Bug 29409

Summary: StatefulDBusProxy should use QDBusServiceWatcher, if available
Product: Telepathy Reporter: Olli Salli <ollisal>
Component: tp-qtAssignee: Andre Moreira Magalhaes <andrunko>
Status: RESOLVED FIXED QA Contact: Telepathy bugs list <telepathy-bugs>
Severity: normal    
Priority: medium Keywords: patch
Version: git master   
Hardware: All   
OS: All   
URL: http://git.collabora.co.uk/?p=user/andrunko/telepathy-qt4.git;a=shortlog;h=refs/heads/dbus-proxy-qdbusservicewatcher-support
Whiteboard: review-, minor changes
i915 platform: i915 features:

Description Olli Salli 2010-08-05 07:44:27 UTC 
StatefulDBusProxy (used by the high-level proxy objects for all stateful service interfaces in tp-qt4) currently connects to the DBus daemon's serviceOwnerChanged signal in a generic way, causing a wakeup and extra processing for every StatefulDBusProxy-derived object in a tp-qt4 application whenever a DBus client enters/exits the bus or registers a well-known name.

Qt 4.6 added the QDBusServiceWatcher class (http://doc.qt.nokia.com/4.6/qdbusservicewatcher.html), which should be used to listen only for the specific name the proxy object is associated with, preventing wakeups from unrelated name changes.
Comment 1 Andre Moreira Magalhaes 2010-08-27 07:31:30 UTC 
Patch attached.
Comment 2 Simon McVittie 2010-09-01 02:55:18 UTC 
Major: please preserve the code order so you connect to the signal before calling the method, to not race.

Minor: in configure.ac, I'd prefer to add an AC_MSG_CHECKING...AC_MSG_RESULT pair, so we get:

    checking for QDBusServiceWatcher... yes

in buildbot logs. You can either check for it like you did, or via a pkg-config check for QtDBus >= 4.6.n, whichever's easier for you.

If you check for the functionality rather than the version, please also add a comment saying "delete this check when we depend on Qt >= 4.6.0" (replace version as appropriate).
Comment 3 Olli Salli 2010-09-10 02:56:14 UTC 
Fix merged to master. Will be in 0.3.9.

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