Class: Spring::Watcher::Abstract

Inherits:
Object
  • Object
show all
Defined in:
lib/spring/watcher/abstract.rb

Overview

A user of a watcher can use IO.select to wait for changes:

watcher = MyWatcher.new(root, latency)
IO.select([watcher]) # watcher is running in background
watcher.stale? # => true

Direct Known Subclasses

Polling

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(root, latency) ⇒ Abstract

Returns a new instance of Abstract.



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# File 'lib/spring/watcher/abstract.rb', line 13

def initialize(root, latency)
  @mutex       = Mutex.new
  @root        = File.realpath(root)
  @latency     = latency
  @files       = {}
  @directories = {}
  @stale       = false
  @listeners   = []

  @on_debug    = nil
end

Instance Attribute Details

#directories ⇒ Object (readonly)

Returns the value of attribute directories.



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# File 'lib/spring/watcher/abstract.rb', line 11

def directories
  @directories
end

#files ⇒ Object (readonly)

Returns the value of attribute files.



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# File 'lib/spring/watcher/abstract.rb', line 11

def files
  @files
end

#latency ⇒ Object (readonly)

Returns the value of attribute latency.



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# File 'lib/spring/watcher/abstract.rb', line 11

def latency
  @latency
end

#root ⇒ Object (readonly)

Returns the value of attribute root.



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# File 'lib/spring/watcher/abstract.rb', line 11

def root
  @root
end

Instance Method Details

#add(*items) ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 38

def add(*items)
  debug { "watcher: add: #{items.inspect}" }

  items = items.flatten.map do |item|
    item = Pathname.new(item)

    if item.relative?
      Pathname.new("#{root}/#{item}")
    else
      item
    end
  end

  items = items.select do |item|
    if item.symlink?
      item.readlink.exist?.tap do |exists|
        if !exists
          debug { "add: ignoring dangling symlink: #{item.inspect} -> #{item.readlink.inspect}" }
        end
      end
    else
      item.exist?
    end
  end

  @mutex.synchronize do
    items.each do |item|
      if item.directory?
        directories[item.realpath.to_s] = true
      else
        begin
          files[item.realpath.to_s] = true
        rescue Errno::ENOENT
          # Race condition. Ignore symlinks whose target was removed
          # since the check above, or are deeply chained.
          debug { "add: ignoring now-dangling symlink: #{item.inspect} -> #{item.readlink.inspect}" }
        end
      end
    end

    subjects_changed
  end
end

#debug ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 34

def debug
  @on_debug.call(yield) if @on_debug
end

#mark_stale ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 91

def mark_stale
  return if stale?
  @stale = true
  debug { "marked stale, calling listeners: listeners=#{@listeners.inspect}" }
  @listeners.each(&:call)
end

#on_debug(&block) ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 30

def on_debug(&block)
  @on_debug = block
end

#on_stale(&block) ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 86

def on_stale(&block)
  debug { "added listener: #{block.inspect}" }
  @listeners << block
end

#restart ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 98

def restart
  debug { "restarting" }
  stop
  start
end

#stale? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spring/watcher/abstract.rb', line 82

def stale?
  @stale
end

#start ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/spring/watcher/abstract.rb', line 104

def start
  raise NotImplementedError
end

#stop ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/spring/watcher/abstract.rb', line 108

def stop
  raise NotImplementedError
end

#subjects_changed ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/spring/watcher/abstract.rb', line 112

def subjects_changed
  raise NotImplementedError
end

#synchronize(&block) ⇒ Object 



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# File 'lib/spring/watcher/abstract.rb', line 25

def synchronize(&block)
  # Used by some gems.
  @mutex.synchronize(&block)
end