inline.hpp

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#pragma once
 
/// @file userver/formats/bson/inline.hpp
/// @brief Inline value builders
 
#include <string_view>
 
#include <userver/formats/bson/bson_builder.hpp>
#include <userver/formats/bson/document.hpp>
#include <userver/formats/bson/types.hpp>
#include <userver/formats/bson/value.hpp>
#include <userver/utils/fast_pimpl.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace formats::bson {
 
/// Constructs a Document from provided key-value pairs
template <typename... Args>
Document MakeDoc(Args&&...);
 
/// Constructs an array Value from provided element list
template <typename... Args>
Value MakeArray(Args&&...);
 
namespace impl {
 
class InlineDocBuilder {
public:
    using Key = std::string_view;
 
    Document Build();
 
    template <typename FieldValue, typename... Tail>
    Document Build(Key key, FieldValue&& value, Tail&&... tail) {
        builder_.Append(key, std::forward<FieldValue>(value));
        return Build(std::forward<Tail>(tail)...);
    }
 
private:
    BsonBuilder builder_;
};
 
class InlineArrayBuilder {
public:
    InlineArrayBuilder();
    ~InlineArrayBuilder();
 
    Value Build();
 
    template <typename Element, typename... Tail>
    Value Build(Element&& element, Tail&&... tail) {
        builder_.Append(GetKey(), std::forward<Element>(element));
        return Build(std::forward<Tail>(tail)...);
    }
 
private:
    std::string_view GetKey();
 
    class Helper;
    static constexpr size_t kSize = 20;
    static constexpr size_t kAlignment = 4;
    utils::FastPimpl<Helper, kSize, kAlignment, true> helper_;
    BsonBuilder builder_;
};
 
}  // namespace impl
 
/// @cond
template <typename... Args>
Document MakeDoc(Args&&... args) {
    return impl::InlineDocBuilder().Build(std::forward<Args>(args)...);
}
 
template <typename... Args>
Value MakeArray(Args&&... args) {
    return impl::InlineArrayBuilder().Build(std::forward<Args>(args)...);
}
/// @endcond
 
}  // namespace formats::bson
 
USERVER_NAMESPACE_END