Open Bug 481740 Opened 11 years ago Updated 1 year ago

test framework for interruptible reflow - trigger a reflow interrupt on textnode containing vertical tab


(Core :: General, enhancement)

Not set




(Reporter: njain, Unassigned)




(1 file, 4 obsolete files)

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB5; .NET CLR 1.1.4322; InfoPath.2; .NET CLR 2.0.50727)
Build Identifier: 

Need a setup to test the interruptible reflow code as well as possible. One approach is to trigger an interrupt when there is a textnode with a particular content (e.g. a textnode containing only a vertical tab) when certain environment variables are set.

This framework would allow us to easily write reftests containing a textnode with a vertical tab, that would trigger reflow interrupts at particular places at particular times.

Reproducible: Always
Created a patch which triggers a reflow interrupt for textnodes containg a vertical tab. This patch adds additional functionality for testing puposes to the patch from bug 67752.

The environment variables needed to trigger an interrupt are:
Sample test file to trigger an interrupt:
<!DOCTYPE html>
Depends on: ireflow
Neeti, I just updated the patch in bug 67752.  Would you mind making an interdiff of your patch against that one?
Assignee: nobody → njain
Ever confirmed: true
Attaching interdiff of test framework patch against the patch in bug 67752 submitted on 03-29-09
Attachment #365753 - Attachment is obsolete: true
Updated interdiff patch against bug 67752(04-22-2009) and added tests to trigger interrupts
Attachment #370443 - Attachment is obsolete: true
Looks like these reftests never made it into the tree.  Are they valid and can they be checked in?
I don't know that anyone's checked that:

1)  The tests pass
2)  The tests actually test something

I suspect that without more changes elsewhere they probably don't.

The patch also enables the interruptible reflow debug spew, which is probably undesirable.
Attached patch updated patch (obsolete) — Splinter Review
I updated this patch so that it applies cleanly and compiles against mozilla-central.  Still need to investigate whether it does anything.
Attachment #375072 - Attachment is obsolete: true
Boris:  the tests all produce output similar to this when hitting the vtab:

*** Entering reflow event (time=1255647089021000)
*** DETECTED pending interrupt (time=1255647089021000)
mFramesToDirty.Count() == 6
*** Returning from reflow event (time=1255647089037000)

Does this qualify as "testing something"?  They also all pass.  The caveat is that these must all be set:


So, I would have to add something to reftest.js to allow these to be set from within a test.

Also, I had to make a small change in nsPresContext::CheckForInterrupt(), from 

  mHasPendingInterrupt =
    TimeStamp::Now() - mReflowStartTime > sInterruptTimeout &&
    HavePendingInputEvent() &&


  mHasPendingInterrupt =
    TimeStamp::Now() - mReflowStartTime >= sInterruptTimeout &&
    HavePendingInputEvent() &&

since for some tests, TimeStamp::Now() - mReflowStartTime = 0, when the vtab is hit, at least on my machine.
> Does this qualify as "testing something"?

Yeah; it means we interrupted the reflow.  We probably don't want to land the part of this patch that enables those printfs... 

I'd been using GECKO_REFLOW_MIN_NOINTERRUPT_DURATION=-1 to disable the timeout check.

As far as setting the env vars from reftest.js, we'd need to make prescontext notice the env var change or something.  I suppose we can hook up an observer notification to reset the prescontext state.  Alternately, we'd need to run these reftests as a separate test run from normal reftests.
Attached patch patch v3Splinter Review
I ended up not setting env vars from reftest.js, since doing so using nsIEnvironment causes a deliberate leak which is no good for tinderbox (see  So instead I'm just using an observer notification to tell nsPresContext to set/reset the ireflow parameters.  I'm sure there are other ways to do this; if you want something else, let me know.
Attachment #405550 - Attachment is obsolete: true
Attachment #416994 - Flags: review?(bzbarsky)
Attachment #416994 - Attachment description: path v3 → patch v3
Assignee: njain → jgriffin
Attachment #416994 - Flags: review?(bzbarsky)
Assignee: jgriffin → nobody
No assignee, updating the status.
No assignee, updating the status.
No assignee, updating the status.
No assignee, updating the status.
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