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DaemonController, an exercise in refactoring
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| #import <Cocoa/Cocoa.h> | ||
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| @interface DaemonController : NSObject | ||
| { | ||
| NSString* root; | ||
| id delegate; | ||
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| NSTask* daemon_task; | ||
| NSTimer* poll_timer; | ||
| NSTimer* check_startup_status_timer; | ||
| pid_t pid; | ||
| } | ||
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| -(id)initWithDelegate:(id)delegate andRootDir:(NSString*)path; | ||
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| -(void)start; | ||
| -(void)startInTerminal; | ||
| -(void)stop; | ||
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| -(bool)isRunning; | ||
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| -(NSString*)playdarctl; | ||
| -(int)numFiles; | ||
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| @end |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,238 @@ | ||
| #import "DaemonController.h" | ||
| #import <sys/sysctl.h> | ||
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| /** returns the pid of the running playdar instance, or 0 if not found */ | ||
| static pid_t playdar_pid() | ||
| { | ||
| int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0 }; | ||
| struct kinfo_proc *info; | ||
| size_t N; | ||
| pid_t pid = 0; | ||
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| if(sysctl(mib, 3, NULL, &N, NULL, 0) < 0) | ||
| return 0; //wrong but unlikely | ||
| if(!(info = NSZoneMalloc(NULL, N))) | ||
| return 0; //wrong but unlikely | ||
| if(sysctl(mib, 3, info, &N, NULL, 0) < 0) | ||
| goto end; | ||
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| N = N / sizeof(struct kinfo_proc); | ||
| for(size_t i = 0; i < N; i++) | ||
| if(strcmp(info[i].kp_proc.p_comm, "playdar.smp") == 0) | ||
| { pid = info[i].kp_proc.p_pid; break; } | ||
| end: | ||
| NSZoneFree(NULL, info); | ||
| return pid; | ||
| } | ||
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| static void kqueue_termination_callback(CFFileDescriptorRef f, CFOptionFlags callBackTypes, void* self) | ||
| { | ||
| [(id)self performSelector:@selector(daemonTerminated:) withObject:nil]; | ||
| } | ||
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| static inline void kqueue_watch_pid(pid_t pid, id self) | ||
| { | ||
| int kq; | ||
| struct kevent changes; | ||
| CFFileDescriptorContext context = { 0, self, NULL, NULL, NULL }; | ||
| CFRunLoopSourceRef rls; | ||
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| // Create the kqueue and set it up to watch for SIGCHLD. Use the | ||
| // new-in-10.5 EV_RECEIPT flag to ensure that we get what we expect. | ||
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| kq = kqueue(); | ||
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| EV_SET(&changes, pid, EVFILT_PROC, EV_ADD | EV_RECEIPT, NOTE_EXIT, 0, NULL); | ||
| (void) kevent(kq, &changes, 1, &changes, 1, NULL); | ||
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| // Wrap the kqueue in a CFFileDescriptor (new in Mac OS X 10.5!). Then | ||
| // create a run-loop source from the CFFileDescriptor and add that to the | ||
| // runloop. | ||
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| CFFileDescriptorRef ref; | ||
| ref = CFFileDescriptorCreate(NULL, kq, true, kqueue_termination_callback, &context); | ||
| rls = CFFileDescriptorCreateRunLoopSource(NULL, ref, 0); | ||
| CFRunLoopAddSource(CFRunLoopGetCurrent(), rls, kCFRunLoopDefaultMode); | ||
| CFRelease(rls); | ||
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| CFFileDescriptorEnableCallBacks(ref, kCFFileDescriptorReadCallBack); | ||
| } | ||
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| #define START_POLL poll_timer = [NSTimer scheduledTimerWithTimeInterval:0.33 target:self selector:@selector(poll:) userInfo:nil repeats:true]; | ||
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| @implementation DaemonController | ||
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| -(id)initWithDelegate:(id)d andRootDir:(NSString*)r | ||
| { | ||
| delegate = [d retain]; | ||
| root = [r retain]; | ||
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| if(pid = playdar_pid()) | ||
| kqueue_watch_pid(pid, self); // watch the pid for termination | ||
| else | ||
| START_POLL; | ||
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| return self; | ||
| } | ||
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| -(bool)isRunning | ||
| { | ||
| return daemon_task && [daemon_task isRunning] || (pid = playdar_pid()); | ||
| } | ||
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| -(NSString*)erlexec_playdar | ||
| { | ||
| return [root stringByAppendingPathComponent:@"Contents/MacOS/erlexec_playdar"]; | ||
| } | ||
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| -(NSString*)playdarctl | ||
| { | ||
| return [root stringByAppendingPathComponent:@"bin/playdarctl"]; | ||
| } | ||
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| -(void)daemonTerminated:(NSNotification*)note | ||
| { | ||
| [[NSNotificationCenter defaultCenter] removeObserver:self name:NSTaskDidTerminateNotification object:daemon_task]; | ||
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| daemon_task = nil; | ||
| pid = 0; | ||
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| START_POLL; | ||
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| [delegate performSelector:@selector(playdarStopped)]; | ||
| } | ||
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| -(void)stop | ||
| { | ||
| NSTask* task = [[NSTask alloc] init]; | ||
| task.launchPath = [self playdarctl]; | ||
| task.arguments = [NSArray arrayWithObjects:@"stop", nil]; | ||
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| [delegate performSelector:@selector(playdarIsStopping)]; | ||
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| [task launch]; | ||
| [task waitUntilExit]; | ||
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| if (task.terminationStatus == 0) | ||
| // the kqueue event will tell us when the process exits | ||
| return; | ||
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| // playdarctl failed to stop the daemon, so it's time to be more forceful | ||
| if(daemon_task) | ||
| [daemon_task terminate]; | ||
| else if (pid = playdar_pid() == 0){ | ||
| // actually we weren't even running in the first place | ||
| START_POLL | ||
| [delegate performSelector:@selector(playdarStopped)]; | ||
| }else if (kill(pid, SIGTERM) == -1 && errno != ESRCH) | ||
| [delegate performSelector:@selector(playdarFailedToStop) withObject:@"Perhaps you don't have the right permissions?"]; | ||
| } | ||
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| -(void)initDaemonTask | ||
| { | ||
| [poll_timer invalidate]; | ||
| poll_timer = nil; | ||
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| [delegate performSelector:@selector(playdarIsStarting)]; | ||
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| daemon_task = [[NSTask alloc] init]; | ||
| } | ||
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| -(void)failedToStartDaemonTask | ||
| { | ||
| NSMutableString* msg = [@"The file at “" mutableCopy]; | ||
| [msg appendString:daemon_task.launchPath]; | ||
| [msg appendString:@"” could not be executed."]; | ||
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| [delegate performSelector:@selector(playdarFailedToStart:) withObject:msg]; | ||
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| daemon_task = nil; | ||
| } | ||
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| -(void)start | ||
| { | ||
| @try { | ||
| [self initDaemonTask]; | ||
| daemon_task.launchPath = [self erlexec_playdar]; | ||
| daemon_task.arguments = [NSArray arrayWithObject:@"-d"]; | ||
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| [[NSNotificationCenter defaultCenter] addObserver:self | ||
| selector:@selector(daemonTerminated:) | ||
| name:NSTaskDidTerminateNotification | ||
| object:daemon_task]; | ||
| [daemon_task launch]; | ||
| pid = daemon_task.processIdentifier; | ||
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| #define CHECK_READY_FOR_SCAN \ | ||
| [self performSelector:@selector(checkReadyForScan) withObject:nil afterDelay:0.2]; | ||
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| CHECK_READY_FOR_SCAN | ||
| } | ||
| @catch (NSException* e) { | ||
| [self failedToStartDaemonTask]; | ||
| } | ||
| } | ||
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| -(void)startInTerminal | ||
| { | ||
| @try { | ||
| [self initDaemonTask]; | ||
| [daemon_task setLaunchPath:@"/usr/bin/open"]; | ||
| [daemon_task setArguments:[NSArray arrayWithObjects:[self erlexec_playdar], @"-aTerminal", nil]]; | ||
| [daemon_task launch]; | ||
| [daemon_task waitUntilExit]; | ||
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| daemon_task = nil; | ||
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| CHECK_READY_FOR_SCAN | ||
| } | ||
| @catch (NSException* e) { | ||
| [self failedToStartDaemonTask]; | ||
| } | ||
| } | ||
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| -(void)checkReadyForScan | ||
| { | ||
| int const n = [self numFiles]; | ||
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| if (n < 0) | ||
| CHECK_READY_FOR_SCAN | ||
| else { | ||
| if (!pid) // started via Terminal route perhaps | ||
| kqueue_watch_pid(pid = playdar_pid(), self); | ||
| [delegate performSelector:@selector(playdarStarted:) withObject:[NSNumber numberWithInt:n]]; | ||
| } | ||
| } | ||
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| -(void)poll:(NSTimer*)t | ||
| { | ||
| if (pid = playdar_pid() == 0) return; | ||
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| [delegate performSelector:@selector(playdarIsStarting)]; | ||
| [poll_timer invalidate]; | ||
| poll_timer = nil; | ||
| kqueue_watch_pid(pid, self); | ||
| [self checkReadyForScan]; | ||
| } | ||
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| /////////////////////////////////////////////////////////////////////////// misc | ||
| -(int)numFiles | ||
| { | ||
| NSTask* task = [[NSTask alloc] init]; | ||
| [task setLaunchPath:[self playdarctl]]; | ||
| [task setArguments:[NSArray arrayWithObject:@"numfiles"]]; | ||
| [task setStandardOutput:[NSPipe pipe]]; | ||
| [task launch]; | ||
| [task waitUntilExit]; | ||
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| // if not zero then we library module isn't ready yet | ||
| if (task.terminationStatus != 0) | ||
| return -1; | ||
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| NSData* data = [[[task standardOutput] fileHandleForReading] readDataToEndOfFile]; | ||
| return [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] intValue]; | ||
| } | ||
|
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| @end |
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