Ability to disable dbus support in Qt client

[nzqr]

Here's sample patch:

app.cc

@@ -14 +14 @@
 #include <ctime>
 #include <iostream>
 
+#ifdef MY_DBUS
 #include <QDBusConnection>
 #include <QDBusConnectionInterface>
 #include <QDBusError>
 #include <QDBusMessage>
+#endif
+
 #include <QDialogButtonBox>
 #include <QIcon>
 #include <QLabel>
@@ -32 +35 @@
 
 #include "add-data.h"
 #include "app.h"
+
+#ifdef MY_DBUS
 #include "dbus-adaptor.h"
+#endif
+
 #include "formatter.h"
 #include "mainwin.h"
 #include "options.h"
@@ -45 +52 @@
 
 namespace
 {
+#ifdef MY_DBUS
     const QString DBUS_SERVICE     = QString::fromAscii( "com.transmissionbt.Transmission"  );
     const QString DBUS_OBJECT_PATH = QString::fromAscii( "/com/transmissionbt/Transmission" );
     const QString DBUS_INTERFACE   = QString::fromAscii( "com.transmissionbt.Transmission"  );
-
+#endif
+                
     const char * MY_READABLE_NAME( "transmission-qt" );
 
     const tr_option opts[] =
@@ -245 +254 @@
         addTorrent( *it );
 
     // register as the dbus handler for Transmission
+#ifdef MY_DBUS
     new TrDBusAdaptor( this );
     QDBusConnection bus = QDBusConnection::sessionBus();
     if( !bus.registerService( DBUS_SERVICE ) )
         std::cerr << "couldn't register " << qPrintable(DBUS_SERVICE) << std::endl;
     if( !bus.registerObject( DBUS_OBJECT_PATH, this ) )
         std::cerr << "couldn't register " << qPrintable(DBUS_OBJECT_PATH) << std::endl;
+#endif
 }
 
 /* these functions are for popping up desktop notifications */
@@ -282 +293 @@
 
     if( tor && !tor->name().isEmpty() )
     {
+#ifdef MY_DBUS
         notify( tr( "Torrent Completed" ), tor->name( ) );
+#endif
 
         disconnect( tor, SIGNAL(torrentCompleted(int)), this, SLOT(onTorrentCompleted(int)) );
     }
@@ -295 +308 @@
 
     if( tor && !tor->name().isEmpty() )
     {
+#ifdef MY_DBUS
         const int age_secs = tor->dateAdded().secsTo(QDateTime::currentDateTime());
         if( age_secs < 30 )
             notify( tr( "Torrent Added" ), tor->name( ) );
+#endif
 
         disconnect( tor, SIGNAL(torrentChanged(int)), this, SLOT(onNewTorrentChanged(int)) );
 
@@ -439 +454 @@
     QApplication :: alert ( myWindow );
 }
 
+#ifdef MY_DBUS
 bool
 MyApp :: notify( const QString& title, const QString& body ) const
 {
@@ -462 +478 @@
     //std::cerr << qPrintable(replyMsg.errorMessage()) << std::endl;
     return (replyMsg.type() == QDBusMessage::ReplyMessage) && !replyMsg.arguments().isEmpty();
 }
+#endif
 
 /***
 ****
@@ -481 +498 @@
 
     // try to delegate the work to an existing copy of Transmission
     // before starting ourselves...
+#ifdef MY_DBUS
     bool delegated = false;
     QDBusConnection bus = QDBusConnection::sessionBus();
     for( int i=0, n=addme.size(); i<n; ++i )
@@ -509 +527 @@
 
     if( delegated )
         return 0;
+#endif
 
     tr_optind = 1;
     MyApp app( argc, argv );

[jordan]

What is the use case for this?

[nzqr]

To conserve ram on older machines, while still using gui.

[jordan]

How much memory is saved by disabling DBus support?

[nzqr]

This will vary based on achitecture and compiler options, and every little bit helps. If this is not enough for substantiation, when compiling why do i bother to build dbus when it's not needed for me?

[jordan]

Top says stock transmission-qt uses 39m RES / 29m SHR.

Top says patched transmission-qt uses 39m RES / 29m SHR.

This patch doesn't seem to save any memory on i686...

[nzqr]

Seems that you done something wrong, for example qtdbus still is linked, thats my results of

ps -o rss,comm `pgrep 'transmission-qt|dbus'`

without patch:

  RSS COMMAND
34452 transmission-qt
  724 dbus-launch
  668 dbus-daemon

with:

  RSS COMMAND
33836 transmission-qt

dbus session daemon included because no other app than transmission uses it on my system.

Btw, what's about porting on windows, has dbus on windows any sense?

[jordan]

Thanks for providing some numbers.

So, this is a pretty limited win that few people will notice. I don't care about this ticket, but if it's important enough to you that you'll finish the patch to handle the qmake plumbing and make a patchfile of the unified diffs, then please reopen this ticket and attach the patchfile.

[rb07]

Replying to nzqr:

Btw, what's about porting on windows, has dbus on windows any sense?

I don't understand why you ask this, but the answer is yes, transmission-qt uses dbus-daemon to implement the file and magnet association (just like it does in Linux).

Perhaps your question is more about dbus on Windows, you probably think it doesn't work there, it does, or that is not used by anyone, is being used by the "KDE on Windows Initiative", and Emacs, and others.

[nzqr]

for transmission 2.52

[nzqr]

I have attached the patch, hope it will do.

[jordan]

I still don't like this ticket because the benefits seem very minimal and difficult to reach -- how many people are going to compile their own version of transmission-qt to disable DBus support?