//

 //  MYDirectoryWatcher.m

 //  Murky

 //

 //  Copyright 2008 Jens Alfke. All rights reserved.

 //

 #import "MYDirectoryWatcher.h"

 #import <CoreServices/CoreServices.h>

 static void directoryWatcherCallback(ConstFSEventStreamRef streamRef,

                                      void *clientCallBackInfo,

                                      size_t numEvents,

                                      void *eventPaths,

                                      const FSEventStreamEventFlags eventFlags[],

                                      const FSEventStreamEventId eventIds[]);

 @interface MYDirectoryEvent ()

 - (id) _initWithWatcher: (MYDirectoryWatcher*)itsWatcher

                    path: (NSString*)itsPath 

                   flags: (FSEventStreamEventFlags)itsFlags

                 eventID: (FSEventStreamEventId)itsEventID;

 @end

 @implementation MYDirectoryWatcher

 - (id) initWithDirectory: (NSString*)path target: (id)target action: (SEL)action

 {

     NSParameterAssert(path);

     self = [super init];

     if (self != nil) {

         _path = path.copy;

         _target = target;

         _action = action;

         _latency = 5.0;

         _lastEventID = kFSEventStreamEventIdSinceNow;

     }

     return self;

 }

 - (void) dealloc

 {

     [self stop];

     [_path release];

     [super dealloc];

 }

 - (void) finalize

 {

     [self stop];

     [super finalize];

 }

 @synthesize path=_path, latency=_latency, lastEventID=_lastEventID;

 - (BOOL) start

 {

     if( ! _stream ) {

         FSEventStreamContext context = {0,self,NULL,NULL,NULL};

         _stream = FSEventStreamCreate(NULL, 

                                       &directoryWatcherCallback, &context,

                                       (CFArrayRef)[NSArray arrayWithObject: _path], 

                                       _lastEventID, 

                                       _latency, 

                                       kFSEventStreamCreateFlagUseCFTypes);

         if( ! _stream )

             return NO;

         FSEventStreamScheduleWithRunLoop(_stream, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);

         if( ! FSEventStreamStart(_stream) ) {

             [self stop];

             return NO;

         }

         _historyDone = (_lastEventID == kFSEventStreamEventIdSinceNow);

         Log(@"MYDirectoryWatcher: Started on %@ (latency=%g, lastEvent=%llu)",_path,_latency,_lastEventID);

     }

     return YES;

 }

 - (void) pause

 {

     if( _stream ) {

         FSEventStreamStop(_stream);

         FSEventStreamInvalidate(_stream);

         FSEventStreamRelease(_stream);

         _stream = NULL;

         Log(@"MYDirectoryWatcher: Stopped on %@ (lastEvent=%llu)",_path,_lastEventID);

     }

 }

 - (void) stop

 {

     [self pause];

     _lastEventID = kFSEventStreamEventIdSinceNow;   // so events from now till next start will be dropped

     [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @selector(start) object: nil];

 }

 - (void) stopTemporarily

 {

     if( _stream ) {

         [self stop];

         [self performSelector: @selector(start) withObject: nil afterDelay: 0.0];

     }

 }

 - (void) _notifyEvents: (size_t)numEvents

                  paths: (NSArray*)paths

                  flags: (const FSEventStreamEventFlags[])eventFlags

               eventIDs: (const FSEventStreamEventId[])eventIDs

 {

     for (size_t i=0; i<numEvents; i++) {

         NSString *path = [paths objectAtIndex: i];

         FSEventStreamEventFlags flags = eventFlags[i];

         FSEventStreamEventId eventID = eventIDs[i];

         if( flags & (kFSEventStreamEventFlagMount | kFSEventStreamEventFlagUnmount) ) {

             if( flags & kFSEventStreamEventFlagMount )

                 Log(@"MYDirectoryWatcher: Volume mounted: %@",path);

             else

                 Log(@"MYDirectoryWatcher: Volume unmounted: %@",path);

         } else if( flags & kFSEventStreamEventFlagHistoryDone ) {

             Log(@"MYDirectoryWatcher: Event #%llu History done",eventID);

             _historyDone = YES;

         } else {

             Log(@"MYDirectoryWatcher: Event #%llu flags=%02x path=%@",eventID,flags,path);

             if( _historyDone )

                 flags |= kFSEventStreamEventFlagHistoryDone;

             MYDirectoryEvent *event = [[MYDirectoryEvent alloc] _initWithWatcher: self

                                                                         path: path 

                                                                        flags: flags

                                                                      eventID: eventID];

             [_target performSelector: _action withObject: event];

             [event release];

         }

         _lastEventID = eventIDs[i];

     }

 }

 static void directoryWatcherCallback(ConstFSEventStreamRef streamRef,

                                      void *watcher,

                                      size_t numEvents,

                                      void *eventPaths,

                                      const FSEventStreamEventFlags eventFlags[],

                                      const FSEventStreamEventId eventIDs[])

 {

     [(MYDirectoryWatcher*)watcher _notifyEvents: numEvents

                                           paths: (NSArray*)eventPaths

                                           flags: eventFlags

                                        eventIDs: eventIDs];

 }

 @end

 @implementation MYDirectoryEvent

 - (id) _initWithWatcher: (MYDirectoryWatcher*)itsWatcher

                    path: (NSString*)itsPath 

                   flags: (FSEventStreamEventFlags)itsFlags

                 eventID: (FSEventStreamEventId)itsEventID

 {

     self = [super init];

     if (self != nil) {

         watcher = itsWatcher;

         path = itsPath.copy;

         flags = itsFlags;

         eventID = itsEventID;

     }

     return self;

 }

 - (void) dealloc

 {

     [path release];

     [super dealloc];

 }

 @synthesize watcher,path,flags,eventID;

 - (NSString*) relativePath

 {

     NSString *base = watcher.path;

     if( ! [path hasPrefix: base] )

         return nil;

     int length = base.length;

     while( length < path.length && [path characterAtIndex: length]=='/' )

         length++;

     return [path substringFromIndex: length];

 }

 - (BOOL) mustScanSubdirectories     {return (flags & kFSEventStreamEventFlagMustScanSubDirs) != 0;}

 - (BOOL) eventsWereDropped          {return (flags & (kFSEventStreamEventFlagUserDropped|kFSEventStreamEventFlagKernelDropped)) != 0;}

 - (BOOL) isHistorical               {return (flags & kFSEventStreamEventFlagHistoryDone)==0;}

 - (BOOL) rootChanged                {return (flags & kFSEventStreamEventFlagRootChanged)!=0;}

 @end