Bug 58063 – CTLine objects should outlive their CTRuns

• Status: RESOLVED
• Resolution: FIXED
• Component: Text

[Ned Holbrook]

CoreText may need to perform some extra work if a CTLine object is released prior to its CTRuns, but this extra work can be avoided by either retaining CTLines longer than their CTRuns (in ComplexTextController), or by not retaining the CTRuns (in ComplexTextRun).

[Ned Holbrook]

The latter approach is less desirable since it would eliminate the possibility of using the CTRunGet*Ptr() accessors, so I'll work up some numbers for the former.

[Ned Holbrook]

Created attachment 88732 [details]
Proposed changes.

Numbers are a bit variable on my machine, but I'm seeing an improvement of around 2% for repeated optimizeLegibility test runs on Latin text—barely above the level of noise but certainly not a slowdown.

Comment on attachment 88732 [details]
Proposed changes.

If the CTLine stays alive, then maybe ComplexTextRun::m_coreTextRun no longer needs to be a RetainPtr?

[Ned Holbrook]

(In reply to comment #3)
> (From update of attachment 88732 [details])
> If the CTLine stays alive, then maybe ComplexTextRun::m_coreTextRun no longer needs to be a RetainPtr?

Good idea! Should it become a different smart pointer or will a bare CTRunRef suffice?

(In reply to comment #4)
> (In reply to comment #3)
> > (From update of attachment 88732 [details] [details])
> > If the CTLine stays alive, then maybe ComplexTextRun::m_coreTextRun no longer needs to be a RetainPtr?
> 
> Good idea! Should it become a different smart pointer or will a bare CTRunRef suffice?

Bare CTRunRef. A comment right above the member variable definition explaining why it’s ok to use a bare CTRunRef would be good.

[Ned Holbrook]

(In reply to comment #5)
> Bare CTRunRef. A comment right above the member variable definition explaining why it’s ok to use a bare CTRunRef would be good.

Theoretically it could be removed entirely since it's only used in the constructor.

(In reply to comment #6)
> (In reply to comment #5)
> > Bare CTRunRef. A comment right above the member variable definition explaining why it’s ok to use a bare CTRunRef would be good.
> 
> Theoretically it could be removed entirely since it's only used in the constructor.

Let’s remove it in practice, then.

[Ned Holbrook]

Created attachment 88743 [details]
Remove m_coreTextRun.

[WebKit Commit Bot]

Comment on attachment 88743 [details]
Remove m_coreTextRun.

Clearing flags on attachment: 88743

Committed r83251: <http://trac.webkit.org/changeset/83251>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

<rdar://problem/9250245>