show warning message when BuildID not found

lib/one_gadget.rb

@@ -25,17 +25,23 @@ class << self
     #   OneGadget.gadgets(build_id: '60131540dadc6796cab33388349e6e4e68692053')
     def gadgets(file: nil, build_id: nil, details: false, force_file: false)
       if build_id
-        OneGadget::Fetcher.from_build_id(build_id, details: details)
+        OneGadget::Fetcher.from_build_id(build_id, details: details) || OneGadget::Logger.not_found(build_id)
       elsif file
         file = OneGadget::Helper.abspath(file)
-        build_id = OneGadget::Helper.build_id_of(file)
-        if !force_file && build_id
-          gadgets = OneGadget::Fetcher.from_build_id(build_id, details: details, remote: false)
-          return gadgets unless gadgets.empty?
-        end
-        OneGadget::Fetcher.from_file(file, details: details)
+        gadgets = try_from_build(file, details) unless force_file
+        gadgets || OneGadget::Fetcher.from_file(file, details: details)
       end
     end
+
+    private
+
+    def try_from_build(file, details)
+      build_id = OneGadget::Helper.build_id_of(file)
+      return unless build_id
+      gadgets = OneGadget::Fetcher.from_build_id(build_id, details: details, remote: false)
+      return if gadgets.nil?
+      gadgets
+    end
   end
 end
 

lib/one_gadget/fetcher.rb

@@ -14,15 +14,16 @@ module ClassMethods
       #   If needs to return the gadgets' constraints.
       # @param [Boolean] remote
       #   When local not found, try search in latest version?
-      # @return [Array<Integer>, Array<OneGadget::Gadget::Gadget>]
-      #   If +details+ is +false+, +Array<Integer>+ is returned, which
-      #   contains offset only.
+      # @return [Array<Integer>, Array<OneGadget::Gadget::Gadget>, nil]
+      #   +nil+ is returned if cannot find target id in database.
+      #   If +details+ is +false+, +Array<Integer>+ is returned, which contains offset only.
       #   Otherwise, array of gadgets is returned.
       def from_build_id(build_id, details: false, remote: true)
         if (build_id =~ /\A#{OneGadget::Helper::BUILD_ID_FORMAT}\Z/).nil?
           raise ArgumentError, format('invalid BuildID format: %p', build_id)
         end
         gadgets = OneGadget::Gadget.builds(build_id, remote: remote)
+        return if gadgets.nil?
         return gadgets if details
         gadgets.map(&:offset)
       end

lib/one_gadget/gadget.rb

@@ -48,14 +48,14 @@ module ClassMethods
       # @param [String] build_id Desired build id.
       # @param [Boolean] remote
       #   When local not found, try search in latest version?
-      # @return [Array<Gadget::Gadget>] Gadgets.
+      # @return [Array<Gadget::Gadget>?] Gadgets.
       def builds(build_id, remote: true)
         require_all if BUILDS.empty?
         return BUILDS[build_id] if BUILDS.key?(build_id)
-        return [] unless remote
+        return build_not_found unless remote
         # fetch remote builds
         table = OneGadget::Helper.remote_builds.find { |c| c.include?(build_id) }
-        return [] if table.nil? # remote doesn't have this one either.
+        return build_not_found if table.nil? # remote doesn't have this one either.
         # builds found in remote! Ask update gem and download remote gadgets.
         OneGadget::Helper.ask_update(msg: 'The desired one-gadget can be found in lastest version!')
         tmp_file = OneGadget::Helper.download_build(table)
@@ -80,6 +80,10 @@ def require_all
           require dic
         end
       end
+
+      def build_not_found
+        nil
+      end
     end
     extend ClassMethods
   end

lib/one_gadget/helper.rb

@@ -60,6 +60,7 @@ def enable_color
         normal_s: "\e[38;5;203m", # red
         integer: "\e[38;5;189m", # light purple
         reg: "\e[38;5;82m", # light green
+        warn: "\e[38;5;230m" # light yellow
       }.freeze
 
       # Wrapper color codes for pretty inspect.

lib/one_gadget/logger.rb

@@ -6,21 +6,33 @@ module OneGadget
   # A logger for internal usage.
   module Logger
     @logger = ::Logger.new(STDOUT)
-    @logger.formatter = proc do |_severity, _datetime, _progname, msg|
+    @logger.formatter = proc do |severity, _datetime, _progname, msg|
       prep = ' ' * 12
       message = msg.lines.map.with_index do |str, i|
         next str if i.zero?
         prep + str
       end
-      "[#{OneGadget::Helper.colorize('OneGadget', sev: :reg)}] #{message.join}"
+      color = case severity
+              when 'WARN' then :warn
+              when 'INFO' then :reg
+              end
+      "[#{OneGadget::Helper.colorize('OneGadget', sev: color)}] #{message.join}"
     end
 
-    # The logger info.
-    # @param [String] msg
-    #   Message to be logged.
-    # @return [void]
-    def self.info(msg)
-      @logger.info(msg)
+    module_function
+
+    # Show warning message of no such build id in database.
+    # @param [String] build_id
+    #   Build ID.
+    def not_found(build_id)
+      warn("Cannot find BuildID [#{build_id}]")
+      []
+    end
+
+    %i[info warn].each do |sym|
+      define_method(sym) do |msg|
+        @logger.send(sym, msg)
+      end
     end
   end
 end

spec/one_gadget_amd64_spec.rb

@@ -47,5 +47,10 @@
       OneGadget::Gadget::ClassMethods::BUILDS.delete(:a)
       OneGadget::Gadget::ClassMethods::BUILDS[@build_id] = entry unless entry.nil?
     end
+
+    it 'not found' do
+      expect(OneGadget.gadgets(build_id: @build_id.reverse)).to be_empty
+      expect(OneGadget::Gadget.builds(@build_id.reverse)).to be_nil
+    end
   end
 end