "str")>::value,
        "value_context must be templatized on a key_context");
#endif
 
   private:
    base unwrap() {
        return base(_core);
    }
 
    array_context<base> wrap_array() {
        return array_context<base>(_core);
    }
 
    key_context<base> wrap_document() {
        return key_context<base>(_core);
    }
 
    core* _core;
};
 
} // namespace stream
} // namespace builder
} // namespace v_noabi
} // namespace bsoncxx
 
#include <bsoncxx/config/postlude.hpp>