Handle auto-height in TextEditorPresenter

spec/text-editor-presenter-spec.coffee

@@ -1655,3 +1655,20 @@ describe "TextEditorPresenter", ->
 
             editor.undo()
             expect(lineNumberStateForScreenRow(presenter, 11).foldable).toBe false
+
+    describe ".height", ->
+      it "tracks the computed content height if ::autoHeight is true so the editor auto-expands vertically", ->
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, autoHeight: true)
+        expect(presenter.state.height).toBe editor.getScreenLineCount() * 10
+
+        expectStateUpdate presenter, -> presenter.setAutoHeight(false)
+        expect(presenter.state.height).toBe null
+
+        expectStateUpdate presenter, -> presenter.setAutoHeight(true)
+        expect(presenter.state.height).toBe editor.getScreenLineCount() * 10
+
+        expectStateUpdate presenter, -> presenter.setLineHeight(20)
+        expect(presenter.state.height).toBe editor.getScreenLineCount() * 20
+
+        expectStateUpdate presenter, -> editor.getBuffer().append("\n\n\n")
+        expect(presenter.state.height).toBe editor.getScreenLineCount() * 20

src/text-editor-component.coffee

@@ -55,7 +55,7 @@ TextEditorComponent = React.createClass
       hiddenInputStyle = @getHiddenInputPosition()
       hiddenInputStyle.WebkitTransform = 'translateZ(0)' if @useHardwareAcceleration
 
-      style.height = @presenter.state.content.scrollHeight if @autoHeight
+      style.height = @presenter.state.height if @presenter.state.height?
 
     if useShadowDOM
       className = 'editor-contents--private'
@@ -675,6 +675,7 @@ TextEditorComponent = React.createClass
     if position is 'absolute' or height
       if @autoHeight
         @autoHeight = false
+        @presenter.setAutoHeight(false)
         @forceUpdate() if not @updatesPaused and @canUpdate()
 
       clientHeight =  scrollViewNode.clientHeight
@@ -682,6 +683,7 @@ TextEditorComponent = React.createClass
         @presenter.setHeight(clientHeight)
         editor.setHeight(clientHeight)
     else
+      @presenter.setAutoHeight(true)
       @presenter.setHeight(null)
       editor.setHeight(null)
       @autoHeight = true

src/text-editor-presenter.coffee

@@ -10,7 +10,7 @@ class TextEditorPresenter
   mouseWheelScreenRow: null
 
   constructor: (params) ->
-    {@model, @height, @contentFrameWidth, @scrollTop, @scrollLeft} = params
+    {@model, @autoHeight, @height, @contentFrameWidth, @scrollTop, @scrollLeft} = params
     {@horizontalScrollbarHeight, @verticalScrollbarWidth} = params
     {@lineHeight, @baseCharacterWidth, @lineOverdrawMargin, @backgroundColor, @gutterBackgroundColor} = params
     {@cursorBlinkPeriod, @cursorBlinkResumeDelay, @stoppedScrollingDelay} = params
@@ -64,6 +64,7 @@ class TextEditorPresenter
     @updateState()
 
   updateState: ->
+    @updateHeightState()
     @updateVerticalScrollState()
     @updateHorizontalScrollState()
     @updateScrollbarsState()
@@ -75,6 +76,14 @@ class TextEditorPresenter
     @updateGutterState()
     @updateLineNumbersState()
 
+  updateHeightState: ->
+    if @hasAutoHeight()
+      @state.height = @computeContentHeight()
+    else
+      @state.height = null
+
+    @emitter.emit 'did-update-state'
+
   updateVerticalScrollState: ->
     scrollHeight = @computeScrollHeight()
     @state.content.scrollHeight = scrollHeight
@@ -456,6 +465,11 @@ class TextEditorPresenter
 
   getVerticalScrollbarWidth: -> @verticalScrollbarWidth
 
+  setAutoHeight: (@autoHeight) ->
+    @updateHeightState()
+
+  hasAutoHeight: -> @autoHeight
+
   setHeight: (@height) ->
     @updateVerticalScrollState()
     @updateScrollbarsState()
@@ -465,7 +479,7 @@ class TextEditorPresenter
     @updateLineNumbersState()
 
   getHeight: ->
-    @height ? @model.getScreenLineCount() * @getLineHeight()
+    @height ? @computeContentHeight()
 
   setContentFrameWidth: (@contentFrameWidth) ->
     @updateHorizontalScrollState()
@@ -490,6 +504,7 @@ class TextEditorPresenter
   getGutterBackgroundColor: -> @gutterBackgroundColor
 
   setLineHeight: (@lineHeight) ->
+    @updateHeightState()
     @updateVerticalScrollState()
     @updateLinesState()
     @updateCursorsState()