Added Mongo#database_info and Mongo#database_names.

lib/mongo/mongo.rb

@@ -57,6 +57,29 @@ module XGen
           XGen::Mongo::Driver::DB.new(db_name, @nodes)
         end
 
+        # Returns a hash containing database names as keys and disk space for
+        # each as values.
+        def database_info
+          admin_db = nil
+          begin
+            admin_db = db('admin')
+            doc = admin_db.db_command(:listDatabases => 1)
+            raise "error retrieving database info" unless admin_db.ok?(doc)
+            h = {}
+            doc['databases'].each { |db|
+              h[db['name']] = db['sizeOnDisk'].to_i
+            }
+            h
+          ensure
+            admin_db.close
+          end
+        end
+
+        # Returns an array of database names.
+        def database_names
+          database_info.keys
+        end
+
         # Not implemented.
         def clone_database(from)
           raise "not implemented"

tests/test_mongo.rb

@@ -0,0 +1,32 @@
+$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+require 'mongo'
+require 'test/unit'
+
+# NOTE: assumes Mongo is running
+class MongoTest < Test::Unit::TestCase
+
+  include XGen::Mongo::Driver
+
+  def setup
+    @host = ENV['MONGO_RUBY_DRIVER_HOST'] || 'localhost'
+    @port = ENV['MONGO_RUBY_DRIVER_PORT'] || Mongo::DEFAULT_PORT
+    @mongo = Mongo.new(@host, @port)
+  end
+
+  def test_database_info
+    info = @mongo.database_info
+    assert_not_nil info
+    assert_kind_of Hash, info
+    assert_not_nil info['admin']
+    assert info['admin'] > 0
+  end
+
+  def test_database_names
+    names = @mongo.database_names
+    assert_not_nil names
+    assert_kind_of Array, names
+    assert names.length >= 1
+    assert names.include?('admin')
+  end
+
+end