Class: INotify::Watcher

Inherits:
Object
  • Object
show all
Defined in:
lib/vendor/linux/lib/rb-inotify/watcher.rb

Overview

Watchers monitor a single path for changes, specified by event flags. A watcher is usually created via Notifier#watch.

One Notifier may have many Watchers. The Notifier actually takes care of the checking for events, via #run or #process. The main purpose of having Watcher objects is to be able to disable them using #close.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(notifier, path, *flags, &callback) ⇒ Watcher

Creates a new INotify::Watcher.

Raises:

  • (SystemCallError)

See Also:



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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 56

def initialize(notifier, path, *flags, &callback)
  @notifier = notifier
  @callback = callback || proc {}
  @path = path
  @flags = flags.freeze
  @id = Native.inotify_add_watch(@notifier.fd, path.dup,
    Native::Flags.to_mask(flags))

  unless @id < 0
    @notifier.watchers[@id] = self
    return
  end

  raise SystemCallError.new(
    "Failed to watch #{path.inspect}" +
    case FFI.errno
    when Errno::EACCES::Errno; ": read access to the given file is not permitted."
    when Errno::EBADF::Errno; ": the given file descriptor is not valid."
    when Errno::EFAULT::Errno; ": path points outside of the process's accessible address space."
    when Errno::EINVAL::Errno; ": the given event mask contains no legal events; or fd is not an inotify file descriptor."
    when Errno::ENOMEM::Errno; ": insufficient kernel memory was available."
    when Errno::ENOSPC::Errno; ": The user limit on the total number of inotify watches was reached or the kernel failed to allocate a needed resource."
    else; ""
    end,
    FFI.errno)
end

Instance Attribute Details

#flags ⇒ Array<Symbol> (readonly)

The flags specifying the events that this Watcher is watching for, and potentially some options as well.

Returns:

  • (Array<Symbol>) 


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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 27

def flags
  @flags
end

#id ⇒ Fixnum (readonly)

The id for this Watcher. Used to retrieve this Watcher from Notifier#watchers.

Returns:

  • (Fixnum) 


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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 34

def id
  @id
end

#notifier ⇒ Notifier (readonly)

The Notifier that this Watcher belongs to.

Returns:



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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 15

def notifier
  @notifier
end

#path ⇒ String (readonly)

The path that this Watcher is watching.

Returns:

  • (String) 


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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 20

def path
  @path
end

Instance Method Details

#callback!(event) ⇒ Object

Calls this Watcher’s callback with the given Event.

Parameters:



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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 40

def callback!(event)
  @callback[event]
end

#close ⇒ Object

Disables this Watcher, so that it doesn’t fire any more events.

Raises:

  • (SystemCallError) —

    if the watch fails to be disabled for some reason



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# File 'lib/vendor/linux/lib/rb-inotify/watcher.rb', line 47

def close
  return if Native.inotify_rm_watch(@notifier.fd, @id) == 0
  raise SystemCallError.new("Failed to stop watching #{path.inspect}", FFI.errno)
end