// __ _____ _____ _____ // __| | __| | | | JSON for Modern C++ (supporting code) // | | |__ | | | | | | version 3.12.0 // |_____|_____|_____|_|___| https://github.com/nlohmann/json // // SPDX-FileCopyrightText: 2013-2026 Niels Lohmann // SPDX-License-Identifier: MIT #include "doctest_compatibility.h" #include using nlohmann::json; using nlohmann::ordered_json; using nlohmann::json_document; using nlohmann::ordered_json_editable_document; using nlohmann::json_view; using nlohmann::ordered_json_document; using nlohmann::ordered_json_view; #include "json_view_test_helpers.hpp" using json_view_test::generator; using json_view_test::has_duplicate_keys; #include #include #include #include #include #include #include #include #include #include #include #include #include // These tests were split off unit-json_view_dump.cpp, whose object file got too large for the MinGW // linker (see json_view_test_helpers.hpp). Like that file, this one is also built // with C++17, as it mentions JSON_HAS_CPP_17. TEST_CASE("json_view dump: escaping, nesting, and output buffers") { SECTION("members in document order, all of them") { const json_document d = json_document::parse(R"({"b": 1, "a": 2, "b": 3})"); CHECK(d.root().dump() == R"({"b":1,"a":2,"b":3})"); CHECK(d.root().dump(1) == "{\n \"b\": 1,\n \"a\": 2,\n \"b\": 3\n}"); // dump() writes all members, though the lookup finds the first CHECK(d.root()["b"].dump() == "1"); } SECTION("deep nesting") { const std::string deep = std::string(100000, '[') + std::string(100000, ']'); const json_document deep_document = json_document::parse(deep); CHECK(deep_document.root().dump() == deep); } SECTION("ensure_ascii: a character that needs an escape at each position of a string") { // string lengths around the width of the vector steps, in a string value, a key, and a value near the end of the text for (const char* const special : { "\xC3\xA9", "\xE4\xB8\xAD", "\xF0\x9F\x98\x80", "\x7F", "\\n", "\\u0001", "\\\"", "\\\\" }) { for (std::size_t length = 0; length <= 40; ++length) { for (std::size_t position = 0; position <= length; ++position) { std::string content(length, 'a'); content.insert(position, special); const std::array texts = { { "\"" + content + "\"", "[\"" + content + "\"]", "{\"" + content + "\":1}", } }; for (const std::string& text : texts) { CAPTURE(text) const ordered_json_document d = ordered_json_document::parse(text); const ordered_json j = ordered_json::parse(text); CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true)); CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true)); CHECK(d.root().dump() == j.dump()); } } } } } SECTION("ensure_ascii: every character of the Basic Multilingual Plane and some beyond") { // (the two- and three-byte sequences, including the ranges that need a check: E0, ED, EF BF BF) std::string text = "["; std::size_t in_chunk = 0; const auto append = [&](std::uint32_t cp) { if (cp < 0x80) { if (cp < 0x20 || cp == '"' || cp == '\\') { return; } text += static_cast(cp); } else if (cp < 0x800) { text += static_cast(0xC0 | (cp >> 6)); text += static_cast(0x80 | (cp & 0x3F)); } else if (cp < 0x10000) { text += static_cast(0xE0 | (cp >> 12)); text += static_cast(0x80 | ((cp >> 6) & 0x3F)); text += static_cast(0x80 | (cp & 0x3F)); } else { text += static_cast(0xF0 | (cp >> 18)); text += static_cast(0x80 | ((cp >> 12) & 0x3F)); text += static_cast(0x80 | ((cp >> 6) & 0x3F)); text += static_cast(0x80 | (cp & 0x3F)); } }; for (std::uint32_t cp = 0x20; cp < 0x10400; ++cp) { if (cp >= 0xD800 && cp < 0xE000) { continue; } if (in_chunk == 0) { text += text.size() > 1 ? ",\"" : "\""; } append(cp); if (++in_chunk == 37) { text += "\""; in_chunk = 0; } } text += in_chunk != 0 ? "\"]" : "]"; const ordered_json_document d = ordered_json_document::parse(text); const ordered_json j = ordered_json::parse(text); CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true)); CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true)); CHECK(d.root().dump() == j.dump()); CHECK(d.root().dump(2) == j.dump(2)); } SECTION("deep nesting, indented") { // indentations of up to and beyond the width of the writer's fixed-size copy for (const int depth : { 1, 5, 20, 70, 300 }) { std::string text; for (int i = 0; i < depth; ++i) { text += i % 2 == 0 ? "[1," : R"({"k":2,"\u00e9":)"; } text += "[]"; for (int i = depth - 1; i >= 0; --i) { text += i % 2 == 0 ? "]" : "}"; } const ordered_json_document d = ordered_json_document::parse(text); const ordered_json j = ordered_json::parse(text); for (const int indent : { 0, 1, 2, 3, 8 }) { CHECK(d.root().dump(indent) == j.dump(indent)); CHECK(d.root().dump(indent, '\t') == j.dump(indent, '\t')); } } } SECTION("the output buffer of a small value is small") { // an escaped key after the value: its node lies in the arena, so the // source extent of the value cannot be read from the next node const std::string big(100000, 'a'); const std::string text = R"({"small":1,"list":[1,2,3],"k\n":")" + big + R"("})"; const json_document d = json_document::parse(text); const auto small = d.root()["small"].dump(); CHECK(small == "1"); CHECK(small.capacity() < 4096); const auto list = d.root()["list"].dump(); CHECK(list == "[1,2,3]"); CHECK(list.capacity() < 4096); CHECK(d.root()["list"].dump(2).capacity() < 4096); // the whole document and the large value are unaffected CHECK(d.root().dump() == ordered_json::parse(text).dump()); CHECK(d.root()["k\n"].dump() == "\"" + big + "\""); } SECTION("output that outgrows the estimate") { // ensure_ascii writes six bytes for each two-byte character std::string chars; for (int i = 0; i < 5000; ++i) { chars += "\xC3\xA9"; } const json_document d = json_document::parse(R"({"a":")" + chars + R"(","k\n":1})"); const json expected = json::parse("\"" + chars + "\""); CHECK(d.root()["a"].dump(-1, ' ', true) == expected.dump(-1, ' ', true)); CHECK(d.root()["a"].dump(-1, ' ', true).size() == 2 + (5000 * 6)); } SECTION("ensure_ascii with strings of the source, decoded strings, and edited strings") { // plain ASCII, non-ASCII, escaped (decoded), and mixed strings, as values and as keys; // the second text has a DEL, which ensure_ascii writes as an escape for (const char* const del : {"", "\x7F" }) { const std::string text = std::string("{\"plain\":\"abc\",\"caf\xC3\xA9\":\"\xC3\xA9\xE2\x82\xAC\xF0\x9F\x98\x80\",") + "\"esc\\n\\\"\":\"a\\tb\\u00e4\\ud83d\\ude00\",\"del\":\"a" + del + "b\",\"\":\"\"," // NOLINT(modernize-raw-string-literal) + "\"list\":[\"x\",\"\xC3\xBC\",\"\\\\\",\"long ASCII string with more than thirty-two bytes in it\"," + "\"long string with more than thirty-two bytes and one non-ASCII byte \xC3\xB6\"]," + "\"n\":[1,2.5,-0,true,null]}"; const ordered_json j = ordered_json::parse(text); const ordered_json_document d = ordered_json_document::parse(text); CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true)); CHECK(d.root().dump(4, ' ', true) == j.dump(4, ' ', true)); CHECK(d.root().dump() == j.dump()); CHECK(d.root()["list"].dump(-1, ' ', true) == j["list"].dump(-1, ' ', true)); CHECK(d.root()["del"].dump(-1, ' ', true) == j["del"].dump(-1, ' ', true)); // strings that an edit wrote (the source strings that they replace were plain) ordered_json_editable_document e = ordered_json_editable_document::parse(text); ordered_json k = j; e.set(e.root()["plain"], std::string("\xC3\xA4gypten")); k["plain"] = "\xC3\xA4gypten"; e.set(e.root()["list"][0], std::string("ascii after edit")); k["list"][0] = "ascii after edit"; e.set(e.root()["list"][1], std::string("\xC3\xA4")); k["list"][1] = "\xC3\xA4"; e.set(e.root()["del"], std::string("tab\there")); k["del"] = "tab\there"; CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true)); CHECK(e.root().dump(2, ' ', true) == k.dump(2, ' ', true)); CHECK(e.root().dump() == k.dump()); // strings that were edited from or to ASCII text e.set(e.root()["list"][2], std::string("\xC3\xA4")); k["list"][2] = "\xC3\xA4"; e.set(e.root()["list"][4], std::string("plain again")); k["list"][4] = "plain again"; CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true)); } } SECTION("ensure_ascii with DEL or a non-ASCII character at every position") { // the check whether a string of the source has no byte >= 0x7F reads // eight bytes at a time and then the rest one by one for (std::size_t length = 1; length <= 20; ++length) { for (std::size_t pos = 0; pos < length; ++pos) { for (const char* const c : { "\x7F", "\x7E", "\xC3\xA4", "\xC3\xBF" // NOLINT(modernize-raw-string-literal) }) { const std::string s = std::string(pos, 'a') + c + std::string(length - pos - 1, 'b'); std::string text = "[\""; text.append(s).append("\",{\"").append(s).append("\":1}]"); const json_document d = json_document::parse(text); const json j = json::parse(text); CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true)); CHECK(d.root().dump(1, ' ', true) == j.dump(1, ' ', true)); } } } } SECTION("streams and discarded views") { const json_document d = json_document::parse(R"({"a": [1, 2]})"); std::ostringstream compact; compact << d.root(); CHECK(compact.str() == R"({"a":[1,2]})"); std::ostringstream pretty; pretty << std::setw(2) << std::setfill('.') << d.root() << d.root()["a"]; CHECK(pretty.str() == "{\n..\"a\": [\n....1,\n....2\n..]\n}[1,2]"); CHECK(json_view().dump() == json(json::value_t::discarded).dump()); } }