1 files changed, 81 insertions, 0 deletions
diff --git a/jni/ruby/lib/rubygems/resolver/requirement_list.rb b/jni/ruby/lib/rubygems/resolver/requirement_list.rb
new file mode 100644
index 0000000..a6bfaab
--- /dev/null
+++ b/jni/ruby/lib/rubygems/resolver/requirement_list.rb
@@ -0,0 +1,81 @@
+##
+# The RequirementList is used to hold the requirements being considered
+# while resolving a set of gems.
+#
+# The RequirementList acts like a queue where the oldest items are removed
+# first.
+
+class Gem::Resolver::RequirementList
+
+  include Enumerable
+
+  ##
+  # Creates a new RequirementList.
+
+  def initialize
+    @exact = []
+    @list = []
+  end
+
+  def initialize_copy other # :nodoc:
+    @exact = @exact.dup
+    @list = @list.dup
+  end
+
+  ##
+  # Adds Resolver::DependencyRequest +req+ to this requirements list.
+
+  def add(req)
+    if req.requirement.exact?
+      @exact.push req
+    else
+      @list.push req
+    end
+    req
+  end
+
+  ##
+  # Enumerates requirements in the list
+
+  def each # :nodoc:
+    return enum_for __method__ unless block_given?
+
+    @exact.each do |requirement|
+      yield requirement
+    end
+
+    @list.each do |requirement|
+      yield requirement
+    end
+  end
+
+  ##
+  # How many elements are in the list
+
+  def size
+    @exact.size + @list.size
+  end
+
+  ##
+  # Is the list empty?
+
+  def empty?
+    @exact.empty? && @list.empty?
+  end
+
+  ##
+  # Remove the oldest DependencyRequest from the list.
+
+  def remove
+    return @exact.shift unless @exact.empty?
+    @list.shift
+  end
+
+  ##
+  # Returns the oldest five entries from the list.
+
+  def next5
+    x = @exact[0,5]
+    x + @list[0,5 - x.size]
+  end
+end