Add initial FileWatcher implementation. The Backend is just an abstract implementation, which will be inherited by backends that do the heavy lifting.

2 files changed, 42 insertions, 0 deletions

diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 6b87774978..6b662ac660 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -42,6 +42,7 @@ module ActiveSupport
 
   autoload :DescendantsTracker
   autoload :FileUpdateChecker
+  autoload :FileWatcher
   autoload :LogSubscriber
   autoload :Notifications
 
diff --git a/activesupport/lib/active_support/file_watcher.rb b/activesupport/lib/active_support/file_watcher.rb
new file mode 100644
index 0000000000..046a5a0309
--- /dev/null
+++ b/activesupport/lib/active_support/file_watcher.rb
@@ -0,0 +1,41 @@
+module ActiveSupport
+  class FileWatcher
+    class Backend
+      def initialize(path, watcher)
+        @watcher = watcher
+        @path    = path
+      end
+
+      def trigger(files)
+        @watcher.trigger(files)
+      end
+    end
+
+    def initialize
+      @regex_matchers = {}
+    end
+
+    def watch(path, &block)
+      return watch_regex(path, &block) if path.is_a?(Regexp)
+      raise "Paths must be regular expressions. #{path.inspect} is a #{path.class}"
+    end
+
+    def watch_regex(regex, &block)
+      @regex_matchers[regex] = block
+    end
+
+    def trigger(files)
+      trigger_files = Hash.new { |h,k| h[k] = Hash.new { |h2,k2| h2[k2] = [] } }
+
+      files.each do |file, state|
+        @regex_matchers.each do |regex, block|
+          trigger_files[block][state] << file if file =~ regex
+        end
+      end
+
+      trigger_files.each do |block, payload|
+        block.call payload
+      end
+    end
+  end
+end