added singleton

lib/sane.rb

@@ -1,5 +1,15 @@
-module Sane
+class Sane
+  include Singleton
+
   class << self
+    extend Forwardable
+    delegate [:init, :exit, :get_devices, :open, :close, :get_option_descriptor, :get_option, :set_option, :strstatus] => :instance
+  end
+
+  def initialize
+    init
+  end
+
   def init
     version_code = FFI::MemoryPointer.new(:int)
     check_status!(API.sane_init(version_code, FFI::Pointer::NULL))
@@ -24,7 +34,7 @@ module Sane
 
   def open(device_name)
     device_handle_pointer = FFI::MemoryPointer.new(:pointer)
-      check_status!(API.sane_open(device_name.to_s, device_handle_pointer))
+    check_status!(API.sane_open(device_name, device_handle_pointer))
     device_handle_pointer.read_pointer
   end
 
@@ -87,8 +97,13 @@ module Sane
     end
   end
 
-    def check_status!(status)
-      raise Error.new(API.sane_strstatus(status), status) if status != :good
+  def strstatus(status)
+    API.sane_strstatus(status)
   end
+
+  private
+
+  def check_status!(status)
+    raise Error.new(strstatus(status), status) if status != :good
   end
 end

lib/sane/api.rb

@@ -1,4 +1,4 @@
-module Sane
+class Sane
   module API
     extend FFI::Library
 
@@ -12,9 +12,6 @@ module Sane
 
     class Device < FFI::Struct
       layout :name, :string, :vendor, :string, :model, :string, :type, :string
-
-      def to_s; self[:name] end
-      def inspect; "#<#{self.class.name}:'#{to_s}'>" end
     end
 
     class OptionDescriptor < FFI::Struct

lib/sane/device.rb

@@ -1,11 +1,29 @@
-module Sane
+class Sane
   class Device
-    def initialize(handle)
-      @handle = handle
+    def initialize(name)
+      @name = name
+      @handle = nil
+    end
+
+    def open
+      @handle = Sane.open(@name) if closed?
+      if block_given?
+        yield self
+        close
+      end
+    end
+
+    def closed?
+      @handle.nil?
+    end
+
+    def opened?
+      !closed?
     end
 
     def close
-      Sane.close(@handle)
+      Sane.close(@handle) if opened?
+      @handle = nil
     end
   end
 end

lib/sane/error.rb

@@ -1,4 +1,4 @@
-module Sane
+class Sane
   class Error < StandardError
     attr_reader :status
 

lib/scanner.rb

@@ -1,8 +1,12 @@
+require "singleton"
+require "forwardable"
+
 require "ffi"
 
 require "sane"
 require "sane/api"
 require "sane/error"
+require "sane/device"
 
 module Scanner