module ZMQ
# General utility methods.
#
class Util
# Returns true when +rc+ is greater than or equal to 0, false otherwise.
#
# We use the >= test because zmq_poll() returns the number of sockets
# that had a read or write event triggered. So, a >= 0 result means
# it succeeded.
#
def self.resultcode_ok? rc
rc >= 0
end
# Returns the +errno+ as set by the libzmq library.
#
def self.errno
LibZMQ.zmq_errno
end
# Returns a string corresponding to the currently set #errno. These
# error strings are defined by libzmq.
#
def self.error_string
LibZMQ.zmq_strerror(errno).read_string
end
# Returns an array of the form [major, minor, patch] to represent the
# version of libzmq.
#
# Class method! Invoke as: ZMQ::Util.version
#
def self.version
major = FFI::MemoryPointer.new :int
minor = FFI::MemoryPointer.new :int
patch = FFI::MemoryPointer.new :int
LibZMQ.zmq_version major, minor, patch
[major.read_int, minor.read_int, patch.read_int]
end
# Attempts to bind to a random tcp port on +host+ up to +max_tries+
# times. Returns the port number upon success or nil upon failure.
#
def self.bind_to_random_tcp_port host = '127.0.0.1', max_tries = 500
tries = 0
rc = -1
while !resultcode_ok?(rc) && tries < max_tries
tries += 1
random = random_port
rc = socket.bind "tcp://#{host}:#{random}"
end
resultcode_ok?(rc) ? random : nil
end
# :doc:
# Called to verify whether there were any errors during
# operation. If any are found, raise the appropriate #ZeroMQError.
#
# When no error is found, this method returns +true+ which is behavior
# used internally by #send and #recv.
#
def self.error_check source, result_code
if -1 == result_code
raise_error source, result_code
end
# used by Socket::send/recv, ignored by others
true
end
private
# generate a random port between 10_000 and 65534
def self.random_port
rand(55534) + 10_000
end
def self.raise_error source, result_code
if context_error?(source)
raise ContextError.new source, result_code, ZMQ::Util.errno, ZMQ::Util.error_string
elsif message_error?(source)
raise MessageError.new source, result_code, ZMQ::Util.errno, ZMQ::Util.error_string
else
raise ZeroMQError.new source, result_code, -1,
"Source [#{source}] does not match any zmq_* strings, rc [#{result_code}], errno [#{ZMQ::Util.errno}], error_string [#{ZMQ::Util.error_string}]"
end
end
def self.eagain?
EAGAIN == ZMQ::Util.errno
end
if LibZMQ.version2?
def self.context_error?(source)
'zmq_init' == source ||
'zmq_socket' == source
end
def self.message_error?(source)
['zmq_msg_init', 'zmq_msg_init_data', 'zmq_msg_copy', 'zmq_msg_move'].include?(source)
end
elsif LibZMQ.version3?
def self.context_error?(source)
'zmq_ctx_new' == source ||
'zmq_ctx_set' == source ||
'zmq_ctx_get' == source ||
'zmq_ctx_destory' == source ||
'zmq_ctx_set_monitor' == source
end
def self.message_error?(source)
['zmq_msg_init', 'zmq_msg_init_data', 'zmq_msg_copy', 'zmq_msg_move', 'zmq_msg_close', 'zmq_msg_get',
'zmq_msg_more', 'zmq_msg_recv', 'zmq_msg_send', 'zmq_msg_set'].include?(source)
end
end # if LibZMQ.version...?
end # module Util
end # module ZMQ