wierd QT warnings and ksycoca errors

[Sunil]

now that's the difference between a rookie getting his
feet wet and a vetaran who's seen some real
code...thanks ralf.

Can I post your email reply to the bug that I have
opened?

http://bugs.kde.org/show_bug.cgi?id=105387

Thanks,
-Sunil

--- Ralf Habacker <ralf.habacker at freenet.de> wrote:

> On Tuesday 10 May 2005 03:56, Sunil wrote:
> > > There are some places in the kde sources where
> > > something like this happens.
> > > Usually there is only a file close required. See
> the
> > > appended patch, which fixes several problems
> >
> > your patch doesn't fix the problem because the
> problem
> > with updating ksycoca database is coming from
> > database.close() line in kbuildsycoca.cpp :
> >
> >     if (!database.close())
> >     {
> >       fprintf(stderr, "kbuildsycoca: ERROR writing
> > database '%s'!\n",
> > database.name().local8Bit().data());
> >       fprintf(stderr, "kbuildsycoca: Disk
> full?\n");
> > #ifdef KBUILDSYCOCA_GUI
> >       if (!silent)
> >         KMessageBox::error(0, i18n("Error writing
> > database '%1'.\nCheck that the permissions are
> correct
> > on the directory and the disk is not
> > full.\n").arg(path.local8Bit().data()),
> > i18n("KBuildSycoca"));
> > #endif
> >       return false;
> >     }
> >
> > kdecore/ksavefile.cpp has the following piece of
> code
> > where close() renames the temporary file to the
> > ksycoca in /var/tmp/kdecache-<username>/. This
> fails
> > because some process has opened that file
> READ_ONLY.
> > It looks like it is kded daemon as one of
> processes
> > which has it opened. 
> And one kdeinit process too 
> > But I am not sure how to ask these processes to
> close this file.
> 
> all access to the ksycoca database is encapsulated 
> by the class KSycoca, 
> which contains a signal handler
> notifyDatabaseChanged(), wich closes the 
> database. from kdecore/ksycoca.cpp
> 
> void KSycoca::notifyDatabaseChanged(const
> QStringList &changeList)
> {
>     d->changeList = changeList;
>     //kdDebug(7011) << "got a notifyDatabaseChanged
> signal !" << endl;
>     // kded tells us the database file changed
>     // Close the database and forget all about what
> we knew
>     // The next call to any public method will
> recreate
>     // everything that's needed.
>     closeDatabase();
> 
>     // Now notify applications
>     emit databaseChanged();
> }
> 
> The relating signal is send after updating the
> database in 
> kbuildsycoca:kdemain():
> 
>    if (args->isSet("signal"))
>    {
>      // Notify ALL applications that have a ksycoca
> object, using a broadcast
>      QByteArray data;
>      QDataStream stream(data, IO_WriteOnly);
>      stream << *g_changeList;
>      dcopClient->send( "*", "ksycoca",
> "notifyDatabaseChanged(QStringList)", 
> data );
>    }
> 
> The problem is that this signal is send to late. A
> workaround could be to send 
> this signal immediatly before the call to
> KBuildSycoca::recreate() in 
> kbuildsycoca:kdemain()
> 
>       KBuildSycoca *sycoca= new KBuildSycoca; //
> Build data base
>       if (args->isSet("track"))
>         
>
sycoca->setTrackId(QString::fromLocal8Bit(args->getOption("track")));
> >>>>>>>>>>>>>>>>>>>> 
>    if (args->isSet("signal"))
>    {
>      // Notify ALL applications that have a ksycoca
> object, using a broadcast
>      QByteArray data;
>      QDataStream stream(data, IO_WriteOnly);
>      stream << *g_changeList;
>      dcopClient->send( "*", "ksycoca",
> "notifyDatabaseChanged(QStringList)", 
> data );
>    }
> <<<<<<<<<<<<<<<<<<<
>       if (!sycoca->recreate()) {
> 
> but I don't do if this works in any cases. 
> 
> A generic approach is to introduce a new signal for
> example 
> notifyDatabaseUpdatePending or so, which could close
> and lock any unwanted 
> access to the database until the
> notifyDatabaseChanged is send. If the 
> workaround doesn't work we can implemented this. If
> you need any assistance, 
> let me know. 
> 
> >
> >    if (mTempFile.close())
> >    {
> >       if
> >
> (0==KDE_rename(QFile::encodeName(mTempFile.name()),
> > QFile::encodeName(mFileName)))
> >          return true; // Success!
> >       mTempFile.setError(errno);
> >    }
> >
> > this is where processes open the ksycoca database
> in
> > kdecore/ksycoca.cpp:
> >
> >    kdDebug(7011) << "Trying to open ksycoca from "
> <<
> > path << endl;
> >    QFile *database = new QFile(path);
> >    bool bOpen = database->open( IO_ReadOnly );
> >
> > I am not sure how to tackle this. In Unix its so
> easy
> > to assume that readers won't stop writers from
> > writing. Do you think cygwin can demand different
> > semantics from kde folks, wherein its the kded
> which
> > does the update to the database always (currently
> eny
> > process can call kbuildsycoca to update the
> database)
> > and everybody, who has the database opened, is
> asked
> > to close the database before rename() is issued by
> > kded? 
> see above 
> > Should I file a bug report with kde? 
> It may be good to ask them what kind of solution
> they prefer for this problem 
> and what they are thinking about the generic
> solution. 
> 
> > > > 2. I get these in my kde session log all the
> time:
> > > >
> > > > QObject::disconnect: Unexpected null parameter
> > > > QObject::connect: Cannot connect
> (null)::hide() to
> > > > Baghira::DeMaximizer::hide()
> > > >
> > > > I am not sure if they are errors or warnings.
> > >
> > > Anyone
> > >
> > > > any idea?
> > >
> > > Which application causes this warnings ?  It
> seems
> > > that a qt signal/slot
> > > connection couldn't be established. The slot is
> > > named in DeMaximizer::hide()
> > > in namespace Baghira.
> >
> > I am not sure which process it is. I just see
> these
> > repeated very often in the log file.
> 
> try 
> find <source path> -name '*.cpp' -exec grep -H
> "Baghira::DeMaximizer" {} \;
>  to find the relating code. 
> 
> 
> regards 
> Ralf 
> > ? .svn
> ? Makefile.out
> ? kded.pro
> ? kded_rel.pro
> ? out.log
> ? test/.svn
> Index: Makefile.am
>
===================================================================
> RCS file: /home/kde/kdelibs/kded/Makefile.am,v
> retrieving revision 1.31
> diff -u -3 -p -B -r1.31 Makefile.am
> --- Makefile.am	26 Oct 2003 23:04:45 -0000	1.31
> +++ Makefile.am	10 May 2005 11:55:46 -0000
> @@ -22,14 +22,14 @@ INCLUDES= -I$(srcdir)/..
> -I$(top_srcdir)
>  lib_LTLIBRARIES =
>  kdeinit_LTLIBRARIES = kded.la kbuildsycoca.la
>  
> -kded_la_LDFLAGS = $(all_libraries) -module
> -avoid-version
> +kded_la_LDFLAGS = $(all_libraries) -module
> -avoid-version -static
>  kded_la_LIBADD = $(LIB_KIO)
>  kded_la_SOURCES = kded.cpp
> kbuildservicetypefactory.cpp \
>  			kbuildservicefactory.cpp \
>  			kbuildservicegroupfactory.cpp kdedmodule.cpp
>  
> -kbuildsycoca_la_LDFLAGS = $(all_libraries) -module
> -avoid-version
> -kbuildsycoca_la_LIBADD = $(LIB_KIO)
> +kbuildsycoca_la_LDFLAGS = $(all_libraries) -module
> -avoid-version -static 
> +kbuildsycoca_la_LIBADD = $(LIB_KIO) 
>  kbuildsycoca_la_SOURCES = kbuildsycoca.cpp
> kbuildservicetypefactory.cpp \
>  				kbuildservicefactory.cpp \
>  				kbuildservicegroupfactory.cpp \
> Index: kbuildsycoca.cpp
>
===================================================================
> RCS file: /home/kde/kdelibs/kded/kbuildsycoca.cpp,v
> retrieving revision 1.111
> diff -u -3 -p -B -r1.111 kbuildsycoca.cpp
> --- kbuildsycoca.cpp	18 Feb 2005 18:03:12 -0000
> 1.111
> +++ kbuildsycoca.cpp	10 May 2005 11:55:46 -0000
> @@ -535,6 +535,9 @@ bool KBuildSycoca::recreate()
>         if (tmp.status() == 0)
>         {
>            QString tmpFile = tmp.name();
> +#ifdef __CYGWIN__
> +          tmp.close();
> +#endif 
>            tmp.unlink();
>            symlink(QFile::encodeName(path),
> QFile::encodeName(tmpFile));
>            rename(QFile::encodeName(tmpFile),
> QFile::encodeName(oldPath));
> @@ -908,6 +911,19 @@ extern "C" KDE_EXPORT int
> kdemain(int ar
>        KBuildSycoca *sycoca= new KBuildSycoca; //
> Build data base
>        if (args->isSet("track"))
>          
>
sycoca->setTrackId(QString::fromLocal8Bit(args->getOption("track")));
> +
> +#ifdef __CYGWIN__
> +      // this is required because windows does not
> allow renaming an open file 
> +      if (args->isSet("signal"))
> +      {
> +        // Notify ALL applications that have a
> ksycoca object, using a broadcast
> +        QByteArray data;
> +        QDataStream stream(data, IO_WriteOnly);
> +        stream << *g_changeList;
> +        dcopClient->send( "*", "ksycoca",
> "notifyDatabaseChanged(QStringList)", data );
> +      }
> +#endif 
> +
>        if (!sycoca->recreate()) {
>  #ifdef KBUILDSYCOCA_GUI
>          if (!silent || showprogress)
> @@ -926,7 +942,7 @@ extern "C" KDE_EXPORT int
> kdemain(int ar
>         
> ::rmdir(QFile::encodeName(servicetypesDir));
>        }
>     }
> -
> +#ifndef __CYGWIN__
>     if (args->isSet("signal"))
>     {
>       // Notify ALL applications that have a ksycoca
> object, using a broadcast
> @@ -935,7 +951,7 @@ extern "C" KDE_EXPORT int
> kdemain(int ar
>       stream << *g_changeList;
>       dcopClient->send( "*", "ksycoca",
> "notifyDatabaseChanged(QStringList)", data );
>     }
> -
> +#endif 
>  #ifdef KBUILDSYCOCA_GUI
>     if (!silent) {
>       progress.close();
> > _______________________________________________
> kde-cygwin mailing list
> kde-cygwin at kde.org
> https://mail.kde.org/mailman/listinfo/kde-cygwin
> 



	
		
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