Move vertical scroll state to root of presenter state object

Signed-off-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

spec/text-editor-presenter-spec.coffee

@@ -33,6 +33,31 @@ describe "TextEditorPresenter", ->
   # These `describe` and `it` blocks mirror the structure of the ::state object.
   # Please maintain this structure when adding specs for new state fields.
   describe "::state", ->
+    describe ".scrollHeight", ->
+      it "is initialized based on the lineHeight, the number of lines, and the clientHeight", ->
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10)
+        expect(presenter.state.scrollHeight).toBe editor.getScreenLineCount() * 10
+
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, clientHeight: 500)
+        expect(presenter.state.scrollHeight).toBe 500
+
+      it "updates when the ::lineHeight changes", ->
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10)
+        expectStateUpdate presenter, -> presenter.setLineHeight(20)
+        expect(presenter.state.scrollHeight).toBe editor.getScreenLineCount() * 20
+
+      it "updates when the line count changes", ->
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10)
+        expectStateUpdate presenter, -> editor.getBuffer().append("\n\n\n")
+        expect(presenter.state.scrollHeight).toBe editor.getScreenLineCount() * 10
+
+    describe ".scrollTop", ->
+      it "tracks the value of ::scrollTop", ->
+        presenter = new TextEditorPresenter(model: editor, scrollTop: 10, lineHeight: 10)
+        expect(presenter.state.scrollTop).toBe 10
+        expectStateUpdate presenter, -> presenter.setScrollTop(50)
+        expect(presenter.state.scrollTop).toBe 50
+
     describe ".content", ->
       describe ".scrollWidth", ->
         it "is initialized as the max of the clientWidth and the width of the longest line", ->
@@ -79,28 +104,6 @@ describe "TextEditorPresenter", ->
           expectStateUpdate presenter, -> editor.setSoftWrapped(false)
           expect(presenter.state.content.scrollWidth).toBe 10 * editor.getMaxScreenLineLength() + 1
 
-      describe ".scrollHeight", ->
-        it "is initialized based on the lineHeight and the number of lines", ->
-          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
-          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 10
-
-        it "updates when the ::lineHeight changes", ->
-          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
-          expectStateUpdate presenter, -> presenter.setLineHeight(20)
-          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 20
-
-        it "updates when the line count changes", ->
-          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
-          expectStateUpdate presenter, -> editor.getBuffer().append("\n\n\n")
-          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 10
-
-      describe ".scrollTop", ->
-        it "tracks the value of ::scrollTop", ->
-          presenter = new TextEditorPresenter(model: editor, scrollTop: 10, lineHeight: 10, lineOverdrawMargin: 1)
-          expect(presenter.state.content.scrollTop).toBe 10
-          expectStateUpdate presenter, -> presenter.setScrollTop(50)
-          expect(presenter.state.content.scrollTop).toBe 50
-
       describe ".scrollLeft", ->
         it "tracks the value of ::scrollLeft", ->
           presenter = new TextEditorPresenter(model: editor, scrollLeft: 10, lineHeight: 10, lineOverdrawMargin: 1)

src/lines-component.coffee

@@ -23,9 +23,10 @@ LinesComponent = React.createClass
       {editor, presenter, overlayDecorations, highlightDecorations, placeholderText, backgroundColor} = @props
       {lineHeightInPixels, defaultCharWidth, scrollViewHeight, scopedCharacterWidthsChangeCount, cursorPixelRects} = @props
 
-      @oldState ?= {lines: {}}
-      @newState = presenter.state.content
-      {scrollWidth, scrollHeight} = @newState
+      @oldState ?= {content: {lines: {}}}
+      @newState = presenter.state
+      {scrollHeight} = @newState
+      {scrollWidth} = @newState.content
 
       style =
         height: Math.max(scrollHeight, scrollViewHeight)
@@ -40,7 +41,8 @@ LinesComponent = React.createClass
       HighlightsComponent {presenter, performedInitialMeasurement}
 
   getTransform: ->
-    {scrollTop, scrollLeft} = @newState
+    {scrollTop} = @newState
+    {scrollLeft} = @newState.content
     {useHardwareAcceleration} = @props
 
     if useHardwareAcceleration
@@ -72,41 +74,41 @@ LinesComponent = React.createClass
     {visible, scrollingVertically, performedInitialMeasurement} = @props
     return unless performedInitialMeasurement
 
-    @removeLineNodes() unless @oldState?.indentGuidesVisible is @newState?.indentGuidesVisible
+    @removeLineNodes() unless @oldState?.content.indentGuidesVisible is @newState?.content.indentGuidesVisible
     @updateLineNodes()
     @measureCharactersInNewLines() if visible and not scrollingVertically
 
     @overlayManager?.render(@props)
 
-    @oldState.indentGuidesVisible = @newState.indentGuidesVisible
-    @oldState.scrollWidth = @newState.scrollWidth
+    @oldState.content.indentGuidesVisible = @newState.content.indentGuidesVisible
+    @oldState.content.scrollWidth = @newState.content.scrollWidth
 
   clearScreenRowCaches: ->
     @screenRowsByLineId = {}
     @lineIdsByScreenRow = {}
 
   removeLineNodes: ->
-    @removeLineNode(id) for id of @oldState.lines
+    @removeLineNode(id) for id of @oldState.content.lines
 
   removeLineNode: (id) ->
     @lineNodesByLineId[id].remove()
     delete @lineNodesByLineId[id]
     delete @lineIdsByScreenRow[@screenRowsByLineId[id]]
     delete @screenRowsByLineId[id]
-    delete @oldState.lines[id]
+    delete @oldState.content.lines[id]
 
   updateLineNodes: ->
     {presenter, mouseWheelScreenRow} = @props
 
-    for id of @oldState.lines
-      unless @newState.lines.hasOwnProperty(id) or mouseWheelScreenRow is @screenRowsByLineId[id]
+    for id of @oldState.content.lines
+      unless @newState.content.lines.hasOwnProperty(id) or mouseWheelScreenRow is @screenRowsByLineId[id]
         @removeLineNode(id)
 
     newLineIds = null
     newLinesHTML = null
 
-    for id, lineState of @newState.lines
-      if @oldState.lines.hasOwnProperty(id)
+    for id, lineState of @newState.content.lines
+      if @oldState.content.lines.hasOwnProperty(id)
         @updateLineNode(id)
       else
         newLineIds ?= []
@@ -115,7 +117,7 @@ LinesComponent = React.createClass
         newLinesHTML += @buildLineHTML(id)
         @screenRowsByLineId[id] = lineState.screenRow
         @lineIdsByScreenRow[lineState.screenRow] = id
-      @oldState.lines[id] = _.clone(lineState)
+      @oldState.content.lines[id] = _.clone(lineState)
 
     return unless newLineIds?
 
@@ -129,8 +131,8 @@ LinesComponent = React.createClass
 
   buildLineHTML: (id) ->
     {presenter} = @props
-    {scrollWidth} = @newState
-    {screenRow, tokens, text, top, lineEnding, fold, isSoftWrapped, indentLevel, decorationClasses} = @newState.lines[id]
+    {scrollWidth} = @newState.content
+    {screenRow, tokens, text, top, lineEnding, fold, isSoftWrapped, indentLevel, decorationClasses} = @newState.content.lines[id]
 
     classes = ''
     if decorationClasses?
@@ -150,8 +152,8 @@ LinesComponent = React.createClass
     lineHTML
 
   buildEmptyLineInnerHTML: (id) ->
-    {indentGuidesVisible} = @newState
-    {indentLevel, tabLength, endOfLineInvisibles} = @newState.lines[id]
+    {indentGuidesVisible} = @newState.content
+    {indentLevel, tabLength, endOfLineInvisibles} = @newState.content.lines[id]
 
     if indentGuidesVisible and indentLevel > 0
       invisibleIndex = 0
@@ -174,8 +176,8 @@ LinesComponent = React.createClass
 
   buildLineInnerHTML: (id) ->
     {editor} = @props
-    {indentGuidesVisible} = @newState
-    {tokens, text} = @newState.lines[id]
+    {indentGuidesVisible} = @newState.content
+    {tokens, text} = @newState.content.lines[id]
     innerHTML = ""
 
     scopeStack = []
@@ -191,7 +193,7 @@ LinesComponent = React.createClass
     innerHTML
 
   buildEndOfLineHTML: (id) ->
-    {endOfLineInvisibles} = @newState.lines[id]
+    {endOfLineInvisibles} = @newState.content.lines[id]
 
     html = ''
     if endOfLineInvisibles?
@@ -225,13 +227,13 @@ LinesComponent = React.createClass
     "<span class=\"#{scope.replace(/\.+/g, ' ')}\">"
 
   updateLineNode: (id) ->
-    {scrollWidth} = @newState
-    {screenRow, top} = @newState.lines[id]
+    {scrollWidth} = @newState.content
+    {screenRow, top} = @newState.content.lines[id]
 
     lineNode = @lineNodesByLineId[id]
 
-    newDecorationClasses = @newState.lines[id].decorationClasses
-    oldDecorationClasses = @oldState.lines[id].decorationClasses
+    newDecorationClasses = @newState.content.lines[id].decorationClasses
+    oldDecorationClasses = @oldState.content.lines[id].decorationClasses
 
     if oldDecorationClasses?
       for decorationClass in oldDecorationClasses
@@ -276,7 +278,7 @@ LinesComponent = React.createClass
     node = @getDOMNode()
 
     editor.batchCharacterMeasurement =>
-      for id, lineState of @oldState.lines
+      for id, lineState of @oldState.content.lines
         unless @measuredLines.has(id)
           lineNode = @lineNodesByLineId[id]
           @measureCharactersInLine(lineState, lineNode)

src/text-editor-presenter.coffee

@@ -47,16 +47,19 @@ class TextEditorPresenter
     @updateState()
 
   updateState: ->
+    @updateVerticalScrollState()
     @updateContentState()
     @updateLinesState()
     @updateCursorsState()
     @updateHighlightsState()
     @updateLineNumbersState()
 
+  updateVerticalScrollState: ->
+    @state.scrollHeight = @computeScrollHeight()
+    @state.scrollTop = @getScrollTop()
+
   updateContentState: ->
     @state.content.scrollWidth = @computeScrollWidth()
-    @state.content.scrollHeight = @computeScrollHeight()
-    @state.content.scrollTop = @getScrollTop()
     @state.content.scrollLeft = @getScrollLeft()
     @state.content.indentGuidesVisible = atom.config.get('editor.showIndentGuide', scope: @model.getRootScopeDescriptor())
     @emitter.emit 'did-update-state'
@@ -230,7 +233,7 @@ class TextEditorPresenter
     Math.max(contentWidth, @getClientWidth())
 
   computeScrollHeight: ->
-    @getLineHeight() * @model.getScreenLineCount()
+    Math.max(@getLineHeight() * @model.getScreenLineCount(), @getClientHeight())
 
   lineDecorationClassesForRow: (row) ->
     return null if @model.isMini()
@@ -277,7 +280,7 @@ class TextEditorPresenter
   getCursorBlinkResumeDelay: -> @cursorBlinkResumeDelay
 
   setScrollTop: (@scrollTop) ->
-    @updateContentState()
+    @updateVerticalScrollState()
     @updateLinesState()
     @updateCursorsState()
     @updateHighlightsState()
@@ -306,7 +309,7 @@ class TextEditorPresenter
   getClientWidth: -> @clientWidth
 
   setLineHeight: (@lineHeight) ->
-    @updateContentState()
+    @updateVerticalScrollState()
     @updateLinesState()
     @updateCursorsState()
     @updateHighlightsState()