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Text File  |  1995-02-17  |  3.1 KB  |  108 lines
  1. /*
  2.    DEOServerMonitor.m created by enoyau on Fri 13-Jan-1995
  3.  
  4.    You may freely copy, distribute, and reuse the code in this example.
  5.    NeXT disclaims any warranty of any kind, expressed or implied, as to its
  6.    fitness for any particular use.
  7. */
  8.  
  9. #import "DEOServerMonitor.h"
  10. #import <foundation/NSNotification.h>
  11. #import <foundation/NSAutoreleasePool.h>
  12. #import <foundation/NSUtilities.h>
  13. #import <foundation/NSBundle.h>
  14. #import <foundation/NSException.h>
  15. #import <remote/NXConnection.h>
  16. #import <remote/NXProxy.h>
  17.  
  18. #import <libc.h>
  19.  
  20. static id instance = nil;
  21. NSString *DEOServerReinitialize = @"DEOServerReinitialize";
  22.  
  23. @implementation DEOServerMonitor
  24.  
  25. - (id <DEOServer>)server
  26. {
  27.     if(server) return server;
  28.  
  29.     if(wantLog) NSLog(@"DEOClient: try to connect to the server...\n");
  30.     // Work around for bug (release note reference 51800):
  31.     // This object is coming back retained instead of autoreleased,
  32.     // so we don't send it retain here.
  33.     server = (id <DEOServer>)[NXConnection connectToName:DEOServerName
  34.                                                   onHost:"*"];
  35.  
  36.     if(!server) {
  37.         NSString *path = [[NSBundle mainBundle] pathForResource:@"DEOServer"
  38.                                                           ofType:nil];
  39.         int pid;
  40.  
  41.         if(wantLog) NSLog(@"DEOClient: fork a new server\n");
  42.  
  43.         if((pid = fork()) == 0  ) { // fork the server
  44.             (void)execlp([path cString], [path cString], (char *)0);
  45.             exit(0); // if exec fail...
  46.  
  47.         } else if(pid != -1) { // try to reconnect
  48.             char here[1024];
  49.             int retry = 20;
  50.  
  51.             gethostname(here, 1024);
  52.  
  53.             while((retry--) && (!server)) {
  54.                 sleep(1);
  55.                 if(wantLog) NSLog(@"DEOClient: try to connect to the new server...\n");
  56.                 // Work around for bug (release note reference 51800):
  57.                 // see above.
  58.                 server = (id <DEOServer>)[NXConnection connectToName:DEOServerName onHost:here];
  59.             }
  60.         }
  61.     }
  62.  
  63.     if(server) {
  64.         NXConnection *myConnection;
  65.  
  66.         if(wantLog) NSLog(@"DEOClient: run the connection");
  67.         [(NXProxy *)server setProtocolForProxy:@protocol(DEOServer)];
  68.  
  69.         myConnection = [(NXProxy*)server connectionForProxy];
  70.         [myConnection registerForInvalidationNotification:self];
  71.         [myConnection runFromAppKit];
  72.     } else {
  73.         if(wantLog) NSLog(@"DEOClient: connection failed\n");
  74.     }
  75.  
  76.     return server;
  77. }
  78.  
  79. + serverMonitor
  80. {
  81.     return [(instance ? [instance retain] : (instance = [self new])) autorelease];
  82. }
  83.  
  84. - (void)dealloc
  85. {
  86.     NXConnection *myConnection = [(NXProxy*)server connectionForProxy];
  87.  
  88.     [myConnection unregisterForInvalidationNotification:self];
  89.     NS_DURING
  90.         [(NSObject *)server release];
  91.     NS_HANDLER
  92.         NSLog(@"Failed to send release to server.\n");
  93.     NS_ENDHANDLER
  94.     server = nil;
  95.     instance = nil;
  96.     [super dealloc];
  97. }
  98.  
  99. - senderIsInvalid:sender
  100. {
  101.     if(wantLog) NSLog(@"DEOClient: Server dead !\n");
  102.     server = nil;
  103.     [[NSNotificationCenter defaultCenter] postNotificationName:DEOServerReinitialize object:self];
  104.     return self;
  105. }
  106.  
  107. @end
  108.