Add file watcher :only option

middleman-cli/lib/middleman-cli/build.rb

@@ -59,7 +59,7 @@ module Middleman::Cli
                                        glob: options['glob'],
                                        clean: options['clean'],
                                        parallel: options['parallel'])
-
+      builder.thor = self
       builder.on_build_event(&method(:on_event))
 
       if builder.run!

middleman-core/lib/middleman-core/builder.rb

@@ -12,6 +12,9 @@ module Middleman
     # Make app & events available to `after_build` callbacks.
     attr_reader :app, :events
 
+    # Reference to the Thor class.
+    attr_accessor :thor
+
     # Logger comes from App.
     def_delegator :@app, :logger
 
@@ -130,7 +133,8 @@ module Middleman
     def write_tempfile(output_file, contents)
       file = Tempfile.new([
         File.basename(output_file),
-        File.extname(output_file)])
+        File.extname(output_file)
+      ])
       file.binmode
       file.write(contents)
       file.close

middleman-core/lib/middleman-core/core_extensions/data.rb

@@ -29,7 +29,7 @@ module Middleman
         # Tell the file watcher to observe the :data_dir
         @watcher = app.files.watch :data,
                                    path: File.join(app.root, dir),
-                                   ignore: proc { |f| !DATA_FILE_MATCHER.match(f[:relative_path]) }
+                                   only: DATA_FILE_MATCHER
 
         # Setup data files before anything else so they are available when
         # parsing config.rb

middleman-core/lib/middleman-core/core_extensions/i18n.rb

@@ -19,7 +19,7 @@ class Middleman::CoreExtensions::Internationalization < ::Middleman::Extension
     # Tell the file watcher to observe the :data_dir
     app.files.watch :locales,
                     path: File.join(app.root, locales_file_path),
-                    ignore: proc { |f| !(/.*(rb|yml|yaml)$/.match(f[:relative_path])) }
+                    only: /.*(rb|yml|yaml)$/
 
     # Setup data files before anything else so they are available when
     # parsing config.rb

middleman-core/lib/middleman-core/extension.rb

@@ -283,6 +283,8 @@ module Middleman
       @app.after_build do |builder|
         if ext.method(:after_build).arity == 1
           ext.after_build(builder)
+        elsif ext.method(:after_build).arity == 2
+          ext.after_build(builder, builder.thor)
         else
           ext.after_build
         end

middleman-core/lib/middleman-core/preview_server.rb

@@ -114,9 +114,7 @@ module Middleman
             # config.rb
             files.watch :reload,
                         path: root,
-                        ignored: proc { |file|
+                        only: match_against
-                          match_against.none? { |m| file[:relative_path].to_s.match(m) }
-                        }
           end
         end
 

middleman-core/lib/middleman-core/sources/source_watcher.rb

@@ -47,6 +47,7 @@ module Middleman
 
       @validator = options.fetch(:validator, proc { true })
       @ignored = options.fetch(:ignored, proc { false })
+      @only = Array(options.fetch(:only, []))
 
       @disable_watcher = app.build? || @parent.options.fetch(:disable_watcher, false)
       @force_polling = @parent.options.fetch(:force_polling, false)
@@ -132,6 +133,8 @@ module Middleman
 
       @listener = ::Listen.to(@directory.to_s, config, &method(:on_listener_change))
       @listener.start
+
+      @listener.only(@only) unless @only.empty?
     end
 
     # Stop the listener.
@@ -259,9 +262,13 @@ module Middleman
     # @return [Boolean]
     Contract IsA['Middleman::SourceFile'] => Bool
     def valid?(file)
-      @validator.call(file) &&
+      globally_valid = @validator.call(file) && !globally_ignored?(file)
-        !globally_ignored?(file) &&
+
+      globally_valid && if @only.empty?
         !@ignored.call(file)
+      else
+        @only.any? { |reg| reg.match(file[:relative_path].to_s) }
+      end
     end
 
     # Convert a path to a file resprentation.