Module: Enumerable::Parallelize

Defined in:
lib/parallelize/enumerable_ext.rb

Class Method Summary collapse

Class Method Details

.it(enum, num_threads, method, collect_exceptions, &block) ⇒ Object

Raises:

  • (ArgumentError)


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# File 'lib/parallelize/enumerable_ext.rb', line 3

def self.it enum, num_threads, method, collect_exceptions, &block
  raise ArgumentError.new("Block not given") unless block_given?
  raise ArgumentError.new("Invalid number of threads") if num_threads < 1

  threads = []
  enum.each_slice((enum.count{true} / num_threads.to_f).ceil) do |slice|
    threads << 
      case block.arity
      when 2
        Thread.new(slice, threads.length) { |my_slice, thread_idx|
          my_slice.send(method) { |e| yield e, thread_idx }
        }
      when 1
        Thread.new(slice) { |my_slice|
          my_slice.send(method) { |e| yield e }
        }
      when 0, -1
        raise ArgumentError.new("Invalid arity: #{block.arity}") if
          RUBY_VERSION !~ /^1.8\./ && block.arity == -1
        Thread.new(slice) { |my_slice|
          my_slice.send(method) { yield }
        }
      else
        raise ArgumentError.new("Invalid arity: #{block.arity}")
      end
  end

  exceptions = {}
  threads.each_with_index do |thr, idx|
    begin
      thr.join
    rescue Exception => e
      if collect_exceptions
        exceptions[idx] = e
        nil
      else
        raise e
      end
    end
  end

  unless exceptions.empty?
    raise ParallelException.new(exceptions)
  end

  if method == :each
    threads
  elsif method == :map
    threads.map(&:value).inject(:+)
  end
end