1 # Copyright 2008 Dag Odenhall <dag.odenhall@gmail.com>
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
18 # Raised by DisplayName#new if called with empty argument, or without
19 # argument and ENV["DISPLAY"] is empty.
20 class EmptyDisplayName < ArgumentError
23 # Raised by DisplayName#new if format of argument or ENV["DISPLAY"] is
25 class InvalidDisplayName < ArgumentError
28 # Parse an X11 display name
30 # display = DisplayName.new("hostname:displaynumber.screennumber")
31 # display.hostname #=> "hostname"
32 # display.display #=> "displaynumber"
33 # display.screen #=> "screennumber"
35 # Without arguments, reads ENV["DISPLAY"]. With empty argument or
36 # DISPLAY environment, raises EmptyDisplayName. With invalid display name
37 # format, raises InvalidDisplayName.
39 attr_reader :hostname, :display, :screen
41 def initialize(display_name=ENV["DISPLAY"])
42 raise EmptyDisplayName, "No display name supplied" if ["", nil].include? display_name
43 @hostname, @display, @screen = display_name.scan(/^(.*):(\d+)(?:\.(\d+))?$/)[0]
44 raise InvalidDisplayName, "Invalid display name" if @display.nil?
45 @hostname = "localhost" if @hostname.empty?
46 @screen = "0" unless @screen