Class: Variable

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

Overview

Lightweight concurrency variables

These are inspired by Haskells MVar and IVar types.

Direct Known Subclasses

IVar, MVar

Defined Under Namespace

Modules: Timer Classes: IVar, MVar, Result

Constant Summary collapse

EMPTY = 
Class.new do
  const_set(:INSPECT, 'Variable::EMPTY')
end.new.freeze
TIMEOUT = 
Class.new do
  const_set(:INSPECT, 'Variable::TIMEOUT')
end.new.freeze

Instance Method Summary collapse

Constructor Details

#initialize(condition_variable:, mutex:, value: EMPTY) ⇒ undefined

Initialize object

Parameters:

  • value (Object) (defaults to: EMPTY) —

    the initial value



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# File 'lib/variable.rb', line 83

def initialize(condition_variable:, mutex:, value: EMPTY)
  @full  = condition_variable.new
  @mutex = mutex.new
  @value = value
end

Instance Method Details

#read ⇒ Object

Read value, block on empty

Returns:

  • (Object) —

    the variable value



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# File 'lib/variable.rb', line 122

def read
  synchronize do
    wait_full
    @value
  end
end

#take ⇒ Object

Take value, block on empty

Returns:

  • (Object) 


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# File 'lib/variable.rb', line 92

def take
  synchronize do
    wait_full
    perform_take
  end
end

#take_timeout(timeout) ⇒ Result::Timeout, Result::Value

Take value, with timeout

Parameters:

  • Timeout (Float)

Returns:



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# File 'lib/variable.rb', line 108

def take_timeout(timeout)
  synchronize do
    if wait_timeout(@full, timeout, &method(:full?))
      Result::Timeout.new
    else
      Result::Value.new(perform_take)
    end
  end
end

#try_put(value) ⇒ self

Try put value into the variable, non blocking

Parameters:

  • value (Object)

Returns:

  • (self) 


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# File 'lib/variable.rb', line 134

def try_put(value)
  synchronize do
    perform_put(value) if empty?
  end

  self
end

#with {|Object| ... } ⇒ Object

Execute block with value, blocking

Yields:

  • (Object)

Returns:

  • (Object) —

    the blocks return value



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# File 'lib/variable.rb', line 148

def with
  synchronize do
    wait_full
    yield @value
  end
end