v1_parser: use URI#open instead of URI.open

Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

lib/fluent/config/v1_parser.rb

@@ -169,10 +169,22 @@ def eval_include(attrs, elems, uri)
             V1Parser.new(ss, basepath, fname, @eval_context).parse_element(true, nil, attrs, elems)
           }
         else
-          require 'open-uri'
           basepath = '/'
           fname = path
-          data = URI.open(uri) { |f| f.read }
+
+          case u.scheme
+          when 'http', 'https', 'ftp'
+            # URI#open can be able to handle URIs for http, https and ftp.
+            require 'open-uri'
+            data = u.open { |f| f.read }
+          else
+            # TODO: This case should be handled in the previous if condition. Glob is not applied to some Windows path formats.
+            # 'c:/path/to/file' will be passed as URI, 'uri' and 'u.path' will be:
+            #   - uri is 'c:/path/to/file'
+            #   - u.path is '/path/to/file' and u.scheme is 'c'
+            # Therefore, the condition of the if statement above is not met and it is handled here.
+            data = File.open(u.path) { |f| f.read }
+          end
           data.force_encoding('UTF-8')
           ss = StringScanner.new(data)
           V1Parser.new(ss, basepath, fname, @eval_context).parse_element(true, nil, attrs, elems)