Don't move the cursor on buffer change unless the editor is focused

Add a boolean isFocused flag to editor that is assigned when the hidden input gains / loses focus. This makes it easier in specs because we can treat the editor as if its focused without having to add it to the DOM. It's also a bit more abstract.

spec/atom/editor-spec.coffee

@@ -16,6 +16,7 @@ describe "Editor", ->
     editor.autoIndent = false
     editor.enableKeymap()
     editor.setBuffer(buffer)
+    editor.isFocused = true
 
   describe "text rendering", ->
     it "creates a line element for each line in the buffer with the html-escaped text of the line", ->
@@ -769,6 +770,11 @@ describe "Editor", ->
           expect(editor.getCursorScreenPosition()).toEqual(row: 1, column: 7)
           expect(editor.lines.find('.line:eq(1)')).toHaveText editor.getCurrentBufferLine()
 
+        it "does not update the cursor position if the editor is not focused", ->
+          editor.isFocused = false
+          editor.buffer.insert([5, 0], 'blah')
+          expect(editor.getCursorScreenPosition()).toEqual [0, 0]
+
       describe "when there is a selection", ->
         it "replaces the selected text with the typed text", ->
           editor.selection.setBufferRange(new Range([1, 6], [2, 4]))
@@ -925,6 +931,16 @@ describe "Editor", ->
       expect(editor).not.toMatchSelector ':focus'
       expect(editor.hiddenInput).toMatchSelector ':focus'
 
+  describe "when the hidden input is focused / unfocused", ->
+    it "assigns the isFocused flag on the editor", ->
+      editor.attachToDom()
+      editor.isFocused = false
+      editor.hiddenInput.focus()
+      expect(editor.isFocused).toBeTruthy()
+
+      editor.hiddenInput.focusout()
+      expect(editor.isFocused).toBeFalsy()
+
   describe "construction", ->
     it "assigns an empty buffer and correctly handles text input (regression coverage)", ->
       editor = new Editor

spec/atom/root-view-spec.coffee

@@ -35,7 +35,7 @@ describe "RootView", ->
 
   describe "split editor panes", ->
     describe "when split-right is triggered on the editor", ->
-      fit "places the a new editor to the right of the current editor in a .horizontal div, and focuses the new editor", ->
+      it "places the a new editor to the right of the current editor in a .horizontal div, and focuses the new editor", ->
         rootView.attachToDom()
 
         expect(rootView.find('.horizontal')).not.toExist()

spec/atom/selection-spec.coffee

@@ -10,6 +10,7 @@ describe "Selection", ->
     editor = new Editor
     editor.enableKeymap()
     editor.setBuffer(buffer)
+    editor.isFocused = true
     selection = editor.selection
 
   describe ".setBufferRange(range)", ->

spec/atom/vim-mode-spec.coffee

@@ -7,6 +7,7 @@ describe "VimMode", ->
   beforeEach ->
     editor = new Editor
     editor.enableKeymap()
+    editor.isFocused = true
     vimMode = new VimMode(editor)
 
   describe "initialize", ->

src/atom/editor.coffee

@@ -37,6 +37,7 @@ class Editor extends View
   renderer: null
   autoIndent: null
   lineCache: null
+  isFocused: false
 
   initialize: ({buffer}) ->
     requireStylesheet 'editor.css'
@@ -105,6 +106,9 @@ class Editor extends View
       @hiddenInput.focus()
       false
 
+    @hiddenInput.on 'focus', => @isFocused = true
+    @hiddenInput.on 'focusout', => @isFocused = false
+
     @on 'mousedown', '.fold-placeholder', (e) =>
       @destroyFold($(e.currentTarget).attr('foldId'))
       false
@@ -178,7 +182,7 @@ class Editor extends View
 
     @loadEditSessionForBuffer(@buffer)
 
-    @buffer.on "change.editor#{@id}", (e) => @cursor.bufferChanged(e)
+    @buffer.on "change.editor#{@id}", (e) => @handleBufferChange(e)
     @renderer.on 'change', (e) => @handleRendererChange(e)
 
   loadEditSessionForBuffer: (buffer) ->
@@ -192,6 +196,9 @@ class Editor extends View
     @editSession.scrollTop = @scrollTop()
     @editSession.scrollLeft = @horizontalScroller.scrollLeft()
 
+  handleBufferChange: (e) ->
+    @cursor.bufferChanged(e) if @isFocused
+
   handleRendererChange: (e) ->
     { oldRange, newRange } = e
     unless newRange.isSingleLine() and newRange.coversSameRows(oldRange)