1 files changed, 40 insertions, 0 deletions
diff --git a/lib/rubygems/resolver/requirement_list.rb b/lib/rubygems/resolver/requirement_list.rb
new file mode 100644
index 0000000000..8123e84fc7
--- /dev/null
+++ b/lib/rubygems/resolver/requirement_list.rb
@@ -0,0 +1,40 @@
+##
+# Used internally to hold the requirements being considered
+# while attempting to find a proper activation set.
+
+class Gem::Resolver::RequirementList
+
+  include Enumerable
+
+  def initialize
+    @list = []
+  end
+
+  def initialize_copy(other)
+    @list = @list.dup
+  end
+
+  def add(req)
+    @list.push req
+    req
+  end
+
+  ##
+  # Enumerates requirements in the list
+
+  def each # :nodoc:
+    return enum_for __method__ unless block_given?
+
+    @list.each do |requirement|
+      yield requirement
+    end
+  end
+
+  def empty?
+    @list.empty?
+  end
+
+  def remove
+    @list.shift
+  end
+end