[mythtv-firehose] mythtv/master commit: 0434cd982 by Daniel Thor Kristjansson (daniel-kristjansson)

[MythTV]

      Author:  Daniel Thor Kristjansson <dkristjansson at mythtv.org>
 Change Date:  2011-05-11T08:42:30-07:00
   Push Date:  2011/05/11 08:48:06 -0700
  Repository:  mythtv
      Branch:  master
New Revision:  0434cd9826a1cd67034315fc4c0999a048296630
   Changeset:  https://github.com/MythTV/mythtv/commit/0434cd982

Log:

Various threading cleanups copied from mythtv-rec2 branch.

Gavin Hurlibut undertook a large code cleanup of our threading some
weeks back. But there were a few systematic problems in the handling
of thread startup and shutdown. Except for adding a QThread::wait()
to QThread dtors and bugs relating to detached threads, the major
ones have been identified and fixed in previous commits by Gavin.
This commit collects a number of minor ones that I accumulated
in the mythtv-rec2 branch, as well as fixes for bugs that I
identified while reviewing Gavin's work but that were in fact
pre-existing bugs, and finally it reverts three commits that are
trouble, but a rework hasn't yet been completed.

NOTE: I did not review the SignalMonitor threading changes, the
code in mythtv-rec2 for these is too different.

There are some systematic changes:
  Important:
    Added QThread::wait(); to all QThread based class destructors
      This ensures that if we try to delete a QThread based class
      while it's underlying thread is still running we get a deadlock
      instead of a stackless segfault. As a deadlock is much easier to debug.
  Minor:
    Got rid of SetParent() call, instead make this a ctor param.
      This just allows us to do the same things in fewer lines of code.
    Fixed member variable names beginning with a capital letter.
    Explicitly allocated and deallocated all QThread based classes.
      We don't always have good control over which thread the parent
      classes ctor/dtor is run. This just gives us a little more
      flexibility.
    Got rid of "#include <pthread.h>" where no pthread stuff was used.

There are some specific changes:
  The housekeeper thread now can be stopped more quickly, and without
    risking a deadlock. The problems here pre-existed recent threading
    changes.
  The recorders now use a pauseLock when handling pausing and unpausing
    of the recorders. A problem was introduced a while back with the
    Qt4 port in the handling of recorder pausing. This just get's
    carried along with the Recorder Thread QThread port because of
    how I had implemented it there.
  Fixed some incorrect locking introduced in the Qt4 port to MHEGContext.
  There were a few cases where the start/stop handling wasn't quite
    right. Unfortunately this often required some class specific code.

There are some reverts:
  Go back to pthread for ddMapLoader.
    This used to create a detached thread in one of the two uses,
    but after recent changes it instead created an attached thread
    which was then leaked. Fixing is non-trivial.
  Go back to pthread for two of the three threads in jobqueue
    A detached thread problem. There are already two efforts underway
    to fix this in different ways.
  DarwinFirewireDevice. This just doesn't look right, before or
    after the pthread->QThread port. We don't appear to guarantee
    that the thread ever finishes. Without a machine to test this
    on I think it's safest just to revert. All OSX machines have
    a decent pthreads implementation.

Modified:

   mythtv/libs/libmythtv/NuppelVideoRecorder.cpp
   mythtv/libs/libmythtv/NuppelVideoRecorder.h
   mythtv/libs/libmythtv/ThreadedFileWriter.cpp
   mythtv/libs/libmythtv/ThreadedFileWriter.h
   mythtv/libs/libmythtv/channelscan/channelscan_sm.cpp
   mythtv/libs/libmythtv/channelscan/channelscan_sm.h
   mythtv/libs/libmythtv/darwinfirewiredevice.cpp
   mythtv/libs/libmythtv/darwinfirewiredevice.h
   mythtv/libs/libmythtv/dvbcam.cpp
   mythtv/libs/libmythtv/dvbcam.h
   mythtv/libs/libmythtv/dvbrecorder.cpp
   mythtv/libs/libmythtv/fifowriter.cpp
   mythtv/libs/libmythtv/fifowriter.h
   mythtv/libs/libmythtv/firewirerecorder.cpp
   mythtv/libs/libmythtv/frequencies.cpp
   mythtv/libs/libmythtv/hdhrrecorder.cpp
   mythtv/libs/libmythtv/hdhrsignalmonitor.cpp
   mythtv/libs/libmythtv/interactivetv.cpp
   mythtv/libs/libmythtv/iptvrecorder.cpp
   mythtv/libs/libmythtv/iptvrecorder.h
   mythtv/libs/libmythtv/jobqueue.cpp
   mythtv/libs/libmythtv/jobqueue.h
   mythtv/libs/libmythtv/linuxfirewiredevice.cpp
   mythtv/libs/libmythtv/linuxfirewiredevice.h
   mythtv/libs/libmythtv/mhi.cpp
   mythtv/libs/libmythtv/mhi.h
   mythtv/libs/libmythtv/mpegrecorder.cpp
   mythtv/libs/libmythtv/nuppeldecoder.cpp
   mythtv/libs/libmythtv/recorderbase.cpp
   mythtv/libs/libmythtv/recorderbase.h
   mythtv/libs/libmythtv/tv_play.cpp
   mythtv/libs/libmythtv/tv_play.h
   mythtv/libs/libmythtv/tv_rec.cpp
   mythtv/libs/libmythtv/tv_rec.h
   mythtv/libs/libmythui/mythmainwindow.cpp
   mythtv/programs/mythbackend/filetransfer.h
   mythtv/programs/mythbackend/housekeeper.cpp
   mythtv/programs/mythbackend/housekeeper.h
   mythtv/programs/mythbackend/main.cpp
   mythtv/programs/mythbackend/main_helpers.cpp
   mythtv/programs/mythbackend/scheduler.cpp
   mythtv/programs/mythbackend/scheduler.h
   mythtv/programs/mythfrontend/networkcontrol.cpp
   mythtv/programs/mythfrontend/networkcontrol.h