Class: DTAS::StateFile

Inherits:
Object
  • Object
show all
Defined in:
lib/dtas/state_file.rb

Overview

state file preserves state across restarts of dtas-player

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path, do_fsync = false) ⇒ StateFile

Returns a new instance of StateFile.



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# File 'lib/dtas/state_file.rb', line 10

def initialize(path, do_fsync = false)
  @path = path
  @do_fsync = do_fsync
end

Instance Attribute Details

#path ⇒ Object (readonly)

:nodoc:



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# File 'lib/dtas/state_file.rb', line 8

def path
  @path
end

Instance Method Details

#dump(obj, force_fsync = false) ⇒ Object 



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# File 'lib/dtas/state_file.rb', line 19

def dump(obj, force_fsync = false)
  yaml = obj.to_hsh.to_yaml.b

  # do not replace existing state file if there are no changes
  # this will be racy if we ever do async dumps or shared state
  # files, but we don't do that...
  return if File.readable?(@path) && IO.binread(@path) == yaml

  dir = File.dirname(@path)
  Tempfile.open(%w(player.state .tmp), dir) do |tmp|
    tmp.binmode
    tmp.write(yaml)
    tmp.flush
    tmp.fsync if @do_fsync || force_fsync
    File.rename(tmp.path, @path)
  end
end

#tryload ⇒ Object 



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# File 'lib/dtas/state_file.rb', line 15

def tryload
  YAML.load(IO.binread(@path)) if File.readable?(@path)
end