Add ctrl-Z keybinding to checkout HEAD revision

spec/app/editor-spec.coffee

@@ -1889,3 +1889,32 @@ describe "Editor", ->
       editor.pageUp()
       expect(editor.getCursor().getScreenPosition().row).toBe(0)
       expect(editor.getFirstVisibleScreenRow()).toBe(0)
+
+  describe ".checkoutHead()", ->
+    [repo, path, originalPathText] = []
+
+    beforeEach ->
+      path = require.resolve('fixtures/git/working-dir/file.txt')
+      originalPathText = fs.read(path)
+      rootView.open(path)
+      editor = rootView.getActiveEditor()
+      editor.attachToDom()
+
+    afterEach ->
+      fs.write(path, originalPathText)
+
+    it "restores the contents of the editor to the HEAD revision", ->
+      editor.setText('')
+      editor.save()
+
+      fileChangeHandler = jasmine.createSpy('fileChange')
+      editor.getBuffer().file.on 'contents-change', fileChangeHandler
+
+      editor.checkoutHead()
+
+      waitsFor "file to trigger contents-change event", ->
+        fileChangeHandler.callCount > 0
+
+      runs ->
+        editor.checkoutHead()
+        expect(editor.getText()).toBe(originalPathText)

spec/app/status-bar-spec.coffee

@@ -146,3 +146,11 @@ describe "StatusBar", ->
     it "displays the new icon for a new file", ->
       rootView.open(newPath)
       expect(statusBar.gitStatusIcon).toHaveText('\uf26b')
+
+    it "updates when an editor-git-status-change event occurs", ->
+      fs.write(path, "i've changed for the worse")
+      rootView.open(path)
+      expect(statusBar.gitStatusIcon).toHaveText('\uf26d')
+      fs.write(path, originalPathText)
+      rootView.getActiveEditor().trigger 'editor-git-status-change'
+      expect(statusBar.gitStatusIcon).toHaveText('')

src/app/editor.coffee

@@ -8,7 +8,7 @@ CursorView = require 'cursor-view'
 SelectionView = require 'selection-view'
 Native = require 'native'
 fs = require 'fs'
-
+Git = require 'git'
 $ = require 'jquery'
 _ = require 'underscore'
 
@@ -154,6 +154,7 @@ class Editor extends View
         'editor:show-previous-buffer': @loadPreviousEditSession
         'editor:toggle-line-comments': @toggleLineCommentsInSelection
         'editor:log-cursor-scope': @logCursorScope
+        'editor:checkout-head-revision': @checkoutHead
 
     documentation = {}
     for name, method of editorBindings
@@ -274,6 +275,11 @@ class Editor extends View
   setInvisibles: (@invisibles={}) ->
     @renderLines()
 
+  checkoutHead: ->
+    if path = @getPath()
+      if new Git(path).checkoutHead(path)
+        @trigger 'editor-git-status-change'
+
   setText: (text) -> @getBuffer().setText(text)
   getText: -> @getBuffer().getText()
   getPath: -> @getBuffer().getPath()

src/app/keymaps/git.coffee

@@ -0,0 +1,2 @@
+window.keymap.bindKeys '.editor',
+  'ctrl-Z': 'editor:checkout-head-revision'

src/app/status-bar.coffee

@@ -40,6 +40,8 @@ class StatusBar extends View
     @updateCursorPositionText()
     @editor.on 'cursor-move', => _.delay (=> @updateCursorPositionText()), 50
 
+    @editor.on 'editor-git-status-change', => @updateStatusBar()
+
     @subscribeToBuffer()
 
   subscribeToBuffer: ->