Class: Rucola::FSEvents

Inherits:
Object
  • Object
show all
Defined in:
lib/fssm/fsevents.rb

Defined Under Namespace

Classes: FSEvent, StreamError

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*params, &block) ⇒ FSEvents

Creates a new FSEvents ‘watchdog` object. You can specify a list of paths to watch and options to control the behaviour of the watchdog. The block you pass serves as a callback when an event is generated on one of the specified paths.

fsevents = FSEvents.new('/etc/passwd') { Mailer.send_mail("Someone touched the password file!") }
fsevents.create_stream
fsevents.start

fsevents = FSEvents.new('/home/upload', :since => UploadWatcher.last_event_id) do |events|
  events.each do |event|
    UploadWatcher.last_event_id = event.id
    event.files.each do |file|
      UploadWatcher.logfile.append("#{file} was changed")
    end
  end
end

*:since: The service will report events that have happened after the supplied event ID. Never use 0 because that 

will cause every fsevent since the "beginning of time" to be reported. Use OSX::KFSEventStreamEventIdSinceNow
if you want to receive events that have happened after this call. (Default: OSX::KFSEventStreamEventIdSinceNow).
You can find the ID's passed with :since in the events passed to your block.

*:latency: Number of seconds to wait until an FSEvent is reported, this allows the service to bundle events. (Default: 0.0)

Please refer to the Cocoa documentation for the rest of the options.

Raises:

  • (ArgumentError) 


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# File 'lib/fssm/fsevents.rb', line 85

def initialize(*params, &block)
  raise ArgumentError, 'No callback block was specified.' unless block_given?
  
  options = params.last.kind_of?(Hash) ? params.pop : {}
  @paths = params.flatten
  
  paths.each { |path| raise ArgumentError, "The specified path (#{path}) does not exist." unless File.exist?(path) }
  
  @allocator = options[:allocator] || OSX::KCFAllocatorDefault
  @context   = options[:context]   || nil
  @since     = options[:since]     || OSX::KFSEventStreamEventIdSinceNow
  @latency   = options[:latency]   || 0.0
  @flags     = options[:flags]     || 0
  @stream    = options[:stream]    || nil
  
  @user_callback = block
  @callback = Proc.new do |stream, client_callback_info, number_of_events, paths_pointer, event_flags, event_ids|
    paths_pointer.regard_as('*')
    events = []
    number_of_events.times {|i| events << Rucola::FSEvents::FSEvent.new(self, event_ids[i], paths_pointer[i]) }
    @user_callback.call(events)
  end
end

Instance Attribute Details

#allocator ⇒ Object

Returns the value of attribute allocator.



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# File 'lib/fssm/fsevents.rb', line 30

def allocator
  @allocator
end

#context ⇒ Object

Returns the value of attribute context.



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# File 'lib/fssm/fsevents.rb', line 31

def context
  @context
end

#flags ⇒ Object

Returns the value of attribute flags.



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# File 'lib/fssm/fsevents.rb', line 34

def flags
  @flags
end

#latency ⇒ Object

Returns the value of attribute latency.



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# File 'lib/fssm/fsevents.rb', line 33

def latency
  @latency
end

#paths ⇒ Object (readonly)

Returns the value of attribute paths.



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# File 'lib/fssm/fsevents.rb', line 27

def paths
  @paths
end

#since ⇒ Object

Returns the value of attribute since.



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# File 'lib/fssm/fsevents.rb', line 32

def since
  @since
end

#stream ⇒ Object (readonly)

Returns the value of attribute stream.



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# File 'lib/fssm/fsevents.rb', line 28

def stream
  @stream
end

Class Method Details

.start_watching(*params, &block) ⇒ Object

Initializes a new FSEvents ‘watchdog` object and starts watching the directories you specify for events. The block is used as a handler for events, which are passed as the block’s argument. This method is the easiest way to start watching some directories if you don’t care about the details of setting up the event stream.

Rucola::FSEvents.start_watching('/tmp') do |events|
  events.each { |event| log.debug("#{event.files.inspect} were changed.") }
end

Rucola::FSEvents.start_watching('/var/log/system.log', '/var/log/secure.log', :since => last_id, :latency => 5) do
  Growl.notify("Something was added to your log files!")
end

Note that the method also returns the FSEvents object. This enables you to control the event stream if you want to.

fsevents = Rucola::FSEvents.start_watching('/Volumes') do |events|
  events.each { |event| Growl.notify("Volume changes: #{event.files.to_sentence}") }
end
fsevents.stop



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# File 'lib/fssm/fsevents.rb', line 54

def self.start_watching(*params, &block)
  fsevents = new(*params, &block)
  fsevents.create_stream
  fsevents.start
  fsevents
end

Instance Method Details

#create_stream ⇒ Object

Create the stream. Raises a Rucola::FSEvents::StreamError if the stream could not be created.

Raises:



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# File 'lib/fssm/fsevents.rb', line 111

def create_stream
  @stream = OSX.FSEventStreamCreate(@allocator, @callback, @context, @paths, @since, @latency, @flags)
  raise(StreamError, 'Unable to create FSEvents stream.') unless @stream
  OSX.FSEventStreamScheduleWithRunLoop(@stream, OSX.CFRunLoopGetCurrent, OSX::KCFRunLoopDefaultMode)
end

#start ⇒ Object

Start the stream. Raises a Rucola::FSEvents::StreamError if the stream could not be started.

Raises:



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# File 'lib/fssm/fsevents.rb', line 119

def start
  raise(StreamError, 'Unable to start FSEvents stream.') unless OSX.FSEventStreamStart(@stream)
end

#stop ⇒ Object

Stop the stream. You can resume it by calling ‘start` again.



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# File 'lib/fssm/fsevents.rb', line 125

def stop
  OSX.FSEventStreamStop(@stream)
end