Bug 65573

Summary: Optimize procedure to find first/last logical box of text
Product: WebKit Reporter: Van Lam <vanlam>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: UNCONFIRMED    
Severity: Normal CC: eric, rniwa, xji, zimmermann
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
One approach none

Van Lam
Reported 2011-08-02 14:19:32 PDT
Using the END key (Windows, Linux) or CMD + right arrow (Mac) in an editable region of bidirectional text results in the call tree: logicalEndOfLine (in visible_units.cpp) -> logicalEndPositionForLine -> RootInlineBox::getLogicalEndBoxWithNode -> InlineFlowBox::collectLeafBoxesInLogicalOrder collectLeafBoxesInLogicalOrder explicitly inverts the visually ordered sequence of boxes into logical order using the bidi algorithm. This can be optimized for time and space as we are only interested in finding the logically last box, not the logical order of the boxes.
Attachments
One approach (9.36 KB, patch)
2011-09-15 20:18 PDT, Van Lam 		no flags
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Van Lam
Comment 1 2011-09-15 20:18:27 PDT
Created attachment 107591 [details] One approach
Ryosuke Niwa
Comment 2 2011-09-19 09:56:40 PDT
I'm very skeptical of 15-20% increase in the performance. If we can really see that much improvement, I'd like to know which tests run that much faster. Also, I'm worried about the fact this code more or less duplicates the existing logic.
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