977430 - forward declare Telemetry::ID when we don't need to use specific values

Status: RESOLVED WONTFIX

(Toolkit :: Telemetry, defect)

Description

[Cameron McCormack (:heycam)]

To avoid rebuilding translation units that declare functions etc. that take/return Telemetry::ID values, we can define it as a sized enum and then forward declare it.  Doing this we can remove the actual inclusion of the generated enum header file from all but one .h file (accessible/src/base/Statistics.h -- that file is only included in a few cpp files though).  That means when histograms get added/removed, we'll rebuild less.

Comment 1

[Cameron McCormack (:heycam)]

Attachment: patch

So this helps a bit, but perhaps not as much as we'd like, as I mention in bug 968923 comment 35.  Might still be worth the churn though.

Will get Vladan to review if you think this is worthwhile, gps.

Comment 2

[Cameron McCormack (:heycam)]

https://tbpl.mozilla.org/?tree=Try&rev=ae94f2474cf0

Comment 3

[Gregory Szorc [:gps]]

Comment on attachment 8382758 [details] [diff] [review]
patch

Review of attachment 8382758 [details] [diff] [review]:
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I'm not a C++ guru and don't know enough to give adequate feedback for this patch.

Comment 4

[Georg Fritzsche [:gfritzsche]]

We already use a sized enum for Telemetry::HistogramID.
The code changes here would be bitrotted a lot.
Heycam, is that something that you'd still want to pick up or can we close this?

Comment 5

[Cameron McCormack (:heycam)]

I think we can close it.