Add rb-fsevent support

README.md

@@ -14,6 +14,13 @@ Install via [RubyGems](http://rubygems.org/pages/download):
 
     $ gem install stasis
 
+By default, Stasis uses [DirectoryWatcher](http://rubygems.org/gems/directory_watcher) to monitor file changes.  DirectoryWatcher scans the file system at periodic intervals looking for changes.  If you are on OSX, you can install the [rb-fsevent](https://rubygems.org/gems/rb-fsevent) gem to tie into OSX's file event API and reduce the impact on your hard drive and CPU.
+
+<!-- language:console -->
+
+    $ gem install rb-fsevent
+
+
 Example
 -------
 
@@ -270,4 +277,4 @@ Stasis uses [Tilt](https://github.com/rtomayko/tilt) to support the following te
 
 ### This Web Site
 
-[Take a look at the Stasis project](https://github.com/winton/stasis/tree/master/site) that automatically generated this web site from the project [README](https://github.com/winton/stasis/blob/master/README.md).
+[Take a look at the Stasis project](https://github.com/winton/stasis/tree/master/site) that automatically generated this web site from the project [README](https://github.com/winton/stasis/blob/master/README.md).

lib/stasis/dev_mode.rb

@@ -1,5 +1,10 @@
-gem 'directory_watcher', '1.4.1'
-require 'directory_watcher'
+begin
+  gem 'rb-fsevent'
+  require 'rb-fsevent'
+rescue LoadError
+  gem 'directory_watcher', '1.4.1'
+  require 'directory_watcher'
+end
 
 require 'logger'
 require 'webrick'
@@ -18,27 +23,12 @@ def initialize(dir, options={})
 
       @stasis = Stasis.new(*[ dir, @options[:public], @options ].compact)
 
-      glob =
-        Dir.chdir(@stasis.root) do
-          # If destination is within root
-          if @stasis.destination[[email protected]] == "#{@stasis.root}/"
-            relative = @stasis.destination[@stasis.root.length+1..-1] rescue nil
-            Dir["*"].inject(["*"]) do |array, path|
-              if File.directory?(path) && path != relative
-                array.push("#{path}/**/*")
-              end
-              array
-            end
-          else
-            [ "*", "**/*" ]
-          end
-        end
+      if defined?(FSEvent)
+        watch_directory_with_fsevent
+      else
+        watch_directory_with_directory_watcher
+      end
 
-      dw = DirectoryWatcher.new(@stasis.root)
-      dw.add_observer { render }
-      dw.glob = glob
-      dw.interval = 0.1
-      dw.start
 
       if @options[:development].is_a?(::Integer)
         mime_types = WEBrick::HTTPUtils::DefaultMimeTypes
@@ -66,6 +56,51 @@ def initialize(dir, options={})
 
     private
 
+    def watch_directory_with_fsevent
+      Thread.new do
+        fsevent = FSEvent.new
+        @last_render_at = Time.now.to_i
+        fsevent.watch(@stasis.root, :latency => 0.1) do |directories|
+          # remove any directory elements that are in public
+          directories.reject!{|d| d.start_with?(@stasis.destination + '/')}
+          # if the only remaining directory is the root, check to see if any files were updated
+          directories.clear if directories.size == 1 && 
+                               directories.first == @stasis.root + '/' && 
+                               Dir["#{@stasis.root}/*"].none?{|p| File.file?(p) && File.mtime(p).to_i > @last_render_at}
+          # only if we have something to do, do it.
+          unless directories.empty?
+            render 
+            @last_render_at = Time.now.to_i
+          end
+        end
+        fsevent.run
+      end
+    end
+
+    def watch_directory_with_directory_watcher
+      glob =
+        Dir.chdir(@stasis.root) do
+          # If destination is within root
+          if @stasis.destination[[email protected]] == "#{@stasis.root}/"
+            relative = @stasis.destination[@stasis.root.length+1..-1] rescue nil
+            Dir["*"].inject(["*"]) do |array, path|
+              if File.directory?(path) && path != relative
+                array.push("#{path}/**/*")
+              end
+              array
+            end
+          else
+            [ "*", "**/*" ]
+          end
+        end
+
+      dw = DirectoryWatcher.new(@stasis.root)
+      dw.add_observer { render }
+      dw.glob = glob
+      dw.interval = 0.1
+      dw.start
+    end
+
     def render
       puts "\n[#{Time.now.strftime("%Y-%m-%d %H:%M:%S")}]" + " Regenerating #{@options[:only] ? @options[:only].join(', ') : 'project'}...".yellow
       begin