Benjamin Gemmill created THRIFT-5637:
----------------------------------------
Summary: Thrift compiler should be able to output c++ Aggregate
types
Key: THRIFT-5637
URL: https://issues.apache.org/jira/browse/THRIFT-5637
Project: Thrift
Issue Type: Improvement
Components: C++ - Compiler
Affects Versions: 0.17.0, 0.16.0
Reporter: Benjamin Gemmill
If we have a thrift struct defined like this:
{{struct thingamabob {}}
{{ 1: i64 a = 0}}
{{ 2: i64 b = 0}}
{{ 3: i64 c = 0}}
{{}}}
Then the generated code contains a few constructors and assignment operators
that look like this:
{{thingamabob(const thingamabob&) noexcept;}}
{{thingamabob&operator=(const thingamabob&) noexcept;}}
{{{}thingamabob() noexcept{}}}{{{}: a(0),{}}}{{{}b(0),{}}}{{{}c(0)
{{}}}{{{}}{}}}
The issue here is that while this class could be an
[AggregateType|http://example.com] and support aggregate initialization, the
way these defaults are generated prevent it.
If instead, thrift used default initializers like this where the the member
objects are defined:
int64_t a\{0};
int64_t b\{0};
int64_t c\{0};
We could then initialize thrift structs with initializer lists, expect
static_assert(std::is_aggregate_v<type>) to work, and we'd still have default
construction and copying.
For this to work, the "templates" option passed to the c++ compiler should
remove the virtual keyword from the generated printTo functions, and the
generated __isset structs would also need to be changed similarly to look like:
{{typedef struct_thingamabob__isset {}}
{{bool a :1\{false};}}
{{bool b :1\{false};}}
{{bool c :1\{false};}}
{{} _thingamabob__isset;}}
{{Happy to take a stab at this and wanted to check for feedback first.}}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
