Getting custom attributes through reflection.

[Zarian Waheed]

Is there a way to get custom attributes defined on a field through reflection. For example can we get attribute "priority" as shown at:

https://google.github.io/flatbuffers/md__schemas.html

I was taking a look at the reflection schema. It has table field defined as:

table Field {

    name:string (required, key);

    type:Type (required);

    id:ushort;

    offset:ushort;  // Offset into the vtable for tables, or into the struct.

    default_integer:long = 0;

    default_real:double = 0.0;

    deprecated:bool = false;

    required:bool = false;

    key:bool = false;

}

It has builtin attributes like deprecated, required etc. but I could not see anything for custom attributes. It will be helpful if we have a vector of Key/Value pair where Key is the attribute name and Value is the attribute value.

The use case I have it that I want to mark certain fields and have special processing for them whenever I encounter them using reflection.

Thanks,

Zarian.

[Wouter van Oortmerssen]

Yes, attributes currently aren't stored in the reflection data, but I agree it would be good if they were.

Are you able to make a PR for this?

A vector of key/value pairs sounds good. They can be written using same key / sorted vector functionality as the array of Fields, etc., so they can be queried easily.

Important would be to not store any non-custom attributes, to save space, and make the attribute vector null (not present) when empty.

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[Zarian Waheed]

I should be able to make a PR. We are using this at work so would I need to sign Corporate Contributor License Agreement?

[Wouter van Oortmerssen]

I am not sure. Most everyone has signed the individual version (even if they work at a company), but I am not a lawyer :)

[Wouter van Oortmerssen]

attributes were added to reflection data here: https://github.com/google/flatbuffers/commit/72fc45aa6acbc11052c6baa462fac26c5075392a

see test.cpp for an example.

[Zarian Waheed]

Thanks. Sorry could not get around to doing it myself. Appreciate all your hard work :)