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Niels LohmannandClaude Sonnet 5.5 07ac676393 Fix clang-tidy modernize-use-auto in json_view from_json tests
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N5NasCxh8jKXBaa6HBx9Xk
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-31 07:28:45 +00:00
Niels Lohmann 1db091b784 Document and test the lifetime of string_view members decoded from a json_view
A struct with a std::string_view member defined via NLOHMANN_DEFINE_TYPE_*
decodes from a json_view without a copy: the member points into the source
text, or, for a string with escape sequences, into the buffer of decoded
strings of the document. It is valid while the document is alive and, for a
document that borrows its text, while that text is.

The feature page now says so, including that the same struct compiles with
json::parse(text).get<T>() and then points into the temporary json value.
The new test checks where plain and escaped members point and that they stay
readable while the document and a borrowed source text are alive. It does not
read dangling memory.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-30 22:41:47 +01:00
7 changed files with 156 additions and 452 deletions

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@@ -13,15 +13,9 @@ function never throws an exception for invalid input, and the returned `#!cpp bo
is returned. is returned.
The result is the same as that of `BasicJsonType::accept()` by design; the difference is how the check is made. This The result is the same as that of `BasicJsonType::accept()` by design; the difference is how the check is made. This
function runs the document's builder, which checks the text as [`parse()`](parse.md) does, while function runs the document's index builder (and discards the index), while `BasicJsonType::accept()` runs the SAX
`BasicJsonType::accept()` runs the SAX parser with a handler that ignores every event. Use this one if you go on to parser with a handler that ignores every event. Use this one if you go on to parse the same input with
parse the same input with [`parse()`](parse.md) anyway, so that both use the same code; either is fine for a plain [`parse()`](parse.md) anyway, so that both use the same code; either is fine for a plain yes/no answer.
yes/no answer.
When both `ignore_comments` and `ignore_trailing_commas` are `#!cpp false` (the default), the builder writes no index.
With either option set, it builds the index as [`parse()`](parse.md) does and discards it: the result is the same, only
the time differs. (Neither option needs the index; the variant that skips it exists only for the default options to
keep the code size down.)
## Template parameters ## Template parameters
+28
View File
@@ -253,6 +253,34 @@ Two conversions never copy at all:
Both results are only valid as long as the view — and, for a string with no escapes, the borrowed source text — is. Both results are only valid as long as the view — and, for a string with no escapes, the borrowed source text — is.
### `string_view` members
A struct whose member is a `#!cpp std::string_view` (C++17) can be decoded from a view with the
`NLOHMANN_DEFINE_TYPE_*` macros, and the member is not copied either: for a string without escape sequences it points
into the document's source text, and for a string with escape sequences into the document's buffer of decoded strings.
The member is valid as long as the document is alive and, for a document that
[borrows its source text](#ownership-and-lifetime) (as [`parse()`](../api/basic_json_document/parse.md) does for
an lvalue `#!cpp std::string`, a `#!cpp std::string_view`, or a C string), as long as that text is.
```cpp
struct record
{
std::string_view name;
int count;
NLOHMANN_DEFINE_TYPE_INTRUSIVE(record, name, count)
};
const std::string text = R"({"name": "widget", "count": 3})";
const json_document doc = json_document::parse(text); // borrows text
const record r = doc.root().get<record>(); // r.name points into text, valid while text and doc are
```
!!! warning "Decoding into a `string_view` from a `json` value dangles at once"
The same struct also compiles with `#!cpp json::parse(text).get<record>()`, but there `name` points into the
temporary `json` value, which is destroyed at the end of the statement. Use a named
[`json_document`](../api/json_document.md), as above, to decode such a struct.
## Writing generic code ## Writing generic code
A view's type names its `BasicJsonType` and its [`view_mode`](../api/view_mode.md): A view's type names its `BasicJsonType` and its [`view_mode`](../api/view_mode.md):
+10 -112
View File
@@ -69,8 +69,7 @@ struct parse_failure
}; };
/// FloatType: the number_float_t of the document, whose overflow parse() rejects /// FloatType: the number_float_t of the document, whose overflow parse() rejects
/// Store: false for accept(): the grammar, number, string and UTF-8 checks run as for parse(), but no node is written template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Sentinel>
template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Sentinel, bool Store>
class builder class builder
{ {
public: public:
@@ -246,87 +245,11 @@ class builder
return p; return p;
} }
/// the string from p, the first backslash, control character, ill-formed UTF-8 byte, or the end, checked and not
/// decoded (accept() stores nothing, so the arena is not written): the checks, errors and error positions of
/// slow_string(), for everything up to the closing quote
NLOHMANN_VIEW_NOINLINE decoded check_string(const unsigned char* p)
{
const unsigned char* const end = m_end;
for (;;)
{
if (p == end)
{
return failed(error_code::string_missing_quote, p);
}
const unsigned char c = *p;
if (c == '"')
{
++p;
return decoded{p, 0, 0};
}
if (c != '\\')
{
return failed(c < 0x20 ? error_code::string_control_character : error_code::string_utf8, p);
}
++p;
if (p == end)
{
return failed(error_code::string_missing_quote, p);
}
const unsigned char d = *p++;
if (d == 'u')
{
const int cp = hex4(p); // (moves p past the four digits)
if (NLOHMANN_VIEW_UNLIKELY(cp < 0))
{
return failed(error_code::string_unicode_hex, p);
}
if (NLOHMANN_VIEW_UNLIKELY((cp & 0xF800) == 0xD800)) // a surrogate
{
if (cp >= 0xDC00)
{
return failed(error_code::string_surrogate_low, p);
}
if (end - p < 2 || p[0] != '\\' || p[1] != 'u')
{
return failed(error_code::string_surrogate_high, p);
}
p += 2;
const int lo = hex4(p); // (moves p past the four digits)
if (lo < 0)
{
return failed(error_code::string_unicode_hex, p);
}
if (lo < 0xDC00 || lo > 0xDFFF)
{
return failed(error_code::string_surrogate_high, p);
}
}
}
else if (!(d == '"' || d == '\\' || d == '/' || d == 'b' || d == 'f' || d == 'n' || d == 'r' || d == 't'))
{
--p;
return failed(error_code::string_escape, p);
}
if (p != end && *p == '\\')
{
continue; // (escapes in a row: no run of text between them)
}
p = scan_string_run(p, end); // the text up to the next backslash, quote, control character, or ill-formed UTF-8
}
}
/// s points to the start of the string, p to a backslash, a control /// s points to the start of the string, p to a backslash, a control
/// character, an ill-formed UTF-8 byte, or the end: decode the string into /// character, an ill-formed UTF-8 byte, or the end: decode the string into
/// the arena /// the arena
NLOHMANN_VIEW_NOINLINE decoded slow_string(const unsigned char* s, const unsigned char* p) NLOHMANN_VIEW_NOINLINE decoded slow_string(const unsigned char* s, const unsigned char* p)
{ {
if (!enabled(Store))
{
// (accept(): the string is checked, not decoded)
static_cast<void>(s);
return check_string(p);
}
// single-character escapes; 0: invalid (and 'u', handled separately) // single-character escapes; 0: invalid (and 'u', handled separately)
static const std::array<char, 128> simple_escape = static const std::array<char, 128> simple_escape =
{ {
@@ -686,14 +609,11 @@ run_found:
std::size_t max_depth = 0; std::size_t max_depth = 0;
NLOHMANN_VIEW_ALWAYS_INLINE bool run() NLOHMANN_VIEW_ALWAYS_INLINE bool run()
{
if (enabled(Store))
{ {
cold.m_doc.reserve(estimate_nodes(reinterpret_cast<const char*>(b), static_cast<std::size_t>(e - b))); cold.m_doc.reserve(estimate_nodes(reinterpret_cast<const char*>(b), static_cast<std::size_t>(e - b)));
base = cold.m_doc.nodes; base = cold.m_doc.nodes;
out = base; out = base;
cap = base + cold.m_doc.node_capacity; cap = base + cold.m_doc.node_capacity;
}
if (e - p >= 3 && p[0] == 0xEF && p[1] == 0xBB && p[2] == 0xBF) if (e - p >= 3 && p[0] == 0xEF && p[1] == 0xBB && p[2] == 0xBF)
{ {
@@ -876,12 +796,9 @@ close_object:
// a large object gets a hash index for its keys (objects only, so that closing // a large object gets a hash index for its keys (objects only, so that closing
// an array pays nothing for this) // an array pays nothing for this)
if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members)) if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members))
{
if (enabled(Store))
{ {
cold.note_large_object(cur_idx); cold.note_large_object(cur_idx);
} }
}
close_container: close_container:
close(); close();
@@ -1040,12 +957,6 @@ indent_done:
/// an integer's value); two stores on little-endian targets /// an integer's value); two stores on little-endian targets
NLOHMANN_VIEW_ALWAYS_INLINE node* push_node(node_kind k, std::uint8_t flags, std::uint16_t extra, std::size_t off, std::uint64_t second) NLOHMANN_VIEW_ALWAYS_INLINE node* push_node(node_kind k, std::uint8_t flags, std::uint16_t extra, std::size_t off, std::uint64_t second)
{ {
if (!enabled(Store))
{
// accept(): nothing is stored, so what computes the arguments is not run either. base and out stay
// null: their difference, which open() takes, is 0.
return out;
}
if (NLOHMANN_VIEW_UNLIKELY(out == cap)) if (NLOHMANN_VIEW_UNLIKELY(out == cap))
{ {
const auto n = static_cast<std::size_t>(out - base); const auto n = static_cast<std::size_t>(out - base);
@@ -1103,13 +1014,10 @@ indent_done:
} }
NLOHMANN_VIEW_ALWAYS_INLINE void close() NLOHMANN_VIEW_ALWAYS_INLINE void close()
{
if (enabled(Store))
{ {
node& n = base[cur_idx]; node& n = base[cur_idx];
n.len = cur_count; n.len = cur_count;
n.next = static_cast<std::uint32_t>(out - base) - cur_idx; n.next = static_cast<std::uint32_t>(out - base) - cur_idx;
}
if (--depth != 0) if (--depth != 0)
{ {
if (NLOHMANN_VIEW_LIKELY(depth <= 64)) if (NLOHMANN_VIEW_LIKELY(depth <= 64))
@@ -1284,44 +1192,34 @@ indent_done:
}; };
/// run the builder with compile-time options /// run the builder with compile-time options
template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Store> template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd>
inline bool build_with(document_data& d, const char* src, std::size_t size, bool sentinel, parse_failure& failure) inline bool build_with(document_data& d, const char* src, std::size_t size, bool sentinel, parse_failure& failure)
{ {
if (sentinel) if (sentinel)
{ {
builder<FloatType, Comments, TrailingCommas, NulIsEnd, true, Store> bld(d, src, size); builder<FloatType, Comments, TrailingCommas, NulIsEnd, true> bld(d, src, size);
const bool ok = bld.run(); const bool ok = bld.run();
failure = bld.failure(); failure = bld.failure();
return ok; return ok;
} }
builder<FloatType, Comments, TrailingCommas, NulIsEnd, false, Store> bld(d, src, size); builder<FloatType, Comments, TrailingCommas, NulIsEnd, false> bld(d, src, size);
const bool ok = bld.run(); const bool ok = bld.run();
failure = bld.failure(); failure = bld.failure();
return ok; return ok;
} }
/// sentinel: src[size] is readable and 0 (e.g. std::string); FloatType: the /// sentinel: src[size] is readable and 0 (e.g. std::string); FloatType: the
/// number_float_t of the document; validate_only: accept(), only the result is /// number_float_t of the document
/// used
template<typename FloatType, bool NulIsEnd> template<typename FloatType, bool NulIsEnd>
inline bool build(document_data& d, const char* src, std::size_t size, bool comments, bool trailing_commas, bool sentinel, bool validate_only, inline bool build(document_data& d, const char* src, std::size_t size, bool comments, bool trailing_commas, bool sentinel, parse_failure& failure)
parse_failure& failure)
{ {
if (validate_only && !comments && !trailing_commas)
{
// accept() of plain JSON: nothing is stored. The other option sets
// could skip the stores just as well; they keep the builder that
// stores only so that there are two more instantiations of the parse
// loop, not eight.
return build_with<FloatType, false, false, NulIsEnd, false>(d, src, size, sentinel, failure);
}
if (comments) if (comments)
{ {
return trailing_commas ? build_with<FloatType, true, true, NulIsEnd, true>(d, src, size, sentinel, failure) return trailing_commas ? build_with<FloatType, true, true, NulIsEnd>(d, src, size, sentinel, failure)
: build_with<FloatType, true, false, NulIsEnd, true>(d, src, size, sentinel, failure); : build_with<FloatType, true, false, NulIsEnd>(d, src, size, sentinel, failure);
} }
return trailing_commas ? build_with<FloatType, false, true, NulIsEnd, true>(d, src, size, sentinel, failure) return trailing_commas ? build_with<FloatType, false, true, NulIsEnd>(d, src, size, sentinel, failure)
: build_with<FloatType, false, false, NulIsEnd, true>(d, src, size, sentinel, failure); : build_with<FloatType, false, false, NulIsEnd>(d, src, size, sentinel, failure);
} }
} // namespace view } // namespace view
+19 -37
View File
@@ -1060,7 +1060,7 @@ class basic_json_document
const bool ignore_trailing_commas = false) const bool ignore_trailing_commas = false)
{ {
basic_json_document d; basic_json_document d;
d.read_range(first, last, error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas); d.read_range(first, last, allow_exceptions, ignore_comments, ignore_trailing_commas);
return d; return d;
} }
@@ -1075,7 +1075,7 @@ class basic_json_document
basic_json_document d; basic_json_document d;
std::string buf; std::string buf;
append_input(buf, std::forward<InputType>(input)); append_input(buf, std::forward<InputType>(input));
d.build_owned(std::move(buf), error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas); d.build_owned(std::move(buf), allow_exceptions, ignore_comments, ignore_trailing_commas);
return d; return d;
} }
@@ -1088,8 +1088,7 @@ class basic_json_document
static bool accept(InputType&& input, const bool ignore_comments = false, const bool ignore_trailing_commas = false) static bool accept(InputType&& input, const bool ignore_comments = false, const bool ignore_trailing_commas = false)
{ {
basic_json_document d; basic_json_document d;
d.read_kind(std::forward<InputType>(input), on_error::validate, ignore_comments, ignore_trailing_commas, d.read(std::forward<InputType>(input), false, ignore_comments, ignore_trailing_commas);
std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {});
return !d.is_discarded(); return !d.is_discarded();
} }
@@ -1105,7 +1104,7 @@ class basic_json_document
const bool ignore_comments = false, const bool ignore_comments = false,
const bool ignore_trailing_commas = false) const bool ignore_trailing_commas = false)
{ {
read_kind(std::forward<InputType>(input), error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas, read_kind(std::forward<InputType>(input), allow_exceptions, ignore_comments, ignore_trailing_commas,
std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {}); std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {});
} }
@@ -1464,22 +1463,6 @@ class basic_json_document
return idx; return idx;
} }
/// what a failed parse does
enum class on_error : std::uint8_t
{
discard, ///< the document is discarded
raise, ///< parse_error is thrown
validate ///< accept(): the document is discarded, and no node is stored while parsing
};
static on_error error_mode(bool allow_exceptions) noexcept
{
return allow_exceptions ? on_error::raise : on_error::discard;
}
/// NulIsEnd of the builder: a null byte ends the input unless strict_nul_handling
static constexpr bool nul_is_end = !detail::abi_config::strict_nul_handling;
/// create the storage (sized for the input) on first use /// create the storage (sized for the input) on first use
void ensure_data(const char* src, std::size_t size) void ensure_data(const char* src, std::size_t size)
{ {
@@ -1491,7 +1474,7 @@ class basic_json_document
/// parse a buffer the document takes ownership of (it replaces the /// parse a buffer the document takes ownership of (it replaces the
/// previous owned copy) /// previous owned copy)
void build_owned(std::string&& buf, on_error allow_exceptions, bool comments, bool trailing_commas) void build_owned(std::string&& buf, bool allow_exceptions, bool comments, bool trailing_commas)
{ {
ensure_data(buf.data(), buf.size()); ensure_data(buf.data(), buf.size());
m_data->owned = std::move(buf); m_data->owned = std::move(buf);
@@ -1501,7 +1484,7 @@ class basic_json_document
/// parse a copy of the input; the copy is appended to the cleared owned /// parse a copy of the input; the copy is appended to the cleared owned
/// buffer, so that its capacity is reused /// buffer, so that its capacity is reused
template<typename T> template<typename T>
void build_copy(T&& input, on_error allow_exceptions, bool comments, bool trailing_commas) void build_copy(T&& input, bool allow_exceptions, bool comments, bool trailing_commas)
{ {
if (!m_data) if (!m_data)
{ {
@@ -1522,7 +1505,7 @@ class basic_json_document
} }
/// sentinel: src[size] is readable and 0 (std::string, C strings) /// sentinel: src[size] is readable and 0 (std::string, C strings)
void build(const char* src, std::size_t size, on_error allow_exceptions, bool comments, bool trailing_commas, bool owned, bool sentinel) void build(const char* src, std::size_t size, bool allow_exceptions, bool comments, bool trailing_commas, bool owned, bool sentinel)
{ {
ensure_data(src, size); ensure_data(src, size);
document_data& d = *m_data; document_data& d = *m_data;
@@ -1549,8 +1532,7 @@ class basic_json_document
} }
else else
{ {
ok = detail::view::build<typename BasicJsonType::number_float_t, nul_is_end>(d, src, size, comments, trailing_commas, sentinel, ok = detail::view::build < typename BasicJsonType::number_float_t, !detail::abi_config::strict_nul_handling > (d, src, size, comments, trailing_commas, sentinel, failure);
allow_exceptions == on_error::validate, failure);
} }
if (NLOHMANN_VIEW_LIKELY(ok)) if (NLOHMANN_VIEW_LIKELY(ok))
{ {
@@ -1563,7 +1545,7 @@ class basic_json_document
return; return;
} }
std::vector<std::uint32_t>().swap(d.large_objects); std::vector<std::uint32_t>().swap(d.large_objects);
if (allow_exceptions == on_error::raise) if (allow_exceptions)
{ {
detail::view::throw_parse_failure<BasicJsonType>(failure, src, size, comments, trailing_commas); detail::view::throw_parse_failure<BasicJsonType>(failure, src, size, comments, trailing_commas);
} }
@@ -1571,13 +1553,13 @@ class basic_json_document
// --- input dispatch (see detail::view::input_kind) --- // --- input dispatch (see detail::view::input_kind) ---
void read_kind(std::string&& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::move_string> /*unused*/) void read_kind(std::string&& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::move_string> /*unused*/)
{ {
build_owned(std::move(s), ae, c, tc); build_owned(std::move(s), ae, c, tc);
} }
template<typename CharT> template<typename CharT>
void read_kind(CharT* s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::c_string> /*unused*/) void read_kind(CharT* s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::c_string> /*unused*/)
{ {
if (s == nullptr) if (s == nullptr)
{ {
@@ -1591,7 +1573,7 @@ class basic_json_document
} }
template<typename Array> template<typename Array>
void read_kind(Array& a, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::char_array> /*unused*/) void read_kind(Array& a, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::char_array> /*unused*/)
{ {
using CharT = typename std::remove_cv<typename std::remove_extent<Array>::type>::type; using CharT = typename std::remove_cv<typename std::remove_extent<Array>::type>::type;
const std::size_t n = std::extent<Array>::value; const std::size_t n = std::extent<Array>::value;
@@ -1602,7 +1584,7 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(const T& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::borrow_range> /*unused*/) void read_kind(const T& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::borrow_range> /*unused*/)
{ {
// std::basic_string guarantees data()[size()] == 0: use it as sentinel // std::basic_string guarantees data()[size()] == 0: use it as sentinel
const auto size = static_cast<std::size_t>(s.size()); const auto size = static_cast<std::size_t>(s.size());
@@ -1611,13 +1593,13 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(const T& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::copy_range> /*unused*/) void read_kind(const T& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::copy_range> /*unused*/)
{ {
build_copy(s, ae, c, tc); build_copy(s, ae, c, tc);
} }
template<typename CharT> template<typename CharT>
void read_kind(CharT* s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::wide_c_string> /*unused*/) void read_kind(CharT* s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::wide_c_string> /*unused*/)
{ {
if (s == nullptr) if (s == nullptr)
{ {
@@ -1629,13 +1611,13 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(T&& input, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::adapter> /*unused*/) void read_kind(T&& input, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::adapter> /*unused*/)
{ {
build_copy(std::forward<T>(input), ae, c, tc); build_copy(std::forward<T>(input), ae, c, tc);
} }
template<typename IteratorType> template<typename IteratorType>
void read_range(IteratorType first, IteratorType last, on_error ae, bool c, bool tc) void read_range(IteratorType first, IteratorType last, bool ae, bool c, bool tc)
{ {
using value_type = typename std::remove_cv<typename std::iterator_traits<IteratorType>::value_type>::type; using value_type = typename std::remove_cv<typename std::iterator_traits<IteratorType>::value_type>::type;
// borrow the range where the library's input adapter scans it as one // borrow the range where the library's input adapter scans it as one
@@ -1646,14 +1628,14 @@ class basic_json_document
} }
template<typename IteratorType> template<typename IteratorType>
void read_range_impl(IteratorType first, IteratorType last, on_error ae, bool c, bool tc, std::true_type /*contiguous bytes*/) void read_range_impl(IteratorType first, IteratorType last, bool ae, bool c, bool tc, std::true_type /*contiguous bytes*/)
{ {
const auto size = static_cast<std::size_t>(std::distance(first, last)); const auto size = static_cast<std::size_t>(std::distance(first, last));
build(size == 0 ? "" : reinterpret_cast<const char*>(&*first), size, ae, c, tc, false, size == 0); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast) build(size == 0 ? "" : reinterpret_cast<const char*>(&*first), size, ae, c, tc, false, size == 0); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
} }
template<typename IteratorType> template<typename IteratorType>
void read_range_impl(IteratorType first, IteratorType last, on_error ae, bool c, bool tc, std::false_type /*other*/) void read_range_impl(IteratorType first, IteratorType last, bool ae, bool c, bool tc, std::false_type /*other*/)
{ {
build_copy(detail::view::make_adapter_input(detail::input_adapter(first, last)), ae, c, tc); build_copy(detail::view::make_adapter_input(detail::input_adapter(first, last)), ae, c, tc);
} }
+29 -149
View File
@@ -1311,8 +1311,7 @@ struct parse_failure
}; };
/// FloatType: the number_float_t of the document, whose overflow parse() rejects /// FloatType: the number_float_t of the document, whose overflow parse() rejects
/// Store: false for accept(): the grammar, number, string and UTF-8 checks run as for parse(), but no node is written template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Sentinel>
template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Sentinel, bool Store>
class builder class builder
{ {
public: public:
@@ -1488,87 +1487,11 @@ class builder
return p; return p;
} }
/// the string from p, the first backslash, control character, ill-formed UTF-8 byte, or the end, checked and not
/// decoded (accept() stores nothing, so the arena is not written): the checks, errors and error positions of
/// slow_string(), for everything up to the closing quote
NLOHMANN_VIEW_NOINLINE decoded check_string(const unsigned char* p)
{
const unsigned char* const end = m_end;
for (;;)
{
if (p == end)
{
return failed(error_code::string_missing_quote, p);
}
const unsigned char c = *p;
if (c == '"')
{
++p;
return decoded{p, 0, 0};
}
if (c != '\\')
{
return failed(c < 0x20 ? error_code::string_control_character : error_code::string_utf8, p);
}
++p;
if (p == end)
{
return failed(error_code::string_missing_quote, p);
}
const unsigned char d = *p++;
if (d == 'u')
{
const int cp = hex4(p); // (moves p past the four digits)
if (NLOHMANN_VIEW_UNLIKELY(cp < 0))
{
return failed(error_code::string_unicode_hex, p);
}
if (NLOHMANN_VIEW_UNLIKELY((cp & 0xF800) == 0xD800)) // a surrogate
{
if (cp >= 0xDC00)
{
return failed(error_code::string_surrogate_low, p);
}
if (end - p < 2 || p[0] != '\\' || p[1] != 'u')
{
return failed(error_code::string_surrogate_high, p);
}
p += 2;
const int lo = hex4(p); // (moves p past the four digits)
if (lo < 0)
{
return failed(error_code::string_unicode_hex, p);
}
if (lo < 0xDC00 || lo > 0xDFFF)
{
return failed(error_code::string_surrogate_high, p);
}
}
}
else if (!(d == '"' || d == '\\' || d == '/' || d == 'b' || d == 'f' || d == 'n' || d == 'r' || d == 't'))
{
--p;
return failed(error_code::string_escape, p);
}
if (p != end && *p == '\\')
{
continue; // (escapes in a row: no run of text between them)
}
p = scan_string_run(p, end); // the text up to the next backslash, quote, control character, or ill-formed UTF-8
}
}
/// s points to the start of the string, p to a backslash, a control /// s points to the start of the string, p to a backslash, a control
/// character, an ill-formed UTF-8 byte, or the end: decode the string into /// character, an ill-formed UTF-8 byte, or the end: decode the string into
/// the arena /// the arena
NLOHMANN_VIEW_NOINLINE decoded slow_string(const unsigned char* s, const unsigned char* p) NLOHMANN_VIEW_NOINLINE decoded slow_string(const unsigned char* s, const unsigned char* p)
{ {
if (!enabled(Store))
{
// (accept(): the string is checked, not decoded)
static_cast<void>(s);
return check_string(p);
}
// single-character escapes; 0: invalid (and 'u', handled separately) // single-character escapes; 0: invalid (and 'u', handled separately)
static const std::array<char, 128> simple_escape = static const std::array<char, 128> simple_escape =
{ {
@@ -1928,14 +1851,11 @@ run_found:
std::size_t max_depth = 0; std::size_t max_depth = 0;
NLOHMANN_VIEW_ALWAYS_INLINE bool run() NLOHMANN_VIEW_ALWAYS_INLINE bool run()
{
if (enabled(Store))
{ {
cold.m_doc.reserve(estimate_nodes(reinterpret_cast<const char*>(b), static_cast<std::size_t>(e - b))); cold.m_doc.reserve(estimate_nodes(reinterpret_cast<const char*>(b), static_cast<std::size_t>(e - b)));
base = cold.m_doc.nodes; base = cold.m_doc.nodes;
out = base; out = base;
cap = base + cold.m_doc.node_capacity; cap = base + cold.m_doc.node_capacity;
}
if (e - p >= 3 && p[0] == 0xEF && p[1] == 0xBB && p[2] == 0xBF) if (e - p >= 3 && p[0] == 0xEF && p[1] == 0xBB && p[2] == 0xBF)
{ {
@@ -2118,12 +2038,9 @@ close_object:
// a large object gets a hash index for its keys (objects only, so that closing // a large object gets a hash index for its keys (objects only, so that closing
// an array pays nothing for this) // an array pays nothing for this)
if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members)) if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members))
{
if (enabled(Store))
{ {
cold.note_large_object(cur_idx); cold.note_large_object(cur_idx);
} }
}
close_container: close_container:
close(); close();
@@ -2282,12 +2199,6 @@ indent_done:
/// an integer's value); two stores on little-endian targets /// an integer's value); two stores on little-endian targets
NLOHMANN_VIEW_ALWAYS_INLINE node* push_node(node_kind k, std::uint8_t flags, std::uint16_t extra, std::size_t off, std::uint64_t second) NLOHMANN_VIEW_ALWAYS_INLINE node* push_node(node_kind k, std::uint8_t flags, std::uint16_t extra, std::size_t off, std::uint64_t second)
{ {
if (!enabled(Store))
{
// accept(): nothing is stored, so what computes the arguments is not run either. base and out stay
// null: their difference, which open() takes, is 0.
return out;
}
if (NLOHMANN_VIEW_UNLIKELY(out == cap)) if (NLOHMANN_VIEW_UNLIKELY(out == cap))
{ {
const auto n = static_cast<std::size_t>(out - base); const auto n = static_cast<std::size_t>(out - base);
@@ -2345,13 +2256,10 @@ indent_done:
} }
NLOHMANN_VIEW_ALWAYS_INLINE void close() NLOHMANN_VIEW_ALWAYS_INLINE void close()
{
if (enabled(Store))
{ {
node& n = base[cur_idx]; node& n = base[cur_idx];
n.len = cur_count; n.len = cur_count;
n.next = static_cast<std::uint32_t>(out - base) - cur_idx; n.next = static_cast<std::uint32_t>(out - base) - cur_idx;
}
if (--depth != 0) if (--depth != 0)
{ {
if (NLOHMANN_VIEW_LIKELY(depth <= 64)) if (NLOHMANN_VIEW_LIKELY(depth <= 64))
@@ -2526,44 +2434,34 @@ indent_done:
}; };
/// run the builder with compile-time options /// run the builder with compile-time options
template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd, bool Store> template<typename FloatType, bool Comments, bool TrailingCommas, bool NulIsEnd>
inline bool build_with(document_data& d, const char* src, std::size_t size, bool sentinel, parse_failure& failure) inline bool build_with(document_data& d, const char* src, std::size_t size, bool sentinel, parse_failure& failure)
{ {
if (sentinel) if (sentinel)
{ {
builder<FloatType, Comments, TrailingCommas, NulIsEnd, true, Store> bld(d, src, size); builder<FloatType, Comments, TrailingCommas, NulIsEnd, true> bld(d, src, size);
const bool ok = bld.run(); const bool ok = bld.run();
failure = bld.failure(); failure = bld.failure();
return ok; return ok;
} }
builder<FloatType, Comments, TrailingCommas, NulIsEnd, false, Store> bld(d, src, size); builder<FloatType, Comments, TrailingCommas, NulIsEnd, false> bld(d, src, size);
const bool ok = bld.run(); const bool ok = bld.run();
failure = bld.failure(); failure = bld.failure();
return ok; return ok;
} }
/// sentinel: src[size] is readable and 0 (e.g. std::string); FloatType: the /// sentinel: src[size] is readable and 0 (e.g. std::string); FloatType: the
/// number_float_t of the document; validate_only: accept(), only the result is /// number_float_t of the document
/// used
template<typename FloatType, bool NulIsEnd> template<typename FloatType, bool NulIsEnd>
inline bool build(document_data& d, const char* src, std::size_t size, bool comments, bool trailing_commas, bool sentinel, bool validate_only, inline bool build(document_data& d, const char* src, std::size_t size, bool comments, bool trailing_commas, bool sentinel, parse_failure& failure)
parse_failure& failure)
{ {
if (validate_only && !comments && !trailing_commas)
{
// accept() of plain JSON: nothing is stored. The other option sets
// could skip the stores just as well; they keep the builder that
// stores only so that there are two more instantiations of the parse
// loop, not eight.
return build_with<FloatType, false, false, NulIsEnd, false>(d, src, size, sentinel, failure);
}
if (comments) if (comments)
{ {
return trailing_commas ? build_with<FloatType, true, true, NulIsEnd, true>(d, src, size, sentinel, failure) return trailing_commas ? build_with<FloatType, true, true, NulIsEnd>(d, src, size, sentinel, failure)
: build_with<FloatType, true, false, NulIsEnd, true>(d, src, size, sentinel, failure); : build_with<FloatType, true, false, NulIsEnd>(d, src, size, sentinel, failure);
} }
return trailing_commas ? build_with<FloatType, false, true, NulIsEnd, true>(d, src, size, sentinel, failure) return trailing_commas ? build_with<FloatType, false, true, NulIsEnd>(d, src, size, sentinel, failure)
: build_with<FloatType, false, false, NulIsEnd, true>(d, src, size, sentinel, failure); : build_with<FloatType, false, false, NulIsEnd>(d, src, size, sentinel, failure);
} }
} // namespace view } // namespace view
@@ -10203,7 +10101,7 @@ class basic_json_document
const bool ignore_trailing_commas = false) const bool ignore_trailing_commas = false)
{ {
basic_json_document d; basic_json_document d;
d.read_range(first, last, error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas); d.read_range(first, last, allow_exceptions, ignore_comments, ignore_trailing_commas);
return d; return d;
} }
@@ -10218,7 +10116,7 @@ class basic_json_document
basic_json_document d; basic_json_document d;
std::string buf; std::string buf;
append_input(buf, std::forward<InputType>(input)); append_input(buf, std::forward<InputType>(input));
d.build_owned(std::move(buf), error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas); d.build_owned(std::move(buf), allow_exceptions, ignore_comments, ignore_trailing_commas);
return d; return d;
} }
@@ -10231,8 +10129,7 @@ class basic_json_document
static bool accept(InputType&& input, const bool ignore_comments = false, const bool ignore_trailing_commas = false) static bool accept(InputType&& input, const bool ignore_comments = false, const bool ignore_trailing_commas = false)
{ {
basic_json_document d; basic_json_document d;
d.read_kind(std::forward<InputType>(input), on_error::validate, ignore_comments, ignore_trailing_commas, d.read(std::forward<InputType>(input), false, ignore_comments, ignore_trailing_commas);
std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {});
return !d.is_discarded(); return !d.is_discarded();
} }
@@ -10248,7 +10145,7 @@ class basic_json_document
const bool ignore_comments = false, const bool ignore_comments = false,
const bool ignore_trailing_commas = false) const bool ignore_trailing_commas = false)
{ {
read_kind(std::forward<InputType>(input), error_mode(allow_exceptions), ignore_comments, ignore_trailing_commas, read_kind(std::forward<InputType>(input), allow_exceptions, ignore_comments, ignore_trailing_commas,
std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {}); std::integral_constant<detail::view::input_kind, detail::view::classify_input<InputType>::value> {});
} }
@@ -10607,22 +10504,6 @@ class basic_json_document
return idx; return idx;
} }
/// what a failed parse does
enum class on_error : std::uint8_t
{
discard, ///< the document is discarded
raise, ///< parse_error is thrown
validate ///< accept(): the document is discarded, and no node is stored while parsing
};
static on_error error_mode(bool allow_exceptions) noexcept
{
return allow_exceptions ? on_error::raise : on_error::discard;
}
/// NulIsEnd of the builder: a null byte ends the input unless strict_nul_handling
static constexpr bool nul_is_end = !detail::abi_config::strict_nul_handling;
/// create the storage (sized for the input) on first use /// create the storage (sized for the input) on first use
void ensure_data(const char* src, std::size_t size) void ensure_data(const char* src, std::size_t size)
{ {
@@ -10634,7 +10515,7 @@ class basic_json_document
/// parse a buffer the document takes ownership of (it replaces the /// parse a buffer the document takes ownership of (it replaces the
/// previous owned copy) /// previous owned copy)
void build_owned(std::string&& buf, on_error allow_exceptions, bool comments, bool trailing_commas) void build_owned(std::string&& buf, bool allow_exceptions, bool comments, bool trailing_commas)
{ {
ensure_data(buf.data(), buf.size()); ensure_data(buf.data(), buf.size());
m_data->owned = std::move(buf); m_data->owned = std::move(buf);
@@ -10644,7 +10525,7 @@ class basic_json_document
/// parse a copy of the input; the copy is appended to the cleared owned /// parse a copy of the input; the copy is appended to the cleared owned
/// buffer, so that its capacity is reused /// buffer, so that its capacity is reused
template<typename T> template<typename T>
void build_copy(T&& input, on_error allow_exceptions, bool comments, bool trailing_commas) void build_copy(T&& input, bool allow_exceptions, bool comments, bool trailing_commas)
{ {
if (!m_data) if (!m_data)
{ {
@@ -10665,7 +10546,7 @@ class basic_json_document
} }
/// sentinel: src[size] is readable and 0 (std::string, C strings) /// sentinel: src[size] is readable and 0 (std::string, C strings)
void build(const char* src, std::size_t size, on_error allow_exceptions, bool comments, bool trailing_commas, bool owned, bool sentinel) void build(const char* src, std::size_t size, bool allow_exceptions, bool comments, bool trailing_commas, bool owned, bool sentinel)
{ {
ensure_data(src, size); ensure_data(src, size);
document_data& d = *m_data; document_data& d = *m_data;
@@ -10692,8 +10573,7 @@ class basic_json_document
} }
else else
{ {
ok = detail::view::build<typename BasicJsonType::number_float_t, nul_is_end>(d, src, size, comments, trailing_commas, sentinel, ok = detail::view::build < typename BasicJsonType::number_float_t, !detail::abi_config::strict_nul_handling > (d, src, size, comments, trailing_commas, sentinel, failure);
allow_exceptions == on_error::validate, failure);
} }
if (NLOHMANN_VIEW_LIKELY(ok)) if (NLOHMANN_VIEW_LIKELY(ok))
{ {
@@ -10706,7 +10586,7 @@ class basic_json_document
return; return;
} }
std::vector<std::uint32_t>().swap(d.large_objects); std::vector<std::uint32_t>().swap(d.large_objects);
if (allow_exceptions == on_error::raise) if (allow_exceptions)
{ {
detail::view::throw_parse_failure<BasicJsonType>(failure, src, size, comments, trailing_commas); detail::view::throw_parse_failure<BasicJsonType>(failure, src, size, comments, trailing_commas);
} }
@@ -10714,13 +10594,13 @@ class basic_json_document
// --- input dispatch (see detail::view::input_kind) --- // --- input dispatch (see detail::view::input_kind) ---
void read_kind(std::string&& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::move_string> /*unused*/) void read_kind(std::string&& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::move_string> /*unused*/)
{ {
build_owned(std::move(s), ae, c, tc); build_owned(std::move(s), ae, c, tc);
} }
template<typename CharT> template<typename CharT>
void read_kind(CharT* s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::c_string> /*unused*/) void read_kind(CharT* s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::c_string> /*unused*/)
{ {
if (s == nullptr) if (s == nullptr)
{ {
@@ -10734,7 +10614,7 @@ class basic_json_document
} }
template<typename Array> template<typename Array>
void read_kind(Array& a, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::char_array> /*unused*/) void read_kind(Array& a, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::char_array> /*unused*/)
{ {
using CharT = typename std::remove_cv<typename std::remove_extent<Array>::type>::type; using CharT = typename std::remove_cv<typename std::remove_extent<Array>::type>::type;
const std::size_t n = std::extent<Array>::value; const std::size_t n = std::extent<Array>::value;
@@ -10745,7 +10625,7 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(const T& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::borrow_range> /*unused*/) void read_kind(const T& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::borrow_range> /*unused*/)
{ {
// std::basic_string guarantees data()[size()] == 0: use it as sentinel // std::basic_string guarantees data()[size()] == 0: use it as sentinel
const auto size = static_cast<std::size_t>(s.size()); const auto size = static_cast<std::size_t>(s.size());
@@ -10754,13 +10634,13 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(const T& s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::copy_range> /*unused*/) void read_kind(const T& s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::copy_range> /*unused*/)
{ {
build_copy(s, ae, c, tc); build_copy(s, ae, c, tc);
} }
template<typename CharT> template<typename CharT>
void read_kind(CharT* s, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::wide_c_string> /*unused*/) void read_kind(CharT* s, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::wide_c_string> /*unused*/)
{ {
if (s == nullptr) if (s == nullptr)
{ {
@@ -10772,13 +10652,13 @@ class basic_json_document
} }
template<typename T> template<typename T>
void read_kind(T&& input, on_error ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::adapter> /*unused*/) void read_kind(T&& input, bool ae, bool c, bool tc, std::integral_constant<input_kind, input_kind::adapter> /*unused*/)
{ {
build_copy(std::forward<T>(input), ae, c, tc); build_copy(std::forward<T>(input), ae, c, tc);
} }
template<typename IteratorType> template<typename IteratorType>
void read_range(IteratorType first, IteratorType last, on_error ae, bool c, bool tc) void read_range(IteratorType first, IteratorType last, bool ae, bool c, bool tc)
{ {
using value_type = typename std::remove_cv<typename std::iterator_traits<IteratorType>::value_type>::type; using value_type = typename std::remove_cv<typename std::iterator_traits<IteratorType>::value_type>::type;
// borrow the range where the library's input adapter scans it as one // borrow the range where the library's input adapter scans it as one
@@ -10789,14 +10669,14 @@ class basic_json_document
} }
template<typename IteratorType> template<typename IteratorType>
void read_range_impl(IteratorType first, IteratorType last, on_error ae, bool c, bool tc, std::true_type /*contiguous bytes*/) void read_range_impl(IteratorType first, IteratorType last, bool ae, bool c, bool tc, std::true_type /*contiguous bytes*/)
{ {
const auto size = static_cast<std::size_t>(std::distance(first, last)); const auto size = static_cast<std::size_t>(std::distance(first, last));
build(size == 0 ? "" : reinterpret_cast<const char*>(&*first), size, ae, c, tc, false, size == 0); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast) build(size == 0 ? "" : reinterpret_cast<const char*>(&*first), size, ae, c, tc, false, size == 0); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
} }
template<typename IteratorType> template<typename IteratorType>
void read_range_impl(IteratorType first, IteratorType last, on_error ae, bool c, bool tc, std::false_type /*other*/) void read_range_impl(IteratorType first, IteratorType last, bool ae, bool c, bool tc, std::false_type /*other*/)
{ {
build_copy(detail::view::make_adapter_input(detail::input_adapter(first, last)), ae, c, tc); build_copy(detail::view::make_adapter_input(detail::input_adapter(first, last)), ae, c, tc);
} }
+1 -145
View File
@@ -59,8 +59,7 @@ built build(const std::string& text, bool comments, bool trailing_commas, bool s
r.copy.assign(text.begin(), text.end()); r.copy.assign(text.begin(), text.end());
src = r.copy.data(); src = r.copy.data();
} }
constexpr bool nul_is_end = !nlohmann::detail::abi_config::strict_nul_handling; r.ok = nlohmann::detail::view::build < FloatType, !nlohmann::detail::abi_config::strict_nul_handling > (*r.data, src, text.size(), comments, trailing_commas, sentinel, r.failure);
r.ok = nlohmann::detail::view::build<FloatType, nul_is_end>(*r.data, src, text.size(), comments, trailing_commas, sentinel, false, r.failure);
r.data->src = src; r.data->src = src;
r.data->base[0] = src; r.data->base[0] = src;
r.data->base[1] = r.data->arena.data(); r.data->base[1] = r.data->arena.data();
@@ -173,22 +172,6 @@ void check_string(const std::string& content)
} }
} }
// accept() stores no nodes: it must accept and reject what json::accept does, for all options and for inputs with
// and without a terminating NUL
void check_accept(const std::string& text)
{
CAPTURE(text)
const std::vector<char> bytes(text.begin(), text.end());
for (int options = 0; options < 4; ++options)
{
const bool comments = (options & 1) != 0;
const bool trailing_commas = (options & 2) != 0;
const bool accepted = json::accept(text, comments, trailing_commas);
CHECK(nlohmann::json_document::accept(text, comments, trailing_commas) == accepted);
CHECK(nlohmann::json_document::accept(bytes, comments, trailing_commas) == accepted);
}
}
// a small deterministic generator of documents // a small deterministic generator of documents
struct generator struct generator
{ {
@@ -440,133 +423,6 @@ TEST_CASE("json_view builder")
} }
} }
SECTION("accept() without an index")
{
for (const char* text :
{
"", " ", "\n", "null", "nul", "true", "[", "]", "[]", "{}", "[1,2,3]", "[1,2,3", "[1,2,3,]", "{\"a\":1,}", "{\"a\"}", "{\"a\":}",
"[1] x", "[1][2]", "\xEF\xBB\xBF[1]", "[\"a\\", "[\"\\u12\"]", "[\"\\ud800\"]", "[\"\x01\"]", "[\"\xff\"]", "[01]", "[1.]",
"[.5]", "[-]", "[1e]", "// c\n[1]", "/* c */ {\"a\" /* x */ : 1}", "/* c", "[1] // c", "1e400", "-1e400", "123456789012345678901234567890",
"{\"a\":1,\"a\":2}", "[[[]]]", "\"\\u00e4\\n\\ud83d\\ude00\""
})
{
check_accept(text);
}
// a null byte inside the text, and after it
check_accept(std::string("[1,\0]", 5));
check_accept(std::string("[1]\0", 4));
check_accept(std::string("\0", 1));
// generated documents and damaged copies, as for the builder above
generator g;
for (int i = 0; i < 2000; ++i)
{
std::string text;
g.value(text, 0);
check_accept(text);
std::string damaged = text;
const auto at = static_cast<std::size_t>(g.r(static_cast<int>(damaged.size())));
static const char replacements[] = {'x', '"', '\\', ',', ':', ']', '}', '[', '{', '1', '-', '.', 'e', '\0', '\n', '/'}; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
damaged[at] = replacements[g.r(16)];
check_accept(damaged);
check_accept(text.substr(0, at));
}
// nesting beyond the 64 levels that are kept on the builder's own stack, closed and not closed
for (const std::size_t depth :
{
63, 64, 65, 66, 200, 1000
})
{
check_accept(std::string(depth, '[') + std::string(depth, ']'));
check_accept(std::string(depth, '[') + std::string(depth - 1, ']'));
std::string objects;
for (std::size_t i = 0; i < depth; ++i)
{
objects += "{\"k\":";
}
objects += "1" + std::string(depth, '}');
check_accept(objects);
check_accept(objects.substr(0, objects.size() - 1));
}
// objects with enough members to get a hash index when they are indexed (and duplicate keys)
std::string large = "{";
for (int i = 0; i < 300; ++i)
{
large += (i == 0 ? "\"k" : ",\"k") + std::to_string(i % 200) + "\":" + std::to_string(i);
}
check_accept(large + "}");
check_accept(large);
check_accept("[" + large + "},{" + large.substr(1) + "}]");
// the overflow check uses the floating-point type of the document
using float_json = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, float>;
for (const char* text :
{
"1e39", "-1e39", "3.4028235e38", "3.4028236e38", "[1.5e38, 3.5e38]", "{\"a\": 1e-50, \"b\": 1e39}", "340282356779733661637539395458142568448"
})
{
CAPTURE(text)
CHECK(nlohmann::basic_json_document<float_json>::accept(text) == float_json::accept(text));
}
// strings are checked and not decoded: runs of text of every length from 0 to 40 between valid and invalid
// escapes, UTF-8 sequences and control characters, in values and in keys, cut near the end of the text
const std::array<const char*, 9> valid = {{"\\n", "\\\"", "\\\\", "\\/", "\\t", "\\u00e4", "\\u20ac", "\\ud83d\\ude00", "\\u0000"}};
const std::array<const char*, 12> invalid = {{"\\x", "\\ud800", "\\udc00", "\\u12G4", "\\u12", "\\ud83dx", "\\ud83d\\u0041", "\\ud83d\\ud83d", "\\", "\x01", "\x1f", "\x7f"}};
const std::array<const char*, 6> utf8 = {{"\xc3\xa4", "\xe2\x82\xac", "\xf0\x9f\x98\x80", "\xc3", "\xff", "\x80"}};
std::mt19937 rng(2029); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed): reproducible
for (std::size_t run = 0; run <= 40; ++run)
{
for (int i = 0; i < 30; ++i)
{
std::string content = std::string(rng() % 20, 'a');
const auto pieces = 1 + (rng() % 6);
for (unsigned k = 0; k < pieces; ++k)
{
content += valid[rng() % valid.size()];
content += std::string(k == 0 ? run : rng() % 41, static_cast<char>('b' + (rng() % 20)));
switch (rng() % 8)
{
case 0:
content += utf8[rng() % 3];
break;
case 1:
content += utf8[rng() % utf8.size()];
break;
case 2:
content += invalid[rng() % invalid.size()];
break;
default:
break;
}
}
for (const std::string& text :
{
"[\"" + content + "\"]", "{\"" + content + "\":1}", "[\"" + content, "[\"" + content.substr(0, content.size() - (rng() % 4)) + "\"]"
})
{
check_accept(text);
}
}
}
}
SECTION("escapes in a row")
{
for (const char* content :
{
"\\n", "\\n\\t\\\\", "\\u00e9\\u00e9\\u4e2d", "\\u00e9\\u00e", "\\u00e9\\", "\\n\\q", "\\n\\ud83d\\ude00\\n",
"\\ud83d\\ude00\\ud83d", "\\n\\n\\n abc \\n\\n", "\\n\x01", "\\n\xC3\x28", "\\n\\"
})
{
check_accept(std::string("[\"") + content + "\"]");
check_accept(std::string("[\"") + content);
check_accept(std::string("{\"") + content + "\":1}");
}
}
SECTION("test files") SECTION("test files")
{ {
for (const char* name : for (const char* name :
+66
View File
@@ -39,6 +39,7 @@ using nlohmann::ordered_json_document;
#ifdef JSON_HAS_CPP_17 #ifdef JSON_HAS_CPP_17
#include <optional> #include <optional>
#include <string_view>
#endif #endif
// NLOHMANN_JSON_SERIALIZE_ENUM uses a static std::pair; same() compares floating-point values on purpose // NLOHMANN_JSON_SERIALIZE_ENUM uses a static std::pair; same() compares floating-point values on purpose
@@ -469,5 +470,70 @@ TEST_CASE("json_view from_json")
#endif #endif
} }
#ifdef JSON_HAS_CPP_17
namespace view_from_json
{
// a string_view member is not copied: it points into the source text or, for a
// string with escape sequences, into the buffer of decoded strings of the document
struct named_view
{
// initialized for GCC -Weffc++
// NOLINTNEXTLINE(readability-redundant-member-init)
std::string_view name{};
int n = 0;
NLOHMANN_DEFINE_TYPE_INTRUSIVE(named_view, name, n)
};
} // namespace view_from_json
TEST_CASE("json_view from_json: string_view members borrow from the document")
{
using view_from_json::named_view;
// whether all of s is inside the bytes of text
const auto within = [](std::string_view s, std::string_view text)
{
const auto first = reinterpret_cast<std::uintptr_t>(text.data());
const auto begin = reinterpret_cast<std::uintptr_t>(s.data());
return begin >= first && begin + s.size() <= first + text.size();
};
SECTION("a string without escapes points into the source text")
{
const std::string text = R"({"name": "hello", "n": 1})";
const json_document d = json_document::parse(text);
REQUIRE_FALSE(d.owns_source());
const auto r = d.root().get<named_view>();
CHECK(r.name == "hello");
CHECK(r.n == 1);
CHECK(within(r.name, text));
CHECK(within(r.name, d.source()));
}
SECTION("a string with escapes points into the document, not into the source text")
{
const std::string text = R"({"name": "a\nb", "n": 2})";
json_document d = json_document::parse(text);
REQUIRE_FALSE(d.owns_source());
const auto r = d.root().get<named_view>();
CHECK(r.name == "a\nb");
CHECK(r.n == 2);
CHECK_FALSE(within(r.name, text));
// valid as long as the document is alive, even if the document is moved
const json_document moved = std::move(d);
CHECK(r.name == "a\nb");
CHECK(moved.root().get<named_view>().name == r.name);
}
SECTION("a document that owns its text keeps the members readable while it is alive")
{
const json_document d = json_document::parse(std::string(R"({"name": "owned", "n": 3})"));
REQUIRE(d.owns_source());
const auto r = d.root().get<named_view>();
CHECK(r.name == "owned");
CHECK(within(r.name, d.source()));
}
}
#endif
DOCTEST_CLANG_SUPPRESS_WARNING_POP DOCTEST_CLANG_SUPPRESS_WARNING_POP
DOCTEST_GCC_SUPPRESS_WARNING_POP DOCTEST_GCC_SUPPRESS_WARNING_POP