added singleton

lib/sane.rb

@@ -1,94 +1,109 @@
-module Sane
+class Sane
+  include Singleton
+
   class << self
-    def init
-      version_code = FFI::MemoryPointer.new(:int)
-      check_status!(API.sane_init(version_code, FFI::Pointer::NULL))
-      version_code.read_int
-    end
+    extend Forwardable
+    delegate [:init, :exit, :get_devices, :open, :close, :get_option_descriptor, :get_option, :set_option, :strstatus] => :instance
+  end
 
-    def exit
-      API.sane_exit
-    end
+  def initialize
+    init
+  end
 
-    def get_devices
-      devices_pointer = FFI::MemoryPointer.new(:pointer)
-      check_status!(API.sane_get_devices(devices_pointer, 0))
-      devices = devices_pointer.read_pointer
-      [].tap do |result|
-        until devices.read_pointer.null?
-          result << API::Device.new(devices.read_pointer)
-          devices += FFI.type_size(:pointer)
-        end
+  def init
+    version_code = FFI::MemoryPointer.new(:int)
+    check_status!(API.sane_init(version_code, FFI::Pointer::NULL))
+    version_code.read_int
+  end
+
+  def exit
+    API.sane_exit
+  end
+
+  def get_devices
+    devices_pointer = FFI::MemoryPointer.new(:pointer)
+    check_status!(API.sane_get_devices(devices_pointer, 0))
+    devices = devices_pointer.read_pointer
+    [].tap do |result|
+      until devices.read_pointer.null?
+        result << API::Device.new(devices.read_pointer)
+        devices += FFI.type_size(:pointer)
       end
     end
-
-    def open(device_name)
-      device_handle_pointer = FFI::MemoryPointer.new(:pointer)
-      check_status!(API.sane_open(device_name.to_s, device_handle_pointer))
-      device_handle_pointer.read_pointer
-    end
-
-    def close(device_handle)
-      API.sane_close(device_handle)
-    end
-
-    def get_option_descriptor(device_handle, option)
-      result = API.sane_get_option_descriptor(device_handle, option)
-      API::OptionDescriptor.new(result)
-    end
-
-    def get_option(device_handle, option)
-      descriptor = get_option_descriptor(device_handle, option)
-
-      case descriptor[:type]
-      when :string
-        value_pointer = FFI::MemoryPointer.new(:pointer)
-      when :bool, :int, :fixed
-        value_pointer = FFI::MemoryPointer.new(:int)
-      else
-        return nil
-      end
-
-      check_status!(API.sane_control_option(device_handle, option, :get_value, value_pointer, FFI::Pointer::NULL))
-
-      case descriptor[:type]
-      when :string
-        value_pointer.read_string
-      when :bool
-        !value_pointer.read_int.zero?
-      when :int, :fixed
-        value_pointer.read_int
-      end
-    end
-
-    def set_option(device_handle, option, value)
-      descriptor = get_option_descriptor(device_handle, option)
-
-      case descriptor[:type]
-      when :string
-        value_pointer = FFI::MemoryPointer.from_string(value)
-      when :int, :fixed
-        value_pointer = FFI::MemoryPointer.new(:int).write_int(value)
-      when :bool
-        value_pointer = FFI::MemoryPointer.new(:int).write_int(value ? 1 : 0)
-      else
-        return nil
-      end
-
-      check_status!(API.sane_control_option(device_handle, option, :set_value, value_pointer, FFI::Pointer::NULL))
-
-      case descriptor[:type]
-      when :string
-        value_pointer.read_string
-      when :bool
-        !value_pointer.read_int.zero?
-      when :int, :fixed
-        value_pointer.read_int
-      end
-    end
-
-    def check_status!(status)
-      raise Error.new(API.sane_strstatus(status), status) if status != :good
-    end
+  end
+
+  def open(device_name)
+    device_handle_pointer = FFI::MemoryPointer.new(:pointer)
+    check_status!(API.sane_open(device_name, device_handle_pointer))
+    device_handle_pointer.read_pointer
+  end
+
+  def close(device_handle)
+    API.sane_close(device_handle)
+  end
+
+  def get_option_descriptor(device_handle, option)
+    result = API.sane_get_option_descriptor(device_handle, option)
+    API::OptionDescriptor.new(result)
+  end
+
+  def get_option(device_handle, option)
+    descriptor = get_option_descriptor(device_handle, option)
+
+    case descriptor[:type]
+    when :string
+      value_pointer = FFI::MemoryPointer.new(:pointer)
+    when :bool, :int, :fixed
+      value_pointer = FFI::MemoryPointer.new(:int)
+    else
+      return nil
+    end
+
+    check_status!(API.sane_control_option(device_handle, option, :get_value, value_pointer, FFI::Pointer::NULL))
+
+    case descriptor[:type]
+    when :string
+      value_pointer.read_string
+    when :bool
+      !value_pointer.read_int.zero?
+    when :int, :fixed
+      value_pointer.read_int
+    end
+  end
+
+  def set_option(device_handle, option, value)
+    descriptor = get_option_descriptor(device_handle, option)
+
+    case descriptor[:type]
+    when :string
+      value_pointer = FFI::MemoryPointer.from_string(value)
+    when :int, :fixed
+      value_pointer = FFI::MemoryPointer.new(:int).write_int(value)
+    when :bool
+      value_pointer = FFI::MemoryPointer.new(:int).write_int(value ? 1 : 0)
+    else
+      return nil
+    end
+
+    check_status!(API.sane_control_option(device_handle, option, :set_value, value_pointer, FFI::Pointer::NULL))
+
+    case descriptor[:type]
+    when :string
+      value_pointer.read_string
+    when :bool
+      !value_pointer.read_int.zero?
+    when :int, :fixed
+      value_pointer.read_int
+    end
+  end
+
+  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