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<title>Registrar Notes</title>
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<!-- Tasks -->
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<b>Registrar Tasks:</b>
<ul>
<li> MIME Database chores (note that BMimeType appears to read from the database directly for <code>Get*()</code> calls.)<br>
<ul>
<li> Writes to the database -- <code>SetLongDescription(), SetPreferredApp(), create_app_meta_mime(), etc</code>
<li> Monitoring of the database -- <code>{Start,Stop}Watching()</code> <br>
<li> Sniffer duties -- Sniffer code plus <code>{Get,Set,Check}SnifferRule()</code>
</ul>
<br>
<li> Timing chores
<ul>
<li> BMessageRunner functionality
</ul>
<li> System Shutdown chores <br>
<ul>
<li> Shutdown cycle
<li> System shutdown window
</ul>
<li> Roster chores
<ul>
<li> Recent documents, folders, and apps
<li> Info about running applications
<li> etc...
</ul>
</ul>
<!-- Internals -->
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<b>Registrar Internals:</b><br>
<br>
The registrar is a non-standard <code>BApplication</code>. It has a shadow app in the <code>app_server</code>
like a normal <code>BApplication</code>, but one of its ports is slightly different:
<ul>
<li> Standard ports -- snd, rcv, AppLooperPort
<li> Registrar ports -- snd, rcv, _roster_port_
</ul>
Since <code>BLooper::port_id</code> is private to <code>BLooper</code> (to whom <code>BApplication</code>
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 <code>AppLooperPort</code> and have the registrar
still be a <code>BApplication</code> is to have <code>BApplication</code> check if it's the
registrar when it's created, and use <code>_roster_port_</code> as the name for what would
otherwise be its <code>AppLooperPort</code>.
<br>
<br>
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).
<br>
<br>
The Registrar has three threads:
<ul>
<li> _roster_thread_
<li> timer_thread
<li> main_mime
</ul>
<!-- BMimeType Notes -->
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<b>BMimeType Notes:</b>
<ul>
<li> The <code>Get*()</code> methods directly access the MIME database.
<li> The <code>Set*()</code> methods send a message to another entity which does the job.
The function that does the sending is called <code>_send_to_roster_()</code>, so I
suppose the roster is the one. Since the registrar has a thread named
<code>_roster_thread_</code>, I assume the roster lives in the registrar.
<li> <code>Start/StopWatching()</code> call <code>BRoster::_Start/_StopWatching()</code>.
<li>Adding/removing a MIME type file in <code>~/config/settings/beos_mime/*/</code> 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.
</ul>
<!-- Links -->
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<b>Links:</b>
<ul>
<li> <a href='http://www.beatjapan.org/mirror/www.be.com/users/iconworld/icon5.html'>Icon World -- The Registrar</a>
<li> <a href='http://www.beosbible.com/exc_filetype.html'>The BeOS Bible -- File Typing and The Registrar</a>
<li> <a href='http://bang.dhs.org/be/bebook/The%20Application%20Kit/Application.html'>BApplication</a>
<li> <a href='http://bang.dhs.org/be/bebook/The%20Storage%20Kit/MimeType.html'>BMimeType</a>
<li> <a href='http://bang.dhs.org/be/bebook/Release%20Notes/StorageKit.html'>BMimeType (sniffer docs)</a>
<li> <a href='http://bang.dhs.org/be/bebook/The%20Application%20Kit/Roster.html'>BRoster</a>
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