1 files changed, 81 insertions, 0 deletions
diff --git a/lib/rubygems/format.rb b/lib/rubygems/format.rb
new file mode 100644
index 0000000000..378a93018c
--- /dev/null
+++ b/lib/rubygems/format.rb
@@ -0,0 +1,81 @@
+#--
+# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
+# All rights reserved.
+# See LICENSE.txt for permissions.
+#++
+
+require 'fileutils'
+
+require 'rubygems/package'
+
+module Gem
+
+  ##
+  # The format class knows the guts of the RubyGem .gem file format
+  # and provides the capability to read gem files
+  #
+  class Format
+    attr_accessor :spec, :file_entries, :gem_path
+    extend Gem::UserInteraction
+  
+    ##
+    # Constructs an instance of a Format object, representing the gem's
+    # data structure.
+    #
+    # gem:: [String] The file name of the gem
+    #
+    def initialize(gem_path)
+      @gem_path = gem_path
+    end
+    
+    ##
+    # Reads the named gem file and returns a Format object, representing 
+    # the data from the gem file
+    #
+    # file_path:: [String] Path to the gem file
+    #
+    def self.from_file_by_path(file_path, security_policy = nil)
+      format = nil
+
+      unless File.exist?(file_path)
+        raise Gem::Exception, "Cannot load gem at [#{file_path}] in #{Dir.pwd}"
+      end
+
+      # check for old version gem
+      if File.read(file_path, 20).include?("MD5SUM =")
+        #alert_warning "Gem #{file_path} is in old format."
+        require 'rubygems/old_format'
+        format = OldFormat.from_file_by_path(file_path)
+      else
+        begin
+          f = File.open(file_path, 'rb')
+          format = from_io(f, file_path, security_policy)
+        ensure
+          f.close unless f.closed?
+        end
+      end
+
+      return format
+    end
+
+    ##
+    # Reads a gem from an io stream and returns a Format object, representing
+    # the data from the gem file
+    #
+    # io:: [IO] Stream from which to read the gem
+    #
+    def self.from_io(io, gem_path="(io)", security_policy = nil)
+      format = self.new(gem_path)
+      Package.open_from_io(io, 'r', security_policy) do |pkg|
+        format.spec = pkg.metadata
+        format.file_entries = []
+        pkg.each do |entry|
+          format.file_entries << [{"size" => entry.size, "mode" => entry.mode,
+              "path" => entry.full_name}, entry.read]
+        end
+      end
+      format
+    end
+
+  end
+end