Augment the C++ generator to emit a C++ copy constructor and a by-value
copy assignment operator. This is enabled by default when the C++
standard is C++11 or later. These additional functions are only emitted
for objects that need it, typically tables containing other tables.
These new functions are declared in the object table type and are
defined as inline functions after table declarations.
When these new functions are declared, a user-defined
explicitly-defaulted default constructor and move constructor are also
emitted.
The copy assignment operator uses the copy-and-swap idiom to provide
strong exception safety, at the expense of keeping 2 full table copies
in memory temporarily.
fixes#5783
* CPP Default Value Generation in Mutators
If the mutator is for a value that is compatible with having a default value, then the single parameter becomes a default parameter. With this, a value can be mutated to it's default value without storing the default value, as that will be stored with the mutate function.
Fixed Casting When Generating Default for Enum Value
Added support for typecasting an int default value into the correct enum type in the default parameter. This fixed the issue of trying to use set a strongly typed enum parameter to an int which fails type checking.
Fixed Boolean Edge Case
Boolean types generate 0 != 0 when generating the underlying type which appears to be unique to the boolean type so it is now checked and the proper default value generated. It may be beneficial to check if it is instead an enum type, however the seeming edge case nature is why boolean was chosen to be checked.
Updated Generated Files
Regenerated the auto generated files to reflect the new changes.
Updated Remaining Files
Should fix auto generated header files that were not updated.
* Unified Repeated Code
Relocated identical append code to outside of conditional. Also changed 'casted' default value name from FIELD to INTERFACE to more accurately describe it.
* Moved Field Name Outside Conditional
Removed duplicate _{{FIELD_NAME}} and moved to unified append.
Causes generated code to check for existing pointers in an object (when using the object based api) and use UnPackTo(existingPointer) rather than just using UnPack() to replace the pointer. This is a performance issue when unpacking to existing objects when using large buffer fields (e.g. image frames)
Co-authored-by: RobWauson <robwauson@gmail.com>
* Improve generated comparisons for tables
Previously, the generated code called std::unique_ptr<>::operator== on
non-scalar members, which would be correct only if the member was null
on both sides. After this CL, comparison is done on the pointed-to
values (including using a default-constructed value if the pointer is
null).
* Don't equate null Tables with all defaults
Also removes the cost of default-constructing tables for comparisons.
* Regenerate code
* fix formatting
* Add codegen test for namespaced unions
* [Rust] Handle cross-namespace union use
* [Rust] Test namespace handling
* [Rust] Drop trailing whitespace in codegen
* [Rust] Set flags in generate_code.bat to match .sh
* [C#] Add additional namespace test file
Prior to this commit the default C++ code generator was `c++0x`.
A code generated with `c++0x` code-gen might have a vulnerability (undefined behavior) connected evolution of enums in a schema. This UB could break the backward compatibility if previously generated code casts an unknown enumerator to enum type that knows nothing about future enumerators added to the schema.
The main differences between `c++0x` and `c++11`:
- generated enums use explicitly declared underlying type;
- generated object-API tables don't declare default ctor() explicitly, instead of it default data member initializers are generated.
Please use `flatc --cpp-std c++0x` option for backward compatibility with old compilers.
This optionally generates a static `getFullyQualifiedName()` function to get
the fully-qualified name of a type in JavaScript and TypeScript in a similar
fashion to the C++ codegen.
For example:
include/flatbuffers/reflection.h:365:8: error: definition of implicit copy
constructor for 'pointer_inside_vector<flatbuffers::Table, unsigned char>'
is deprecated because it has a user-declared copy assignment operator
[-Werror,-Wdeprecated-copy]
void operator=(const pointer_inside_vector &piv);
^
It's unclear why the old code wanted to declare a public `operator=`
without defining it; that just seems like a misunderstanding of the C++03 idiom
for deleting a member function. And anyway, we don't *want* to delete the
assignment operator; these are polymorphic types that do not follow value
semantics and nobody should ever be trying to copy them. So the simplest fix
is just to go back to the Rule of Zero: remove the declaration of `operator=`
and let the compiler do what it wanted to do originally anyway.
"The best code is no code."
Also, update the generated .h files.
Fixes#5649.
Previously UnPack would allocate data with new and assign it to a
raw pointer. This behavior makes it possible for the pointer to be
leaked in case of OOM. This commit defaults to use the user specified
pointer (which needs to implement a move constructor, a .get() and a
.release() operators), thus preventing these leaks.
* Add Builder and Table typedefs
This gives us a way to use templates to go from a builder to a table
and back again without having to pass both types in.
* Fix tests/cpp17/generated_cpp17/monster_test_generated.h
* Add flatc '--cpp_std' switch and sandbox for C++17 code generator
- Added 'flac --cpp_std legacy' for compatibility with old compilers (VS2010);
- Added experimental switch 'flac --cpp_std c++17' for future development;
- Added C++17 sandbox test_cpp17.cpp;
- C++ code generator generates enums with explicit underlying type to avoid problems with the forward and backward schema compatibility;
- Adjusted CMakeLists.txt, CI and generate code scripts to support of introduced '--cpp_std';
* Fix --cpp_std values: c++0x, c++11, c++17
* Add 'cpp::CppStandard' enum
* Add testing engine into test_cpp17
* Rebase to upstream/master
* Set default '--cpp-std C++0x'
* Fix code generation (--cpp_std C++11) in CMakeLists.txt
- Fix dependency declaration of grpctest target
* Revert --cpp-std for the tests from explicit C++11 to flatc default value (C++0x)
Give the vtable offset enum inside each table the name
"FlatBuffersVTableOffset" and base type voffset_t so it can be used as a
dependent type in IsFieldPresent. This makes that function slightly
safer since it prevents calling it with arbitrary, non-table types.
Now, the only way to use IsFieldPresent incorrectly is to create your
own type which does not inherit from flatbuffers::Table but has a
dependent voffset convertible type "FlatBuffersVTableOffset".
* mini_reflect: Add DefaultTypeTable
Currently it's very easy to make a mistake when it comes to
instantiating the TypeTable to print a buffer because it is not type
safe.
This will allow us to write safer cpp code:
flatbuffers::FlatBufferToString(reinterpret_cast<const uint8_t *>(&t),
decltype(t)::DefaultTypeTable());
* c++: mini_reflect: update generated code
* Ensure types and names are set for mini_reflect
* c++: mini_refelct: update unit tests with new typed TypeTable
* Adding PR feedback of sylte and naming convention
This is something the format supports, but none of the builders
were doing. Can save 10-20% on FlatBuffer binary size!
Also fixed the Go tests.
Change-Id: I616c56ce9bbcfcaee23aa24f0532fcb60b6a8c75
Tested: on Linux.
Zero offsets are non-sensical in FlatBuffers (since offsets are
relative to themselves) but were allowed by the verifier. This could
cause buffers made up of all zeroes to be interpreted as correct
buffers with an empty root object.
Generally, not allowing such offsets will make the verifier more
likely to catch problems earlier.
Change-Id: I54010bea29721b326ff8e5348fcd9fe78e5e7506
Tested: on Linux.
* Add default value handling to mutation/SetField code
* Shorten reflection SetField impl
* Modify impl to work with C++03
* Add more mutation tests
* Fail SetField if non-scalar
* Add IsScalar/IsInteger/IsFloat for reflection::BaseType
* Use new IsScalar/IsInteger/IsFloat in reflection SetField
* Assume scalar is either int or float
Helps simplify code generation code. Instead of this:
code += "inline const " + cpp_qualified_name + " *Get";
code += name;
code += "(const void *buf) {\n return flatbuffers::GetRoot<";
code += cpp_qualified_name + ">(buf);\n}\n\n";
You do this:
code.SetValue("NAME", struct_def.name);
code.SetValue("CPP_NAME", cpp_qualified_name);
code += "inline const {{CPP_NAME}} *Get{{NAME}}(const void *buf) {";
code += " return flatbuffers::GetRoot<{{CPP_NAME}}>(buf);";
code += "}";
code += "";
Updated the CPP code generator to use the CodeWriter class. Most of the
changes in the generated code are white-space changes, esp. around new
lines (since the code generator class automatically appends new lines
when appending a string). Actual code changes include:
* Renamed "rehasher" to "_rehasher" for consistency with other args in
Pack function.
* Renamed "union_obj" to "obj: in UnPack function.
* Always do "(void)_o;" to prevent unused variable warning in Create
function (instead of only doing it if there are no fields) in order
to avoid two-passes.
* Renamed padding variables from __paddingX to paddingX__.
"Each name that contains a double underscore (_ _) [...] is reserved
to the implementation for any use." C++ standards 17.4.3.1.2.
* Add braces around switch cases.
* Calculate index as a separate statement in EnumName function, eg.
const size_t index = ...;
return EnumNamesX()[index];
vs.
return EnumNamesX()[...];
* Stored end table offset in variable in Finish() functions, eg.
const auto end = fbb_.EndTable(start_, ...);
auto o = flatbuffers::Offset<T>(end);
vs.
auto o = flatbuffers::Offset<T>(fbb_.EndTable(start, ...));
* Separate reinterpret_cast calls from function calls in Union
functions, eg.
auto ptr = reinterpret_cast<const T *>(obj);
return ptr->UnPack(resolver);
vs.
return reinterpret_cast<const T *>(obj)->UnPack(resolver);
* Removed unecessary (void)(padding__X) no-ops from constructors, eg.
Test(int16_t a, int8_t b) : ... {
(void)__padding0; // <-- Removed this line.
}
In the idl_gen_cpp.cpp file itself, I refactored some code generation into
new functions: GenParam, GenNativeTable, GenVerifyCall, GenBuilders,
GenUnpackFieldStatement, and GenCreateParam.
Change-Id: I727b1bd8719d05b7ce33cbce00eb58fda817b25d
- Update to be const-correct where possible.
- Consistently pass |code| as pointer instead of non-const-ref.
- No newlines (\n) characters in the middle of code strings.
- Use if-else if-else statements instead of nested ternary operators.
- Ensure all lines end at 80 chars.
- Make utility functions static.
From cl/143505731.
Change-Id: If0fab9ee75de5af963367a948dddf53af93f73b4
