1798080 - Annotate some stack-only classes and const members in SVG-text-related layout code

Status: RESOLVED FIXED

(Core :: SVG, task)

Description

[Daniel Holbert [:dholbert]]

Building towards some minor refactoring in bug 1798048, I'm using this bug to add some trivial-ish annotations in svg text code to reflect reality and improve reasoning ability for this code.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: Bug 1798080 part 1: Add MOZ_STACK_CLASS annotation to some text layout/painting classes, to reflect reality. r?jfkthame

This patch doesn't impact behavior; it's just adding an annotation to activate
a static analysis check for various classes.

The annotation gives us some confidence that these instances are tightly scoped
to a particular function-call. This helps reduce concerns about to-what-extent
the affected classes might need to worry about the lifetimes of the objects
pointed to by their member-vars.

The specific classes I'm annotating are:

• gfxTextRunDrawCallbacks and PaintTextParams, both of which have multiple
  subclasses, all of which will automatically inherit this annotation and
  benefit from it.

• TextFrameIterator and CharIterator, two local utility classes in
  SVGTextFrame.cpp.

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: Bug 1798080 part 2: Add const annotation to some never-modified member-vars in SVGTextFrame's helper classes, to reflect reality. r?jfkthame

This patch doesn't impact behavior.

The new const annotations will help to simplify reasoning about these various
helper classes & what states they could possibly be in.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d172c72030b9
part 1: Add MOZ_STACK_CLASS annotation to some text layout/painting classes, to reflect reality. r=jfkthame
https://hg.mozilla.org/integration/autoland/rev/c3adab330847
part 2: Add const annotation to some never-modified member-vars in SVGTextFrame's helper classes, to reflect reality. r=jfkthame

Comment 4

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/d172c72030b9
https://hg.mozilla.org/mozilla-central/rev/c3adab330847