Add bin and edit workflow

bin/gems/async-2.23.0/lib/async/worker_pool.rb

@@ -0,0 +1,182 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2024, by Samuel Williams.
+
+require "etc"
+
+module Async
+	# A simple work pool that offloads work to a background thread.
+	#
+	# @private
+	class WorkerPool
+		# Used to augment the scheduler to add support for blocking operations.
+		module BlockingOperationWait
+			# Wait for the given work to be executed.
+			#
+			# @public Since *Async v2.19* and *Ruby v3.4*.
+			# @asynchronous May be non-blocking.
+			#
+			# @parameter work [Proc] The work to execute on a background thread.
+			# @returns [Object] The result of the work.
+			def blocking_operation_wait(work)
+				@worker_pool.call(work)
+			end
+		end
+		
+		# Execute the given work in a background thread.
+		class Promise
+			# Create a new promise.
+			#
+			# @parameter work [Proc] The work to be done.
+			def initialize(work)
+				@work = work
+				@state = :pending
+				@value = nil
+				@guard = ::Mutex.new
+				@condition = ::ConditionVariable.new
+				@thread = nil
+			end
+			
+			# Execute the work and resolve the promise.
+			def call
+				work = nil
+				
+				@guard.synchronize do
+					@thread = ::Thread.current
+					
+					return unless work = @work
+				end
+				
+				resolve(work.call)
+			rescue Exception => error
+				reject(error)
+			end
+			
+			private def resolve(value)
+				@guard.synchronize do
+					@work = nil
+					@thread = nil
+					@value = value
+					@state = :resolved
+					@condition.broadcast
+				end
+			end
+			
+			private def reject(error)
+				@guard.synchronize do
+					@work = nil
+					@thread = nil
+					@value = error
+					@state = :failed
+					@condition.broadcast
+				end
+			end
+			
+			# Cancel the work and raise an exception in the background thread.
+			def cancel
+				return unless @work
+				
+				@guard.synchronize do
+					@work = nil
+					@state = :cancelled
+					@thread&.raise(Interrupt)
+				end
+			end
+			
+			# Wait for the work to be done.
+			#
+			# @returns [Object] The result of the work.
+			def wait
+				@guard.synchronize do
+					while @state == :pending
+						@condition.wait(@guard)
+					end
+					
+					if @state == :failed
+						raise @value
+					else
+						return @value
+					end
+				end
+			end
+		end
+		
+		# A background worker thread.
+		class Worker
+			# Create a new worker.
+			def initialize
+				@work = ::Thread::Queue.new
+				@thread = ::Thread.new(&method(:run))
+			end
+			
+			# Execute work until the queue is closed.
+			def run
+				while work = @work.pop
+					work.call
+				end
+			end
+			
+			# Close the worker thread.
+			def close
+				if thread = @thread
+					@thread = nil
+					thread.kill
+				end
+			end
+			
+			# Call the work and notify the scheduler when it is done.
+			def call(work)
+				promise = Promise.new(work)
+				
+				@work.push(promise)
+				
+				begin
+					return promise.wait
+				ensure
+					promise.cancel
+				end
+			end
+		end
+		
+		# Create a new work pool.
+		#
+		# @parameter size [Integer] The number of threads to use.
+		def initialize(size: Etc.nprocessors)
+			@ready = ::Thread::Queue.new
+			
+			size.times do
+				@ready.push(Worker.new)
+			end
+		end
+		
+		# Close the work pool. Kills all outstanding work.
+		def close
+			if ready = @ready
+				@ready = nil
+				ready.close
+				
+				while worker = ready.pop
+					worker.close
+				end
+			end
+		end
+		
+		# Offload work to a thread.
+		#
+		# @parameter work [Proc] The work to be done.
+		def call(work)
+			if ready = @ready
+				worker = ready.pop
+				
+				begin
+					worker.call(work)
+				ensure
+					ready.push(worker)
+				end
+			else
+				raise RuntimeError, "No worker available!"
+			end
+		end
+	end
+end