Commit Graph
5 Commits
Author SHA1 Message Date
Niels Lohmann 7dae258350 Add element access, lookup, and iteration to json_view
basic_json_view gains the read-only access functions of basic_json:
operator[] and at() with keys and indices, front(), back(), find(),
contains(), count(), begin()/end(), items() (with structured bindings from
C++17 on), and type_name(). They throw the exceptions (ids and messages)
that the const functions of basic_json throw; where basic_json has
undefined behavior (operator[] with a missing key or an index out of
range, front()/back() of an empty container), the view returns a
discarded view or throws invalid_iterator.214.

Objects are iterated in document order, and all members are visited. With
duplicate keys, lookups find the first member, so that a lookup can stop
at the first match; parse() keeps the last value. Keys of up to 16 bytes
are compared with two overlapping loads instead of memcmp, and most keys
are rejected by their length alone, from the index.

The iterators and items live in detail/view/iterator.hpp, the lookups in
detail/view/lookup.hpp. Tests compare every element and member of 2,000
generated documents with ordered_json, keys of every length around the
load sizes, the exceptions against const basic_json, and the iterators.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 21:01:32 +02:00
Niels Lohmann d71a494367 Fix CI: json_view tests without exceptions, on clang 3.6, and single header
- ci_test_noexceptions: the helpers that compare the exceptions of
  json_document::parse() and json::parse() catch them outside a
  CHECK_THROWS, so with JSON_NOEXCEPTION the first parse error aborted
  the test. Compile those comparisons only with exceptions, as
  unit-class_parser.cpp does.
- ci_test_gcc: -Werror=unused-result for CHECK_THROWS_AS(json_document::
  parse(...)); assign the result to a dummy document.
- ci_test_compilers_clang (3.6): `const json_view invalid;` needs a
  user-provided default constructor there (CWG 253); value-initialize it.
- ci_test_single_header: json_view.hpp now exists as a single header and
  contains the internal view headers, so unit-json_view_builder.cpp
  includes it instead of the detail headers in that mode, and the test
  is built again with the single header.
- Regenerate single_include/nlohmann/json_view.hpp for the builder change
  merged from json-view/08-view-builder.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:58:49 +02:00
Niels Lohmann 06bebe2af6 Mark the code of json_view that tests cannot reach
The 4 GiB limit and the fallback for an input that parse() accepts but
the view rejects (a bug) are excluded from the coverage; shrink_to_fit()
of an empty document is tested.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:58:47 +02:00
Niels Lohmann 723cf14be4 Address the clang-tidy findings of json_document and json_view
- the input dispatch takes byte ranges by const reference and reads the
  size once (which also settles a finding of the static analyzer); input
  adapters are taken by value
- the classification of inputs keeps its nested conditional operators, a
  constant expression of C++11 (NOLINT)
- the test's C arrays, fixed seed, and escaped literals are marked, as in
  the other tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:58:46 +02:00
Niels Lohmann d7c6c36979 Test json_document and json_view
unit-json_view.cpp: type queries, size, and empty against basic_json;
materialize() against parse() (json and ordered_json, generated documents,
duplicate keys, 100,000 levels of nesting, parent pointers with
JSON_DIAGNOSTICS); parse errors and their messages equal to parse() for
malformed inputs and all option combinations; the overflow of a float
document (1e39, 3.4028236e38) as in parse(); NUL and BOM; borrowed and
owned inputs (strings, C strings, literals, vectors, string_view, streams,
wide strings, parse_copy, and iterator ranges over pointers, vectors,
strings, and lists); reuse with read(); moves; shrink_to_fit() of the index
and of the decoded strings; source offsets.

unit-json_view_macros.cpp includes the header without
JSON_TEST_KEEP_MACROS, as users do: the view must not depend on the macros
json.hpp undefines, and must not leak its own.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:57:44 +02:00