RE: Diskarbitration callback

8 May 2008

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Thread-index: AcixDK5OFD303bvnSfWpoo07qb/QWQAH4G6Q
Thread-topic: Diskarbitration callback
...
...
I've written some code which uses the diskArbitration framework to
unmount (and eject) a disk.
It works, in that the disk gets unmounted, but my callback isn't
being called, even though the operation is successful. Any
chance of
spotting the mistake in this code fragment? :-
I think you'll have to schedule the session with a run loop
to get any
callback actions.
Wow - works like a charm!
When I say that, I mean it works, but I have no idea how! I'll have to
go read up on run loops: in the meantime here's the working code for
posterity - is this what you meant?

And an awkward question: my 'real' code will be in a library, called
from both command line tools, and from a cocoa app. Is this run-loop
hocus pocus safe in both environments?

struct Nothing
{
    bool dummy;
};

static void AndygDiskArbCallback( DADiskRef disk, DADissenterRef
dissenter, void * context)
{
    TRACE("callback...");
    if (dissenter)
    {
        DAReturn status = DADissenterGetStatus( dissenter );
        TRACE("DENIED (0x%x)!...", status);
    }
    else
    {
        TRACE("granted...");
        Nothing * n = (Nothing *)context;
        assert(n);
        n->dummy = true;
    }

    // unlock the main thread
    CFRunLoopStop(CFRunLoopGetCurrent());
}

int main(int argc, const char *argv[])
{
    const char * cStr = "disk3s10";
    Nothing * n = new Nothing;
    n->dummy = false;

    DASessionRef diskArbSession = DASessionCreate(kCFAllocatorDefault);
    assert(diskArbSession);
    DASessionScheduleWithRunLoop(diskArbSession, CFRunLoopGetCurrent(),
kCFRunLoopDefaultMode);
    DADiskRef disk = DADiskCreateFromBSDName( kCFAllocatorDefault,
diskArbSession, cStr );
    assert(disk);
    TRACE("confirming %s == %s??\n", DADiskGetBSDName(disk), cStr);
    DADiskRef whole = DADiskCopyWholeDisk( disk );
    if ( whole )
    {
        TRACE("wholedisk == %s\n", DADiskGetBSDName(whole));
        DADiskUnmount(whole, kDADiskUnmountOptionWhole |
kDADiskUnmountOptionForce, AndygDiskArbCallback, n);
        TRACE("------Wait1...");
        CFRunLoopRun();
        TRACE("Ping!\n");

        if (n->dummy)
        {
            TRACE("UNMOUNT successful\n");
            n->dummy = false;
            DADiskEject( whole, kDADiskEjectOptionDefault,
AndygDiskArbCallback, n );
            TRACE("------Wait2...");
            CFRunLoopRun();
            TRACE("Ping!\n");
            if (n->dummy)
            {
                TRACE("EJECT SUCCESSFUL\n");
            }
        }

        CFRelease(whole);
    }

    CFRelease(disk);
    DASessionUnscheduleFromRunLoop(diskArbSession,
CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
    CFRelease(diskArbSession);
    TRACE("AT THE END OF IT ALL, n=%d\n", n->dummy);
    delete(n);

}

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RE: Diskarbitration callback

Andy Green