Start on directory change events

src/app/directory.coffee

@@ -1,5 +1,7 @@
+_ = require 'underscore'
 fs = require 'fs'
 File = require 'file'
+EventEmitter = require 'event-emitter'
 
 module.exports =
 class Directory
@@ -18,3 +20,18 @@ class Directory
         files.push(new File(path))
     directories.concat(files)
 
+  afterSubscribe: ->
+    @subscribeToNativeChangeEvents() if @subscriptionCount() == 1
+
+  afterUnsubscribe: ->
+    @unsubscribeFromNativeChangeEvents() if @subscriptionCount() == 0
+
+  subscribeToNativeChangeEvents: ->
+    $native.watchPath @path, (eventTypes) =>
+      @trigger 'contents-change' if eventTypes.modified?
+
+  unsubscribeFromNativeChangeEvents: ->
+    $native.unwatchPath(@path)
+
+_.extend Directory.prototype, EventEmitter
+

src/app/event-emitter.coffee

@@ -14,6 +14,8 @@ module.exports =
       @eventHandlersByNamespace[namespace][eventName] ?= []
       @eventHandlersByNamespace[namespace][eventName].push(handler)
 
+    @afterSubscribe?()
+
   trigger: (eventName, event) ->
     [eventName, namespace] = eventName.split('.')
 
@@ -43,6 +45,8 @@ module.exports =
       else
         delete @eventHandlersByEventName?[eventName]
 
+    @afterUnsubscribe?()
+
   subscriptionCount: ->
     count = 0
     for name, handlers of @eventHandlersByEventName

src/app/project.coffee

@@ -10,9 +10,10 @@ class Project
 
   constructor: (@path) ->
     @buffers = []
+    @rootDirectory = new Directory(@path)
 
   getRootDirectory: ->
-    new Directory(@path)
+    @rootDirectory
 
   getFilePaths: ->
     projectPath = @path
@@ -36,6 +37,9 @@ class Project
     filePath = fs.join(@path, filePath) unless filePath[0] == '/'
     fs.absolute filePath
 
+  relativize: (fullPath) ->
+    fullPath.replace(@path, "")
+
   bufferWithId: (id) ->
     return buffer for buffer in @buffers when buffer.id == id
 

src/app/root-view.coffee

@@ -117,7 +117,7 @@ class RootView extends View
       @fileFinder = null
     else
       @project.getFilePaths().done (paths) =>
-        relativePaths = (path.replace(@project.path, "") for path in paths)
+        relativePaths = (@project.relativize(path) for path in paths)
         @fileFinder = new FileFinder
           paths: relativePaths
           selected: (relativePath) => @open(relativePath)

src/extensions/tree-view.coffee

@@ -87,6 +87,7 @@ class DirectoryView extends View
     @disclosureArrow.on 'click', => @toggleExpansion()
 
   buildEntries: ->
+    @entries?.remove()
     @entries = $$ -> @ol class: 'entries'
     for entry in @directory.getEntries()
       if entry instanceof Directory
@@ -105,6 +106,7 @@ class DirectoryView extends View
     @buildEntries()
     @deserializeEntryExpansionsStates(@entryStates) if @entryStates?
     @isExpanded = true
+    @watchEntries()
     false
 
   collapse: ->
@@ -113,8 +115,15 @@ class DirectoryView extends View
     @disclosureArrow.text('▸')
     @entries.remove()
     @entries = null
+    @unwatchEntries()
     @isExpanded = false
 
+  watchEntries: ->
+    @directory.on "contents-change.#{@directory.path}", => @buildEntries()
+
+  unwatchEntries: ->
+    @directory.off ".#{@directory.path}"
+
   serializeEntryExpansionStates: ->
     entryStates = {}
     @entries.find('> .directory.expanded').each ->