Maintain cursor position when buffer is reloaded

spec/app/buffer-spec.coffee

@@ -359,6 +359,14 @@ describe 'Buffer', ->
         saveBuffer.save()
         expect(events).toEqual ['beforeSave1', 'beforeSave2', 'fs.write', 'afterSave1', 'afterSave2']
 
+      it "fires before-reload and after-reload events when reloaded", ->
+        events = []
+
+        saveBuffer.on 'before-reload', -> events.push 'before-reload'
+        saveBuffer.on 'after-reload', -> events.push 'after-reload'
+        saveBuffer.reload()
+        expect(events).toEqual ['before-reload', 'after-reload']
+
     describe "when the buffer has no path", ->
       it "throws an exception", ->
         saveBuffer = new Buffer

spec/app/edit-session-spec.coffee

@@ -1822,3 +1822,9 @@ describe "EditSession", ->
       expect(editSession.indentLevelForLine("  \thello")).toBe(2)
       expect(editSession.indentLevelForLine("  \t hello")).toBe(2.5)
       expect(editSession.indentLevelForLine("  \t \thello")).toBe(3.5)
+
+  describe "when the buffer is reloaded", ->
+    it "preserves the current cursor position", ->
+      editSession.setCursorScreenPosition([0, 1])
+      editSession.buffer.reload()
+      expect(editSession.getCursorScreenPosition()).toEqual [0,1]

src/app/buffer.coffee

@@ -73,8 +73,10 @@ class Buffer
       @trigger "path-change", this
 
   reload: ->
+    @trigger 'before-reload'
     @updateCachedDiskContents()
     @setText(@cachedDiskContents)
+    @trigger 'after-reload'
 
   updateCachedDiskContents: ->
     @cachedDiskContents = @file.read()

src/app/edit-session.coffee

@@ -59,6 +59,8 @@ class EditSession
     @buffer.on "update-anchors-after-change.edit-session-#{@id}", =>
       @mergeCursors()
 
+    @preserveCursorPositionOnBufferReload()
+
     @displayBuffer.on "change.edit-session-#{@id}", (e) =>
       @refreshAnchorScreenPositions() unless e.bufferDelta
       @trigger 'screen-lines-change', e
@@ -597,4 +599,12 @@ class EditSession
   inspect: ->
     JSON.stringify @serialize()
 
+  preserveCursorPositionOnBufferReload: ->
+    cursorPosition = null
+    @buffer.on "before-reload.edit-session-#{@id}", =>
+      cursorPosition = @getCursorBufferPosition()
+    @buffer.on "after-reload.edit-session-#{@id}", =>
+      @setCursorBufferPosition(cursorPosition) if cursorPosition
+      cursorPosition = null
+
 _.extend(EditSession.prototype, EventEmitter)