Re: [Xsltforms-support] conflict between subforms and the profiler?

[Alain C. <ala...@ag...>]

Hello Michael,

Thank you for this fix. I will have to check whether this is due to a 
missing treatment for XPath expression objects when unloading a subform 
because there might be some memory leak.

-Alain

Le 30/06/2012 04:36, C. M. Sperberg-McQueen a écrit :
> On Jun 26, 2012, at 7:38 PM, C. M. Sperberg-McQueen wrote:
>
>> I've encountered an unexpected behavior in 1.0RC.  I first encountered
>> it in one of my own forms, but the simplest way to recreate it may be:
>>
>> (1) Load the writers.xml example from the 1.0RC distribution, or from
>>
>>     http://www.agencexml.com/xsltforms/writers.xml
>>
>> (2) Click Show Books and Hide Books a few times.
>>
>> (3) Click Profiler.
>>
>> This ought in normal operation to produce a profile showing the profiler
>> information we have all come to love.  What it produces instead, at the
>> moment, is a Javascript error message saying
>>
>>   XSLTForms Exception
>>   --------------------------
>>
>>   Error dispatching event 'xforms-model-construct' :
>>
>>   xforms-link-exception
>
> I think I have now identified the source of this error.
>
> Adding calls to Xsltforms_browser.debugConsole.write
> at various locations makes clear that the error is arising in the
> Xsltforms_globals.profiling_data() function, specifically in the loop
>
> 	for (var expr in XsltForms_xpath.expressions) {
> 			if (XsltForms_xpath.expressions.hasOwnProperty(expr)) {
> 				exprtab[exprtab.length] = {expr: expr, evaltime: XsltForms_xpath.expressions[expr].evaltime};
> 			}
> 	}
>
> When I load writers.xml and click the Profiler button before having
> unloaded any author's booklist, then this loop executes eight times,
> for the expressions
>
>    . != 'true'
>    @firstname
>    @lastname
>    @selected
>    @selected != 'true'
>    @selected = 'true'
>    choose(@selected != 'true', 'Show', 'Hide')
>    writer
>
> These are the XPath expressions occurring in writers.xml.
>
> When I load the subform, by clicking Show Books, and then click Profiler,
> the loop executes eleven times:  eight times for the XPath expressions shown
> above, and three more times for
>
>    @title
>    @year
>    book
>
> These are the XPath expressions in books.xml, the subform.
>
> When I then unload the subform by clicking Hide Books, and click Profiler
> a third time, I get an error message in the Profiler window, and the debugging
> trace in the main-form window shows the loop being entered nine times; it
> looks a lot as if the error were being raised when the loop tries to evaluate
> XsltForms_xpath.expressions['@title'].evaltime.
>
> A little further examination suggests that after the subform is
> unloaded, XsltForms_xpath.expressions['@title'] is null, so
> the attempt to get its 'evaltime' property produces an error,
> which causes the load of the profiler to fail.
>
> Changing the conditional in lines 302-304 of xsltforms.js (in 1.0RC) to
>
>    if (XsltForms_xpath.expressions.hasOwnProperty(expr) && XsltForms_xpath.expressions[expr]) {
>       exprtab[exprtab.length] = {expr: expr, evaltime: XsltForms_xpath.expressions[expr].evaltime};
>    }
>
> seems to allow the Profiler to launch normally even after the subform is
> unloaded.
>
> Michael
>