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Niels Lohmann
731f1b5bfb
* json_view: view_mode enum instead of bool Editable, node_kind for node::kind basic_json_document and basic_json_view take a view_mode (read_only, the default, or editable) instead of a bool: basic_json_document<json, true> did not say what true means. The shortcut aliases are unchanged. The kind of a node is a node_kind (the value_t values plus link, 10 as before), which removes the static_cast<std::uint8_t>(value_t::...) of every comparison. The node and image layouts are unchanged. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * json_view: node_kind in the node writers, spell out read_only, comment fixes The builder and the edit functions take and store a node_kind instead of casting a value_t; the numbering assertions and the comments now speak of node_kind, and the link kind notes that it follows value_t::discarded. The read-only aliases name view_mode::read_only like the editable ones. view_mode.md says the mode is a compile-time property of the type. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * json_view: views of read-only documents convert to editable views A read-only document has no edits, so a view of it reads correctly as a view of an editable document before its first edit. The implicit conversion lets a function taking a json_editable_view accept the views of both modes. There is no conversion the other way: a read-only view of an editable document would read wrong values after the next edit. The mode comparisons in the cross-mode operator==/!= use an is_other_mode trait, which astyle keeps compact. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
53 lines
1.4 KiB
C++
53 lines
1.4 KiB
C++
// __ _____ _____ _____
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// __| | __| | | | JSON for Modern C++
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// | | |__ | | | | | | version 3.12.0
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// |_____|_____|_____|_|___| https://github.com/nlohmann/json
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//
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// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
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// SPDX-License-Identifier: MIT
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#pragma once
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#include <cstdint> // uint8_t
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#include <type_traits> // false_type, true_type
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#include <nlohmann/json.hpp>
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NLOHMANN_JSON_NAMESPACE_BEGIN
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/// whether a basic_json_document and its views can be edited
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enum class view_mode : std::uint8_t
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{
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read_only, ///< parsed once, then only read (the default)
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editable, ///< also has set(), push_back(), insert(), and erase()
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};
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template<typename BasicJsonType, view_mode Mode>
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class basic_json_view;
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namespace detail
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{
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namespace view
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{
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/// whether two view modes differ
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template<view_mode A, view_mode B>
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struct is_other_mode : std::true_type {};
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template<view_mode A>
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struct is_other_mode<A, A> : std::false_type {};
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/// whether a view of mode From converts implicitly to one of mode To: a
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/// read-only document has no edits, so a view of it is read correctly as a
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/// view of an editable document that has not been edited yet
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template<view_mode From, view_mode To>
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struct is_widening_mode : std::false_type {};
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template<>
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struct is_widening_mode<view_mode::read_only, view_mode::editable> : std::true_type {};
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} // namespace view
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} // namespace detail
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NLOHMANN_JSON_NAMESPACE_END
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