Import RubyGems trunk revision 1493.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/command_manager.rb

@@ -0,0 +1,144 @@
+#--
+# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
+# All rights reserved.
+# See LICENSE.txt for permissions.
+#++
+
+require 'timeout'
+require 'rubygems/command'
+require 'rubygems/user_interaction'
+
+module Gem
+
+  ####################################################################
+  # The command manager registers and installs all the individual
+  # sub-commands supported by the gem command.
+  class CommandManager
+    include UserInteraction
+    
+    # Return the authoratative instance of the command manager.
+    def self.instance
+      @command_manager ||= CommandManager.new
+    end
+    
+    # Register all the subcommands supported by the gem command.
+    def initialize
+      @commands = {}
+      register_command :build
+      register_command :cert
+      register_command :check
+      register_command :cleanup
+      register_command :contents
+      register_command :dependency
+      register_command :environment
+      register_command :fetch
+      register_command :generate_index
+      register_command :help
+      register_command :install
+      register_command :list
+      register_command :lock
+      register_command :mirror
+      register_command :outdated
+      register_command :pristine
+      register_command :query
+      register_command :rdoc
+      register_command :search
+      register_command :server
+      register_command :sources
+      register_command :specification
+      register_command :uninstall
+      register_command :unpack
+      register_command :update
+      register_command :which
+    end
+    
+    # Register the command object.
+    def register_command(command_obj)
+      @commands[command_obj] = false
+    end
+    
+    # Return the registered command from the command name.
+    def [](command_name)
+      command_name = command_name.intern
+      return nil if @commands[command_name].nil?
+      @commands[command_name] ||= load_and_instantiate(command_name)
+    end
+    
+    # Return a list of all command names (as strings).
+    def command_names
+      @commands.keys.collect {|key| key.to_s}.sort
+    end
+    
+    # Run the config specificed by +args+.
+    def run(args)
+      process_args(args)
+    rescue StandardError, Timeout::Error => ex
+      alert_error "While executing gem ... (#{ex.class})\n    #{ex.to_s}"
+      ui.errs.puts "\t#{ex.backtrace.join "\n\t"}" if
+        Gem.configuration.backtrace
+      terminate_interaction(1)
+    rescue Interrupt
+      alert_error "Interrupted"
+      terminate_interaction(1)
+    end
+
+    def process_args(args)
+      args = args.to_str.split(/\s+/) if args.respond_to?(:to_str)
+      if args.size == 0
+        say Gem::Command::HELP
+        terminate_interaction(1)
+      end 
+      case args[0]
+      when '-h', '--help'
+        say Gem::Command::HELP
+        terminate_interaction(0)
+      when '-v', '--version'
+        say Gem::RubyGemsPackageVersion
+        terminate_interaction(0)
+      when /^-/
+        alert_error "Invalid option: #{args[0]}.  See 'gem --help'."
+        terminate_interaction(1)
+      else
+        cmd_name = args.shift.downcase
+        cmd = find_command(cmd_name)
+        cmd.invoke(*args)
+      end
+    end
+
+    def find_command(cmd_name)
+      possibilities = find_command_possibilities(cmd_name)
+      if possibilities.size > 1
+        raise "Ambiguous command #{cmd_name} matches [#{possibilities.join(', ')}]"
+      end
+      if possibilities.size < 1
+        raise "Unknown command #{cmd_name}"
+      end
+
+      self[possibilities.first]
+    end
+
+    def find_command_possibilities(cmd_name)
+      len = cmd_name.length
+      self.command_names.select { |n| cmd_name == n[0,len] }
+    end
+    
+    private
+    def load_and_instantiate(command_name)
+      command_name = command_name.to_s
+      retried = false
+
+      begin
+        const_name = command_name.capitalize.gsub(/_(.)/) { $1.upcase }
+        Gem::Commands.const_get("#{const_name}Command").new
+      rescue NameError
+        if retried then
+          raise
+        else
+          retried = true
+          require "rubygems/commands/#{command_name}_command"
+          retry
+        end
+      end
+    end
+  end
+end