true cross-platform `command?` and `browser_launcher` methods

lib/hub/args.rb

@@ -54,7 +54,7 @@ module Hub
     # Array of `executable` followed by all args suitable as arguments
     # for `exec` or `system` calls.
     def to_exec(args = self)
-      [executable].concat args
+      [*executable].concat args
     end
 
     # All the words (as opposed to flags) contained in this argument

lib/hub/commands.rb

@@ -556,35 +556,6 @@ help
     # from the command line.
     #
 
-    # Checks whether a command exists on this system in the $PATH.
-    #
-    # name - The String name of the command to check for.
-    #
-    # Returns a Boolean.
-    def command?(name)
-      `which #{name} 2>/dev/null`
-      $?.success?
-    end
-
-    # Detects commands to launch the user's browser, checking $BROWSER
-    # first then falling back to a few common launchers. Aborts with
-    # an error if it can't find anything appropriate.
-    #
-    # Returns a launch command.
-    def browser_launcher
-      if ENV['BROWSER']
-        ENV['BROWSER']
-      elsif RUBY_PLATFORM.include?('darwin')
-        "open"
-      elsif command?("xdg-open")
-        "xdg-open"
-      elsif command?("cygstart")
-        "cygstart"
-      else
-        abort "Please set $BROWSER to a web launcher to use this command."
-      end
-    end
-
     # Handles common functionality of browser commands like `browse`
     # and `compare`. Yields a block that returns params for `github_url`.
     def browse_command(args)
@@ -596,7 +567,6 @@ help
       args.push github_url({:web => true, :private => true}.update(params))
     end
 
-
     # Returns the terminal-formatted manpage, ready to be printed to
     # the screen.
     def hub_manpage

lib/hub/context.rb

@@ -155,5 +155,42 @@ module Hub
     def current_dirname
       DIRNAME
     end
+
+    # Cross-platform web browser command; respects the value set in $BROWSER.
+    # 
+    # Returns an array, e.g.: ['open']
+    def browser_launcher
+      require 'rbconfig'
+      browser = ENV['BROWSER'] ||
+        (RbConfig::CONFIG['host_os'].include?('darwin') && 'open') ||
+        (RbConfig::CONFIG['host_os'] =~ /msdos|mswin|djgpp|mingw|windows/ && 'start') ||
+        %w[xdg-open cygstart x-www-browser firefox opera mozilla netscape].find { |comm| which comm }
+
+      abort "Please set $BROWSER to a web launcher to use this command." unless browser
+      Array(browser)
+    end
+
+    # Cross-platform way of finding an executable in the $PATH.
+    #
+    #   which('ruby') #=> /usr/bin/ruby
+    def which(cmd)
+      exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
+      ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
+        exts.each { |ext|
+          exe = "#{path}/#{cmd}#{ext}"
+          return exe if File.executable? exe
+        }
+      end
+      return nil
+    end
+
+    # Checks whether a command exists on this system in the $PATH.
+    #
+    # name - The String name of the command to check for.
+    #
+    # Returns a Boolean.
+    def command?(name)
+      !which(name).nil?
+    end
   end
 end

test/hub_test.rb

 $LOAD_PATH.unshift File.dirname(__FILE__)
 require 'helper'
 require 'webmock/test_unit'
+require 'rbconfig'
 
 WebMock::BodyPattern.class_eval do
   undef normalize_hash
@@ -17,10 +18,10 @@ class HubTest < Test::Unit::TestCase
 
   COMMANDS = []
 
-  Hub::Commands.class_eval do
-    remove_method :command?
-    define_method :command? do |name|
-      COMMANDS.include?(name)
+  Hub::Context.class_eval do
+    remove_method :which
+    define_method :which do |name|
+      COMMANDS.include?(name) ? "/usr/bin/#{name}" : nil
     end
   end
 
@@ -720,7 +721,7 @@ config
   def test_linux_browser
     stub_available_commands "open", "xdg-open", "cygstart"
     with_browser_env(nil) do
-      with_ruby_platform("i686-linux") do
+      with_host_os("i686-linux") do
         assert_browser("xdg-open")
       end
     end
@@ -729,7 +730,7 @@ config
   def test_cygwin_browser
     stub_available_commands "open", "cygstart"
     with_browser_env(nil) do
-      with_ruby_platform("i686-linux") do
+      with_host_os("i686-linux") do
         assert_browser("cygstart")
       end
     end
@@ -739,7 +740,7 @@ config
     stub_available_commands()
     expected = "Please set $BROWSER to a web launcher to use this command.\n"
     with_browser_env(nil) do
-      with_ruby_platform("i686-linux") do
+      with_host_os("i686-linux") do
         assert_equal expected, hub("browse")
       end
     end
@@ -834,14 +835,14 @@ config
       assert_command "browse", "#{browser} https://github.com/defunkt/hub"
     end
 
-    def with_ruby_platform(value)
-      platform = RUBY_PLATFORM
-      Object.send(:remove_const, :RUBY_PLATFORM)
-      Object.const_set(:RUBY_PLATFORM, value)
-      yield
-    ensure
-      Object.send(:remove_const, :RUBY_PLATFORM)
-      Object.const_set(:RUBY_PLATFORM, platform)
+    def with_host_os(value)
+      host_os = RbConfig::CONFIG['host_os']
+      RbConfig::CONFIG['host_os'] = value
+      begin
+        yield
+      ensure
+        RbConfig::CONFIG['host_os'] = host_os
+      end
     end
 
 end