1271471 - Eliminate MaybePrefValue

Status: RESOLVED DUPLICATE of bug 1536163

(Core :: DOM: Content Processes, defect, P3)

Description

[Andrew McCreight [:mccr8]]

MaybePrefValue is defined as a union, but PrefValue is also a union, so it might be okay to inline MaybePrefValue into PrefValue. If I'm reading the generated code correctly, this will save one word per PrefValue. Or maybe one byte. There can be a few thousand of these, so it would not be a large gain. It might also make it easier to manipulate these values.

Comment 1

[Andrew McCreight [:mccr8]]

This would make a good little introductory bug for messing around with IPDL from C++.

Comment 2

[Andrew McCreight [:mccr8]]

Both prefValues have to be the same type, so another approach would be to replace the pair of unions with a union of pairs of unions. Maybe that's not better, in terms of size.

Comment 3

[Rofael Aleezada [:rofael]]

So would this require changing PrefValue to

union PrefValue {
  nsCString;
  int32_t;
  bool;
  union MaybePrefValue {
    PrefValue;
    null_t;
  };
};

and prepending PrefValue:: in front of any MaybePrefValue::?

Comment 4

[Andrew McCreight [:mccr8]]

I think I was thinking of something more like

union PrefValue {
  nsCString;
  int32_t;
  bool;
  null_t;
};

I'm not sure how well that will work on the C++ side.

Comment 5

[Rofael Aleezada [:rofael]]

Seems like a good ol' "delete and fix compilation errors". I'll pick it up. 

Might not get to it for a week or two, though.

Comment 6

[Andrew McCreight [:mccr8]]

Fixed in bug 1536163.