Registrar Tasks:
- MIME Database chores (note that BMimeType appears to read from the database directly for
Get*() calls.)
- Writes to the database --
SetLongDescription(), SetPreferredApp(), create_app_meta_mime(), etc
- Monitoring of the database --
{Start,Stop}Watching()
- Sniffer duties -- Sniffer code plus
{Get,Set,Check}SnifferRule()
- Timing chores
- BMessageRunner functionality
- System Shutdown chores
- Shutdown cycle
- System shutdown window
- Roster chores
- Recent documents, folders, and apps
- Info about running applications
- etc...
Registrar Internals:
The registrar is a non-standard BApplication. It has a shadow app in the app_server
like a normal BApplication, but one of its ports is slightly different:
- Standard ports -- snd, rcv, AppLooperPort
- Registrar ports -- snd, rcv, _roster_port_
Since BLooper::port_id is private to BLooper (to whom BApplication
is a friend), and since you can't rename a port after it's been created,
it's likely that the only way to rename the AppLooperPort and have the registrar
still be a BApplication is to have BApplication check if it's the
registrar when it's created, and use _roster_port_ as the name for what would
otherwise be its AppLooperPort.
The rationale behind having a port with a specific name is that the registrar
implements the roster functionality. Thus one can't address it using the app signature
constructor of BMessenger, but rather must send the message directly to
a named port (for example, upon creation, a BApplication object must find and contact
the registrar to notify it of another running application; if the registrar
cannot be found, the application putzes out).
The Registrar has three threads:
- _roster_thread_
- timer_thread
- main_mime
BMimeType Notes:
- The
Get*() methods directly access the MIME database.
- The
Set*() methods send a message to another entity which does the job.
The function that does the sending is called _send_to_roster_(), so I
suppose the roster is the one. Since the registrar has a thread named
_roster_thread_, I assume the roster lives in the registrar.
-
Start/StopWatching() call BRoster::_Start/_StopWatching().
- Adding/removing a MIME type file in
~/config/settings/beos_mime/*/ does
not trigger a notification message. So obviously no node monitoring is
done and changes to the database are supposed to be done using the API.
Links: