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d4fab0971f
Preparation for editable documents, without a change in behavior: views and documents get a template parameter Editable (false by default), and every walk over the index (iterators, lookups, dump(), materialize()) goes through detail::view::navigation<Editable>. For read-only documents it is the plain node array, as before, so they compile without any of the edit handling. For editable documents it also follows the representation of edits, which this commit defines: - node flags `edited` (a string or number token in the edit arena), `moved` (the elements of an array/object live in a separate sequence), and `is_new` (no source position), and link nodes (kind_link) that stand for a value stored elsewhere - document_data::edit_state: the moved sequences, the storage of new values, and the edit arena materialize() now keeps a frame per open container instead of returning to the end of a closed one, as the serializer does, so that it can follow moved sequences. Floats whose token lives in the edit arena (also "nan", "inf", "-inf") are converted out of line. dump() copies only strings of the source without escaping, and shrink_to_fit() leaves the node array in place once there are edits, as they link into it. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
138 lines
4.1 KiB
C++
138 lines
4.1 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> // int64_t, uint8_t
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#include <string> // string
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#include <vector> // vector
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#include <nlohmann/json.hpp>
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#include <nlohmann/detail/view/document_data.hpp>
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#include <nlohmann/detail/view/macro_scope.hpp>
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#include <nlohmann/detail/view/node.hpp>
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#include <nlohmann/detail/view/number.hpp>
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NLOHMANN_JSON_NAMESPACE_BEGIN
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namespace detail
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{
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namespace view
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{
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/*!
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@brief the basic_json value of the subtree at n
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The subtree is replayed into the SAX handler that parse() uses to build its
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values, so the result is the value parse() would produce: duplicate keys keep
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the last value, and with JSON_DIAGNOSTICS the parent pointers are set. It is
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iterative, so the nesting depth is limited by memory only, as for parse().
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Without a lexer the handler records no source positions
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(JSON_DIAGNOSTIC_POSITIONS).
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*/
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template<typename BasicJsonType, bool Editable>
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BasicJsonType materialize(const document_data& d, const node* n)
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{
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using string_t = typename BasicJsonType::string_t;
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using sax_t = json_sax_dom_parser<BasicJsonType, iterator_input_adapter<const char*>>;
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using nav = navigation<Editable>;
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struct frame
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{
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const node* pos; ///< next element, or key of the next member
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const node* end;
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bool object;
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};
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BasicJsonType result;
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sax_t sax(result, true);
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const string_t no_token{};
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std::vector<frame> open;
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for (;;)
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{
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switch (static_cast<value_t>(n->kind))
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{
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case value_t::object:
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case value_t::array:
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{
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const bool object = n->kind == static_cast<std::uint8_t>(value_t::object);
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if (object)
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{
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sax.start_object(n->len);
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}
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else
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{
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sax.start_array(n->len);
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}
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open.push_back(frame{nav::first(d, n), nav::end(d, n), object});
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break;
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}
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case value_t::string:
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{
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string_t s(d.str(*n), n->len);
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sax.string(s);
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break;
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}
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case value_t::number_integer:
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sax.number_integer(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(*n))));
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break;
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case value_t::number_unsigned:
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sax.number_unsigned(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(*n)));
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break;
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case value_t::number_float:
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sax.number_float(float_value<typename BasicJsonType::number_float_t>(d, *n), no_token);
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break;
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case value_t::boolean:
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sax.boolean((n->flags & node_flags::is_true) != 0);
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break;
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case value_t::null:
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case value_t::binary:
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case value_t::discarded:
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default:
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sax.null();
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break;
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}
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// the next value: close finished containers, then read the key
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for (;;)
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{
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if (open.empty())
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{
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return result;
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}
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frame& f = open.back();
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if (f.pos == f.end)
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{
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if (f.object)
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{
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sax.end_object();
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}
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else
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{
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sax.end_array();
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}
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open.pop_back();
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continue;
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}
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const node* entry = f.pos;
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if (f.object)
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{
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string_t key(d.str(*entry), entry->len);
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sax.key(key);
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++entry;
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}
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n = nav::value(entry);
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f.pos = document_data::after(entry);
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break;
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}
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}
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}
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} // namespace view
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} // namespace detail
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NLOHMANN_JSON_NAMESPACE_END
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