New CD Monitoring code (was Re: [mythtv] Revamping the plugin system.)

J. Donavan Stanley jdonavan at
Mon Dec 1 06:17:03 EST 2003

thor wrote:

>On Thursday 27 November 2003 20:00, J. Donavan Stanley wrote:
>> I'll start working on the MediaHandler
>>stuff as an optional extension to the existing plguins.
>	I'm looking forward to that code, as it's exactly what I need for 
>dynamic build up and tear down of metadata collections in the mfd. :-)
I've rewritten the actual monitoring of the CD media so that all of the 
logic for the mounting/unmounting and notification takes place within 
the object itself.  I've also refactored it into two classes 
MythMediaDevice and MythCDROM.  The former contains baseline logic and 
functionality that's needed for any removable media, the latter contains 
CD specific stuff (like audio/DVD detection and locking the CDROM 
tray).  MythMediaDevices send their state changes via signals now 
instead of callbacks.

 Unfortunately I've not had as much time for things as I'd wanted during 
my time off so I still need to sit down and rewrite the monitor object 
and get it plugged into the frontend. Initially I plan on hooking into 
the jump off logic from Issac and having it jump to the appropriate 
plugin.  Then, I'll start looking into adding the media actions into the 
existing plugin framework.  Though, with what you're working on, I'm not 
sure that's needed...

The way I see it working is this:  At startup the MediaMonitor will 
create MythMediaDevices for the removable drives in fstab. It'll then 
create a separate thread that sits loops calling CheckDevices and 
usleep.  Whenever a MythMediaDevice raises it's signal the MediaMonitor 
will post an event to itself so that it can take action once the main 
thread processes it's message queue.  During the handling of that event, 
is when the switch to the proper plugin will take place.

Depending on what direction you're going with things, I'll either start 
working on the media actions so that we're not limited to one plugin per 
media type.  Or I'll start working on new subclasses of MythMediaDevice 
to handle different media types.  Since I've gotten my flash card reader 
up an running under Linux this weekend I'll start with removable SCSI 
devices I imagine.  Extra media types aren't very useful without the 
media actions though since they're all going to have a media type of 

Question: Does anyone have one of those USB flash drives like they sell 
at ThinkGeek?  I'm wondering if they work the same as normal flash 
readers under Linux (i.e. usb-storage with SCSI emulation).

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