Hello again,

> No, there are several search tasks running but all of their calls to the
> DjVuLibre API are serialized, so they are not really running in parallel
> but rather interleaved. And this is then also true for rendering which
> is not an acceptable limitation.


OK, then I think a workaround is using a threadpool with max thread count
set to one on Windows.
But I think for now we can leave it because there are no lots of Windows
users. (maybe just me :D )

Thanks,
Razi.


2014-09-21 20:09 GMT+03:30 Adam Reichold <email address hidden>:

Hello again,

Am 21.09.2014 um 18:29 schrieb S. Razi Alavizadeh:
> Hello Adam,
>
>> your change fixes the symptom because all DjVu API access is serialize
>> as if there was only a single thread
>
>
> No, maybe I explain it badly, with changes that I pushed yesterday, search
> works as expected, i.e. there are parallel searches started on all opened
> document without crash.

No, there are several search tasks running but all of their calls to the
DjVuLibre API are serialized, so they are not really running in parallel
but rather interleaved. And this is then also true for rendering which
is not an acceptable limitation.

Best regards, Adam.

> Best Regards,
> Razi.
>
> 2014-09-21 19:33 GMT+03:30 Adam Reichold <email address hidden>:
>
>> Hello Razi,
>>
>> your change fixes the symptom because all DjVu API access is serialize
>> as if there was only a single thread, but not the issue since the
>> problem is most likely within the Windows of DjVuLibre as other
>> platforms can happily render or search pages of different documents and
>> hence contexts in parallel which is a performance improvement I would
>> not miss because of one problematic port. My suggestion was in any case
>> meant to isolate the problem so that we now know that the Windows
>> implemenation of DjVuLibre has a threading problem for text extraction
>> which the POSIX port does not seem to have. (Or our usage of the API is
>> wrong and it works on Linux by pure luck which have no indication for so
>> far.)
>>
>> Best regards, Adam.
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1370540
>>
>> Title:
>>   Search within multiple DjVu files.
>>
>> Status in qpdfview:
>>   Incomplete
>>
>> Bug description:
>>   Steps to reproduce:
>>   1- Open more than two DjVu that you know have the text you trying to
>> search.
>>   2- Write the string you want to search if search-line edit and use
>> SHIFT+Enter to start search within all opened documents.
>>   3- Crash!!
>>   4- There's no problem when at most one DjVu document is opened.
>>
>>   Call stack from WinDbg:
>>   ntdll!RtlpNtSetValueKey+0x12b
>>   ntdll!RtlpNtSetValueKey+0x2914
>>   ntdll!RtlpNtSetValueKey+0x31c5
>>   ntdll!LdrSetAppCompatDllRedirectionCallback+0x11442
>>   MSVCR100!free+0x1c
>>   libdjvulibre!DJVU::GExceptionHandler::operator=+0x5e
>>   libdjvulibre!miniobj_t::destroy+0xc
>>   libdjvulibre!miniexp_symbol+0x564
>>   libdjvulibre!ddjvu_document_get_outline+0x39b
>>   libdjvulibre!ddjvu_document_get_outline+0x43d
>>   libdjvulibre!ddjvu_document_get_outline+0x43d
>>   libdjvulibre!ddjvu_document_get_pagetext+0x1c9
>>   qpdfview_djvu!qt_plugin_instance+0x24b4
>>   ntdll!RtlAllocateHeap+0xc6
>>   QtCore4!QAbstractEventDispatcher::QAbstractEventDispatcher+0x39
>>   qpdfview+0x18a16
>>   QtCore4!QThread::setPriority+0x3a3
>>   QtCore4!QString::toStdWString+0x1b3b
>>   MSVCR100!endthreadex+0xe4
>>   ntdll!RtlCreateMemoryZone+0x9b
>>   ntdll!RtlCaptureContext+0xeb
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/qpdfview/+bug/1370540/+subscriptions
>>
>
>

--
You received this bug notification because you are subscribed to the bug
report.
https://bugs.launchpad.net/bugs/1370540

Title:
  Search within multiple DjVu files.

Status in qpdfview:
  Incomplete

Bug description:
  Steps to reproduce:
  1- Open more than two DjVu that you know have the text you trying to
search.
  2- Write the string you want to search if search-line edit and use
SHIFT+Enter to start search within all opened documents.
  3- Crash!!
  4- There's no problem when at most one DjVu document is opened.

  Call stack from WinDbg:
  ntdll!RtlpNtSetValueKey+0x12b
  ntdll!RtlpNtSetValueKey+0x2914
  ntdll!RtlpNtSetValueKey+0x31c5
  ntdll!LdrSetAppCompatDllRedirectionCallback+0x11442
  MSVCR100!free+0x1c
  libdjvulibre!DJVU::GExceptionHandler::operator=+0x5e
  libdjvulibre!miniobj_t::destroy+0xc
  libdjvulibre!miniexp_symbol+0x564
  libdjvulibre!ddjvu_document_get_outline+0x39b
  libdjvulibre!ddjvu_document_get_outline+0x43d
  libdjvulibre!ddjvu_document_get_outline+0x43d
  libdjvulibre!ddjvu_document_get_pagetext+0x1c9
  qpdfview_djvu!qt_plugin_instance+0x24b4
  ntdll!RtlAllocateHeap+0xc6
  QtCore4!QAbstractEventDispatcher::QAbstractEventDispatcher+0x39
  qpdfview+0x18a16
  QtCore4!QThread::setPriority+0x3a3
  QtCore4!QString::toStdWString+0x1b3b
  MSVCR100!endthreadex+0xe4
  ntdll!RtlCreateMemoryZone+0x9b
  ntdll!RtlCaptureContext+0xeb

To manage notifications about this bug go to:
https://bugs.launchpad.net/qpdfview/+bug/1370540/+subscriptions




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Alavizadeh, Sayed Razi
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