└── lib
    └── task.rb


/lib/task.rb:
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 1 | require 'set'
 2 | 
 3 | class Task
 4 |   attr_reader :name, :task, :status, :deps
 5 | 
 6 |   def initialize(name, &task)
 7 |     @name = name
 8 |     @task = task
 9 |     @status = :unborn
10 |     @deps = Set.new
11 |     @mutex = Mutex.new
12 |   end
13 | 
14 |   def add_dependency(tasks)
15 |     tasks.each do |t|
16 |       raise "#{t} should be an object of class Task" unless t.is_a? Task
17 |       @deps.add t
18 |     end
19 |   end
20 | 
21 |   def do_it
22 |     @mutex.synchronize do
23 |       unless @status == :unborn
24 |         return
25 |       end
26 |       @status = :pending
27 | 
28 |       if @deps.empty?
29 |         @status = :done
30 |       else
31 |         tasks = []
32 |         @deps.each do |t|
33 |           tasks << Thread.new { t.do_it }
34 |         end
35 |         tasks.each { |t| t.join }
36 |       end
37 |       @status = :running
38 |       @task.call
39 |       @status = :done
40 |     end
41 |   end
42 | end
43 | 
44 | t1 = Task.new "t1", &lambda { puts "t1" }
45 | t2 = Task.new "t2", &lambda { puts "t2" }
46 | t3 = Task.new "t3", &lambda { puts "t3" }
47 | t4 = Task.new "t4", &lambda { puts "t4" }
48 | t5 = Task.new "t5", &lambda { puts "t5" }
49 | t6 = Task.new "t6", &lambda { puts "t6" }
50 | t7 = Task.new "t7", &lambda { puts "t7" }
51 | t1.add_dependency [t2, t3]
52 | t2.add_dependency [t4]
53 | t3.add_dependency [t4, t6, t7]
54 | t4.add_dependency [t5, t6]
55 | t1.do_it
56 | 


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