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# frozen_string_literal: true
# Released under the MIT License.
# Copyright, 2022-2025, by Samuel Williams.
class IO
module Event
# Helper methods for detecting support for various features.
module Support
# Some features are only availble if the IO::Buffer class is available.
#
# @returns [Boolean] Whether the IO::Buffer class is available.
def self.buffer?
IO.const_defined?(:Buffer)
end
# More advanced read/write methods and blocking controls were introduced in Ruby 3.2.
#
# To be removed on 31 Mar 2026.
def self.fiber_scheduler_v2?
if RUBY_VERSION >= "3.2"
return true if RUBY_VERSION >= "3.2.6"
# Some interface changes were back-ported incorrectly and released in 3.2.5 <https://github.com/ruby/ruby/pull/10778> - Specifically "Improvements to IO::Buffer read/write/pread/pwrite." is missing correct size calculation.
return false if RUBY_VERSION >= "3.2.5"
# Feature detection:
IO.const_defined?(:Buffer) and Fiber.respond_to?(:blocking) and IO::Buffer.instance_method(:read).arity == -1
end
end
# Updated inferfaces for read/write and IO::Buffer were introduced in Ruby 3.3, including pread/pwrite.
#
# To become the default 31 Mar 2026.
def self.fiber_scheduler_v3?
return true if RUBY_VERSION >= "3.3"
if fiber_scheduler_v2?
# Feature detection if required:
begin
IO::Buffer.new.slice(0, 0).write(STDOUT)
return true
rescue
return false
end
end
end
end
end
end
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