Import RubyGems trunk revision 1493.

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

lib/rubygems/commands/which_command.rb

@@ -0,0 +1,86 @@
+require 'rubygems/command'
+require 'rubygems/gem_path_searcher'
+
+class Gem::Commands::WhichCommand < Gem::Command
+
+  EXT = %w[.rb .rbw .so .dll] # HACK
+
+  def initialize
+    super 'which', 'Find the location of a library',
+          :search_gems_first => false, :show_all => false
+
+    add_option '-a', '--[no-]all', 'show all matching files' do |show_all, options|
+      options[:show_all] = show_all
+    end
+
+    add_option '-g', '--[no-]gems-first',
+               'search gems before non-gems' do |gems_first, options|
+      options[:search_gems_first] = gems_first
+    end
+  end
+
+  def arguments # :nodoc:
+    "FILE          name of file to find"
+  end
+
+  def defaults_str # :nodoc:
+    "--no-gems-first --no-all"
+  end
+
+  def usage # :nodoc:
+    "#{program_name} FILE [FILE ...]"
+  end
+
+  def execute
+    searcher = Gem::GemPathSearcher.new
+
+    options[:args].each do |arg|
+      dirs = $LOAD_PATH
+      spec = searcher.find arg
+
+      if spec then
+        if options[:search_gems_first] then
+          dirs = gem_paths(spec) + $LOAD_PATH
+        else
+          dirs = $LOAD_PATH + gem_paths(spec)
+        end
+
+        say "(checking gem #{spec.full_name} for #{arg})" if
+          Gem.configuration.verbose
+      end
+
+      paths = find_paths arg, dirs
+
+      if paths.empty? then
+        say "Can't find #{arg}"
+      else
+        say paths
+      end
+    end
+  end
+
+  def find_paths(package_name, dirs)
+    result = []
+
+    dirs.each do |dir|
+      EXT.each do |ext|
+        full_path = File.join dir, "#{package_name}#{ext}"
+        if File.exist? full_path then
+          result << full_path
+          return result unless options[:show_all]
+        end
+      end
+    end
+
+    result
+  end
+
+  def gem_paths(spec)
+    spec.require_paths.collect { |d| File.join spec.full_gem_path, d }
+  end
+
+  def usage # :nodoc:
+    "#{program_name} FILE [...]"
+  end
+
+end