Class: Eldritch::Task

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

Overview

Runs a block in parallel and allows for interaction with said block

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize {|Task| ... } ⇒ Task

Creates a new Task instance

Note: this method does not yield the block directly this is done by #start

Yields:

  • (Task) —

    the task itself



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# File 'lib/eldritch/task.rb', line 12

def initialize(&block)
  @block = block
end

Instance Attribute Details

#thread ⇒ Thread (readonly)

Returns underlying ruby thread.

Returns:

  • (Thread) —

    underlying ruby thread



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# File 'lib/eldritch/task.rb', line 5

def thread
  @thread
end

Instance Method Details

#abort ⇒ Object

Forces the task to end

This kills the underlying thread. This is a dangerous call.



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# File 'lib/eldritch/task.rb', line 49

def abort
  @thread.kill
  unset_thread_task
end

#interrupt ⇒ Object

Interrupts the task

This is done by raising an InterruptedError in the task block. This can be caught to perform cleanup before exiting. Tasks started with DSL#async will automatically handle the exception and stop cleanly. You can still handle the exception yourself.



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# File 'lib/eldritch/task.rb', line 60

def interrupt
  @thread.raise InterruptedError.new
  unset_thread_task
end

#join ⇒ Object

Waits for the task to complete



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# File 'lib/eldritch/task.rb', line 30

def join
  @thread.join
  unset_thread_task
end

#start ⇒ Object

Starts the task

This will yield the task to the block passed in the constructor.

task = Eldritch::Task.new do |task|
  # do something
end
task.start  # calls the block in parallel



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# File 'lib/eldritch/task.rb', line 24

def start
  @thread = Thread.new &@block
  @thread.eldritch_task = self
end

#value ⇒ Object

The return value of the task

If the task is still running, it will block until it is done and then fetch the return value.

Returns:

  • whatever the block returns



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# File 'lib/eldritch/task.rb', line 40

def value
  val = @thread.value
  unset_thread_task
  val
end