Ruby

# Linux-specific optimizations to avoid fcntl for IO#read_nonblock

# and IO#write_nonblock using MSG_DONTWAIT

# Do other platforms suport MSG_DONTWAIT reliably?

if RUBY_PLATFORM =~ /linux/ && Socket.const_defined?(:MSG_DONTWAIT)

def read_nonblock(len, str = nil, exception: true) # :nodoc:

case rv = __recv_nonblock(len, 0, str, exception)

when '' # recv_nonblock returns empty string on EOF

exception ? raise(EOFError, 'end of file reached') : nil

else

rv

end

end

def write_nonblock(buf, exception: true) # :nodoc:

__sendmsg_nonblock(buf, 0, nil, nil, exception)

end

end

def test_read_write_nonblock

socks do |sserv, ssock, csock|

buf = String.new

assert_equal :wait_readable, ssock.read_nonblock(1, buf, exception: false)

assert_equal 5, csock.write_nonblock('hello')

IO.select([ssock])

assert_same buf, ssock.read_nonblock(5, buf, exception: false)

assert_equal 'hello', buf

buf = '*' * 16384

n = 0

case w = csock.write_nonblock(buf, exception: false)

when Integer

n += w

when :wait_writable

break

end while true

assert_equal :wait_writable, w

assert_raise(IO::WaitWritable) { loop { csock.write_nonblock(buf) } }

assert_operator n, :>, 0

csock.close

case r = ssock.read_nonblock(16384, buf, exception: false)

when String

next

when nil

break

else

flunk "unexpected read_nonblock return: #{r.inspect}"

end while true

assert_raise(EOFError) { ssock.read_nonblock(1) }

end

end