Rework Buffer's 'contents-modified' event

This event now fires whenever the content of the buffer changes (after 
a rate-limiting delay) with a single boolean indicating the modified
status of the buffer. There's now a separate event called
'modified-status-changed' to indicate events that change the boolean
value of the isModified method, so we don't need to fire
'contents-modified' when the underlying file is deleted for instance.

spec/app/buffer-spec.coffee

@@ -1105,61 +1105,30 @@ describe 'Buffer', ->
       expect(buffer.isEmpty()).toBeFalsy()
 
   describe "'contents-modified' event", ->
-    describe "when the buffer is deleted", ->
-      it "triggers the contents-modified event", ->
-        delay = buffer.stoppedChangingDelay
-        path = "/tmp/atom-file-to-delete.txt"
-        fs.write(path, 'delete me')
-        bufferToDelete = new Buffer(path)
-        contentsModifiedHandler = jasmine.createSpy("contentsModifiedHandler")
-        bufferToDelete.on 'contents-modified', contentsModifiedHandler
+    it "triggers the 'contents-modified' event with the current modified status when the buffer changes, rate-limiting events with a delay", ->
+      delay = buffer.stoppedChangingDelay
+      contentsModifiedHandler = jasmine.createSpy("contentsModifiedHandler")
+      buffer.on 'contents-modified', contentsModifiedHandler
 
-        expect(bufferToDelete.getPath()).toBe path
-        expect(bufferToDelete.isModified()).toBeFalsy()
-        expect(contentsModifiedHandler).not.toHaveBeenCalled()
+      buffer.insert([0, 0], 'a')
+      expect(contentsModifiedHandler).not.toHaveBeenCalled()
 
-        removeHandler = jasmine.createSpy('removeHandler')
-        bufferToDelete.file.on 'removed', removeHandler
-        fs.remove(path)
-        waitsFor "file to be removed", ->
-          removeHandler.callCount > 0
+      advanceClock(delay / 2)
 
-        runs ->
-          expect(contentsModifiedHandler).toHaveBeenCalledWith(differsFromDisk:true)
-          bufferToDelete.destroy()
+      buffer.insert([0, 0], 'b')
+      expect(contentsModifiedHandler).not.toHaveBeenCalled()
 
-    describe "when the buffer text has been changed", ->
-      it "triggers the contents-modified event 'stoppedChangingDelay' ms after the last buffer change", ->
-        delay = buffer.stoppedChangingDelay
-        contentsModifiedHandler = jasmine.createSpy("contentsModifiedHandler")
-        buffer.on 'contents-modified', contentsModifiedHandler
+      advanceClock(delay / 2)
+      expect(contentsModifiedHandler).not.toHaveBeenCalled()
 
-        buffer.insert([0, 0], 'a')
-        expect(contentsModifiedHandler).not.toHaveBeenCalled()
+      advanceClock(delay / 2)
+      expect(contentsModifiedHandler).toHaveBeenCalledWith(true)
 
-        advanceClock(delay / 2)
-
-        buffer.insert([0, 0], 'b')
-        expect(contentsModifiedHandler).not.toHaveBeenCalled()
-
-        advanceClock(delay / 2)
-        expect(contentsModifiedHandler).not.toHaveBeenCalled()
-
-        advanceClock(delay / 2)
-        expect(contentsModifiedHandler).toHaveBeenCalled()
-
-      it "triggers the contents-modified event with data about whether its contents differ from the contents on disk", ->
-        delay = buffer.stoppedChangingDelay
-        contentsModifiedHandler = jasmine.createSpy("contentsModifiedHandler")
-        buffer.on 'contents-modified', contentsModifiedHandler
-
-        buffer.insert([0, 0], 'a')
-        advanceClock(delay)
-        expect(contentsModifiedHandler).toHaveBeenCalledWith(differsFromDisk:true)
-
-        buffer.delete([[0, 0], [0, 1]], '')
-        advanceClock(delay)
-        expect(contentsModifiedHandler).toHaveBeenCalledWith(differsFromDisk:false)
+      contentsModifiedHandler.reset()
+      buffer.undo()
+      buffer.undo()
+      advanceClock(delay)
+      expect(contentsModifiedHandler).toHaveBeenCalledWith(false)
 
   describe ".append(text)", ->
     it "adds text to the end of the buffer", ->

src/app/buffer-change-operation.coffee

@@ -73,7 +73,7 @@ class BufferChangeOperation
     event = { oldRange, newRange, oldText, newText }
     @updateMarkers(event)
     @buffer.trigger 'changed', event
-    @buffer.scheduleModifiedStatusChangedEvent()
+    @buffer.scheduleModifiedEvents()
     @resumeMarkerObservation()
     @buffer.trigger 'markers-updated'
 

src/app/buffer.coffee

@@ -70,7 +70,6 @@ class Buffer
     @file.on "removed", =>
       @updateCachedDiskContents()
       @trigger "modified-status-changed", @isModified()
-      @trigger "contents-modified", {differsFromDisk: true}
 
     @file.on "moved", =>
       @trigger "path-changed", this
@@ -427,15 +426,15 @@ class Buffer
     return unless path
     git?.checkoutHead(path)
 
-  scheduleModifiedStatusChangedEvent: ->
+  scheduleModifiedEvents: ->
     clearTimeout(@stoppedChangingTimeout) if @stoppedChangingTimeout
     stoppedChangingCallback = =>
       @stoppedChangingTimeout = null
       modifiedStatus = @isModified()
+      @trigger 'contents-modified', modifiedStatus
       unless modifiedStatus is @previousModifiedStatus
         @previousModifiedStatus = modifiedStatus
         @trigger 'modified-status-changed', modifiedStatus
-      @trigger 'contents-modified', {differsFromDisk: @isModified()}
     @stoppedChangingTimeout = setTimeout(stoppedChangingCallback, @stoppedChangingDelay)
 
   fileExists: ->

src/packages/status-bar/lib/status-bar-view.coffee

@@ -47,7 +47,7 @@ class StatusBarView extends View
   subscribeToBuffer: ->
     @buffer?.off '.status-bar'
     @buffer = @editor.getBuffer()
-    @buffer.on 'contents-modified.status-bar', (e) => @updateBufferHasModifiedText(e.differsFromDisk)
+    @buffer.on 'modified-status-changed.status-bar', (isModified) => @updateBufferHasModifiedText(isModified)
     @buffer.on 'saved.status-bar', => @updateStatusBar()
     @updateStatusBar()
 
@@ -60,8 +60,8 @@ class StatusBarView extends View
   updateGrammarText: ->
     @grammarName.text(@editor.getGrammar().name)
 
-  updateBufferHasModifiedText: (differsFromDisk)->
-    if differsFromDisk
+  updateBufferHasModifiedText: (isModified)->
+    if isModified
       @bufferModified.text('*') unless @isModified
       @isModified = true
     else