json-c v0.15 Release Notes
Release Date: 2020-07-26 // almost 2 years ago-
🚚 Deprecated and removed features:
- Deprecate
array_list_new()
in favor ofarray_list_new2()
- Remove the THIS_FUNCTION_IS_DEPRECATED define.
- ✂ Remove config.h.win32
🆕 New features
- Add a
JSON_TOKENER_ALLOW_TRAILING_CHARS
flag to allow multiple objects to be parsed even whenJSON_TOKENER_STRICT
is set. - Add
json_object_new_array_ext(int)
andarray_list_new_2(int)
to allow arrays to be allocated with the exact size needed, when known. - Add
json_object_array_shrink()
(andarray_list_shrink()
) and use it in json_tokener to minimize the amount of memory used. - ➕ Add a json_parse binary, for use in testing changes (not installed, but available in the apps directory).
🏗 Build changes
- #639/#621 - Add symbol versions to all exported symbols
- #508/#634 - Always enable -fPIC to allow use of the json-c static library in other libraries
- 🏗 Build both static and shared libraries at the same time.
- ⏪ #626 - Restore compatibility with cmake 2.8
- #471 - Always create directories with mode 0755, regardless of umask.
- 👍 #606/#604 - Improve support for OSes like AIX and IBM i, as well as for MINGW32 and old versions of MSVC
- #451/#617 - Add a DISABLE_THREAD_LOCAL_STORAGE cmake option to disable the use of thread-local storage.
🛠 Significant changes and bug fixes
- Split the internal json_object structure into several sub-types, one for each json_type (json_object_object, json_object_string, etc...). This improves memory usage and speed, with the benchmark under bench/ report 5.8% faster test time and 6%(max RSS)-12%(peak heap) less memory usage. Memory used just for json_object structures decreased 27%, so use cases with fewer arrays and/or strings would benefit more.
- Minimize memory usage in array handling in json_tokener by shrinking arrays to the exact number of elements parsed. On bench/ benchmark: 9% faster test time, 39%(max RSS)-50%(peak heap) less memory usage. Add json_object_array_shrink() and array_list_shrink() functions.
- 📜 #616 - Parsing of surrogate pairs in unicode escapes now properly handles incremental parsing.
- 🛠 Fix incremental parsing of numbers, especially those with exponents, e.g. so parsing "[0", "e+", "-]" now properly returns an error. Strict mode now rejects missing exponents ("0e").
- Successfully return number objects at the top level even when they are followed by a "-", "." or "e". This makes parsing things like "123-45" behave consistently with things like "123xyz".
Other changes
- #589 - Detect broken RDRAND during initialization; also, fix segfault in the CPUID check.
- ⏪ #592 - Fix integer overflows to prevert out of bounds write on large input.
- Protect against division by zero in linkhash, when creaed with zero size.
- 📜 #602 - Fix json_parse_uint64() internal error checking, leaving the retval untouched in more failure cases.
- #614 - Prevent truncation when custom double formatters insert extra \0's
- Deprecate
Previous changes from v0.14
-
🚚 Deprecated and removed features:
- 🚚 bits.h has been removed
- 🚚 lh_abort() has been removed
- lh_table_lookup() has been removed, use lh_table_lookup_ex() instead.
- ✂ Remove TRUE and FALSE defines, use 1 and 0 instead.
🏗 Build changes:
🚚 Deprecated and removed features:
- 🚚 bits.h has been removed
- 🚚 lh_abort() has been removed
- lh_table_lookup() has been removed, use lh_table_lookup_ex() instead.
- ✂ Remove TRUE and FALSE defines, use 1 and 0 instead.
- 👀 autoconf support, including autogen.sh, has been removed. See details about cmake, below.
- With the addition of json_tokener_get_parse_end(), access to internal fields of json_tokener, as well as use of many other symbols and types in json_tokener.h, is deprecated now.
- 🏗 The use of Android.configure.mk to build for Android no longer works, and it is unknown how (or if) the new cmake-based build machinery can be used.
- Reports of success, or pull requests to correct issues are welcome.
Notable improvements and new features
📚 Builds and documentation
- 🏗 Build machinery has been switched to CMake. See README.md for details about how to build.
- TL;DR:
mkdir build ; cd build ; cmake -DCMAKE_INSTALL_PREFIX=/some/path ../json-c ; make all test install
- To ease the transition, there is a
cmake-configure
wrapper that emulates the old autoconf-based configure script. - This has enabled improvements to the build on Windows system; also all public functions have been fixed to be properly exported. For best results, use Visual Studio 2015 or newer.
- TL;DR:
- 💅 The json-c style guide has been updated to specify the use of clang-format, and all code has been reformatted.
- Since many lines of code have trivial changes now, when using git blame, be sure to specify -w
- 📚 Numerous improvements have been made to the documentation including function effects on refcounts, when passing a NULL is safe, and so on.
json_tokener changes
- Added a json_tokener_get_parse_end() function to replace direct access of tok->char_offset.
- The char_offset field, and the rest of the json_tokener structure remain exposed for now, but expect a future release to hide it like is done with json_object_private.h
- json_tokener_parse_ex() now accepts a new JSON_TOKENER_VALIDATE_UTF8 flag to validate that input is UTF8.
- If validation fails, json_tokener_get_error(tok) will return json_tokener_error_parse_utf8_string (see enum json_tokener_error).
Other changes and additions
- ➕ Add support for unsigned 64-bit integers, uint64_t, to gain one extra bit of magnitude for positive ints.
- json_tokener will now parse values up to UINT64_MAX (18446744073709551615)
- Existing methods returning int32_t or int64_t will cap out-of-range values at INT32_MAX or INT64_MAX, preserving existing behavior.
- The implementation includes the possibility of easily extending this to larger sizes in the future.
- A total of 7 new functions were added:
- json_object_get_uint64 ( struct json_object const* jso )
- json_object_new_uint64 ( uint64_t i )
- json_object_set_uint64 ( struct json_object* jso, uint64_t new_value )
- json_parse_uint64 ( char const* buf, uint64_t* retval )
- See description of uint64 support, above.
- json_tokener_get_parse_end ( struct json_tokener* tok )
- See details under "json_tokener changes", above.
- json_object_from_fd_ex ( int fd, int in_depth )
- Allows the max nesting depth to be specified.
- json_object_new_null ( )
- Simply returns NULL. Its use is not recommended.
- The size of struct json_object has decreased from 96 bytes to 88 bytes.
✅ Testing
- ⚡️ Many updates were made to test cases, increasing code coverage.
- ✅ There is now a quick way (JSONC_TEST_TRACE=1) to turn on shell tracing in tests.
- ✅ To run tests, use
make test
; the old "check" target no longer exists.
🛠 Significant bug fixes
For the full list of issues and pull requests since the previous release, please see issues_closed_for_0.14.md
- Issue #389: Add an assert to explicitly crash when _ref_count is corrupted, instead of a later "double free" error.
- 📜 Issue #407: fix incorrect casts in calls to ctype functions (isdigit and isspace) so we don't crash when asserts are enabled on certain platforms and characters > 128 are parsed.
- Issue #418: Fix docs for json_util_from_fd and json_util_from_file to say that they return NULL on failures.
- Issue #422: json_object.c:set errno in json_object_get_double() when called on a json_type_string object with bad content.
- Issue #453: Fixed misalignment in JSON serialization when JSON_C_TO_STRING_SPACED and JSON_C_TO_STRING_PRETTY are used together.
- Issue #463: fix newlocale() call to use LC_NUMERIC_MASK instead of LC_NUMERIC, and remove incorrect comment.
- Issue #486: append a missing ".0" to negative double values to ensure they are serialized as floating point numbers.
- 🏁 Issue #488: use JSON_EXPORT on functions so they are properly exported on Windows.
- Issue #539: use an internal-only serializer function in json_object_new_double_s() to avoid potential conflicts with user code that uses the json_object_userdata_to_json_string serializer.