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fuchsia/third_party/json/refs/heads/upstream/develop/./tests/src/unit-json_view.cpp
blob: e87162d98a58d08a4247ab2e86f54292d4fda82f [file] [edit]
// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++ (supporting code)
// | | |__ | | | | | | version 3.12.0
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT
#include "doctest_compatibility.h"
#include <nlohmann/json_view.hpp>
using nlohmann::json;
using nlohmann::ordered_json;
using nlohmann::json_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 <algorithm>
#include <array>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <ios>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <random>
#include <sstream>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include <vector>
#ifdef JSON_HAS_CPP_17
#include <string_view>
#endif
namespace
{
// the value of a text, through a named document: the views of a temporary
// document would dangle (root() of an rvalue document does not compile)
template<typename Document, typename... Args>
auto materialized(Args&& ... args) -> decltype(std::declval<typename Document::view_type>().materialize())
{
const Document d = Document::parse(std::forward<Args>(args)...);
return d.root().materialize();
}
template<typename Document, typename Input>
auto materialized_copy(Input&& input) -> decltype(std::declval<typename Document::view_type>().materialize())
{
const Document d = Document::parse_copy(std::forward<Input>(input));
return d.root().materialize();
}
// a "byte container" that claims to hold `size` bytes, to reach the limit on
// the size of the input without allocating gigabytes; nothing past the first
// bytes is ever read, because the size is checked before the parse starts
struct oversized_input
{
using value_type = char;
std::size_t claimed;
const char* data() const // NOLINT(readability-convert-member-functions-to-static): container interface
{
return "[1]";
}
std::size_t size() const
{
return claimed;
}
};
// detection of calls that must not compile
template<typename... Args>
using parse_call_t = decltype(json_document::parse(std::declval<Args>()...));
template<typename... Args>
using parse_copy_call_t = decltype(json_document::parse_copy(std::declval<Args>()...));
template<typename... Args>
using accept_call_t = decltype(json_document::accept(std::declval<Args>()...));
template<typename... Args>
using read_call_t = decltype(std::declval<json_document&>().read(std::declval<Args>()...));
template<typename Document>
using root_call_t = decltype(std::declval<Document>().root());
template<typename View>
using bool_conversion_t = decltype(static_cast<bool>(std::declval<View>()));
#if !defined(JSON_NOEXCEPTION)
// the exception parse() throws for a text, or "" if it accepts it
std::string parse_exception(const std::string& text, bool comments = false, bool trailing_commas = false)
{
try
{
const json j = json::parse(text, nullptr, true, comments, trailing_commas);
static_cast<void>(j);
}
catch (const json::exception& e)
{
return e.what();
}
return "";
}
std::string view_exception(const std::string& text, bool comments = false, bool trailing_commas = false)
{
try
{
const json_document d = json_document::parse(text, true, comments, trailing_commas);
static_cast<void>(d);
}
catch (const json::exception& e)
{
return e.what();
}
return "";
}
#endif
} // namespace
TEST_CASE("json_view")
{
SECTION("types and capacity")
{
for (const char* text :
{"null", "true", "false", "0", "-1", "18446744073709551615", "-9223372036854775808", "18446744073709551616", "1.5",
"\"\"", "\"text\"", "[]", "[1,2,3]", "{}", "{\"a\":1,\"b\":2}" // NOLINT(modernize-raw-string-literal)
})
{
CAPTURE(text)
const json j = json::parse(text);
const json_document d = json_document::parse(text);
const json_view v = d.root();
CHECK(v.type() == j.type());
CHECK(v.is_null() == j.is_null());
CHECK(v.is_boolean() == j.is_boolean());
CHECK(v.is_number() == j.is_number());
CHECK(v.is_number_integer() == j.is_number_integer());
CHECK(v.is_number_unsigned() == j.is_number_unsigned());
CHECK(v.is_number_float() == j.is_number_float());
CHECK(v.is_string() == j.is_string());
CHECK(v.is_array() == j.is_array());
CHECK(v.is_object() == j.is_object());
CHECK(v.is_binary() == j.is_binary());
CHECK(v.is_primitive() == j.is_primitive());
CHECK(v.is_structured() == j.is_structured());
CHECK(!v.is_discarded());
CHECK(v.size() == j.size());
CHECK(v.empty() == j.empty());
CHECK(v.materialize() == j);
}
const json_view invalid{};
CHECK(invalid.is_discarded());
CHECK(invalid.type() == json::value_t::discarded);
CHECK(invalid.size() == 0);
CHECK(invalid.empty());
CHECK(invalid.materialize().is_discarded());
CHECK(invalid.source_offset() == static_cast<std::size_t>(-1));
}
SECTION("materialize")
{
generator g;
for (int i = 0; i < 2000; ++i)
{
std::string text;
g.value(text, 0);
CAPTURE(text)
CHECK(materialized<json_document>(text) == json::parse(text));
// member order as ordered_json::parse keeps it
CHECK(materialized<ordered_json_document>(text).dump() == ordered_json::parse(text).dump());
}
// duplicate keys: the last value, at the position of the first key
CHECK(materialized<json_document>(R"({"a":1,"b":2,"a":3})") == json::parse(R"({"a":1,"b":2,"a":3})"));
CHECK(materialized<ordered_json_document>(R"({"a":1,"b":2,"a":3})").dump() == R"({"a":3,"b":2})");
// scalars (made without the handler), and nesting around the depth up to which the stack of open containers is local
for (const char* scalar :
{"null", "true", "false", "0", "-7", "18446744073709551615", "1.5e300", "-0.0", "\"\"", "\"short\"", "\"a string that is longer than fifteen bytes\"", R"("\u00e4\n")"
})
{
CAPTURE(scalar)
CHECK(materialized<json_document>(scalar) == json::parse(scalar));
const std::string in_array = std::string("[1,") + scalar + "]";
const json_document d = json_document::parse(in_array);
CHECK(d.root()[1].materialize() == json::parse(scalar));
CHECK(d.root()[1].get<json>() == json::parse(scalar));
}
for (const std::size_t levels :
{
std::size_t{1}, std::size_t{15}, std::size_t{16}, std::size_t{17}, std::size_t{32}, std::size_t{33}
})
{
CAPTURE(levels)
const std::string nested = std::string(levels, '[') + R"({"k":[1,{"j":2}]})" + std::string(levels, ']');
CHECK(materialized<json_document>(nested) == json::parse(nested));
std::string wide = R"({"a":)";
wide += nested;
wide += R"(,"b":)";
wide += nested;
wide += "}";
CHECK(materialized<json_document>(wide) == json::parse(wide));
}
// very deep nesting (iterative, as parse())
const std::string deep = std::string(100000, '[') + std::string(100000, ']');
// (one check per step, so that a failure shows which step it is)
const json_document deep_document = json_document::parse(deep);
CHECK(deep_document.root().is_array());
const json deep_value = deep_document.root().materialize();
CHECK(deep_value.is_array());
const json deep_parsed = json::parse(deep);
CHECK(deep_parsed.is_array());
CHECK(deep_value == deep_parsed);
#if JSON_DIAGNOSTICS
// the parents are set, so errors name the path
const json m = materialized<json_document>(R"({"a":{"b":[1]}})");
CHECK_THROWS_WITH_AS(m.at("a").at("b").at(0).at("x"), "[json.exception.type_error.304] (/a/b/0) cannot use at() with number", json::type_error&);
#endif
}
SECTION("parse errors are those of parse()")
{
for (const char* text :
{
"", " ", "[", "]", "{", "[1,]", "{\"a\":1,}", "[1 2]", "{\"a\" 1}", "{1:2}", "tru", "nul", "fals", "truex", "-", "01", "1.", ".5", "1e",
"\"", "\"abc", "\"\\x\"", "\"\\u12\"", "\"\\ud800\"", "\"\\udc00\"", "\"\x01\"", "\"\xff\"", "\"\xc3\"", "[1]x", "/", "/*", "[\n 1,\n x\n]", // NOLINT(modernize-raw-string-literal)
"1e400", "-1e400", "[1.7976931348623159e308]", "{\"a\":\n{\"b\": [1, 2,\n 3 x]}}"
})
{
CAPTURE(text)
#if !defined(JSON_NOEXCEPTION)
const std::string expected = parse_exception(text);
REQUIRE(!expected.empty());
CHECK(view_exception(text) == expected);
#endif
CHECK(!json_document::accept(text));
const json_document d = json_document::parse(text, false);
CHECK(d.is_discarded());
CHECK(d.root().is_discarded());
CHECK(d.node_count() == 0);
}
// the exception types
json_document _;
CHECK_THROWS_AS(_ = json_document::parse("[1,"), json::parse_error&);
CHECK_THROWS_AS(_ = json_document::parse("1e400"), json::out_of_range&);
}
SECTION("parse options")
{
for (const char* text :
{"// c\n[1]", "[1, /* c */ 2]", "[1,]", "{\"a\":1,}", "[1,/* c */]", "/", "/* ", "[1,,]"
})
{
CAPTURE(text)
for (int options = 0; options < 4; ++options)
{
const bool comments = (options & 1) != 0;
const bool trailing_commas = (options & 2) != 0;
CHECK(json_document::accept(text, comments, trailing_commas) == json::accept(text, comments, trailing_commas));
#if !defined(JSON_NOEXCEPTION)
CHECK(view_exception(text, comments, trailing_commas) == parse_exception(text, comments, trailing_commas));
#endif
}
}
}
SECTION("overflow of the floating-point type")
{
// the overflow is that of the document's number_float_t: 1e39
// overflows a float, the largest float 3.4028235e38 does not, but
// 3.4028236e38 rounds beyond it; a double document is not affected
using json_float = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, float>;
using float_document = nlohmann::basic_json_document<json_float>;
CHECK_FALSE(json_float::accept("1e39"));
CHECK(json_float::accept("3.4028235e38"));
CHECK_FALSE(json_float::accept("3.4028236e38"));
for (const char* text :
{
"1e39", "-1e39", "[3.4028235e38]", "[3.4028236e38]", "{\"a\": [1e38, -3.4028235e38]}", "{\"a\": [1e-50, 1e39]}"
})
{
CAPTURE(text)
const bool accepted = json_float::accept(text);
CHECK(float_document::accept(text) == accepted);
CHECK(float_document::parse(text, false).is_discarded() == !accepted);
CHECK(json_document::accept(text));
if (accepted)
{
CHECK(materialized<float_document>(text) == json_float::parse(text));
}
}
float_document f;
CHECK_THROWS_WITH_AS(f = float_document::parse("1e39"), "[json.exception.out_of_range.406] number overflow parsing '1e39'", json::out_of_range&);
CHECK_THROWS_WITH_AS(f = float_document::parse("[3.4028236e38]"), "[json.exception.out_of_range.406] number overflow parsing '3.4028236e38'", json::out_of_range&);
}
SECTION("NUL and BOM")
{
const std::string with_nul("[1]\0garbage", 11);
CHECK(json_document::accept(with_nul) == json::accept(with_nul));
const std::string nul_in_comment("[1, // c\0\n2]", 12);
CHECK(json_document::accept(nul_in_comment, true) == json::accept(nul_in_comment, true));
CHECK(materialized<json_document>("\xEF\xBB\xBF[1]") == json::parse("\xEF\xBB\xBF[1]"));
#if !defined(JSON_NOEXCEPTION)
CHECK(view_exception("\xEF\xBB") == parse_exception("\xEF\xBB"));
#endif
}
SECTION("inputs")
{
const std::string text = R"([1, "two", {"three": 3.5}])";
const json expected = json::parse(text);
// borrowed: the text must outlive the document
const json_document borrowed = json_document::parse(text);
CHECK(!borrowed.owns_source());
CHECK(borrowed.source().data() == text.data());
CHECK(borrowed.root().materialize() == expected);
CHECK(materialized<json_document>(text.c_str()) == expected);
CHECK(materialized<json_document>(R"([1, "two", {"three": 3.5}])") == expected);
CHECK(materialized<json_document>(text.data(), text.data() + text.size()) == expected);
const std::vector<char> chars(text.begin(), text.end());
CHECK(!json_document::parse(chars).owns_source());
CHECK(materialized<json_document>(chars) == expected);
const std::vector<std::uint8_t> bytes(text.begin(), text.end());
CHECK(materialized<json_document>(bytes) == expected);
#ifdef JSON_HAS_CPP_17
const std::string_view sv = text;
CHECK(!json_document::parse(sv).owns_source());
CHECK(materialized<json_document>(sv) == expected);
#endif
// owned
std::string moved = text;
const json_document from_rvalue = json_document::parse(std::move(moved));
CHECK(from_rvalue.owns_source());
CHECK(from_rvalue.root().materialize() == expected);
CHECK(json_document::parse(std::vector<char>(text.begin(), text.end())).owns_source());
// a const rvalue cannot be moved from, and is not borrowed (it may be a
// temporary): it is copied, as is a const rvalue of any container
const std::string const_text = text; // NOLINT(performance-unnecessary-copy-initialization)
const json_document from_const_rvalue = json_document::parse(std::move(const_text)); // NOLINT(performance-move-const-arg,hicpp-move-const-arg)
CHECK(from_const_rvalue.owns_source());
CHECK(from_const_rvalue.source().data() != const_text.data()); // NOLINT(bugprone-use-after-move,hicpp-invalid-access-moved): const, not moved from
CHECK(from_const_rvalue.root().materialize() == expected);
json_document read_const_rvalue;
read_const_rvalue.read(std::move(const_text)); // NOLINT(performance-move-const-arg,hicpp-move-const-arg,bugprone-use-after-move,hicpp-invalid-access-moved)
CHECK(read_const_rvalue.owns_source());
CHECK(read_const_rvalue.root().materialize() == expected);
const std::vector<char> const_chars(text.begin(), text.end());
CHECK(json_document::parse(std::move(const_chars)).owns_source()); // NOLINT(performance-move-const-arg,hicpp-move-const-arg)
CHECK(json_document::parse_copy(text).owns_source());
CHECK(materialized_copy<json_document>(text) == expected);
std::istringstream stream(text);
const json_document from_stream = json_document::parse(stream);
CHECK(from_stream.owns_source());
CHECK(from_stream.root().materialize() == expected);
const std::list<char> list(text.begin(), text.end());
CHECK(json_document::parse(list.begin(), list.end()).owns_source());
CHECK(materialized<json_document>(list.begin(), list.end()) == expected);
// iterator pairs: pointers are borrowed, and so are contiguous library
// iterators where the input adapter detects them (C++20)
CHECK(!json_document::parse(text.data(), text.data() + text.size()).owns_source());
const bool contiguous = nlohmann::detail::iterator_input_adapter<std::vector<char>::const_iterator>::supports_bulk_scan;
const json_document from_iterators = json_document::parse(chars.cbegin(), chars.cend());
CHECK(from_iterators.owns_source() != contiguous);
CHECK((from_iterators.source().data() == chars.data()) == contiguous);
CHECK(from_iterators.root().materialize() == expected);
const std::string padded = "x" + text + "x";
CHECK(materialized<json_document>(padded.begin() + 1, padded.end() - 1) == expected);
CHECK(json_document::parse(chars.cbegin(), chars.cbegin(), false).is_discarded());
const std::wstring wide = L"[\"\u00e4\u20ac\", 1]";
CHECK(materialized<json_document>(wide) == json::parse(wide));
CHECK(json_document::parse(static_cast<const char*>(nullptr), false).is_discarded());
CHECK(json_document::parse("", false).is_discarded());
// wide-character arrays and pointers are converted to UTF-8, as by
// parse(); the pointers are NUL-terminated
CHECK(materialized<json_document>(L"[\"ä€\", 1]") == json::parse(L"[\"ä€\", 1]"));
CHECK(materialized<json_document>(u"[\"ä€\", 1]") == json::parse(u"[\"ä€\", 1]"));
CHECK(materialized<json_document>(U"[\"ä€\", 1]") == json::parse(U"[\"ä€\", 1]"));
const wchar_t* const wide_pointer = wide.c_str();
const json_document from_wide_pointer = json_document::parse(wide_pointer);
CHECK(from_wide_pointer.owns_source());
CHECK(from_wide_pointer.root().materialize() == json::parse(wide));
const std::u16string wide16 = u"{\"\U0001F600\": [true]}";
CHECK(materialized<json_document>(wide16.c_str()) == json::parse(wide16));
const std::u32string wide32 = U"{\"\U0001F600\": [true]}";
CHECK(materialized<json_document>(wide32.c_str()) == json::parse(wide32));
CHECK(json_document::parse(static_cast<const wchar_t*>(nullptr), false).is_discarded());
// FILE*: read to its end
std::FILE* file = std::tmpfile(); // NOLINT(cppcoreguidelines-owning-memory)
if (file != nullptr)
{
CHECK(std::fputs(text.c_str(), file) >= 0);
CHECK(std::fseek(file, 0, SEEK_SET) == 0);
const json_document from_file = json_document::parse(file);
CHECK(from_file.owns_source());
CHECK(from_file.root().materialize() == expected);
CHECK(std::fclose(file) == 0); // NOLINT(cppcoreguidelines-owning-memory)
}
}
SECTION("streams")
{
// longer than one block of the bulk read
std::string text = "[";
for (int i = 0; i < 5000; ++i)
{
text += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\"";
}
text += ']';
std::istringstream stream(text);
const json_document from_stream = json_document::parse(stream);
CHECK(from_stream.source() == text);
CHECK(from_stream.root().materialize() == json::parse(text));
// the stream is read to its end, and eofbit set, as by parse()
CHECK(stream.eof());
CHECK(!stream.bad());
std::istringstream empty_stream;
CHECK(json_document::parse(empty_stream, false).is_discarded());
CHECK(empty_stream.eof());
std::istringstream rvalue_source("[1]");
CHECK(json_document::parse_copy(std::move(rvalue_source)).owns_source());
// a C stream is read in blocks as well (more than one block, and a
// text whose length is a multiple of the block size)
for (const std::size_t extra :
{
std::size_t{0}, std::size_t{1}
})
{
std::FILE* long_file = std::tmpfile(); // NOLINT(cppcoreguidelines-owning-memory)
if (long_file != nullptr)
{
std::string padded = text;
padded.append(((4096 - (padded.size() % 4096)) % 4096) + extra, ' ');
CHECK(std::fwrite(padded.data(), 1, padded.size(), long_file) == padded.size());
CHECK(std::fseek(long_file, 0, SEEK_SET) == 0);
const json_document from_long_file = json_document::parse(long_file);
CHECK(from_long_file.source() == padded);
CHECK(from_long_file.root().materialize() == json::parse(text));
CHECK(std::fclose(long_file) == 0); // NOLINT(cppcoreguidelines-owning-memory)
}
}
{
json_document from_null;
CHECK_THROWS_AS(from_null = json_document::parse(static_cast<std::FILE*>(nullptr)), json::parse_error&);
}
// a stream without a buffer is an empty input
std::istream no_buffer(nullptr);
CHECK(json_document::parse(no_buffer, false).is_discarded());
#if !defined(JSON_NOEXCEPTION)
// an exception while reading the input leaves a discarded document
json_document d = json_document::parse(std::vector<char>(text.begin(), text.end()));
std::istringstream throwing("[1]");
throwing.exceptions(std::ios::eofbit);
CHECK_THROWS_AS(d.read(throwing), std::ios_base::failure&);
CHECK(d.is_discarded());
CHECK(d.root().is_discarded());
d.read("[2]");
CHECK(d.root().materialize() == json::parse("[2]"));
#endif
}
SECTION("read() reuses the owned copy")
{
std::string big = "[";
for (int i = 0; i < 1000; ++i)
{
big += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\"";
}
big += ']';
const std::string small = "{\"a\": [1, 2]}";
// copied inputs are written into the existing buffer
json_document d = json_document::parse(std::vector<char>(big.begin(), big.end()));
REQUIRE(d.owns_source());
const char* const buffer = d.source().data();
d.read(std::vector<char>(small.begin(), small.end()));
CHECK(d.owns_source());
CHECK(d.source().data() == buffer);
CHECK(d.root().materialize() == json::parse(small));
std::istringstream stream(small);
d.read(stream);
CHECK(d.source().data() == buffer);
CHECK(d.root().materialize() == json::parse(small));
d.read(std::wstring(L"[3]"));
CHECK(d.source().data() == buffer);
CHECK(d.root().materialize() == json::parse("[3]"));
// a moved-in string replaces it (long enough to be on the heap)
std::string moved = big;
const char* const moved_buffer = moved.data();
d.read(std::move(moved));
CHECK(d.source().data() == moved_buffer);
CHECK(d.root().materialize() == json::parse(big));
// a borrowed input leaves nothing owned
d.read(big);
CHECK(!d.owns_source());
CHECK(d.source().data() == big.data());
}
SECTION("integer arguments do not compile")
{
using nlohmann::detail::is_detected;
static_assert(is_detected<parse_call_t, const char*, bool>::value, "parse(ptr, bool) is valid");
static_assert(is_detected<parse_call_t, const char*, bool, bool, bool>::value, "parse(ptr, bool, bool, bool) is valid");
static_assert(is_detected<parse_call_t, const char*, const char*>::value, "parse(first, last) is valid");
static_assert(is_detected<parse_call_t, const char*, const char*, bool>::value, "parse(first, last, bool) is valid");
static_assert(is_detected<parse_copy_call_t, const char*, bool>::value, "parse_copy(ptr, bool) is valid");
static_assert(is_detected<accept_call_t, const char*, bool>::value, "accept(ptr, bool) is valid");
static_assert(is_detected<read_call_t, const char*, bool>::value, "read(ptr, bool) is valid");
// a length is not a flag: parse(ptr, len) would convert len to
// allow_exceptions and read ptr as a C string, which need not end
//
// MSVC 2015 does not treat selecting a deleted function in decltype as
// a substitution failure, so it detects the deleted overloads as
// callable; calling them still fails to compile
#if !(defined(_MSC_VER) && _MSC_VER < 1910)
static_assert(!is_detected<parse_call_t, const char*, std::size_t>::value, "parse(ptr, len) must not compile");
static_assert(!is_detected<parse_call_t, const char*, int>::value, "parse(ptr, int) must not compile");
static_assert(!is_detected<parse_call_t, const char*, char>::value, "parse(ptr, char) must not compile");
static_assert(!is_detected<parse_call_t, const char*, std::size_t, bool>::value, "parse(ptr, len, bool) must not compile");
static_assert(!is_detected<parse_call_t, const std::string&, std::size_t>::value, "parse(string, len) must not compile");
static_assert(!is_detected<parse_call_t, const std::vector<char>&, std::size_t>::value, "parse(vector, len) must not compile");
static_assert(!is_detected<parse_copy_call_t, const char*, std::size_t>::value, "parse_copy(ptr, len) must not compile");
static_assert(!is_detected<accept_call_t, const char*, std::size_t>::value, "accept(ptr, len) must not compile");
static_assert(!is_detected<read_call_t, const char*, std::size_t>::value, "read(ptr, len) must not compile");
#endif
// json_view has no conversion to bool: unlike basic_json's, it would
// mean "exists", not "is not null"; use is_discarded()
static_assert(!is_detected<bool_conversion_t, json_view>::value, "json_view must not convert to bool");
// the valid calls still work
const char* const text = "[1]";
CHECK(materialized<json_document>(text, true) == json::parse(text));
CHECK(json_document::accept(text, true, true));
}
SECTION("root of a temporary document does not compile")
{
using nlohmann::detail::is_detected;
// the view would dangle: auto v = json_document::parse(text).root();
static_assert(is_detected<root_call_t, json_document&>::value, "root() of an lvalue is valid");
static_assert(is_detected<root_call_t, const json_document&>::value, "root() of a const lvalue is valid");
static_assert(!is_detected<root_call_t, json_document>::value, "root() of an rvalue must not compile");
static_assert(!is_detected < root_call_t, json_document && >::value, "root() of an rvalue must not compile");
static_assert(!is_detected < root_call_t, const json_document && >::value, "root() of a const rvalue must not compile");
static_assert(!is_detected<root_call_t, ordered_json_document>::value, "root() of an rvalue must not compile");
// a named document is fine, also after a move
json_document d = json_document::parse("[1]");
CHECK(d.root().size() == 1);
const json_document moved = std::move(d);
CHECK(moved.root().size() == 1);
}
SECTION("input size limit")
{
// 32-bit offsets: the limit is 4 GiB minus 16 bytes (a margin below 2^32),
// which is what the exception message and the documentation say
const std::size_t limit = nlohmann::detail::view::max_input_size();
CHECK(limit == std::size_t{4294967279u});
const oversized_input input{limit + 1};
CHECK(!json_document::accept(input));
CHECK(json_document::parse(input, false).is_discarded());
#if !defined(JSON_NOEXCEPTION)
json_document d;
CHECK_THROWS_WITH_AS(d = json_document::parse(input), "[json.exception.out_of_range.416] input of 4294967280 bytes or more is not supported by json_document", json::out_of_range&);
#endif
}
SECTION("document lifetime and reuse")
{
json_document d;
CHECK(d.is_discarded());
CHECK(d.root().is_discarded());
CHECK(d.node_count() == 0);
CHECK(d.memory_usage() == 0);
CHECK(d.source().empty());
const std::string a = "[1,2,3]";
const std::string b = "{\"x\":[true]}";
d.read(a);
CHECK(d.node_count() == 4);
CHECK(d.root().materialize() == json::parse(a));
d.read(b);
CHECK(d.node_count() == 4);
CHECK(d.root().materialize() == json::parse(b));
d.read("[", false);
CHECK(d.is_discarded());
// views stay valid when the document moves
json_document first = json_document::parse(a);
const json_view root = first.root();
const json_document second = std::move(first);
CHECK(root.materialize() == json::parse(a));
CHECK(second.root().materialize() == json::parse(a));
}
SECTION("memory")
{
std::string big = "[";
for (int i = 0; i < 10000; ++i)
{
big += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\"";
}
big += ']';
json_document d = json_document::parse(big);
CHECK(d.node_count() == 10001);
const std::size_t before = d.memory_usage();
d.shrink_to_fit(); // (invalidates views, like std::vector::shrink_to_fit)
CHECK(d.memory_usage() <= before);
CHECK(d.node_count() == 10001);
CHECK(d.root().materialize() == json::parse(big));
CHECK(d.root().size() == 10000);
d.shrink_to_fit(); // nothing left to release
// after reading a smaller text, both the index and the decoded strings
// shrink, and the strings are found in their new place
std::string escaped = "[";
for (int i = 0; i < 1000; ++i)
{
escaped += (i != 0 ? ",\"a\\n" : "\"a\\n") + std::to_string(i) + "\"";
}
escaped += ']';
json_document reused = json_document::parse(escaped);
const std::string smaller = "[\"x\\ty\", [true, \"\\u00e4\"]]"; // NOLINT(modernize-raw-string-literal)
reused.read(smaller);
const std::size_t grown = reused.memory_usage();
reused.shrink_to_fit();
CHECK(reused.memory_usage() < grown);
CHECK(reused.root().materialize() == json::parse(smaller));
// an empty document has nothing to release
json_document empty;
empty.shrink_to_fit();
CHECK(empty.memory_usage() == 0);
// a small document stays in the storage block of the header
json_document small = json_document::parse("[1,[2,3],{\"a\":\"b\\n\"}]"); // NOLINT(modernize-raw-string-literal)
small.shrink_to_fit();
CHECK(small.root().materialize() == json::parse("[1,[2,3],{\"a\":\"b\\n\"}]"));
}
SECTION("source offsets")
{
const std::string text = R"( {"key": "value", "escaped": "a\nb", "n": 42})";
const json_document d = json_document::parse(text);
CHECK(d.root().source_offset() == 2);
CHECK(d.root()["key"].source_offset() == text.find("value"));
CHECK(d.root()["escaped"].source_offset() == static_cast<std::size_t>(-1));
CHECK(d.root()["n"].source_offset() == text.find("42"));
}
}
namespace
{
#if !defined(JSON_NOEXCEPTION)
// the exception a call throws, or "" if it throws none
template<typename F>
std::string exception_of(F f)
{
try
{
f();
}
catch (const json::exception& e)
{
return e.what();
}
return "";
}
#endif
// compares a view with the ordered_json value materialize() gives for it:
// types, sizes, elements and members (by index, key, and iteration), in
// document order; duplicate keys are found as their first occurrence
void check_access(const ordered_json_view& v, const ordered_json& j)
{
REQUIRE(v.type() == j.type());
CHECK(std::string(v.type_name()) == j.type_name());
if (v.is_array())
{
REQUIRE(v.size() == j.size());
std::size_t i = 0;
for (const ordered_json_view e : v)
{
CHECK(v[i].materialize() == e.materialize());
CHECK(v.at(i).materialize() == e.materialize());
check_access(e, j[i]);
++i;
}
CHECK(i == v.size());
CHECK(v[v.size()].is_discarded());
std::size_t index = 0;
for (const auto& item : v.items())
{
CHECK(item.key() == std::to_string(index));
CHECK(item.value().materialize() == j[index]);
++index;
}
if (!v.empty())
{
CHECK(v.front().materialize() == j.front());
CHECK(v.back().materialize() == j.back());
}
}
else if (v.is_object())
{
std::vector<std::string> keys; // first occurrences, in order
std::size_t members = 0;
for (auto it = v.begin(); it != v.end(); ++it)
{
++members;
const std::string key(it.key().data(), it.key().size());
CHECK(v.contains(key));
std::size_t occurrences = 0;
for (auto other = v.begin(); other != v.end(); ++other)
{
occurrences += other.key() == it.key() ? 1u : 0u;
}
CHECK(v.count(key) == occurrences);
// lookups find the first member with the key, which is this one if
// there is no earlier one
if (std::find(keys.begin(), keys.end(), key) != keys.end())
{
continue;
}
keys.push_back(key);
CHECK(v.find(key) == it);
CHECK(v[key].materialize() == it->materialize());
CHECK(v.at(key).materialize() == it.value().materialize());
CHECK(v[key.c_str()].materialize() == (*it).materialize());
}
CHECK(members == v.size());
REQUIRE(keys.size() == j.size());
std::size_t k = 0;
for (const auto& member : j.items())
{
CHECK(keys[k++] == member.key());
}
if (keys.size() == members)
{
// no duplicates: the values are those of the object
for (const auto& key : keys)
{
check_access(v[key], j[key]);
}
if (!v.empty())
{
CHECK(v.front().materialize() == j.front());
CHECK(v.back().materialize() == j.back());
}
}
CHECK(v["not a key in the generated documents"].is_discarded());
CHECK(v.find("not a key in the generated documents") == v.end());
}
else
{
// a primitive is a range of one element; null is empty
CHECK(static_cast<std::size_t>(std::distance(v.begin(), v.end())) == (v.is_null() ? 0u : 1u));
if (!v.is_null())
{
CHECK((*v.begin()).materialize() == j);
CHECK(v.front().materialize() == j);
CHECK(v.back().materialize() == j);
}
}
}
} // namespace
TEST_CASE("json_view element access and iteration")
{
SECTION("generated documents")
{
generator g;
for (int i = 0; i < 2000; ++i)
{
std::string text;
g.value(text, 0);
CAPTURE(text)
const ordered_json_document d = ordered_json_document::parse(text);
check_access(d.root(), ordered_json::parse(text));
}
}
SECTION("keys")
{
// keys of every length around the 2/4/8/16-byte loads, with escapes
std::string text = "{";
std::vector<std::string> keys = {"", "x"};
for (std::size_t n = 1; n <= 40; ++n)
{
keys.emplace_back(n, 'k');
keys.push_back(std::string(n, 'k') + "x");
keys.push_back("x" + std::string(n, 'k'));
}
for (std::size_t i = 0; i < keys.size(); ++i)
{
text += (i != 0 ? ",\"" : "\"") + keys[i] + "\":" + std::to_string(i);
}
text += ",\"esc\\u0061ped\":\"escaped key\"}"; // NOLINT(modernize-raw-string-literal)
const json_document d = json_document::parse(text);
const json_view root = d.root();
for (std::size_t i = 0; i < keys.size(); ++i)
{
CAPTURE(keys[i])
CHECK(root[keys[i]].materialize() == i);
CHECK(root.at(keys[i]).materialize() == i);
CHECK(root.find(keys[i]).key() == keys[i]);
CHECK(!root.contains(keys[i] + "y"));
}
CHECK(root["escaped"].materialize() == "escaped key");
CHECK(!root.contains("esc\\u0061ped"));
#ifdef JSON_HAS_CPP_17
CHECK(root[std::string_view("kkk")].materialize() == root["kkk"].materialize());
#endif
}
SECTION("duplicate keys: lookups find the first member, iteration all")
{
const json_document d = json_document::parse(R"({"a":1,"b":2,"a":3})");
const json_view v = d.root();
CHECK(v.size() == 3);
CHECK(v["a"].materialize() == 1);
CHECK(v.at("a").materialize() == 1);
CHECK(v.find("a") == v.begin());
CHECK(v.find("a").value().materialize() == 1);
CHECK(v.find("b") == std::next(v.begin()));
CHECK(v.count("a") == 2); // every member, unlike materialize()
CHECK(v.count("b") == 1);
CHECK(v.contains("a"));
CHECK(v.value("a", 0) == 1);
CHECK(v.materialize()["a"] == 3); // materialize() keeps the last value, unlike the lookups
// JSON pointers resolve to the first member at every level
const json_document dp = json_document::parse(R"({"a":{"b":1},"a":{"b":2,"b":3}})");
CHECK(dp.root()[json::json_pointer("/a/b")].materialize() == 1);
CHECK(dp.root().at(json::json_pointer("/a/b")).materialize() == 1);
CHECK(dp.root().value(json::json_pointer("/a/b"), 0) == 1);
CHECK(dp.root().materialize()[json::json_pointer("/a/b")] == 3);
// get<map> keeps the last value, as materialize()
CHECK((v.get<std::map<std::string, int>>() == std::map<std::string, int> {{"a", 3}, {"b", 2}}));
// keys of every length class (the 16-byte short compare and memcmp)
for (const std::size_t n :
{
0u, 1u, 3u, 7u, 8u, 15u, 16u, 17u, 40u
})
{
const std::string key(n, 'k');
const json_document dk = json_document::parse("{\"" + key + "\":1,\"" + key + "x\":2,\"" + key + "\":3,\"" + key + "\":4}"); // NOLINT(performance-inefficient-string-concatenation)
CAPTURE(n)
CHECK(dk.root()[key].materialize() == 1);
CHECK(dk.root().at(key).materialize() == 1);
CHECK(dk.root().find(key) == dk.root().begin());
CHECK(dk.root().value(key, 0) == 1);
CHECK(dk.root()[key + "x"].materialize() == 2);
}
std::string order;
for (auto it = v.begin(); it != v.end(); ++it)
{
order += std::string(it.key().data(), it.key().size()) + it->materialize().dump();
}
CHECK(order == "a1b2a3");
CHECK(v.back().materialize() == 3);
CHECK(v.materialize() == json::parse(R"({"a":1,"b":2,"a":3})")); // the last value, as parse()
}
SECTION("errors are those of const basic_json")
{
for (const char* text :
{"null", "true", "42", "-1", "1.5", "\"s\"", "[]", "[1,2]", "{}", "{\"a\":1}"
})
{
CAPTURE(text)
const json_document d = json_document::parse(text);
const json_view v = d.root();
const json j = v.materialize();
#if !defined(JSON_NOEXCEPTION)
if (!j.is_object())
{
CHECK(exception_of([&] { static_cast<void>(v["a"]); }) == exception_of([&] { static_cast<void>(j["a"]); }));
}
if (!j.is_array())
{
CHECK(exception_of([&] { static_cast<void>(v[0]); }) == exception_of([&] { static_cast<void>(j[0]); }));
}
CHECK(exception_of([&] { static_cast<void>(v.at("a")); }) == exception_of([&] { static_cast<void>(j.at("a")); }));
CHECK(exception_of([&] { static_cast<void>(v.at("missing")); }) == exception_of([&] { static_cast<void>(j.at("missing")); }));
CHECK(exception_of([&] { static_cast<void>(v.at(0)); }) == exception_of([&] { static_cast<void>(j.at(0)); }));
CHECK(exception_of([&] { static_cast<void>(v.at(5)); }) == exception_of([&] { static_cast<void>(j.at(5)); }));
if (!(j.is_object() && j.empty())) // (key() of an end iterator)
{
CHECK(exception_of([&] { static_cast<void>(v.begin().key()); }) == exception_of([&] { static_cast<void>(j.begin().key()); }));
}
if (!j.empty() || j.is_null())
{
CHECK(exception_of([&] { static_cast<void>(v.front()); }) == exception_of([&] { static_cast<void>(j.front()); }));
CHECK(exception_of([&] { static_cast<void>(v.back()); }) == exception_of([&] { static_cast<void>(j.back()); }));
}
#endif
CHECK(v.contains("a") == j.contains("a"));
CHECK(v.count("a") == j.count("a"));
CHECK((v.find("a") == v.end()) == (j.find("a") == j.end())); // NOLINT(readability-container-contains): find() is what is tested
}
// where basic_json has undefined behavior, the view answers safely
const json_document d = json_document::parse(R"({"a":[]})");
CHECK(d.root()["b"].is_discarded());
CHECK(d.root()["a"][0].is_discarded());
CHECK_THROWS_WITH_AS(d.root()["a"].front(), "[json.exception.invalid_iterator.214] cannot get value", json::invalid_iterator&);
CHECK_THROWS_WITH_AS(d.root()["a"].back(), "[json.exception.invalid_iterator.214] cannot get value", json::invalid_iterator&);
const json_view invalid{};
CHECK(invalid.begin() == invalid.end());
CHECK(std::string(invalid.type_name()) == "discarded");
}
SECTION("chained access is safe: operator[] of a discarded view is discarded")
{
const json_document d = json_document::parse(R"({"a":{"b":[10,20]},"s":"str"})");
const json_view v = d.root();
// missing keys and indexes
CHECK(v["x"].is_discarded());
CHECK(v["x"]["y"].is_discarded());
CHECK(v["x"]["y"]["z"].is_discarded());
CHECK(v["x"][0].is_discarded());
CHECK(v["x"][0u][1L].is_discarded());
CHECK(v["a"]["b"][2].is_discarded());
CHECK(v["a"]["b"][2]["c"].is_discarded());
CHECK(v["a"]["b"][2][json_view::json_pointer("/c")].is_discarded());
CHECK(v["x"][json_view::json_pointer("/a/b")].is_discarded());
CHECK(v["x"][json_view::json_pointer("")].is_discarded());
CHECK(v["x"]["y"].is_discarded());
CHECK(v["x"][std::string("y")].is_discarded());
// a resolvable path still resolves
CHECK(v["a"]["b"][1].materialize() == 20);
CHECK(v[json_view::json_pointer("/a/b/1")].materialize() == 20);
// the discarded view of an unresolved pointer is discarded too
CHECK(v[json_view::json_pointer("/x/y")]["z"].is_discarded());
CHECK(v[json_view::json_pointer("/a/b/5")][0].is_discarded());
#if !defined(JSON_NOEXCEPTION)
// type errors on values that are not discarded stay
CHECK_THROWS_WITH_AS(v[0], "[json.exception.type_error.305] cannot use operator[] with a numeric argument with object", json::type_error&);
CHECK_THROWS_WITH_AS(v["a"]["b"]["c"], "[json.exception.type_error.305] cannot use operator[] with a string argument with array", json::type_error&);
CHECK_THROWS_WITH_AS(v["s"]["c"], "[json.exception.type_error.305] cannot use operator[] with a string argument with string", json::type_error&);
CHECK_THROWS_WITH_AS(v["s"][0], "[json.exception.type_error.305] cannot use operator[] with a numeric argument with string", json::type_error&);
CHECK_THROWS_AS(v["a"]["b"][0]["c"], json::type_error&);
CHECK_THROWS_AS(v["s"][json_view::json_pointer("/x")], json::out_of_range&);
// at() keeps throwing on a discarded view
const json_view invalid{};
CHECK(invalid["a"].is_discarded());
CHECK(invalid[0].is_discarded());
CHECK(invalid[json_view::json_pointer("/a")].is_discarded());
CHECK_THROWS_WITH_AS(invalid.at("a"), "[json.exception.type_error.304] cannot use at() with discarded", json::type_error&);
CHECK_THROWS_WITH_AS(invalid.at(0), "[json.exception.type_error.304] cannot use at() with discarded", json::type_error&);
CHECK_THROWS_AS(v.at("x").at("y"), json::out_of_range&);
CHECK_THROWS_AS(v["x"].at("y"), json::type_error&);
CHECK_THROWS_AS(v.at(json_view::json_pointer("/x/y")), json::out_of_range&);
CHECK_THROWS_AS(v["x"].at(json_view::json_pointer("/y")), json::out_of_range&);
#endif
}
SECTION("integer types as array indexes")
{
const json_document d = json_document::parse("[10,20,30]");
const json_view v = d.root();
const json j = v.materialize();
// (a variable: a cast of a constant to int32_t is a useless cast to GCC)
const std::int32_t int32_index = 1;
// (compile-time: no overload is ambiguous)
CHECK(v[0].materialize() == 10);
CHECK(v[1].materialize() == 20);
CHECK(v[0u].materialize() == 10);
CHECK(v[1u].materialize() == 20);
CHECK(v[1L].materialize() == 20);
CHECK(v[2UL].materialize() == 30);
CHECK(v[1LL].materialize() == 20);
CHECK(v[2ULL].materialize() == 30);
CHECK(v[static_cast<short>(1)].materialize() == 20);
CHECK(v[static_cast<unsigned short>(2)].materialize() == 30);
CHECK(v[static_cast<signed char>(1)].materialize() == 20);
CHECK(v[static_cast<unsigned char>(2)].materialize() == 30);
CHECK(v[std::int8_t(1)].materialize() == 20);
CHECK(v[std::int16_t(2)].materialize() == 30);
CHECK(v[int32_index].materialize() == 20);
CHECK(v[std::int64_t(2)].materialize() == 30);
CHECK(v[std::uint32_t(0)].materialize() == 10);
CHECK(v[std::uint64_t(1)].materialize() == 20);
CHECK(v[std::size_t(2)].materialize() == 30);
CHECK(v[std::ptrdiff_t(1)].materialize() == 20);
CHECK(j[0u] == 10); // as basic_json
CHECK(v.at(0).materialize() == 10);
CHECK(v.at(1u).materialize() == 20);
CHECK(v.at(1L).materialize() == 20);
CHECK(v.at(2LL).materialize() == 30);
CHECK(v.at(2ULL).materialize() == 30);
CHECK(v.at(static_cast<short>(1)).materialize() == 20);
CHECK(v.at(static_cast<unsigned short>(2)).materialize() == 30);
CHECK(v.at(int32_index - 1).materialize() == 10);
CHECK(v.at(std::uint32_t(0)).materialize() == 10);
CHECK(v.at(std::int64_t(0)).materialize() == 10);
CHECK(v.at(std::uint64_t(1)).materialize() == 20);
CHECK(v.at(std::size_t(2)).materialize() == 30);
CHECK(j.at(std::uint32_t(0)) == 10); // as basic_json
// out of range, including negative values (no wrap-around)
CHECK(v[3].is_discarded());
CHECK(v[3u].is_discarded());
CHECK(v[3L].is_discarded());
CHECK(v[-1].is_discarded());
CHECK(v[-1L].is_discarded());
CHECK(v[-1LL].is_discarded());
CHECK(v[static_cast<short>(-1)].is_discarded());
CHECK(v[std::int64_t(-3)].is_discarded());
CHECK(v[(std::numeric_limits<std::int64_t>::min)()].is_discarded());
CHECK(v[(std::numeric_limits<std::uint64_t>::max)()].is_discarded());
CHECK(v[(std::numeric_limits<std::size_t>::max)()].is_discarded());
CHECK(v[std::numeric_limits<int>::max()].is_discarded());
#if !defined(JSON_NOEXCEPTION)
CHECK_THROWS_WITH_AS(v.at(3), "[json.exception.out_of_range.401] array index 3 is out of range", json::out_of_range&);
CHECK_THROWS_WITH_AS(v.at(3u), "[json.exception.out_of_range.401] array index 3 is out of range", json::out_of_range&);
CHECK_THROWS_WITH_AS(v.at(std::int64_t(3)), "[json.exception.out_of_range.401] array index 3 is out of range", json::out_of_range&);
CHECK_THROWS_AS(v.at(-1), json::out_of_range&);
CHECK_THROWS_AS(v.at(-1L), json::out_of_range&);
CHECK_THROWS_AS(v.at(std::int64_t(-1)), json::out_of_range&);
CHECK_THROWS_AS(v.at((std::numeric_limits<std::int64_t>::min)()), json::out_of_range&);
CHECK_THROWS_AS(v.at((std::numeric_limits<std::uint64_t>::max)()), json::out_of_range&);
// not an array
const json_document o = json_document::parse("{}");
CHECK_THROWS_AS(o.root()[0u], json::type_error&);
CHECK_THROWS_AS(o.root()[1L], json::type_error&);
CHECK_THROWS_AS(o.root().at(std::uint32_t(0)), json::type_error&);
CHECK_THROWS_AS(o.root().at(std::int64_t(0)), json::type_error&);
#endif
}
SECTION("arrays whose elements have no subtrees: index and back()")
{
// (the elements are adjacent in the index; an array, an object, or an
// empty container anywhere makes the lookup skip element by element)
const std::vector<std::string> texts =
{
"[]", "[1]", "[1,2,3]", "[1,\"two\",3.5,true,null,-7,18446744073709551615]", "[[]]", "[{}]", "[1,[2],3]",
"[1,2,{\"a\":3}]", "[[1,2],3,4]", "[1,2,3,[4,5,6,7,8],9,10,11,12]", "[{\"a\":[1]},2]", R"(["a\u00e4","b"])"
};
for (const std::string& text : texts)
{
CAPTURE(text)
const json_document d = json_document::parse(text);
const json_view v = d.root();
const json expected = json::parse(text);
for (std::size_t i = 0; i < expected.size(); ++i)
{
CHECK(v[i].materialize() == expected[i]);
CHECK(v.at(i).materialize() == expected[i]);
}
CHECK(v[expected.size()].is_discarded());
if (!expected.empty())
{
CHECK(v.back().materialize() == expected.back());
}
}
// a long array (the direct lookup is not limited to short ones), also with a container at its end
std::string text = "[0";
for (int i = 1; i < 1000; ++i)
{
text += "," + std::to_string(i);
}
const json_document scalars = json_document::parse(text + "]");
CHECK(scalars.root()[999].get<int>() == 999);
CHECK(scalars.root()[500].get<int>() == 500);
CHECK(scalars.root().at(1).get<int>() == 1);
CHECK(scalars.root().back().get<int>() == 999);
const json_document container_last = json_document::parse(text + ",[1000]]");
CHECK(container_last.root()[999].get<int>() == 999);
CHECK(container_last.root()[1000][0].get<int>() == 1000);
CHECK(container_last.root().back()[0].get<int>() == 1000);
}
SECTION("iterators")
{
const json_document d = json_document::parse(R"({"x":[1,{"y":2}],"z":null})");
const json_view v = d.root();
json_view::iterator it = v.begin();
CHECK(it.is_object_iterator());
CHECK(it->is_array());
CHECK(it->size() == 2);
const json_view::iterator previous = it++;
CHECK(previous.key() == "x");
CHECK(it.key() == "z");
CHECK(it.value().is_null());
CHECK(++it == v.end());
CHECK(v.cbegin() == v.begin());
CHECK(v.cend() == v.end());
CHECK(!v["x"].begin().is_object_iterator());
CHECK(json_view::iterator() == json_view::iterator());
// standard algorithms
CHECK(std::count_if(v["x"].begin(), v["x"].end(), [](const json_view & e)
{
return e.is_object();
}) == 1);
}
SECTION("items")
{
const json_document d = json_document::parse(R"({"a":1,"b":[true,false]})");
std::string keys;
for (const auto& item : d.root().items())
{
keys += std::string(item.key().data(), item.key().size());
CHECK(item.value().materialize() == d.root()[item.key()].materialize());
}
CHECK(keys == "ab");
auto items = d.root()["b"].items();
auto first = items.begin();
CHECK((*first++).key() == "0");
CHECK((*first).key() == "1");
CHECK(++first == items.end());
// the keys of array elements are their indexes, whether or not they are asked for
std::string numbers = "[0";
for (int i = 1; i < 1234; ++i)
{
numbers += "," + std::to_string(i);
}
const json_document array = json_document::parse(numbers + "]");
std::size_t position = 0;
for (const auto& item : array.root().items())
{
CHECK(item.value().get<std::size_t>() == position);
if (position % 3 != 0) // (not for every item: values alone do not make the key)
{
CHECK(item.key() == std::to_string(position));
CHECK(item.key().data() == item.key().data()); // (the same text every time)
const json_view::item copy = item;
CHECK(copy.key() == std::to_string(position));
}
++position;
}
CHECK(position == 1234);
#ifdef JSON_HAS_CPP_17
std::string pairs;
for (const auto [key, value] : d.root().items())
{
pairs += std::string(key) + "=" + value.materialize().dump() + ";";
}
CHECK(pairs == "a=1;b=[true,false];");
static_assert(std::tuple_size<json_view::item>::value == 2, "tuple_size of an item is 2");
static_assert(std::is_same<std::tuple_element<1, json_view::item>::type, json_view>::value, "the second element of an item is a view");
#endif
}
}
namespace
{
#if !defined(JSON_NOEXCEPTION)
// an exception message without the context that basic_json adds with
// JSON_DIAGNOSTICS ("(/path) ") and JSON_DIAGNOSTIC_POSITIONS ("(bytes 1-2) ");
// the view's exceptions have no such context
std::string without_path(std::string msg)
{
for (const char* prefix :
{"] (/", "] (bytes "
})
{
const std::size_t open = msg.find(prefix);
if (open != std::string::npos)
{
msg.erase(open + 2, msg.find(") ", open) + 2 - (open + 2));
}
}
return msg;
}
#endif
// the bits of a float, to compare values bit for bit
std::uint64_t bits(double x)
{
std::uint64_t r = 0;
std::memcpy(&r, &x, sizeof(r));
return r;
}
std::uint32_t bits(float x)
{
std::uint32_t r = 0;
std::memcpy(&r, &x, sizeof(r));
return r;
}
// compares the conversions of a view with those of ordered_json
void check_values(const ordered_json_view& v, const ordered_json& j, const std::string& text)
{
CHECK(v.get<ordered_json>() == j);
switch (j.type())
{
case json::value_t::number_integer:
case json::value_t::number_unsigned:
case json::value_t::number_float:
{
// (converting a float out of range of the target type is undefined)
if (j.is_number_unsigned())
{
CHECK(v.get<std::uint64_t>() == j.get<std::uint64_t>());
}
else if (j.is_number_integer())
{
CHECK(v.get<std::int64_t>() == j.get<std::int64_t>());
}
CHECK(bits(v.get<double>()) == bits(j.get<double>()));
if (std::abs(j.get<double>()) < 1e9)
{
CHECK(v.get<int>() == j.get<int>());
}
const auto token = v.number_token();
CHECK(text.compare(v.source_offset(), token.size(), token.data(), token.size()) == 0);
break;
}
case json::value_t::string:
CHECK(v.get<std::string>() == j.get<std::string>());
CHECK(std::string(v.get_string().data(), v.get_string().size()) == j.get<std::string>());
break;
case json::value_t::boolean:
CHECK(v.get<bool>() == j.get<bool>());
CHECK(v.get<int>() == j.get<int>());
break;
case json::value_t::null:
CHECK(v.get<std::nullptr_t>() == nullptr);
break;
case json::value_t::array:
CHECK(v.get<std::vector<ordered_json>>() == j.get<std::vector<ordered_json>>());
break;
case json::value_t::object:
CHECK((v.get<std::map<std::string, ordered_json>>() == j.get<std::map<std::string, ordered_json>>()));
break;
case json::value_t::binary:
case json::value_t::discarded:
default:
break;
}
#if !defined(JSON_NOEXCEPTION)
// conversions to the wrong type throw what basic_json throws
if (!j.is_number())
{
CHECK(exception_of([&] { static_cast<void>(v.get<int>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<int>()); })));
}
CHECK(exception_of([&] { static_cast<void>(v.get<bool>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<bool>()); })));
CHECK(exception_of([&] { static_cast<void>(v.get<std::string>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::string>()); })));
CHECK(exception_of([&] { static_cast<void>(v.get<std::nullptr_t>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::nullptr_t>()); })));
if (!j.is_array())
{
CHECK(exception_of([&] { static_cast<void>(v.get<std::vector<int>>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::vector<int>>()); })));
}
if (!j.is_object())
{
CHECK(exception_of([&] { static_cast<void>(v.get<std::map<std::string, int>>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::map<std::string, int>>()); })));
}
#endif
if (v.is_array())
{
std::size_t i = 0;
for (const ordered_json_view e : v)
{
check_values(e, j[i++], text);
}
}
else if (v.is_object())
{
for (auto it = v.begin(); it != v.end(); ++it)
{
const std::string key(it.key().data(), it.key().size());
if (v.size() == j.size()) // (no duplicate keys)
{
check_values(it.value(), j[key], text);
}
}
}
}
struct record
{
std::string name{}; // NOLINT(readability-redundant-member-init)
int count = 0;
};
void from_json(const json& j, record& r)
{
j.at("name").get_to(r.name);
j.at("count").get_to(r.count);
}
struct defaults
{
int a = 1;
int b = 2;
};
// sets only the members the JSON value has
void from_json(const json& j, defaults& d)
{
if (j.contains("a"))
{
j.at("a").get_to(d.a);
}
if (j.contains("b"))
{
j.at("b").get_to(d.b);
}
}
} // namespace
TEST_CASE("json_view values")
{
SECTION("generated documents")
{
generator g;
for (int i = 0; i < 2000; ++i)
{
std::string text;
g.value(text, 0);
CAPTURE(text)
const ordered_json_document d = ordered_json_document::parse(text);
check_values(d.root(), ordered_json::parse(text), text);
}
}
SECTION("floats are converted as parse() converts them")
{
std::mt19937_64 rng(5295); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
std::vector<std::string> tokens = {"0.1", "-0.0", "1e308", "1.7976931348623157e308", "2.2250738585072011e-308", "4.9e-324", "5e-324",
"0.1000000000000000055511151231257827021181583404541015625", "123456789012345678901234567890",
"9007199254740993", "1.00000000000000011102230246251565404236316680908203125", "7.2057594037927933e16",
// around the limits of the conversion from the digit layout: 19 and 20
// digits, and those of Clinger's fast path (2^53, 10^22)
"1234567890.123456789", "1234567890.1234567891", "0.0000000000000000001", "123456789012345678.9",
"9007199254740992.0", "9007199254740993.0", "9007199254740994.0", "1.5e22", "1.5e23", "15e-22", "15e-23",
"1e-400", "0.0e0", "-0.0e-5", "12E+3", "12e-0",
// and of float: 2^24 + 1 and 2^24 + 3 (ties), the subnormal and normal limits
"16777217", "16777219", "1.4e-45", "7.006492321624085e-46", "7.006492321624086e-46",
"1.17549435e-38", "0.30000001192092896", "3.4028234e37"
};
for (int i = 0; i < 20000; ++i)
{
const std::uint64_t bits = rng();
double d = 0;
std::memcpy(&d, &bits, sizeof(d));
if (!std::isfinite(d))
{
continue;
}
std::array<char, 400> buf{};
switch (i % 5) // NOLINT(hicpp-multiway-paths-covered)
{
case 0:
static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.17g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
break;
case 1:
static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.15g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
break;
case 2:
static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.3e", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
break;
case 3:
static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.25g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
break;
default:
static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.0f", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
break;
}
tokens.emplace_back(buf.data());
}
using json_float = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, float>;
for (const auto& token : tokens)
{
CAPTURE(token)
const std::string text = "[" + token + "]";
const double b = json::parse(text)[0].get<double>();
const json_document dd = json_document::parse(text);
CHECK(bits(dd.root()[0].get<double>()) == bits(b));
if (std::abs(b) < 1e38)
{
const nlohmann::basic_json_document<json_float> df = nlohmann::basic_json_document<json_float>::parse(text);
CHECK(bits(df.root()[0].get<float>()) == bits(json_float::parse(text)[0].get<float>()));
}
}
}
SECTION("number tokens")
{
const json_document d = json_document::parse(R"([1.50, 1E2, -0, 123456789012345678901234567890, -12, 7, "x"])");
const json_view v = d.root();
CHECK(v[0].number_token() == "1.50");
CHECK(v[1].number_token() == "1E2");
CHECK(v[2].number_token() == "-0");
CHECK(v[3].number_token() == "123456789012345678901234567890");
CHECK(v[4].number_token() == "-12");
CHECK(v[5].number_token() == "7");
CHECK_THROWS_WITH_AS(v[6].number_token(), "[json.exception.type_error.302] type must be number, but is string", json::type_error&);
CHECK_THROWS_WITH_AS(v.get_string(), "[json.exception.type_error.302] type must be string, but is array", json::type_error&);
}
SECTION("conversions")
{
const std::string text = R"({"name": "widget", "count": 3, "tags": ["a", "b\n"], "sizes": {"s": 1, "m": 2}, "pair": [1, "x"]})";
const json_document d = json_document::parse(text);
const json_view v = d.root();
const json j = json::parse(text);
// user types with from_json, and other types, through basic_json
const auto r = v.get<record>();
CHECK(r.name == "widget");
CHECK(r.count == 3);
CHECK((v["pair"].get<std::pair<int, std::string>>() == j["pair"].get<std::pair<int, std::string>>()));
CHECK(v["tags"].get<std::list<std::string>>() == j["tags"].get<std::list<std::string>>());
CHECK((v["sizes"].get<std::unordered_map<std::string, int>>() == j["sizes"].get<std::unordered_map<std::string, int>>()));
CHECK(v["tags"].get<std::vector<std::string>>() == std::vector<std::string> {"a", "b\n"});
// views of the elements
const auto views = v["tags"].get<std::vector<json_view>>();
CHECK(views.size() == 2);
CHECK(views[1].get_string() == "b\n");
const auto members = v.get<std::map<std::string, json_view>>();
CHECK(members.at("count").get<int>() == 3);
CHECK(v.get<json_view>()["name"].get_string() == "widget");
// strings without a copy point into the source text
CHECK(v["name"].get_string().data() == text.data() + text.find("widget"));
#ifdef JSON_HAS_CPP_17
CHECK(v["name"].get<std::string_view>() == "widget");
#endif
std::string name;
int count = 0;
CHECK(&v["name"].get_to(name) == &name);
v["count"].get_to(count);
CHECK(name == "widget");
CHECK(count == 3);
// other types go to from_json with the existing value, as basic_json::get_to()
defaults def;
def.b = 5;
const json_document partial = json_document::parse(R"({"a":4})");
partial.root().get_to(def);
CHECK(def.a == 4);
CHECK(def.b == 5);
// a duplicate key: the last value, as parse()
const json_document dup = json_document::parse(R"({"a":1,"a":2})");
CHECK((dup.root().get<std::map<std::string, int>>() == std::map<std::string, int> {{"a", 2}}));
const json_view invalid{};
CHECK_THROWS_WITH_AS(invalid.get<int>(), "[json.exception.type_error.302] type must be number, but is discarded", json::type_error&);
CHECK(invalid.get<json>().is_discarded());
}
SECTION("value")
{
const json_document d = json_document::parse(R"({"n": 1, "s": "text", "o": {"x": [10, 20]}})");
const json_view v = d.root();
const json j = v.materialize();
CHECK(v.value("n", 0) == j.value("n", 0));
CHECK(v.value("missing", 42) == j.value("missing", 42));
CHECK(v.value("s", "default") == j.value("s", "default"));
CHECK(v.value("missing", "default") == j.value("missing", "default"));
CHECK(v.value(std::string("n"), 2.5) == j.value(std::string("n"), 2.5));
CHECK(v.value(json::json_pointer("/o/x/1"), 0) == j.value(json::json_pointer("/o/x/1"), 0));
CHECK(v.value(json::json_pointer("/o/x/5"), 0) == j.value(json::json_pointer("/o/x/5"), 0));
CHECK(v.value(json::json_pointer("/o/y"), "none") == j.value(json::json_pointer("/o/y"), "none"));
// with a JSON pointer, arrays can be asked as well
CHECK(v["o"]["x"].value(json::json_pointer("/1"), 0) == j["o"]["x"].value(json::json_pointer("/1"), 0));
CHECK(v["o"]["x"].value(json::json_pointer("/7"), 3) == j["o"]["x"].value(json::json_pointer("/7"), 3));
#if !defined(JSON_NOEXCEPTION)
CHECK(exception_of([&] { static_cast<void>(v["o"]["x"].value("k", 0)); }) == without_path(exception_of([&] { static_cast<void>(j["o"]["x"].value("k", 0)); })));
CHECK(exception_of([&] { static_cast<void>(v.value("s", 0)); }) == without_path(exception_of([&] { static_cast<void>(j.value("s", 0)); })));
CHECK(exception_of([&] { static_cast<void>(v["n"].value("x", 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value("x", 0)); })));
CHECK(exception_of([&] { static_cast<void>(v["n"].value(json::json_pointer("/x"), 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value(json::json_pointer("/x"), 0)); })));
// string defaults: the member is not a string, or the value is neither an object nor an array
CHECK(exception_of([&] { static_cast<void>(v.value("n", "default")); }) == without_path(exception_of([&] { static_cast<void>(j.value("n", "default")); })));
CHECK(exception_of([&] { static_cast<void>(v["n"].value("x", "default")); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value("x", "default")); })));
CHECK(exception_of([&] { static_cast<void>(v.value(json::json_pointer("/n"), "default")); }) == without_path(exception_of([&] { static_cast<void>(j.value(json::json_pointer("/n"), "default")); })));
CHECK(exception_of([&] { static_cast<void>(v["s"].value(json::json_pointer("/x"), "default")); }) == without_path(exception_of([&] { static_cast<void>(j["s"].value(json::json_pointer("/x"), "default")); })));
#endif
// (defaults and members longer than the short string optimization)
CHECK(v.value("s", "a default longer than fifteen characters") == "text");
CHECK(v.value("missing", "a default longer than fifteen characters") == "a default longer than fifteen characters");
CHECK(v.value(json::json_pointer("/s"), "a default longer than fifteen characters") == "text");
CHECK(v.value(json::json_pointer("/zz"), "a default longer than fifteen characters") == "a default longer than fifteen characters");
}
}
TEST_CASE("json_view JSON pointers")
{
SECTION("every value of generated documents")
{
generator g;
for (int i = 0; i < 1000; ++i)
{
std::string text;
g.value(text, 0);
const ordered_json_document d = ordered_json_document::parse(text);
if (has_duplicate_keys(d.root()))
{
continue;
}
CAPTURE(text)
const ordered_json j = ordered_json::parse(text);
const ordered_json flat = j.flatten();
for (const auto& leaf : flat.items())
{
// the leaf and each of its parents
for (ordered_json::json_pointer p(leaf.key());; p = p.parent_pointer())
{
CAPTURE(p.to_string())
CHECK(d.root()[p].materialize() == j[p]);
CHECK(d.root().at(p).materialize() == j.at(p));
CHECK(d.root().contains(p));
if (p.empty())
{
break;
}
}
}
}
}
#if !defined(JSON_NOEXCEPTION)
SECTION("errors are those of basic_json")
{
const std::string text = R"({"a": [1, {"b": null}], "c": "s", "": {"": 0}, "a~b": 1, "c/d": 2})";
const json_document d = json_document::parse(text);
const json_view v = d.root();
const json j = v.materialize();
for (const char* pointer :
{"", "/", "//", "/a", "/a/0", "/a/1/b", "/a/-", "/a/01", "/a/00", "/a/1a", "/a/a", "/a/", "/a/2", "/a/99", "/a/99999999999999999999",
"/a/18446744073709551615", "/a/-1", "/a/+1", "/a/ 1", "/x", "/c/x", "/a/0/x", "/a/1/b/c", "/a~0b", "/c~1d", "/c~1d/x", "/a/1/-"
})
{
CAPTURE(pointer)
const json::json_pointer p(pointer);
const std::string at_error = without_path(exception_of([&] { static_cast<void>(j.at(p)); }));
CHECK(exception_of([&] { static_cast<void>(v.at(p)); }) == at_error);
if (at_error.empty())
{
CHECK(v.at(p).materialize() == j.at(p));
CHECK(v[p].materialize() == j[p]);
}
else if (at_error.find("out_of_range.401") != std::string::npos || at_error.find("out_of_range.403") != std::string::npos) // NOLINT(abseil-string-find-str-contains)
{
// undefined behavior for const basic_json::operator[]
CHECK(v[p].is_discarded());
}
else
{
CHECK(exception_of([&] { static_cast<void>(v[p]); }) == without_path(exception_of([&] { static_cast<void>(j[p]); })));
}
// (basic_json::contains() throws out_of_range.404 for an empty
// array index token, although it is not meant to throw; the view
// answers false)
const std::string contains_error = exception_of([&]
{
const bool found = j.contains(p);
static_cast<void>(found);
});
CHECK(v.contains(p) == (contains_error.empty() && j.contains(p)));
CHECK(exception_of([&] { static_cast<void>(v.value(p, 5)); }) == without_path(exception_of([&] { static_cast<void>(j.value(p, 5)); })));
}
}
#endif
}