Towards an automatic update mechanism

lib/cask.rb

@@ -3,6 +3,7 @@
 class Cask; end
 
 require 'download_strategy'
+require 'rubygems' # for version comparison
 
 require 'cask/artifact'
 require 'cask/audit'
@@ -86,6 +87,23 @@ def installed?
     destination_path.exist?
   end
 
+  def installed_version?
+    !installed_version.nil?
+  end
+
+  def installed_version
+    # returns latest installed version if possible
+    Pathname.glob(caskroom_path.join('*')).map(&:basename).sort{|x,y|
+      Gem::Version.new(x) <=> Gem::Version.new(y) # throws exception if invalid version is provided ...
+    }.last rescue nil # ... return nil in this case
+  end
+
+  def update_available?
+    Gem::Version.correct?(version) && # we have something to compare against in Cask file ...
+      installed_version? && # ... we can determine current installed version ...
+      Gem::Version.new(installed_version) < Gem::Version.new(version) # ... compare
+  end
+
   def to_s
     @title
   end

lib/cask/cli.rb

@@ -14,8 +14,10 @@ class Cask::CLI; end
 require 'cask/cli/info'
 require 'cask/cli/install'
 require 'cask/cli/list'
+require 'cask/cli/outdated'
 require 'cask/cli/search'
 require 'cask/cli/uninstall'
+require 'cask/cli/upgrade'
 
 class Cask::CLI
   def self.commands

lib/cask/cli/outdated.rb

@@ -0,0 +1,15 @@
+class Cask::CLI::Outdated
+  def self.run(*args)
+    upgradable = Cask.upgradable
+
+    if upgradable.length == 0
+      puts "All Casks up to date"
+    else
+      puts upgradable
+    end
+  end
+
+  def self.help
+    "lists all outdated Casks"
+  end
+end

lib/cask/cli/upgrade.rb

@@ -0,0 +1,24 @@
+class Cask::CLI::Upgrade
+  def self.run(*args)
+    cask_names_cmdline = args.reject { |a| a.chars.first == '-' }
+
+    if cask_names_cmdline.length > 0
+      upgradable_casks = cask_names_cmdline.map{|name| Cask.load(name)}.select(&:update_available?)
+    else
+      upgradable_casks = Cask.upgradable
+    end
+
+    odebug "Upgradable casks: #{upgradable_casks}"
+
+    puts "No upgrade available" if upgradable_casks.length == 0
+
+    upgradable_casks.each do |cask|
+      puts "Upgrading #{cask} from #{cask.installed_version} to #{cask.version}"
+      Cask::Installer.new(cask).install()
+    end
+  end
+
+  def self.help
+    "upgrades the cask (of the given name if name given)"
+  end
+end

lib/cask/scopes.rb

@@ -28,5 +28,9 @@ def installed
         Cask.load(dir.basename.to_s)
       end
     end
+
+    def upgradable
+      Cask.installed.select(&:update_available?)
+    end
   end
 end