From 0a232bd922695f6f659fac9f90466745d4425839 Mon Sep 17 00:00:00 2001
From: Chris Eppstein <chris@eppsteins.net>
Date: Sat, 27 Jun 2009 18:29:47 -0700
Subject: [PATCH] [Compiler] Rewrite of the watch command that adds the
 following improvements: 1. For robustness, recompile is now based on
 comparison of corresponding css/sass file timestamps. 2. If a sass file is
 removed, the corresponding css file is automatically deleted. 3. CSS files
 will be automatically recompiled if removed. It is no longer necessary to
 resave the sass file. 4. First time compile is not performed if not
 necessary.

---
 lib/compass/actions.rb                 |  7 +++
 lib/compass/commands/update_project.rb |  4 +-
 lib/compass/commands/watch_project.rb  | 59 +++++++++++++-------------
 lib/compass/compiler.rb                | 14 +++++-
 4 files changed, 51 insertions(+), 33 deletions(-)

diff --git a/lib/compass/actions.rb b/lib/compass/actions.rb
index 10fd7c5f..95b9b06b 100644
--- a/lib/compass/actions.rb
+++ b/lib/compass/actions.rb
@@ -73,6 +73,13 @@ module Compass
       end
     end
 
+    def remove(file_name)
+      if File.exists?(file_name)
+        File.unlink file_name
+        logger.record :remove, basename(file_name)
+      end
+    end
+
     def basename(file)
       relativize(file) {|f| File.basename(file)}
     end
diff --git a/lib/compass/commands/update_project.rb b/lib/compass/commands/update_project.rb
index 821a94ed..e00e7a8f 100644
--- a/lib/compass/commands/update_project.rb
+++ b/lib/compass/commands/update_project.rb
@@ -21,12 +21,12 @@ module Compass
         end
       end
 
-      def new_compiler_instance(options = {})
+      def new_compiler_instance(additional_options = {})
         Compass::Compiler.new(working_path,
           projectize(Compass.configuration.sass_dir),
           projectize(Compass.configuration.css_dir),
           Compass.sass_engine_options.merge(:quiet => options[:quiet],
-                                            :force => options[:force]).merge(options))
+                                            :force => options[:force]).merge(additional_options))
       end
 
     end
diff --git a/lib/compass/commands/watch_project.rb b/lib/compass/commands/watch_project.rb
index 698d9be9..97eb2fe9 100644
--- a/lib/compass/commands/watch_project.rb
+++ b/lib/compass/commands/watch_project.rb
@@ -7,45 +7,44 @@ module Compass
   module Commands
     class WatchProject < UpdateProject
 
-      attr_accessor :last_update_time
+      attr_accessor :last_update_time, :last_sass_files
 
       def perform
-        puts ">>> Compiling all stylesheets."
-        super
-        self.last_update_time = most_recent_update_time
-        puts ">>> Compass is now watching for changes. Press Ctrl-C to Stop."
+        Signal.trap("INT") do
+          puts ""
+          exit 0
+        end
+        puts ">>> Compass is watching for changes. Press Ctrl-C to Stop."
         loop do
           # TODO: Make this efficient by using filesystem monitoring.
+          compiler = new_compiler_instance(:quiet => true)
+          remove_obsolete_css(compiler)
+          recompile(compiler)
+          sleep 1
+        end
+      end
+
+      def remove_obsolete_css(compiler)
+        sass_files = compiler.sass_files
+        deleted_sass_files = (last_sass_files || []) - sass_files
+        deleted_sass_files.each do |deleted_sass_file|
+          css_file = compiler.corresponding_css_file(deleted_sass_file)
+          remove(css_file) if File.exists?(css_file)
+        end
+        self.last_sass_files = sass_files
+      end
+
+      def recompile(compiler)
+        if file = compiler.out_of_date?
           begin
-            sleep 1
-          rescue Interrupt
-            puts ""
-            exit 0
-          end
-          file, t = should_update?
-          if t
-            begin
-              puts ">>> Change detected to: #{file}"
-              super
-            rescue StandardError => e
-              ::Compass::Exec.report_error(e, options)
-            end
-            self.last_update_time = t
+            puts ">>> Change detected to: #{file}"
+            compiler.run
+          rescue StandardError => e
+            ::Compass::Exec.report_error(e, options)
           end
         end
       end
 
-      def most_recent_update_time
-        Dir.glob(separate("#{projectize(Compass.configuration.sass_dir)}/**/*.sass")).map {|sass_file| File.stat(sass_file).mtime}.max
-      end
-
-      def should_update?
-        t = most_recent_update_time
-        if t > last_update_time
-          file = Dir.glob(separate("#{projectize(Compass.configuration.sass_dir)}/**/*.sass")).detect {|sass_file| File.stat(sass_file).mtime >= t}
-          [file, t]
-        end
-      end
     end
   end
 end
\ No newline at end of file
diff --git a/lib/compass/compiler.rb b/lib/compass/compiler.rb
index 9134553e..84fb3945 100644
--- a/lib/compass/compiler.rb
+++ b/lib/compass/compiler.rb
@@ -22,13 +22,25 @@ module Compass
     end
 
     def css_files
-      @css_files ||= sass_files.map{|sass_file| "#{to}/#{stylesheet_name(sass_file)}.css"}
+      @css_files ||= sass_files.map{|sass_file| corresponding_css_file(sass_file)}
+    end
+
+    def corresponding_css_file(sass_file)
+      "#{to}/#{stylesheet_name(sass_file)}.css"
     end
 
     def target_directories
       css_files.map{|css_file| File.dirname(css_file)}.uniq.sort.sort_by{|d| d.length }
     end
 
+    def out_of_date?
+      sass_files.zip(css_files).each do |sass_filename, css_filename|
+        return sass_filename unless File.exists?(css_filename)
+        return sass_filename if File.stat(sass_filename).mtime > File.stat(css_filename).mtime
+      end
+      false
+    end
+
     def run
       Compass.configure_sass_plugin!
       target_directories.each do |dir|