Improve DBUS_SESSION_BUS_ADDRESS extraction

[grauwoelfchen]

Hi :-D

I've got following error after update of dbus (system dbus, not ruby-dbus)

% bundle exec ruby -e 'require "dbus"; DBus::SessionBus.instance'               
/path/to/gems/ruby/2.3.0/gems/ruby-dbus-0.11.1/lib/dbus/message_queue.rb:46:in `push': undefined method `write' for nil:NilClass (NoMethodError)
        from /path/to/gems/ruby/2.3.0/gems/ruby-dbus-0.11.1/lib/dbus/bus.rb:442:in `send_sync'
        from /path/to/gems/ruby/2.3.0/gems/ruby-dbus-0.11.1/lib/dbus/bus.rb:582:in `send_hello'
        from /path/to/gems/ruby/2.3.0/gems/ruby-dbus-0.11.1/lib/dbus/bus.rb:601:in `initialize'        from /path/to/ruby/2.3.0/singleton.rb:142:in `new'                      
        from /path/to/ruby/2.3.0/singleton.rb:142:in `block in instance'        
        from /path/to/ruby/2.3.0/singleton.rb:140:in `synchronize'              
        from /path/to/ruby/2.3.0/singleton.rb:140:in `instance'                    
        from -e:1:in `<main>'

The cause of this error was DBUS_SESSION_BUS_ADDRESS value surrounded by single quotation from generated file in ~/.dbus/session-bus/#{MACHINE_ID}-#{ENV["DISPLAY"]}

% cat ~/.dbus/session-bus/MACHINE_ID-0 
# This file allows processes on the machine with id MACHINE_ID using 
# display :0.0 to find the D-Bus session bus with the below address.
# If the DBUS_SESSION_BUS_ADDRESS environment variable is set, it will
# be used rather than this file.
# See "man dbus-launch" for more details.
DBUS_SESSION_BUS_ADDRESS='unix:abstract=/tmp/dbus-foo,guid=12345...'
DBUS_SESSION_BUS_PID=...
DBUS_SESSION_BUS_WINDOWID=...

If I remove this single quotations from this file, then error has gone.
But I think that It would might be better to support it in ruby-dbus.

Then I've just created this pull request ;)
How dou you think about this?

I tested this change in ruby {2.3.1|1.9.3-p551|2.0.0-p648} in local.
If I need some thing change about code or style, please tell me.

especially, I used some mocks at rspec instead of real file for testing or Tempfile.

Improvement

• Add support DBUS_SESSION_BUS_ADDRESS value surrounded by quotation marks (' and ")

Environment

The OS on my latop is Gentoo Linux.

% uname -a
Linux HOSTNAME 4.5.2-gentoo #18 SMP Sun Aug 7 14:23:24 CEST 2016 x86_64 Intel(R) Core(TM) i7-5500U CPU @ 2.40GHz GenuineIntel GNU/Linux

The dbus version is 1.10.10

% dbus-launch --version
D-Bus Message Bus Launcher 1.10.10
Copyright (C) 2003 Red Hat, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I'm using dbus without user session support.
And it is compiled for 32 bit and 64 bit both.

% eix sys-apps/dbus
[I] sys-apps/dbus
     Available versions:  1.8.16 (~)1.8.20 1.10.8-r1^t (~)1.10.10^t {X debug doc selinux static-libs systemd test user-session ABI_MIPS="n32 n64 o32" ABI_PPC="32 64" ABI_S390="32 64" ABI_X86="32 64 x32"}
     Installed versions:  1.10.10^t(11:15:09 PM 09/03/2016)(X -debug -doc -selinux -static-libs -systemd -test -user-session ABI_MIPS="-n32 -n64 -o32" ABI_PPC="-32 -64" ABI_S390="-32 -64" ABI_X86="32 64 -x32")
     Homepage:            https://dbus.freedesktop.org/
     Description:         A message bus system, a simple way for applications to talk to each other

I'm using ruby-dbus 0.11.1 on ruby {2.3.1|1.9.3-p551|2.0.0-p648} :)

% bundle list | grep dbus
  * ruby-dbus (0.11.1)

thanks

[coveralls]

Changes Unknown when pulling 67aa6ef on grauwoelfchen:fix-dbus-session-bus-address-extraction into * on mvidner:master*.

[grauwoelfchen]

@mvidner
The job on CI fails for problem of json and tins version
https://travis-ci.org/mvidner/ruby-dbus/jobs/157432617

I was able to run tests fine on ruby 1.9.3 with following Gemfile:

source "http://rubygems.org"

# ruby-1.9.3p551
if RUBY_VERSION =~ /\A1\.9/
  gem "json", "1.8.0"
  gem "tins", "1.6.0"
end

gem "rake"
gem "packaging_rake_tasks"
gem "nokogiri"
gem "rspec"
gem "simplecov"
gem "coveralls"
platforms :rbx do
  gem "racc"
end

[grauwoelfchen]

I've also created pull request #63 for test failure for ruby 1.9.3 on ci :)

[mvidner]

Thank you for the detailed report, and the fix, and the tests!

The dbus behavior changed with the release of 1.10.10:

Output valid shell syntax in ~/.dbus/session-bus/ if the bus address contains a semicolon (fd.o #94746, Thiago Macieira)

[grauwoelfchen]

Oh, I didn't notice mentioned this entry on release note. thanks!

[grauwoelfchen]

And, ah, I had to use ENV["DBUS_SESSION_BUS_ADDRESS"] as it is...
Thank you for your improvements ;)