Added SDBM store. Appears faster than file or xattr, and has no depen…

…dencies.

lib/moneta/sdbm.rb

@@ -0,0 +1,40 @@
+require "sdbm"
+
+module Moneta
+  class BasicSDBM < ::SDBM
+
+    def [](key)
+      if val = super
+        Marshal.load(val)
+      end
+    end
+
+    def []=(key, value)
+      super(key, Marshal.dump(value))
+    end
+
+    def fetch(key, default)
+      self[key] || default
+    end
+
+    def store(key, value, options = {})
+      self[key] = value
+    end
+
+    def delete(key)
+      if val = super
+        Marshal.load(val)
+      end
+    end
+  end
+
+  class SDBM < BasicSDBM
+    include Expires
+
+    def initialize(options = {})
+      raise "No :file option specified" unless file = options[:file]
+      @expiration = BasicSDBM.new("#{file}_expires")
+      super(file)
+    end
+  end
+end

spec/moneta_sdbm_spec.rb

@@ -0,0 +1,17 @@
+require File.dirname(__FILE__) + '/spec_helper'
+require "moneta/sdbm"
+
+describe "Moneta::SDBM" do
+  before(:each) do
+    @cache = Moneta::SDBM.new(:file => File.join(File.dirname(__FILE__), "sdbm_cache"))
+    @cache.clear
+  end
+
+  after(:all) do
+    FileUtils.rm_rf(Dir.glob(File.join(File.dirname(__FILE__), "sdbm_cache*")))
+  end
+
+  if ENV['MONETA_TEST'].nil? || ENV['MONETA_TEST'] == 'sdbm'
+    it_should_behave_like "a read/write Moneta cache"
+  end
+end