327532 - Content inserted before an element with a long (multi-line) ":before" text is inserted in the wrong place

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Uri Bernstein]

Smontagu and I came across this when investigating possible calls to nsFrameManager::InstertFrames() with continuation frames:

If an element has a very long (and therefore line-wrapped) "before:" text, then dynamically inserting content immediately before this element results in the content being inserted at the bginning of the last line of the "before:" text, instead of immediately before the element (and after the "before:" text).

This is due to nsLayoutUtils::IsGeneratedContentFor() returning FALSE for the last continuation of the generated content, in http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/layout/base/nsCSSFrameConstructor.cpp&rev=1.1195#9708

Testcase coming up.

Comment 1

[Uri Bernstein]

Attachment: testcase

Hit the button. The span with the red text gets inserted at the beginning of the last line of gray text (the ":before" text). It should be inserted immediately before the black text.

Comment 2

[Simon Montagu :smontagu]

(In reply to comment #0)
> This is due to nsLayoutUtils::IsGeneratedContentFor() returning FALSE for the
> last continuation of the generated content,

... which is due to the continuation not having the NS_FRAME_GENERATED_CONTENT bit copied over when created. There are probably parallel bugs with other bits from mState.

Comment 3

[Uri Bernstein]

I have a patch for this, but it's adjacent to code changed in bug 299065, so I'll attach it after that bug lands.

Comment 4

[Uri Bernstein]

Attachment: patch

Comment 5

[Uri Bernstein]

Checked in:
Checking in layout/base/nsCSSFrameConstructor.cpp;
/cvsroot/mozilla/layout/base/nsCSSFrameConstructor.cpp,v  <--  nsCSSFrameConstructor.cpp
new revision: 1.1197; previous revision: 1.1196
done