1 files changed, 76 insertions, 0 deletions
diff --git a/lib/rubygems/commands/unpack_command.rb b/lib/rubygems/commands/unpack_command.rb
new file mode 100644
index 0000000000..ece24745a2
--- /dev/null
+++ b/lib/rubygems/commands/unpack_command.rb
@@ -0,0 +1,76 @@
+require 'fileutils'
+require 'rubygems/command'
+require 'rubygems/installer'
+require 'rubygems/version_option'
+
+class Gem::Commands::UnpackCommand < Gem::Command
+
+  include Gem::VersionOption
+
+  def initialize
+    super 'unpack', 'Unpack an installed gem to the current directory',
+          :version => Gem::Requirement.default
+    add_version_option
+  end
+
+  def arguments # :nodoc:
+    "GEMNAME       name of gem to unpack"
+  end
+
+  def defaults_str # :nodoc:
+    "--version '#{Gem::Requirement.default}'"
+  end
+
+  def usage # :nodoc:
+    "#{program_name} GEMNAME"
+  end
+
+  #--
+  # TODO: allow, e.g., 'gem unpack rake-0.3.1'.  Find a general solution for
+  # this, so that it works for uninstall as well.  (And check other commands
+  # at the same time.)
+  def execute
+    gemname = get_one_gem_name
+    path = get_path(gemname, options[:version])
+    if path
+      target_dir = File.basename(path).sub(/\.gem$/, '')
+      FileUtils.mkdir_p target_dir
+      Gem::Installer.new(path).unpack(File.expand_path(target_dir))
+      say "Unpacked gem: '#{target_dir}'"
+    else
+      alert_error "Gem '#{gemname}' not installed."
+    end
+  end
+
+  # Return the full path to the cached gem file matching the given
+  # name and version requirement.  Returns 'nil' if no match.
+  #
+  # Example:
+  #
+  #   get_path('rake', '> 0.4')   # -> '/usr/lib/ruby/gems/1.8/cache/rake-0.4.2.gem'
+  #   get_path('rake', '< 0.1')   # -> nil
+  #   get_path('rak')             # -> nil (exact name required)
+  #--
+  # TODO: This should be refactored so that it's a general service. I don't
+  # think any of our existing classes are the right place though.  Just maybe
+  # 'Cache'?
+  #
+  # TODO: It just uses Gem.dir for now.  What's an easy way to get the list of
+  # source directories?
+  def get_path(gemname, version_req)
+    return gemname if gemname =~ /\.gem$/i
+    specs = Gem::SourceIndex.from_installed_gems.search(/\A#{gemname}\z/, version_req)
+    selected = specs.sort_by { |s| s.version }.last
+    return nil if selected.nil?
+    # We expect to find (basename).gem in the 'cache' directory.
+    # Furthermore, the name match must be exact (ignoring case).
+    if gemname =~ /^#{selected.name}$/i
+      filename = selected.full_name + '.gem'
+      return File.join(Gem.dir, 'cache', filename)
+    else
+      return nil
+    end
+  end
+
+end
+