lib/zold/hands.rb
# frozen_string_literal: true
# Copyright (c) 2018-2023 Zerocracy
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the 'Software'), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
require 'concurrent'
require 'total'
require_relative 'thread_pool'
require_relative 'log'
require_relative 'endless'
# Multiple threads that can do something useful together.
# Author:: Yegor Bugayenko (yegor256@gmail.com)
# Copyright:: Copyright (c) 2018 Yegor Bugayenko
# License:: MIT
module Zold
# Hands
class Hands
# Pool of threads
POOL = ThreadPool.new('default')
private_constant :POOL
# Queue of jobs
QUEUE = Queue.new
private_constant :QUEUE
def self.threshold
advised = Total::Mem.new.bytes / (128 * 1024 * 1024)
advised.clamp(4, Concurrent.processor_count * 4)
rescue Total::CantDetect
4
end
# Start
def self.start(max = Hands.threshold, log: Log::NULL)
while POOL.count < max
POOL.add do
Endless.new('hands').run do
QUEUE.pop.call
end
end
end
log.debug("There are #{POOL.count} threads in the 'hands' pool")
end
# Stop
def self.stop
POOL.kill
end
# Run this code in many threads
def self.exec(threads, set = (0..threads - 1).to_a, &block)
raise 'The thread pool is empty' if POOL.empty?
raise "Number of threads #{threads} has to be positive" unless threads.positive?
list = set.dup
total = [threads, set.count].min
if total == 1
list.each_with_index(&block)
elsif total.positive?
idx = Concurrent::AtomicFixnum.new
mutex = Mutex.new
latch = Concurrent::CountDownLatch.new(total)
errors = Set.new
total.times do |i|
QUEUE.push(
lambda do
Thread.current.name = "#{@title}-#{i}"
loop do
r = mutex.synchronize { list.pop }
break if r.nil?
yield(r, idx.increment - 1)
end
rescue StandardError => e
errors << e
raise e
ensure
latch.count_down
end
)
end
latch.wait
raise errors.to_a[0] unless errors.empty?
end
end
end
end