/*

    File:       TransferServer.m

    Contains:   Sample server class, talked to through Distributed Objects.

    Written by: Quinn "The Eskimo!".

    Modified by Timothy Carroll

    Created:    Tue 10-Jun-1997

    Copyright:  (c)1997 by Apple Computer, Inc., all rights reserved.

    Change History (most recent first):

    You may incorporate this sample code into your applications without

    restriction, though the sample code has been provided "AS IS" and the

    responsibility for its operation is 100% yours.  However, what you are

    not permitted to do is to redistribute the source as "DSC Sample Code"

    after having made changes. If you're going to re-distribute the source,

    we require that you make it clear in the source that the code was

    descended from Apple Sample Code, but that you've made changes.

*/

#import "TransferServer.h"

#import "Controller.h"

// IMPORTANT: See the documentation ("ReadMe.rtf" under Supporting Files) for

// big picture information about this project.

static long transferCount;

    // This variable holds the count of the number of transfers

    // by any object of this class.  We use this to generate the

    // transfer ID for a transfer, which is helpful in debugging

    // the output of the transfers, matching up starts with finishes

    // and so on.

static NSLock *transferCountLock;

    // This is a lock for the above variable because it's used by

    // multiple different threads.

static long threadCount;

static NSLock *threadCountLock;

static NSConnection *theConnection;

@implementation TransferServer

+ (void)initialize

    // This method is called before any other methods in our class

    // are called.  We use it to set up the transferCount variable

    // and its lock.

{

    static BOOL tooLate = NO;

    // initialize should only be called once.  If it's called

    // a second time, something weird is happening, and we want

    // to know about it.

    NSAssert( ! tooLate, @"Hmm, duplicate initialize messages");

    transferCount = 0;

    transferCountLock = [[NSLock alloc] init];

    NSAssert( transferCountLock != nil, @"Could not create transferCountLock");

    threadCount = 0;

    threadCountLock = [[NSLock alloc] init];

    NSAssert( threadCountLock != nil, @"Could not create threadCountLock");

    tooLate = YES;

}

+ (long)newTransferID

    // This method increments the transferCount global variable

    // and returns it as the new transfer ID.  Transfer operations

    // call this method to get a unique ID with which to stamp

    // their transfers, which helps in debugging the concurrent

    // operations in progress.  Note that we have to lock

    // transferCount before modifying it, let another thread

    // execute while we're halfway through modifying it.

{

    long result;

    [transferCountLock lock];

    transferCount += 1;

    result = transferCount;

    [transferCountLock unlock];

    return (result);

}

+ (void)connectWithPorts:(NSArray *)portArray

    // See comments in implementation part.

{

    NSAutoreleasePool *pool;

    NSConnection *connectionToController;

    TransferServer *serverObject;

    // First we must create an autorelease pool.  Methods that we invoke

    // are going to expect to be able to do [object autorelease], but this

    // doesn't work unless we explicitly create an autorelease pool because

    // we're running in a new thread, and threads don't start off with a

    // default autorelease pool.

    pool = [[NSAutoreleasePool alloc] init];

    // Now we connect back to the main thread using the ports given in our

    // portArray argument.  Note the subtle difference in that we use

    // connectWithReceivePort here, whereas Controller's init method uses

    // initWithReceivePort.

    connectionToController = [NSConnection connectionWithReceivePort:[portArray objectAtIndex:0]

                                        sendPort:[portArray objectAtIndex:1]];

    // Now create a server object.  In this example, we only have one server

    // object to handle all requests.

    serverObject = [[self alloc] init];

    // Now get the proxy of the root object at the other end of the connection

    // (which was set to be the controller object in Controller's init method)

    // and send it the setServer message so that it knows about our server object.

    // Note that there is nothing magic about the method name "setServer"; it's

    // merely the name I decided to use when designing these two objects.

    [connectionToController setRootObject:serverObject];

    // We now release our server object, so the controller has the only reference

    // to it.  Well, actually, the NSConnection also has a reference to it,

    // which is what keeps the object around until the main thread picks it up.

    [serverObject release];

theConnection = connectionToController;

    // Now we enter our run loop.  The run loop waits looking for events and

    // executes them.  In the case of a non-application thread, the source

    // of events is the NSConnections installed in the loop.  In our case, this

    // in the NSConnection we created earlier in this routine.  When a DO

    // message arrives on our receive port, the run loop unpackages the message

    // and executes the corresponding Objective-C method.

    [[NSRunLoop currentRunLoop] run];

    // Clean up.

    [pool release];

    [NSThread exit];

    return;

}

- (id)init

    // See comments in interface part.

{

    self = [super init];

    if (self != nil) {

        [threadCountLock lock];

        threadCount += 1;

        threadID = threadCount;

        [threadCountLock unlock];

    }

    return (self);

}

- (oneway void)slowTransfer:(Controller *)controller

    // See comments in interface part.

{

    long i;

    long transferID;

    transferID = [TransferServer newTransferID];

    [controller outputString:[NSString stringWithFormat:@"Thread = %02ld, Connection's retain count is %02ld\n", threadID , [theConnection retainCount]]];

    [controller outputString:[NSString stringWithFormat:@"Thread = %02ld, Connection's retain count is %02ld\n", threadID , [theConnection retainCount]]];

    [controller outputString:[NSString stringWithFormat:@"  Starting slowTransfer   Thread=%02ld, ID=%02ld\n",

                                                        threadID, transferID] ];

    for (i = 0; i < 3; i++) {

        // Sleep for 1 second and then output a progress string to the controller.

        // You could substitute any other synchronous activity here, such as an

        // extended computation, or blocking I/O (file system or network).

        [NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];

        [controller outputString:

                    [NSString stringWithFormat:@"    Doing slowTransfer    Thread=%02ld, ID=%02ld, Step=%ld\n",

                                            threadID, transferID , i] ];

    }

    [controller outputString:[NSString stringWithFormat:@"  Finished slowTransfer   Thread=%02ld, ID=%02ld\n",

                                                        threadID, transferID]];

    [controller outputString:[NSString stringWithFormat:@"Thread = %02ld, Connection's retain count is %02ld\n", threadID , [theConnection retainCount]]];

    [controller serverFinished:self];

}

- (oneway void)slowerTransfer:(Controller *)controller

    // See comments in interface part.

{

    long i;

    long transferID;

    transferID = [TransferServer newTransferID];

    [controller outputString:[NSString stringWithFormat:@"  Starting slowerTransfer Thread=%02ld, ID=%02ld\n",

                                                        threadID, transferID]];

    for (i = 0; i < 10; i++) {

        // See comment in slowTransfer:.

        [NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];

        [controller outputString:

                    [NSString stringWithFormat:@"    Doing slowerTransfer  Thread=%02ld, ID=%02ld, Step=%ld\n",

                                            threadID, transferID , i] ];

    }

    [controller outputString:[NSString stringWithFormat:@"  Finished slowerTransfer Thread=%02ld, ID=%02ld\n",

                                                    threadID, transferID]];

    [controller outputString:[NSString stringWithFormat:@"Thread = %02ld, Connection's retain count is %02ld\n", threadID , [theConnection retainCount]]];

    [controller serverFinished:self];

}

@end