Merge pull request #1883 from atom/ns-react-editor-view

React Editor View, Take 2

package.json

@@ -40,6 +40,8 @@
     "property-accessors": "1.x",
     "q": "^1.0.1",
     "random-words": "0.0.1",
+    "react": "^0.10.0",
+    "reactionary": "^0.8.0",
     "runas": "0.5.x",
     "scandal": "0.15.2",
     "scoped-property-store": "^0.8.0",
@@ -51,7 +53,7 @@
     "temp": "0.5.0",
     "text-buffer": "^2.1.0",
     "theorist": "1.x",
-    "underscore-plus": "^1.1.2",
+    "underscore-plus": "^1.2.1",
     "vm-compatibility-layer": "0.1.0"
   },
   "packageDependencies": {

spec/display-buffer-spec.coffee

@@ -943,3 +943,69 @@ describe "DisplayBuffer", ->
         expect(displayBuffer.getMarkerCount()).toBe initialMarkerCount + 2
         expect(marker1.getAttributes()).toEqual a: 1, b: 2
         expect(marker2.getAttributes()).toEqual a: 1, b: 3
+
+    describe "DisplayBufferMarker::getPixelRange()", ->
+      it "returns the start and end positions of the marker based on the line height and character widths assigned to the DisplayBuffer", ->
+        marker = displayBuffer.markScreenRange([[5, 10], [6, 4]])
+
+        displayBuffer.setLineHeight(20)
+        displayBuffer.setDefaultCharWidth(10)
+        displayBuffer.setScopedCharWidths(["source.js", "keyword.control.js"], r: 11, e: 11, t: 11, u: 11, n: 11)
+
+        {start, end} = marker.getPixelRange()
+        expect(start.top).toBe 5 * 20
+        expect(start.left).toBe (4 * 10) + (6 * 11)
+
+  describe "::setScrollTop", ->
+    beforeEach ->
+      displayBuffer.manageScrollPosition = true
+      displayBuffer.setLineHeight(10)
+
+    it "disallows negative values", ->
+      displayBuffer.setHeight(displayBuffer.getScrollHeight() + 100)
+      expect(displayBuffer.setScrollTop(-10)).toBe 0
+      expect(displayBuffer.getScrollTop()).toBe 0
+
+    it "disallows values that would make ::getScrollBottom() exceed ::getScrollHeight()", ->
+      displayBuffer.setHeight(50)
+      maxScrollTop = displayBuffer.getScrollHeight() - displayBuffer.getHeight()
+
+      expect(displayBuffer.setScrollTop(maxScrollTop)).toBe maxScrollTop
+      expect(displayBuffer.getScrollTop()).toBe maxScrollTop
+
+      expect(displayBuffer.setScrollTop(maxScrollTop + 50)).toBe maxScrollTop
+      expect(displayBuffer.getScrollTop()).toBe maxScrollTop
+
+  describe "::setScrollLeft", ->
+    beforeEach ->
+      displayBuffer.manageScrollPosition = true
+      displayBuffer.setDefaultCharWidth(10)
+
+    it "disallows negative values", ->
+      displayBuffer.setWidth(displayBuffer.getScrollWidth() + 100)
+      expect(displayBuffer.setScrollLeft(-10)).toBe 0
+      expect(displayBuffer.getScrollLeft()).toBe 0
+
+    it "disallows values that would make ::getScrollRight() exceed ::getScrollWidth()", ->
+      displayBuffer.setWidth(50)
+      maxScrollLeft = displayBuffer.getScrollWidth() - displayBuffer.getWidth()
+
+      expect(displayBuffer.setScrollLeft(maxScrollLeft)).toBe maxScrollLeft
+      expect(displayBuffer.getScrollLeft()).toBe maxScrollLeft
+
+      expect(displayBuffer.setScrollLeft(maxScrollLeft + 50)).toBe maxScrollLeft
+      expect(displayBuffer.getScrollLeft()).toBe maxScrollLeft
+
+  describe "::scrollToScreenPosition(position)", ->
+    it "sets the scroll top and scroll left so the given screen position is in view", ->
+      displayBuffer.manageScrollPosition = true
+      displayBuffer.setLineHeight(10)
+      displayBuffer.setDefaultCharWidth(10)
+
+      displayBuffer.setHeight(50)
+      displayBuffer.setWidth(50)
+      maxScrollTop = displayBuffer.getScrollHeight() - displayBuffer.getHeight()
+
+      displayBuffer.scrollToScreenPosition([8, 20])
+      expect(displayBuffer.getScrollBottom()).toBe (9 + displayBuffer.getVerticalScrollMargin()) * 10
+      expect(displayBuffer.getScrollRight()).toBe (20 + displayBuffer.getHorizontalScrollMargin()) * 10

spec/editor-component-spec.coffee

@@ -0,0 +1,580 @@
+{extend, flatten, toArray} = require 'underscore-plus'
+ReactEditorView = require '../src/react-editor-view'
+nbsp = String.fromCharCode(160)
+
+describe "EditorComponent", ->
+  [editor, wrapperView, component, node, verticalScrollbarNode, horizontalScrollbarNode] = []
+  [lineHeightInPixels, charWidth, delayAnimationFrames, nextAnimationFrame] = []
+
+  beforeEach ->
+    waitsForPromise ->
+      atom.packages.activatePackage('language-javascript')
+
+    runs ->
+      spyOn(window, "setInterval").andCallFake window.fakeSetInterval
+      spyOn(window, "clearInterval").andCallFake window.fakeClearInterval
+
+      delayAnimationFrames = false
+      nextAnimationFrame = null
+      spyOn(window, 'requestAnimationFrame').andCallFake (fn) ->
+        if delayAnimationFrames
+          nextAnimationFrame = fn
+        else
+          fn()
+
+      editor = atom.project.openSync('sample.js')
+      wrapperView = new ReactEditorView(editor)
+      wrapperView.attachToDom()
+      {component} = wrapperView
+      component.setLineHeight(1.3)
+      component.setFontSize(20)
+
+      lineHeightInPixels = editor.getLineHeight()
+      charWidth = editor.getDefaultCharWidth()
+      node = component.getDOMNode()
+      verticalScrollbarNode = node.querySelector('.vertical-scrollbar')
+      horizontalScrollbarNode = node.querySelector('.horizontal-scrollbar')
+
+  describe "line rendering", ->
+    it "renders only the currently-visible lines", ->
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+
+      lines = node.querySelectorAll('.line')
+      expect(lines.length).toBe 6
+      expect(lines[0].textContent).toBe editor.lineForScreenRow(0).text
+      expect(lines[5].textContent).toBe editor.lineForScreenRow(5).text
+
+      verticalScrollbarNode.scrollTop = 2.5 * lineHeightInPixels
+      verticalScrollbarNode.dispatchEvent(new UIEvent('scroll'))
+
+      expect(node.querySelector('.scroll-view-content').style['-webkit-transform']).toBe "translate3d(0px, #{-2.5 * lineHeightInPixels}px, 0)"
+
+      lineNodes = node.querySelectorAll('.line')
+      expect(lineNodes.length).toBe 6
+      expect(lineNodes[0].offsetTop).toBe 2 * lineHeightInPixels
+      expect(lineNodes[0].textContent).toBe editor.lineForScreenRow(2).text
+      expect(lineNodes[5].textContent).toBe editor.lineForScreenRow(7).text
+
+    it "updates absolute positions of subsequent lines when lines are inserted or removed", ->
+      editor.getBuffer().deleteRows(0, 1)
+      lineNodes = node.querySelectorAll('.line')
+      expect(lineNodes[0].offsetTop).toBe 0
+      expect(lineNodes[1].offsetTop).toBe 1 * lineHeightInPixels
+      expect(lineNodes[2].offsetTop).toBe 2 * lineHeightInPixels
+
+      editor.getBuffer().insert([0, 0], '\n\n')
+      lineNodes = node.querySelectorAll('.line')
+      expect(lineNodes[0].offsetTop).toBe 0
+      expect(lineNodes[1].offsetTop).toBe 1 * lineHeightInPixels
+      expect(lineNodes[2].offsetTop).toBe 2 * lineHeightInPixels
+      expect(lineNodes[3].offsetTop).toBe 3 * lineHeightInPixels
+      expect(lineNodes[4].offsetTop).toBe 4 * lineHeightInPixels
+
+    describe "when indent guides are enabled", ->
+      beforeEach ->
+        component.setShowIndentGuide(true)
+
+      it "adds an 'indent-guide' class to spans comprising the leading whitespace", ->
+        lines = node.querySelectorAll('.line')
+        line1LeafNodes = getLeafNodes(lines[1])
+        expect(line1LeafNodes[0].textContent).toBe '  '
+        expect(line1LeafNodes[0].classList.contains('indent-guide')).toBe true
+        expect(line1LeafNodes[1].classList.contains('indent-guide')).toBe false
+
+        line2LeafNodes = getLeafNodes(lines[2])
+        expect(line2LeafNodes[0].textContent).toBe '  '
+        expect(line2LeafNodes[0].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[1].textContent).toBe '  '
+        expect(line2LeafNodes[1].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[2].classList.contains('indent-guide')).toBe false
+
+      it "renders leading whitespace spans with the 'indent-guide' class for empty lines", ->
+        editor.getBuffer().insert([1, Infinity], '\n')
+
+        lines = node.querySelectorAll('.line')
+        line2LeafNodes = getLeafNodes(lines[2])
+
+        expect(line2LeafNodes.length).toBe 3
+        expect(line2LeafNodes[0].textContent).toBe '  '
+        expect(line2LeafNodes[0].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[1].textContent).toBe '  '
+        expect(line2LeafNodes[1].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[2].textContent).toBe '  '
+        expect(line2LeafNodes[2].classList.contains('indent-guide')).toBe true
+
+      it "renders indent guides correctly on lines containing only whitespace", ->
+        editor.getBuffer().insert([1, Infinity], '\n      ')
+        lines = node.querySelectorAll('.line')
+        line2LeafNodes = getLeafNodes(lines[2])
+        expect(line2LeafNodes.length).toBe 3
+        expect(line2LeafNodes[0].textContent).toBe '  '
+        expect(line2LeafNodes[0].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[1].textContent).toBe '  '
+        expect(line2LeafNodes[1].classList.contains('indent-guide')).toBe true
+        expect(line2LeafNodes[2].textContent).toBe '  '
+        expect(line2LeafNodes[2].classList.contains('indent-guide')).toBe true
+
+      it "does not render indent guides in trailing whitespace for lines containing non whitespace characters", ->
+        editor.getBuffer().setText ("  hi  ")
+        lines = node.querySelectorAll('.line')
+        line0LeafNodes = getLeafNodes(lines[0])
+        expect(line0LeafNodes[0].textContent).toBe '  '
+        expect(line0LeafNodes[0].classList.contains('indent-guide')).toBe true
+        expect(line0LeafNodes[1].textContent).toBe '  '
+        expect(line0LeafNodes[1].classList.contains('indent-guide')).toBe false
+
+      getLeafNodes = (node) ->
+        if node.children.length > 0
+          flatten(toArray(node.children).map(getLeafNodes))
+        else
+          [node]
+
+  describe "gutter rendering", ->
+    it "renders the currently-visible line numbers", ->
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+
+      lines = node.querySelectorAll('.line-number')
+      expect(lines.length).toBe 6
+      expect(lines[0].textContent).toBe "#{nbsp}1"
+      expect(lines[5].textContent).toBe "#{nbsp}6"
+
+      verticalScrollbarNode.scrollTop = 2.5 * lineHeightInPixels
+      verticalScrollbarNode.dispatchEvent(new UIEvent('scroll'))
+
+      expect(node.querySelector('.line-numbers').style['-webkit-transform']).toBe "translate3d(0, #{-2.5 * lineHeightInPixels}px, 0)"
+
+      lineNumberNodes = node.querySelectorAll('.line-number')
+      expect(lineNumberNodes.length).toBe 6
+      expect(lineNumberNodes[0].offsetTop).toBe 2 * lineHeightInPixels
+      expect(lineNumberNodes[5].offsetTop).toBe 7 * lineHeightInPixels
+      expect(lineNumberNodes[0].textContent).toBe "#{nbsp}3"
+      expect(lineNumberNodes[5].textContent).toBe "#{nbsp}8"
+
+    it "updates absolute positions of subsequent line numbers when lines are inserted or removed", ->
+      editor.getBuffer().insert([0, 0], '\n\n')
+
+      lineNumberNodes = node.querySelectorAll('.line-number')
+      expect(lineNumberNodes[0].offsetTop).toBe 0
+      expect(lineNumberNodes[1].offsetTop).toBe 1 * lineHeightInPixels
+      expect(lineNumberNodes[2].offsetTop).toBe 2 * lineHeightInPixels
+      expect(lineNumberNodes[3].offsetTop).toBe 3 * lineHeightInPixels
+      expect(lineNumberNodes[4].offsetTop).toBe 4 * lineHeightInPixels
+
+      editor.getBuffer().insert([0, 0], '\n\n')
+      lineNumberNodes = node.querySelectorAll('.line-number')
+      expect(lineNumberNodes[0].offsetTop).toBe 0
+      expect(lineNumberNodes[1].offsetTop).toBe 1 * lineHeightInPixels
+      expect(lineNumberNodes[2].offsetTop).toBe 2 * lineHeightInPixels
+      expect(lineNumberNodes[3].offsetTop).toBe 3 * lineHeightInPixels
+      expect(lineNumberNodes[4].offsetTop).toBe 4 * lineHeightInPixels
+
+    it "renders • characters for soft-wrapped lines", ->
+      editor.setSoftWrap(true)
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      node.style.width = 30 * charWidth + 'px'
+      component.measureHeightAndWidth()
+
+      lines = node.querySelectorAll('.line-number')
+      expect(lines.length).toBe 6
+      expect(lines[0].textContent).toBe "#{nbsp}1"
+      expect(lines[1].textContent).toBe "#{nbsp}•"
+      expect(lines[2].textContent).toBe "#{nbsp}2"
+      expect(lines[3].textContent).toBe "#{nbsp}•"
+      expect(lines[4].textContent).toBe "#{nbsp}3"
+      expect(lines[5].textContent).toBe "#{nbsp}•"
+
+  describe "cursor rendering", ->
+    it "renders the currently visible cursors", ->
+      cursor1 = editor.getCursor()
+      cursor1.setScreenPosition([0, 5])
+
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+
+      cursorNodes = node.querySelectorAll('.cursor')
+      expect(cursorNodes.length).toBe 1
+      expect(cursorNodes[0].offsetHeight).toBe lineHeightInPixels
+      expect(cursorNodes[0].offsetWidth).toBe charWidth
+      expect(cursorNodes[0].offsetTop).toBe 0
+      expect(cursorNodes[0].offsetLeft).toBe 5 * charWidth
+
+      cursor2 = editor.addCursorAtScreenPosition([6, 11])
+      cursor3 = editor.addCursorAtScreenPosition([4, 10])
+
+      cursorNodes = node.querySelectorAll('.cursor')
+      expect(cursorNodes.length).toBe 2
+      expect(cursorNodes[0].offsetTop).toBe 0
+      expect(cursorNodes[0].offsetLeft).toBe 5 * charWidth
+      expect(cursorNodes[1].offsetTop).toBe 4 * lineHeightInPixels
+      expect(cursorNodes[1].offsetLeft).toBe 10 * charWidth
+
+      verticalScrollbarNode.scrollTop = 2.5 * lineHeightInPixels
+      verticalScrollbarNode.dispatchEvent(new UIEvent('scroll'))
+
+      cursorNodes = node.querySelectorAll('.cursor')
+      expect(cursorNodes.length).toBe 2
+      expect(cursorNodes[0].offsetTop).toBe 6 * lineHeightInPixels
+      expect(cursorNodes[0].offsetLeft).toBe 11 * charWidth
+      expect(cursorNodes[1].offsetTop).toBe 4 * lineHeightInPixels
+      expect(cursorNodes[1].offsetLeft).toBe 10 * charWidth
+
+      cursor3.destroy()
+      cursorNodes = node.querySelectorAll('.cursor')
+      expect(cursorNodes.length).toBe 1
+      expect(cursorNodes[0].offsetTop).toBe 6 * lineHeightInPixels
+      expect(cursorNodes[0].offsetLeft).toBe 11 * charWidth
+
+    it "accounts for character widths when positioning cursors", ->
+      atom.config.set('editor.fontFamily', 'sans-serif')
+      editor.setCursorScreenPosition([0, 16])
+
+      cursor = node.querySelector('.cursor')
+      cursorRect = cursor.getBoundingClientRect()
+
+      cursorLocationTextNode = node.querySelector('.storage.type.function.js').firstChild.firstChild
+      range = document.createRange()
+      range.setStart(cursorLocationTextNode, 0)
+      range.setEnd(cursorLocationTextNode, 1)
+      rangeRect = range.getBoundingClientRect()
+
+      expect(cursorRect.left).toBe rangeRect.left
+      expect(cursorRect.width).toBe rangeRect.width
+
+    it "blinks cursors when they aren't moving", ->
+      editor.addCursorAtScreenPosition([1, 0])
+      [cursorNode1, cursorNode2] = node.querySelectorAll('.cursor')
+      expect(cursorNode1.classList.contains('blink-off')).toBe false
+      expect(cursorNode2.classList.contains('blink-off')).toBe false
+
+      advanceClock(component.props.cursorBlinkPeriod / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe true
+      expect(cursorNode2.classList.contains('blink-off')).toBe true
+
+      advanceClock(component.props.cursorBlinkPeriod / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe false
+      expect(cursorNode2.classList.contains('blink-off')).toBe false
+
+      advanceClock(component.props.cursorBlinkPeriod / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe true
+      expect(cursorNode2.classList.contains('blink-off')).toBe true
+
+      # Stop blinking immediately when cursors move
+      advanceClock(component.props.cursorBlinkPeriod / 4)
+      expect(cursorNode1.classList.contains('blink-off')).toBe true
+      expect(cursorNode2.classList.contains('blink-off')).toBe true
+
+      # Stop blinking for one full period after moving the cursor
+      editor.moveCursorRight()
+      expect(cursorNode1.classList.contains('blink-off')).toBe false
+      expect(cursorNode2.classList.contains('blink-off')).toBe false
+
+      advanceClock(component.props.cursorBlinkResumeDelay / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe false
+      expect(cursorNode2.classList.contains('blink-off')).toBe false
+
+      advanceClock(component.props.cursorBlinkResumeDelay / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe true
+      expect(cursorNode2.classList.contains('blink-off')).toBe true
+
+      advanceClock(component.props.cursorBlinkPeriod / 2)
+      expect(cursorNode1.classList.contains('blink-off')).toBe false
+      expect(cursorNode2.classList.contains('blink-off')).toBe false
+
+    it "renders the hidden input field at the position of the last cursor if it is on screen", ->
+      inputNode = node.querySelector('.hidden-input')
+      node.style.height = 5 * lineHeightInPixels + 'px'
+      node.style.width = 10 * charWidth + 'px'
+      component.measureHeightAndWidth()
+
+      expect(editor.getCursorScreenPosition()).toEqual [0, 0]
+      editor.setScrollTop(3 * lineHeightInPixels)
+      editor.setScrollLeft(3 * charWidth)
+      expect(inputNode.offsetTop).toBe 0
+      expect(inputNode.offsetLeft).toBe 0
+
+      editor.setCursorBufferPosition([5, 5])
+      cursorRect = editor.getCursor().getPixelRect()
+      cursorTop = cursorRect.top
+      cursorLeft = cursorRect.left
+      expect(inputNode.offsetTop).toBe cursorTop - editor.getScrollTop()
+      expect(inputNode.offsetLeft).toBe cursorLeft - editor.getScrollLeft()
+
+    it "does not render cursors that are associated with non-empty selections", ->
+      editor.setSelectedScreenRange([[0, 4], [4, 6]])
+      editor.addCursorAtScreenPosition([6, 8])
+
+      cursorNodes = node.querySelectorAll('.cursor')
+      expect(cursorNodes.length).toBe 1
+      expect(cursorNodes[0].offsetTop).toBe 6 * lineHeightInPixels
+      expect(cursorNodes[0].offsetLeft).toBe 8 * charWidth
+
+  describe "selection rendering", ->
+    scrollViewClientLeft = null
+
+    beforeEach ->
+      scrollViewClientLeft = node.querySelector('.scroll-view').getBoundingClientRect().left
+
+    it "renders 1 region for 1-line selections", ->
+      # 1-line selection
+      editor.setSelectedScreenRange([[1, 6], [1, 10]])
+      regions = node.querySelectorAll('.selection .region')
+
+      expect(regions.length).toBe 1
+      regionRect = regions[0].getBoundingClientRect()
+      expect(regionRect.top).toBe 1 * lineHeightInPixels
+      expect(regionRect.height).toBe 1 * lineHeightInPixels
+      expect(regionRect.left).toBe scrollViewClientLeft + 6 * charWidth
+      expect(regionRect.width).toBe 4 * charWidth
+
+    it "renders 2 regions for 2-line selections", ->
+      editor.setSelectedScreenRange([[1, 6], [2, 10]])
+      regions = node.querySelectorAll('.selection .region')
+      expect(regions.length).toBe 2
+
+      region1Rect = regions[0].getBoundingClientRect()
+      expect(region1Rect.top).toBe 1 * lineHeightInPixels
+      expect(region1Rect.height).toBe 1 * lineHeightInPixels
+      expect(region1Rect.left).toBe scrollViewClientLeft + 6 * charWidth
+      expect(Math.ceil(region1Rect.right)).toBe node.clientWidth # TODO: Remove ceiling when react-wrapper is removed
+
+      region2Rect = regions[1].getBoundingClientRect()
+      expect(region2Rect.top).toBe 2 * lineHeightInPixels
+      expect(region2Rect.height).toBe 1 * lineHeightInPixels
+      expect(region2Rect.left).toBe scrollViewClientLeft + 0
+      expect(region2Rect.width).toBe 10 * charWidth
+
+    it "renders 3 regions for selections with more than 2 lines", ->
+      editor.setSelectedScreenRange([[1, 6], [5, 10]])
+      regions = node.querySelectorAll('.selection .region')
+      expect(regions.length).toBe 3
+
+      region1Rect = regions[0].getBoundingClientRect()
+      expect(region1Rect.top).toBe 1 * lineHeightInPixels
+      expect(region1Rect.height).toBe 1 * lineHeightInPixels
+      expect(region1Rect.left).toBe scrollViewClientLeft + 6 * charWidth
+      expect(Math.ceil(region1Rect.right)).toBe node.clientWidth # TODO: Remove ceiling when react-wrapper is removed
+
+      region2Rect = regions[1].getBoundingClientRect()
+      expect(region2Rect.top).toBe 2 * lineHeightInPixels
+      expect(region2Rect.height).toBe 3 * lineHeightInPixels
+      expect(region2Rect.left).toBe scrollViewClientLeft + 0
+      expect(Math.ceil(region2Rect.right)).toBe node.clientWidth # TODO: Remove ceiling when react-wrapper is removed
+
+      region3Rect = regions[2].getBoundingClientRect()
+      expect(region3Rect.top).toBe 5 * lineHeightInPixels
+      expect(region3Rect.height).toBe 1 * lineHeightInPixels
+      expect(region3Rect.left).toBe scrollViewClientLeft + 0
+      expect(region3Rect.width).toBe 10 * charWidth
+
+    it "does not render empty selections", ->
+      expect(editor.getSelection().isEmpty()).toBe true
+      expect(node.querySelectorAll('.selection').length).toBe 0
+
+  describe "mouse interactions", ->
+    linesNode = null
+
+    beforeEach ->
+      delayAnimationFrames = true
+      linesNode = node.querySelector('.lines')
+
+    describe "when a non-folded line is single-clicked", ->
+      describe "when no modifier keys are held down", ->
+        it "moves the cursor to the nearest screen position", ->
+          node.style.height = 4.5 * lineHeightInPixels + 'px'
+          node.style.width = 10 * charWidth + 'px'
+          component.measureHeightAndWidth()
+          editor.setScrollTop(3.5 * lineHeightInPixels)
+          editor.setScrollLeft(2 * charWidth)
+
+          linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([4, 8])))
+          expect(editor.getCursorScreenPosition()).toEqual [4, 8]
+
+      describe "when the shift key is held down", ->
+        it "selects to the nearest screen position", ->
+          editor.setCursorScreenPosition([3, 4])
+          linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([5, 6]), shiftKey: true))
+          expect(editor.getSelectedScreenRange()).toEqual [[3, 4], [5, 6]]
+
+      describe "when the command key is held down", ->
+        it "adds a cursor at the nearest screen position", ->
+          editor.setCursorScreenPosition([3, 4])
+          linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([5, 6]), metaKey: true))
+          expect(editor.getSelectedScreenRanges()).toEqual [[[3, 4], [3, 4]], [[5, 6], [5, 6]]]
+
+    describe "when a non-folded line is double-clicked", ->
+      it "selects the word containing the nearest screen position", ->
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([5, 10]), detail: 2))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[5, 6], [5, 13]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([6, 6]), detail: 1))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[6, 6], [6, 6]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([8, 8]), detail: 1, shiftKey: true))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[6, 6], [8, 8]]
+
+    describe "when a non-folded line is triple-clicked", ->
+      it "selects the line containing the nearest screen position", ->
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([5, 10]), detail: 3))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[5, 0], [6, 0]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([6, 6]), detail: 1, shiftKey: true))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[5, 0], [7, 0]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([7, 5]), detail: 1))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([8, 8]), detail: 1, shiftKey: true))
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        expect(editor.getSelectedScreenRange()).toEqual [[7, 5], [8, 8]]
+
+    describe "when the mouse is clicked and dragged", ->
+      it "selects to the nearest screen position until the mouse button is released", ->
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([2, 4]), which: 1))
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([6, 8]), which: 1))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [6, 8]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([10, 0]), which: 1))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [10, 0]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mouseup'))
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([12, 0]), which: 1))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [10, 0]]
+
+      it "stops selecting if the mouse is dragged into the dev tools", ->
+        linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([2, 4]), which: 1))
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([6, 8]), which: 1))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [6, 8]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([10, 0]), which: 0))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [6, 8]]
+
+        linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([8, 0]), which: 1))
+        nextAnimationFrame()
+        expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [6, 8]]
+
+    clientCoordinatesForScreenPosition = (screenPosition) ->
+      positionOffset = editor.pixelPositionForScreenPosition(screenPosition)
+      scrollViewClientRect = node.querySelector('.scroll-view').getBoundingClientRect()
+      clientX = scrollViewClientRect.left + positionOffset.left - editor.getScrollLeft()
+      clientY = scrollViewClientRect.top + positionOffset.top - editor.getScrollTop()
+      {clientX, clientY}
+
+    buildMouseEvent = (type, properties...) ->
+      properties = extend({bubbles: true, cancelable: true}, properties...)
+      event = new MouseEvent(type, properties)
+      Object.defineProperty(event, 'which', get: -> properties.which) if properties.which?
+      event
+
+  describe "focus handling", ->
+    inputNode = null
+
+    beforeEach ->
+      inputNode = node.querySelector('.hidden-input')
+
+    it "transfers focus to the hidden input", ->
+      expect(document.activeElement).toBe document.body
+      node.focus()
+      expect(document.activeElement).toBe inputNode
+
+    it "adds the 'is-focused' class to the editor when the hidden input is focused", ->
+      expect(document.activeElement).toBe document.body
+      inputNode.focus()
+      expect(node.classList.contains('is-focused')).toBe true
+      inputNode.blur()
+      expect(node.classList.contains('is-focused')).toBe false
+
+  describe "scrolling", ->
+    it "updates the vertical scrollbar when the scrollTop is changed in the model", ->
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+
+      expect(verticalScrollbarNode.scrollTop).toBe 0
+
+      editor.setScrollTop(10)
+      expect(verticalScrollbarNode.scrollTop).toBe 10
+
+    it "updates the horizontal scrollbar and scroll view content x transform based on the scrollLeft of the model", ->
+      node.style.width = 30 * charWidth + 'px'
+      component.measureHeightAndWidth()
+
+      scrollViewContentNode = node.querySelector('.scroll-view-content')
+      expect(scrollViewContentNode.style['-webkit-transform']).toBe "translate3d(0px, 0px, 0)"
+      expect(horizontalScrollbarNode.scrollLeft).toBe 0
+
+      editor.setScrollLeft(100)
+      expect(scrollViewContentNode.style['-webkit-transform']).toBe "translate3d(-100px, 0px, 0)"
+      expect(horizontalScrollbarNode.scrollLeft).toBe 100
+
+    it "updates the scrollLeft of the model when the scrollLeft of the horizontal scrollbar changes", ->
+      node.style.width = 30 * charWidth + 'px'
+      component.measureHeightAndWidth()
+
+      expect(editor.getScrollLeft()).toBe 0
+      horizontalScrollbarNode.scrollLeft = 100
+      horizontalScrollbarNode.dispatchEvent(new UIEvent('scroll'))
+
+      expect(editor.getScrollLeft()).toBe 100
+
+    describe "when a mousewheel event occurs on the editor", ->
+      it "updates the horizontal or vertical scrollbar depending on which delta is greater (x or y)", ->
+        node.style.height = 4.5 * lineHeightInPixels + 'px'
+        node.style.width = 20 * charWidth + 'px'
+        component.measureHeightAndWidth()
+
+        expect(verticalScrollbarNode.scrollTop).toBe 0
+        expect(horizontalScrollbarNode.scrollLeft).toBe 0
+
+        node.dispatchEvent(new WheelEvent('mousewheel', wheelDeltaX: -5, wheelDeltaY: -10))
+        expect(verticalScrollbarNode.scrollTop).toBe 10
+        expect(horizontalScrollbarNode.scrollLeft).toBe 0
+
+        node.dispatchEvent(new WheelEvent('mousewheel', wheelDeltaX: -15, wheelDeltaY: -5))
+        expect(verticalScrollbarNode.scrollTop).toBe 10
+        expect(horizontalScrollbarNode.scrollLeft).toBe 15
+
+  describe "input events", ->
+    inputNode = null
+
+    beforeEach ->
+      inputNode = node.querySelector('.hidden-input')
+
+    it "inserts the newest character in the input's value into the buffer", ->
+      inputNode.value = 'x'
+      inputNode.dispatchEvent(new Event('input'))
+      expect(editor.lineForBufferRow(0)).toBe 'xvar quicksort = function () {'
+
+      inputNode.value = 'xy'
+      inputNode.dispatchEvent(new Event('input'))
+      expect(editor.lineForBufferRow(0)).toBe 'xyvar quicksort = function () {'
+
+    it "replaces the last character if the length of the input's value doesn't increase, as occurs with the accented character menu", ->
+      inputNode.value = 'u'
+      inputNode.dispatchEvent(new Event('input'))
+      expect(editor.lineForBufferRow(0)).toBe 'uvar quicksort = function () {'
+
+      inputNode.value = 'ü'
+      inputNode.dispatchEvent(new Event('input'))
+      expect(editor.lineForBufferRow(0)).toBe 'üvar quicksort = function () {'
+
+  describe "commands", ->
+    describe "editor:consolidate-selections", ->
+      it "consolidates selections on the editor model, aborting the key binding if there is only one selection", ->
+        spyOn(editor, 'consolidateSelections').andCallThrough()
+
+        event = new CustomEvent('editor:consolidate-selections', bubbles: true, cancelable: true)
+        event.abortKeyBinding = jasmine.createSpy("event.abortKeyBinding")
+        node.dispatchEvent(event)
+
+        expect(editor.consolidateSelections).toHaveBeenCalled()
+        expect(event.abortKeyBinding).toHaveBeenCalled()

spec/editor-spec.coffee

@@ -111,6 +111,21 @@ describe "Editor", ->
         editor.moveCursorDown()
         expect(editor.getCursorBufferPosition()).toEqual [1, 1]
 
+      it "emits a single 'cursors-moved' event for all moved cursors", ->
+        editor.on 'cursors-moved', cursorsMovedHandler = jasmine.createSpy("cursorsMovedHandler")
+
+        editor.moveCursorDown()
+        expect(cursorsMovedHandler.callCount).toBe 1
+
+        cursorsMovedHandler.reset()
+        editor.addCursorAtScreenPosition([3, 0])
+        editor.moveCursorDown()
+        expect(cursorsMovedHandler.callCount).toBe 1
+
+        cursorsMovedHandler.reset()
+        editor.getCursor().moveDown()
+        expect(cursorsMovedHandler.callCount).toBe 1
+
     describe ".setCursorScreenPosition(screenPosition)", ->
       it "clears a goal column established by vertical movement", ->
         # set a goal column by moving down
@@ -645,6 +660,67 @@ describe "Editor", ->
           cursor2 = editor.addCursorAtBufferPosition([1,4])
           expect(cursor2.marker).toBe cursor1.marker
 
+    describe "autoscroll", ->
+      beforeEach ->
+        editor.manageScrollPosition = true
+        editor.setVerticalScrollMargin(2)
+        editor.setHorizontalScrollMargin(2)
+        editor.setLineHeight(10)
+        editor.setDefaultCharWidth(10)
+        editor.setHeight(5.5 * 10)
+        editor.setWidth(5.5 * 10)
+
+      it "scrolls down when the last cursor gets closer than ::verticalScrollMargin to the bottom of the editor", ->
+        expect(editor.getScrollTop()).toBe 0
+        expect(editor.getScrollBottom()).toBe 5.5 * 10
+
+        editor.setCursorScreenPosition([2, 0])
+        expect(editor.getScrollBottom()).toBe 5.5 * 10
+
+        editor.moveCursorDown()
+        expect(editor.getScrollBottom()).toBe 6 * 10
+
+        editor.moveCursorDown()
+        expect(editor.getScrollBottom()).toBe 7 * 10
+
+      it "scrolls up when the last cursor gets closer than ::verticalScrollMargin to the top of the editor", ->
+        editor.setCursorScreenPosition([11, 0])
+        editor.setScrollBottom(editor.getScrollHeight())
+
+        editor.moveCursorUp()
+        expect(editor.getScrollBottom()).toBe editor.getScrollHeight()
+
+        editor.moveCursorUp()
+        expect(editor.getScrollTop()).toBe 7 * 10
+
+        editor.moveCursorUp()
+        expect(editor.getScrollTop()).toBe 6 * 10
+
+      it "scrolls right when the last cursor gets closer than ::horizontalScrollMargin to the right of the editor", ->
+        expect(editor.getScrollLeft()).toBe 0
+        expect(editor.getScrollRight()).toBe 5.5 * 10
+
+        editor.setCursorScreenPosition([0, 2])
+        expect(editor.getScrollRight()).toBe 5.5 * 10
+
+        editor.moveCursorRight()
+        expect(editor.getScrollRight()).toBe 6 * 10
+
+        editor.moveCursorRight()
+        expect(editor.getScrollRight()).toBe 7 * 10
+
+      it "scrolls left when the last cursor gets closer than ::horizontalScrollMargin to the left of the editor", ->
+        editor.setScrollRight(editor.getScrollWidth())
+        editor.setCursorScreenPosition([6, 62])
+
+        expect(editor.getScrollRight()).toBe editor.getScrollWidth()
+
+        editor.moveCursorLeft()
+        expect(editor.getScrollLeft()).toBe 59 * 10
+
+        editor.moveCursorLeft()
+        expect(editor.getScrollLeft()).toBe 58 * 10
+
   describe "selection", ->
     selection = null
 
@@ -1000,7 +1076,7 @@ describe "Editor", ->
         expect(selection1).toBe selection
         expect(selection1.getBufferRange()).toEqual [[2, 2], [3, 3]]
 
-      describe "when the preserveFolds option is false (the default)", ->
+      describe "when the 'preserveFolds' option is false (the default)", ->
         it "removes folds that contain the selections", ->
           editor.setSelectedBufferRange([[0,0], [0,0]])
           editor.createFold(1, 4)
@@ -1014,7 +1090,7 @@ describe "Editor", ->
           expect(editor.lineForScreenRow(6).fold).toBeUndefined()
           expect(editor.lineForScreenRow(10).fold).toBeDefined()
 
-      describe "when the preserve folds option is true", ->
+      describe "when the 'preserveFolds' option is true", ->
         it "does not remove folds that contain the selections", ->
           editor.setSelectedBufferRange([[0,0], [0,0]])
           editor.createFold(1, 4)
@@ -1023,6 +1099,24 @@ describe "Editor", ->
           expect(editor.isFoldedAtBufferRow(1)).toBeTruthy()
           expect(editor.isFoldedAtBufferRow(6)).toBeTruthy()
 
+    describe ".setSelectedBufferRange(range)", ->
+      describe "when the 'autoscroll' option is true", ->
+        it "autoscrolls to the selection", ->
+          editor.manageScrollPosition = true
+          editor.setLineHeight(10)
+          editor.setDefaultCharWidth(10)
+          editor.setHeight(50)
+          editor.setWidth(50)
+          expect(editor.getScrollTop()).toBe 0
+
+          editor.setSelectedBufferRange([[5, 6], [6, 8]], autoscroll: true)
+          expect(editor.getScrollBottom()).toBe (7 + editor.getVerticalScrollMargin()) * 10
+          expect(editor.getScrollRight()).toBe 50
+
+          editor.setSelectedBufferRange([[6, 6], [6, 8]], autoscroll: true)
+          expect(editor.getScrollBottom()).toBe (7 + editor.getVerticalScrollMargin()) * 10
+          expect(editor.getScrollRight()).toBe (8 + editor.getHorizontalScrollMargin()) * 10
+
     describe ".selectMarker(marker)", ->
       describe "if the marker is valid", ->
         it "selects the marker's range and returns the selected range", ->
@@ -2934,3 +3028,37 @@ describe "Editor", ->
       editor.setSoftTabs(false)
       editor.normalizeTabsInBufferRange([[0, 0], [Infinity, Infinity]])
       expect(editor.getText()).toBe '     '
+
+  describe ".scrollToCursorPosition()", ->
+    it "scrolls the last cursor into view", ->
+      editor.setCursorScreenPosition([8, 8])
+      editor.setLineHeight(10)
+      editor.setDefaultCharWidth(10)
+      editor.setHeight(50)
+      editor.setWidth(50)
+      expect(editor.getScrollTop()).toBe 0
+      expect(editor.getScrollLeft()).toBe 0
+
+      editor.scrollToCursorPosition()
+      expect(editor.getScrollBottom()).toBe (9 + editor.getVerticalScrollMargin()) * 10
+      expect(editor.getScrollRight()).toBe (9 + editor.getHorizontalScrollMargin()) * 10
+
+  describe ".pageUp/Down()", ->
+    it "scrolls one screen height up or down", ->
+      editor.manageScrollPosition = true
+
+      editor.setLineHeight(10)
+      editor.setHeight(50)
+      expect(editor.getScrollHeight()).toBe 130
+
+      editor.pageDown()
+      expect(editor.getScrollTop()).toBe 50
+
+      editor.pageDown()
+      expect(editor.getScrollTop()).toBe 80
+
+      editor.pageUp()
+      expect(editor.getScrollTop()).toBe 30
+
+      editor.pageUp()
+      expect(editor.getScrollTop()).toBe 0

spec/editor-view-spec.coffee

@@ -1596,7 +1596,7 @@ describe "EditorView", ->
           editor.setSoftWrap(true)
 
         it "doesn't show the end of line invisible at the end of lines broken due to wrapping", ->
-          editor.setText "a line that wraps"
+          editor.setText "a line that wraps "
           editorView.attachToDom()
           editorView.setWidthInChars(6)
           atom.config.set "editor.showInvisibles", true
@@ -1604,11 +1604,11 @@ describe "EditorView", ->
           expect(space).toBeTruthy()
           eol = editorView.invisibles?.eol
           expect(eol).toBeTruthy()
-          expect(editorView.renderedLines.find('.line:first').text()).toBe "a line#{space}"
+          expect(editorView.renderedLines.find('.line:first').text()).toBe "a line "
-          expect(editorView.renderedLines.find('.line:last').text()).toBe "wraps#{eol}"
+          expect(editorView.renderedLines.find('.line:last').text()).toBe "wraps#{space}#{eol}"
 
         it "displays trailing carriage return using a visible non-empty value", ->
-          editor.setText "a line that\r\n"
+          editor.setText "a line that \r\n"
           editorView.attachToDom()
           editorView.setWidthInChars(6)
           atom.config.set "editor.showInvisibles", true
@@ -1618,8 +1618,8 @@ describe "EditorView", ->
           expect(cr).toBeTruthy()
           eol = editorView.invisibles?.eol
           expect(eol).toBeTruthy()
-          expect(editorView.renderedLines.find('.line:first').text()).toBe "a line#{space}"
+          expect(editorView.renderedLines.find('.line:first').text()).toBe "a line "
-          expect(editorView.renderedLines.find('.line:eq(1)').text()).toBe "that#{cr}#{eol}"
+          expect(editorView.renderedLines.find('.line:eq(1)').text()).toBe "that#{space}#{cr}#{eol}"
           expect(editorView.renderedLines.find('.line:last').text()).toBe "#{eol}"
 
     describe "when editor.showIndentGuide is set to true", ->

spec/spec-helper.coffee

@@ -84,6 +84,7 @@ beforeEach ->
   config.set "editor.autoIndent", false
   config.set "core.disabledPackages", ["package-that-throws-an-exception",
     "package-with-broken-package-json", "package-with-broken-keymap"]
+  config.set "core.useReactEditor", false
   config.save.reset()
   atom.config = config
 
@@ -243,6 +244,15 @@ window.fakeSetTimeout = (callback, ms) ->
 window.fakeClearTimeout = (idToClear) ->
   window.timeouts = window.timeouts.filter ([id]) -> id != idToClear
 
+window.fakeSetInterval = (callback, ms) ->
+  action = ->
+    callback()
+    window.fakeSetTimeout(action, ms)
+  window.fakeSetTimeout(action, ms)
+
+window.fakeClearInterval = (idToClear) ->
+  window.fakeClearTimeout(idToClear)
+
 window.advanceClock = (delta=1) ->
   window.now += delta
   callbacks = []

spec/tokenized-buffer-spec.coffee

@@ -463,3 +463,77 @@ describe "TokenizedBuffer", ->
       expect(tokenizedBuffer.tokenForPosition([0,0]).value).toBe ' '
       atom.config.set('editor.tabLength', 0)
       expect(tokenizedBuffer.tokenForPosition([0,0]).value).toBe '  '
+
+  describe "leading and trailing whitespace", ->
+    beforeEach ->
+      buffer = atom.project.bufferForPathSync('sample.js')
+      tokenizedBuffer = new TokenizedBuffer({buffer})
+      fullyTokenize(tokenizedBuffer)
+
+    it "sets ::hasLeadingWhitespace to true on tokens that have leading whitespace", ->
+      expect(tokenizedBuffer.lineForScreenRow(0).tokens[0].hasLeadingWhitespace).toBe false
+      expect(tokenizedBuffer.lineForScreenRow(1).tokens[0].hasLeadingWhitespace).toBe true
+      expect(tokenizedBuffer.lineForScreenRow(1).tokens[1].hasLeadingWhitespace).toBe false
+      expect(tokenizedBuffer.lineForScreenRow(2).tokens[0].hasLeadingWhitespace).toBe true
+      expect(tokenizedBuffer.lineForScreenRow(2).tokens[1].hasLeadingWhitespace).toBe true
+      expect(tokenizedBuffer.lineForScreenRow(2).tokens[2].hasLeadingWhitespace).toBe false
+
+      # The 4th token *has* leading whitespace, but isn't entirely whitespace
+      buffer.insert([5, 0], ' ')
+      expect(tokenizedBuffer.lineForScreenRow(5).tokens[3].hasLeadingWhitespace).toBe true
+      expect(tokenizedBuffer.lineForScreenRow(5).tokens[4].hasLeadingWhitespace).toBe false
+
+      # Lines that are *only* whitespace are not considered to have leading whitespace
+      buffer.insert([10, 0], '  ')
+      expect(tokenizedBuffer.lineForScreenRow(10).tokens[0].hasLeadingWhitespace).toBe false
+
+    it "sets ::hasTrailingWhitespace to true on tokens that have trailing whitespace", ->
+      buffer.insert([0, Infinity], '  ')
+      expect(tokenizedBuffer.lineForScreenRow(0).tokens[11].hasTrailingWhitespace).toBe false
+      expect(tokenizedBuffer.lineForScreenRow(0).tokens[12].hasTrailingWhitespace).toBe true
+
+      # The last token *has* trailing whitespace, but isn't entirely whitespace
+      buffer.setTextInRange([[2, 39], [2, 40]], '  ')
+      expect(tokenizedBuffer.lineForScreenRow(2).tokens[14].hasTrailingWhitespace).toBe false
+      expect(tokenizedBuffer.lineForScreenRow(2).tokens[15].hasTrailingWhitespace).toBe true
+
+      # Lines that are *only* whitespace are considered to have trailing whitespace
+      buffer.insert([10, 0], '  ')
+      expect(tokenizedBuffer.lineForScreenRow(10).tokens[0].hasTrailingWhitespace).toBe true
+
+    it "only marks trailing whitespace on the last segment of a soft-wrapped line", ->
+      buffer.insert([0, Infinity], '  ')
+      tokenizedLine = tokenizedBuffer.lineForScreenRow(0)
+      [segment1, segment2] = tokenizedLine.softWrapAt(16)
+      expect(segment1.tokens[5].value).toBe ' '
+      expect(segment1.tokens[5].hasTrailingWhitespace).toBe false
+      expect(segment2.tokens[6].value).toBe '  '
+      expect(segment2.tokens[6].hasTrailingWhitespace).toBe true
+
+  describe "indent level", ->
+    beforeEach ->
+      buffer = atom.project.bufferForPathSync('sample.js')
+      tokenizedBuffer = new TokenizedBuffer({buffer})
+      fullyTokenize(tokenizedBuffer)
+
+    describe "when the line is non-empty", ->
+      it "has an indent level based on the leading whitespace on the line", ->
+        expect(tokenizedBuffer.lineForScreenRow(0).indentLevel).toBe 0
+        expect(tokenizedBuffer.lineForScreenRow(1).indentLevel).toBe 1
+        expect(tokenizedBuffer.lineForScreenRow(2).indentLevel).toBe 2
+        buffer.insert([2, 0], ' ')
+        expect(tokenizedBuffer.lineForScreenRow(2).indentLevel).toBe 2.5
+
+    describe "when the line is empty", ->
+      it "assumes the indentation level of the first non-empty line below or above if one exists", ->
+        buffer.insert([12, 0], '    ')
+        buffer.insert([12, Infinity], '\n\n')
+        expect(tokenizedBuffer.lineForScreenRow(13).indentLevel).toBe 2
+        expect(tokenizedBuffer.lineForScreenRow(14).indentLevel).toBe 2
+
+        buffer.insert([1, Infinity], '\n\n')
+        expect(tokenizedBuffer.lineForScreenRow(2).indentLevel).toBe 2
+        expect(tokenizedBuffer.lineForScreenRow(3).indentLevel).toBe 2
+
+        buffer.setText('\n\n\n')
+        expect(tokenizedBuffer.lineForScreenRow(1).indentLevel).toBe 0

spec/tokenized-line-spec.coffee

@@ -0,0 +1,22 @@
+describe "TokenizedLine", ->
+  editor = null
+
+  beforeEach ->
+    waitsForPromise -> atom.packages.activatePackage('language-coffee-script')
+
+  describe "::getScopeTree()", ->
+    it "returns a tree whose inner nodes are scopes and whose leaf nodes are tokens in those scopes", ->
+      editor = atom.project.openSync('coffee.coffee')
+
+      ensureValidScopeTree = (scopeTree, scopes=[]) ->
+        if scopeTree.children?
+          for child in scopeTree.children
+            ensureValidScopeTree(child, scopes.concat([scopeTree.scope]))
+        else
+          expect(scopeTree).toBe tokens[tokenIndex++]
+          expect(scopes).toEqual scopeTree.scopes
+
+      tokenIndex = 0
+      tokens = editor.lineForScreenRow(1).tokens
+      scopeTree = editor.lineForScreenRow(1).getScopeTree()
+      ensureValidScopeTree(scopeTree)

src/atom.coffee

@@ -157,6 +157,9 @@ class Atom extends Model
     # Still set NODE_PATH since tasks may need it.
     process.env.NODE_PATH = exportsPath
 
+    # Make react.js faster
+    process.env.NODE_ENV ?= 'production'
+
     @config = new Config({configDirPath, resourcePath})
     @keymaps = new KeymapManager({configDirPath, resourcePath})
     @keymap = @keymaps # Deprecated

src/cursor-component.coffee

@@ -0,0 +1,13 @@
+React = require 'react'
+{div} = require 'reactionary'
+
+module.exports =
+CursorComponent = React.createClass
+  displayName: 'CursorComponent'
+
+  render: ->
+    {top, left, height, width} = @props.cursor.getPixelRect()
+    className = 'cursor'
+    className += ' blink-off' if @props.blinkOff
+
+    div className: className, style: {top, left, height, width}

src/cursor.coffee

@@ -1,5 +1,5 @@
 {Point, Range} = require 'text-buffer'
-{Emitter} = require 'emissary'
+{Model} = require 'theorist'
 _ = require 'underscore-plus'
 
 # Public: The `Cursor` class represents the little blinking line identifying
@@ -8,9 +8,7 @@ _ = require 'underscore-plus'
 # Cursors belong to {Editor}s and have some metadata attached in the form
 # of a {Marker}.
 module.exports =
-class Cursor
+class Cursor extends Model
-  Emitter.includeInto(this)
-
   screenPosition: null
   bufferPosition: null
   goalColumn: null
@@ -18,7 +16,8 @@ class Cursor
   needsAutoscroll: null
 
   # Instantiated by an {Editor}
-  constructor: ({@editor, @marker}) ->
+  constructor: ({@editor, @marker, id}) ->
+    @assignId(id)
     @updateVisibility()
     @marker.on 'changed', (e) =>
       @updateVisibility()
@@ -27,7 +26,12 @@ class Cursor
       {textChanged} = e
       return if oldHeadScreenPosition.isEqual(newHeadScreenPosition)
 
+      # Supports old editor view
       @needsAutoscroll ?= @isLastCursor() and !textChanged
+
+      # Supports react editor view
+      @autoscroll() if @needsAutoscroll and @editor.manageScrollPosition
+
       @goalColumn = null
 
       movedEvent =
@@ -38,7 +42,7 @@ class Cursor
         textChanged: textChanged
 
       @emit 'moved', movedEvent
-      @editor.emit 'cursor-moved', movedEvent
+      @editor.cursorMoved(movedEvent)
     @marker.on 'destroyed', =>
       @destroyed = true
       @editor.removeCursor(this)
@@ -54,6 +58,9 @@ class Cursor
     unless fn()
       @emit 'autoscrolled' if @needsAutoscroll
 
+  getPixelRect: ->
+    @editor.pixelRectForScreenRange(@getScreenRange())
+
   # Public: Moves a cursor to a given screen position.
   #
   # screenPosition - An {Array} of two numbers: the screen row, and the screen
@@ -69,6 +76,10 @@ class Cursor
   getScreenPosition: ->
     @marker.getHeadScreenPosition()
 
+  getScreenRange: ->
+    {row, column} = @getScreenPosition()
+    new Range(new Point(row, column), new Point(row, column + 1))
+
   # Public: Moves a cursor to a given buffer position.
   #
   # bufferPosition - An {Array} of two numbers: the buffer row, and the buffer
@@ -84,6 +95,9 @@ class Cursor
   getBufferPosition: ->
     @marker.getHeadBufferPosition()
 
+  autoscroll: ->
+    @editor.scrollToScreenRange(@getScreenRange())
+
   # Public: If the marker range is empty, the cursor is marked as being visible.
   updateVisibility: ->
     @setVisible(@marker.getBufferRange().isEmpty())

src/cursors-component.coffee

@@ -0,0 +1,50 @@
+React = require 'react'
+{div} = require 'reactionary'
+{debounce} = require 'underscore-plus'
+SubscriberMixin = require './subscriber-mixin'
+CursorComponent = require './cursor-component'
+
+
+module.exports =
+CursorsComponent = React.createClass
+  displayName: 'CursorsComponent'
+  mixins: [SubscriberMixin]
+
+  cursorBlinkIntervalHandle: null
+
+  render: ->
+    {editor} = @props
+    blinkOff = @state.blinkCursorsOff
+
+    div className: 'cursors',
+      if @isMounted()
+        for selection in editor.getSelections()
+          if selection.isEmpty() and editor.selectionIntersectsVisibleRowRange(selection)
+            {cursor} = selection
+            CursorComponent({key: cursor.id, cursor, blinkOff})
+
+  getInitialState: ->
+    blinkCursorsOff: false
+
+  componentDidMount: ->
+    {editor} = @props
+    @startBlinkingCursors()
+
+  componentWillUnmount: ->
+    clearInterval(@cursorBlinkIntervalHandle)
+
+  componentWillUpdate: ({cursorsMoved}) ->
+    @pauseCursorBlinking() if cursorsMoved
+
+  startBlinkingCursors: ->
+    @cursorBlinkIntervalHandle = setInterval(@toggleCursorBlink, @props.cursorBlinkPeriod / 2)
+
+  startBlinkingCursorsAfterDelay: null # Created lazily
+
+  toggleCursorBlink: -> @setState(blinkCursorsOff: not @state.blinkCursorsOff)
+
+  pauseCursorBlinking: ->
+    @state.blinkCursorsOff = false
+    clearInterval(@cursorBlinkIntervalHandle)
+    @startBlinkingCursorsAfterDelay ?= debounce(@startBlinkingCursors, @props.cursorBlinkResumeDelay)
+    @startBlinkingCursorsAfterDelay()

src/custom-event-mixin.coffee

@@ -0,0 +1,15 @@
+module.exports =
+CustomEventMixin =
+  componentWillMount: ->
+    @customEventListeners = {}
+
+  componentWillUnmount: ->
+    for name, listeners in @customEventListeners
+      for listener in listeners
+        @getDOMNode().removeEventListener(name, listener)
+
+  addCustomEventListeners: (customEventListeners) ->
+    for name, listener of customEventListeners
+      @customEventListeners[name] ?= []
+      @customEventListeners[name].push(listener)
+      @getDOMNode().addEventListener(name, listener)

src/display-buffer-marker.coffee

@@ -54,6 +54,9 @@ class DisplayBufferMarker
   setBufferRange: (bufferRange, options) ->
     @bufferMarker.setRange(bufferRange, options)
 
+  getPixelRange: ->
+    @displayBuffer.pixelRangeForScreenRange(@getScreenRange(), false)
+
   # Retrieves the screen position of the marker's head.
   #
   # Returns a {Point}.

src/display-buffer.coffee

@@ -20,14 +20,25 @@ class DisplayBuffer extends Model
   Serializable.includeInto(this)
 
   @properties
+    manageScrollPosition: false
     softWrap: null
     editorWidthInChars: null
+    lineHeight: null
+    defaultCharWidth: null
+    height: null
+    width: null
+    scrollTop: 0
+    scrollLeft: 0
+
+  verticalScrollMargin: 2
+  horizontalScrollMargin: 6
 
   constructor: ({tabLength, @editorWidthInChars, @tokenizedBuffer, buffer}={}) ->
     super
     @softWrap ?= atom.config.get('editor.softWrap') ? false
     @tokenizedBuffer ?= new TokenizedBuffer({tabLength, buffer})
     @buffer = @tokenizedBuffer.buffer
+    @charWidthsByScope = {}
     @markers = {}
     @foldsByMarkerId = {}
     @updateAllScreenLines()
@@ -51,6 +62,8 @@ class DisplayBuffer extends Model
     id: @id
     softWrap: @softWrap
     editorWidthInChars: @editorWidthInChars
+    scrollTop: @scrollTop
+    scrollLeft: @scrollLeft
     tokenizedBuffer: @tokenizedBuffer.serialize()
 
   deserializeParams: (params) ->
@@ -59,6 +72,9 @@ class DisplayBuffer extends Model
 
   copy: ->
     newDisplayBuffer = new DisplayBuffer({@buffer, tabLength: @getTabLength()})
+    newDisplayBuffer.setScrollTop(@getScrollTop())
+    newDisplayBuffer.setScrollLeft(@getScrollLeft())
+
     for marker in @findMarkers(displayBufferId: @id)
       marker.copy(displayBufferId: newDisplayBuffer.id)
     newDisplayBuffer
@@ -89,6 +105,151 @@ class DisplayBuffer extends Model
   # visible - A {Boolean} indicating of the tokenized buffer is shown
   setVisible: (visible) -> @tokenizedBuffer.setVisible(visible)
 
+  getVerticalScrollMargin: -> @verticalScrollMargin
+  setVerticalScrollMargin: (@verticalScrollMargin) -> @verticalScrollMargin
+
+  getHorizontalScrollMargin: -> @horizontalScrollMargin
+  setHorizontalScrollMargin: (@horizontalScrollMargin) -> @horizontalScrollMargin
+
+  getHeight: -> @height ? @getScrollHeight()
+  setHeight: (@height) -> @height
+
+  getWidth: -> @width ? @getScrollWidth()
+  setWidth: (newWidth) ->
+    oldWidth = @width
+    @width = newWidth
+    @updateWrappedScreenLines() if newWidth isnt oldWidth and @softWrap
+    @width
+
+  getScrollTop: -> @scrollTop
+  setScrollTop: (scrollTop) ->
+    if @manageScrollPosition
+      @scrollTop = Math.max(0, Math.min(@getScrollHeight() - @getHeight(), scrollTop))
+    else
+      @scrollTop = scrollTop
+
+  getScrollBottom: -> @scrollTop + @height
+  setScrollBottom: (scrollBottom) ->
+    @setScrollTop(scrollBottom - @height)
+    @getScrollBottom()
+
+  getScrollLeft: -> @scrollLeft
+  setScrollLeft: (scrollLeft) ->
+    if @manageScrollPosition
+      @scrollLeft = Math.max(0, Math.min(@getScrollWidth() - @getWidth(), scrollLeft))
+    else
+      @scrollLeft = scrollLeft
+
+  getScrollRight: -> @scrollLeft + @width
+  setScrollRight: (scrollRight) ->
+    @setScrollLeft(scrollRight - @width)
+    @getScrollRight()
+
+  getLineHeight: -> @lineHeight
+  setLineHeight: (@lineHeight) -> @lineHeight
+
+  getDefaultCharWidth: -> @defaultCharWidth
+  setDefaultCharWidth: (@defaultCharWidth) -> @defaultCharWidth
+
+  getScopedCharWidth: (scopeNames, char) ->
+    @getScopedCharWidths(scopeNames)[char]
+
+  getScopedCharWidths: (scopeNames) ->
+    scope = @charWidthsByScope
+    for scopeName in scopeNames
+      scope[scopeName] ?= {}
+      scope = scope[scopeName]
+    scope.charWidths ?= {}
+    scope.charWidths
+
+  setScopedCharWidth: (scopeNames, char, width) ->
+    @getScopedCharWidths(scopeNames)[char] = width
+
+  setScopedCharWidths: (scopeNames, charWidths) ->
+    _.extend(@getScopedCharWidths(scopeNames), charWidths)
+
+  clearScopedCharWidths: ->
+    @charWidthsByScope = {}
+
+  getScrollHeight: ->
+    unless @getLineHeight() > 0
+      throw new Error("You must assign lineHeight before calling ::getScrollHeight()")
+
+    @getLineCount() * @getLineHeight()
+
+  getScrollWidth: ->
+    @getMaxLineLength() * @getDefaultCharWidth()
+
+  getVisibleRowRange: ->
+    unless @getLineHeight() > 0
+      throw new Error("You must assign a non-zero lineHeight before calling ::getVisibleRowRange()")
+
+    heightInLines = Math.ceil(@getHeight() / @getLineHeight()) + 1
+    startRow = Math.floor(@getScrollTop() / @getLineHeight())
+    endRow = Math.min(@getLineCount(), Math.ceil(startRow + heightInLines))
+    [startRow, endRow]
+
+  intersectsVisibleRowRange: (startRow, endRow) ->
+    [visibleStart, visibleEnd] = @getVisibleRowRange()
+    not (endRow <= visibleStart or visibleEnd <= startRow)
+
+  selectionIntersectsVisibleRowRange: (selection) ->
+    {start, end} = selection.getScreenRange()
+    @intersectsVisibleRowRange(start.row, end.row + 1)
+
+  scrollToScreenRange: (screenRange) ->
+    verticalScrollMarginInPixels = @getVerticalScrollMargin() * @getLineHeight()
+    horizontalScrollMarginInPixels = @getHorizontalScrollMargin() * @getDefaultCharWidth()
+
+    {top, left, height, width} = @pixelRectForScreenRange(screenRange)
+    bottom = top + height
+    right = left + width
+    desiredScrollTop = top - verticalScrollMarginInPixels
+    desiredScrollBottom = bottom + verticalScrollMarginInPixels
+    desiredScrollLeft = left - horizontalScrollMarginInPixels
+    desiredScrollRight = right + horizontalScrollMarginInPixels
+
+    if desiredScrollTop < @getScrollTop()
+      @setScrollTop(desiredScrollTop)
+    else if desiredScrollBottom > @getScrollBottom()
+      @setScrollBottom(desiredScrollBottom)
+
+    if desiredScrollLeft < @getScrollLeft()
+      @setScrollLeft(desiredScrollLeft)
+    else if desiredScrollRight > @getScrollRight()
+      @setScrollRight(desiredScrollRight)
+
+  scrollToScreenPosition: (screenPosition) ->
+    @scrollToScreenRange(new Range(screenPosition, screenPosition))
+
+  scrollToBufferPosition: (bufferPosition) ->
+    @scrollToScreenPosition(@screenPositionForBufferPosition(bufferPosition))
+
+  pixelRectForScreenRange: (screenRange) ->
+    if screenRange.end.row > screenRange.start.row
+      top = @pixelPositionForScreenPosition(screenRange.start).top
+      left = 0
+      height = (screenRange.end.row - screenRange.start.row + 1) * @getLineHeight()
+      width = @getScrollWidth()
+    else
+      {top, left} = @pixelPositionForScreenPosition(screenRange.start)
+      height = @getLineHeight()
+      width = @pixelPositionForScreenPosition(screenRange.end).left - left
+
+    {top, left, width, height}
+
+  # Retrieves the current tab length.
+  #
+  # Returns a {Number}.
+  getTabLength: ->
+    @tokenizedBuffer.getTabLength()
+
+  # Specifies the tab length.
+  #
+  # tabLength - A {Number} that defines the new tab length.
+  setTabLength: (tabLength) ->
+    @tokenizedBuffer.setTabLength(tabLength)
+
   # Deprecated: Use the softWrap property directly
   setSoftWrap: (@softWrap) -> @softWrap
 
@@ -105,12 +266,19 @@ class DisplayBuffer extends Model
       if editorWidthInChars isnt previousWidthInChars and @softWrap
         @updateWrappedScreenLines()
 
-  getSoftWrapColumn: ->
+  getEditorWidthInChars: ->
-    if atom.config.get('editor.softWrapAtPreferredLineLength')
+    width = @getWidth()
-      Math.min(@editorWidthInChars, atom.config.getPositiveInt('editor.preferredLineLength', @editorWidthInChars))
+    if width? and @defaultCharWidth > 0
+      Math.floor(width / @defaultCharWidth)
     else
       @editorWidthInChars
 
+  getSoftWrapColumn: ->
+    if atom.config.get('editor.softWrapAtPreferredLineLength')
+      Math.min(@getEditorWidthInChars(), atom.config.getPositiveInt('editor.preferredLineLength', @getEditorWidthInChars()))
+    else
+      @getEditorWidthInChars()
+
   # Gets the screen line for the given screen row.
   #
   # screenRow - A {Number} indicating the screen row.
@@ -134,6 +302,9 @@ class DisplayBuffer extends Model
   getLines: ->
     new Array(@screenLines...)
 
+  indentLevelForLine: (line) ->
+    @tokenizedBuffer.indentLevelForLine(line)
+
   # Given starting and ending screen rows, this returns an array of the
   # buffer rows corresponding to every screen row in the range
   #
@@ -273,6 +444,52 @@ class DisplayBuffer extends Model
     end = @bufferPositionForScreenPosition(screenRange.end)
     new Range(start, end)
 
+  pixelRangeForScreenRange: (screenRange, clip=true) ->
+    {start, end} = Range.fromObject(screenRange)
+    {start: @pixelPositionForScreenPosition(start, clip), end: @pixelPositionForScreenPosition(end, clip)}
+
+  pixelPositionForScreenPosition: (screenPosition, clip=true) ->
+    screenPosition = Point.fromObject(screenPosition)
+    screenPosition = @clipScreenPosition(screenPosition) if clip
+
+    targetRow = screenPosition.row
+    targetColumn = screenPosition.column
+    defaultCharWidth = @defaultCharWidth
+
+    top = targetRow * @lineHeight
+    left = 0
+    column = 0
+    for token in @lineForRow(targetRow).tokens
+      charWidths = @getScopedCharWidths(token.scopes)
+      for char in token.value
+        return {top, left} if column is targetColumn
+        left += charWidths[char] ? defaultCharWidth
+        column++
+    {top, left}
+
+  screenPositionForPixelPosition: (pixelPosition) ->
+    targetTop = pixelPosition.top
+    targetLeft = pixelPosition.left
+    defaultCharWidth = @defaultCharWidth
+    row = Math.floor(targetTop / @getLineHeight())
+    row = Math.min(row, @getLastRow())
+    row = Math.max(0, row)
+
+    left = 0
+    column = 0
+    for token in @lineForRow(row).tokens
+      charWidths = @getScopedCharWidths(token.scopes)
+      for char in token.value
+        charWidth = charWidths[char] ? defaultCharWidth
+        break if targetLeft <= left + (charWidth / 2)
+        left += charWidth
+        column++
+
+    new Point(row, column)
+
+  pixelPositionForBufferPosition: (bufferPosition) ->
+    @pixelPositionForScreenPosition(@screenPositionForBufferPosition(bufferPosition))
+
   # Gets the number of screen lines.
   #
   # Returns a {Number}.
@@ -358,18 +575,6 @@ class DisplayBuffer extends Model
   tokenForBufferPosition: (bufferPosition) ->
     @tokenizedBuffer.tokenForPosition(bufferPosition)
 
-  # Retrieves the current tab length.
-  #
-  # Returns a {Number}.
-  getTabLength: ->
-    @tokenizedBuffer.getTabLength()
-
-  # Specifies the tab length.
-  #
-  # tabLength - A {Number} that defines the new tab length.
-  setTabLength: (tabLength) ->
-    @tokenizedBuffer.setTabLength(tabLength)
-
   # Get the grammar for this buffer.
   #
   # Returns the current {Grammar} or the {NullGrammar}.

src/editor-component.coffee

@@ -0,0 +1,338 @@
+React = require 'react'
+{div, span} = require 'reactionary'
+{debounce} = require 'underscore-plus'
+
+GutterComponent = require './gutter-component'
+EditorScrollViewComponent = require './editor-scroll-view-component'
+ScrollbarComponent = require './scrollbar-component'
+SubscriberMixin = require './subscriber-mixin'
+
+module.exports =
+EditorComponent = React.createClass
+  displayName: 'EditorComponent'
+  mixins: [SubscriberMixin]
+
+  pendingScrollTop: null
+  pendingScrollLeft: null
+  selectOnMouseMove: false
+  batchingUpdates: false
+  updateRequested: false
+  cursorsMoved: false
+  preservedRowRange: null
+  scrollingVertically: false
+
+  render: ->
+    {focused, fontSize, lineHeight, fontFamily, showIndentGuide} = @state
+    {editor, cursorBlinkPeriod, cursorBlinkResumeDelay} = @props
+    if @isMounted()
+      renderedRowRange = @getRenderedRowRange()
+      scrollHeight = editor.getScrollHeight()
+      scrollWidth = editor.getScrollWidth()
+      scrollTop = editor.getScrollTop()
+      scrollLeft = editor.getScrollLeft()
+      lineHeightInPixels = editor.getLineHeight()
+
+    className = 'editor editor-colors react'
+    className += ' is-focused' if focused
+
+    div className: className, style: {fontSize, lineHeight, fontFamily}, tabIndex: -1,
+      GutterComponent {
+        editor, renderedRowRange, scrollTop, scrollHeight,
+        lineHeight: lineHeightInPixels, @pendingChanges
+      }
+
+      EditorScrollViewComponent {
+        ref: 'scrollView', editor, fontSize, fontFamily, showIndentGuide
+        scrollHeight, scrollWidth, lineHeight: lineHeightInPixels,
+        renderedRowRange, @pendingChanges, @scrollingVertically, @cursorsMoved,
+        cursorBlinkPeriod, cursorBlinkResumeDelay, @onInputFocused, @onInputBlurred
+      }
+
+      ScrollbarComponent
+        ref: 'verticalScrollbar'
+        className: 'vertical-scrollbar'
+        orientation: 'vertical'
+        onScroll: @onVerticalScroll
+        scrollTop: scrollTop
+        scrollHeight: scrollHeight
+
+      ScrollbarComponent
+        ref: 'horizontalScrollbar'
+        className: 'horizontal-scrollbar'
+        orientation: 'horizontal'
+        onScroll: @onHorizontalScroll
+        scrollLeft: scrollLeft
+        scrollWidth: scrollWidth
+
+  getRenderedRowRange: ->
+    renderedRowRange = @props.editor.getVisibleRowRange()
+    if @preservedRowRange?
+      renderedRowRange[0] = Math.min(@preservedRowRange[0], renderedRowRange[0])
+      renderedRowRange[1] = Math.max(@preservedRowRange[1], renderedRowRange[1])
+    renderedRowRange
+
+  getInitialState: -> {}
+
+  getDefaultProps: ->
+    cursorBlinkPeriod: 800
+    cursorBlinkResumeDelay: 200
+
+  componentWillMount: ->
+    @pendingChanges = []
+    @props.editor.manageScrollPosition = true
+    @observeConfig()
+
+  componentDidMount: ->
+    @observeEditor()
+    @listenForDOMEvents()
+    @listenForCommands()
+    @props.editor.setVisible(true)
+    @requestUpdate()
+
+  componentWillUnmount: ->
+    @unsubscribe()
+    @getDOMNode().removeEventListener 'mousewheel', @onMouseWheel
+
+  componentWillUpdate: ->
+    @props.parentView.trigger 'cursor:moved' if @cursorsMoved
+
+  componentDidUpdate: ->
+    @pendingChanges.length = 0
+    @cursorsMoved = false
+    @props.parentView.trigger 'editor:display-updated'
+
+  observeEditor: ->
+    {editor} = @props
+    @subscribe editor, 'batched-updates-started', @onBatchedUpdatesStarted
+    @subscribe editor, 'batched-updates-ended', @onBatchedUpdatesEnded
+    @subscribe editor, 'screen-lines-changed', @onScreenLinesChanged
+    @subscribe editor, 'cursors-moved', @onCursorsMoved
+    @subscribe editor, 'selection-screen-range-changed', @requestUpdate
+    @subscribe editor, 'selection-added', @onSelectionAdded
+    @subscribe editor, 'selection-removed', @onSelectionAdded
+    @subscribe editor.$scrollTop.changes, @onScrollTopChanged
+    @subscribe editor.$scrollLeft.changes, @requestUpdate
+    @subscribe editor.$height.changes, @requestUpdate
+    @subscribe editor.$width.changes, @requestUpdate
+    @subscribe editor.$defaultCharWidth.changes, @requestUpdate
+    @subscribe editor.$lineHeight.changes, @requestUpdate
+
+  listenForDOMEvents: ->
+    node = @getDOMNode()
+    node.addEventListener 'mousewheel', @onMouseWheel
+    node.addEventListener 'focus', @onFocus # For some reason, React's built in focus events seem to bubble
+
+  listenForCommands: ->
+    {parentView, editor, mini} = @props
+
+    @addCommandListeners
+      'core:move-left': => editor.moveCursorLeft()
+      'core:move-right': => editor.moveCursorRight()
+      'core:select-left': => editor.selectLeft()
+      'core:select-right': => editor.selectRight()
+      'core:select-all': => editor.selectAll()
+      'core:backspace': => editor.backspace()
+      'core:delete': => editor.delete()
+      'core:undo': => editor.undo()
+      'core:redo': => editor.redo()
+      'core:cut': => editor.cutSelectedText()
+      'core:copy': => editor.copySelectedText()
+      'core:paste': => editor.pasteText()
+      'editor:move-to-previous-word': => editor.moveCursorToPreviousWord()
+      'editor:select-word': => editor.selectWord()
+      'editor:consolidate-selections': @consolidateSelections
+      'editor:backspace-to-beginning-of-word': => editor.backspaceToBeginningOfWord()
+      'editor:backspace-to-beginning-of-line': => editor.backspaceToBeginningOfLine()
+      'editor:delete-to-end-of-word': => editor.deleteToEndOfWord()
+      'editor:delete-line': => editor.deleteLine()
+      'editor:cut-to-end-of-line': => editor.cutToEndOfLine()
+      'editor:move-to-beginning-of-screen-line': => editor.moveCursorToBeginningOfScreenLine()
+      'editor:move-to-beginning-of-line': => editor.moveCursorToBeginningOfLine()
+      'editor:move-to-end-of-screen-line': => editor.moveCursorToEndOfScreenLine()
+      'editor:move-to-end-of-line': => editor.moveCursorToEndOfLine()
+      'editor:move-to-first-character-of-line': => editor.moveCursorToFirstCharacterOfLine()
+      'editor:move-to-beginning-of-word': => editor.moveCursorToBeginningOfWord()
+      'editor:move-to-end-of-word': => editor.moveCursorToEndOfWord()
+      'editor:move-to-beginning-of-next-word': => editor.moveCursorToBeginningOfNextWord()
+      'editor:move-to-previous-word-boundary': => editor.moveCursorToPreviousWordBoundary()
+      'editor:move-to-next-word-boundary': => editor.moveCursorToNextWordBoundary()
+      'editor:select-to-end-of-line': => editor.selectToEndOfLine()
+      'editor:select-to-beginning-of-line': => editor.selectToBeginningOfLine()
+      'editor:select-to-end-of-word': => editor.selectToEndOfWord()
+      'editor:select-to-beginning-of-word': => editor.selectToBeginningOfWord()
+      'editor:select-to-beginning-of-next-word': => editor.selectToBeginningOfNextWord()
+      'editor:select-to-next-word-boundary': => editor.selectToNextWordBoundary()
+      'editor:select-to-previous-word-boundary': => editor.selectToPreviousWordBoundary()
+      'editor:select-to-first-character-of-line': => editor.selectToFirstCharacterOfLine()
+      'editor:select-line': => editor.selectLine()
+      'editor:transpose': => editor.transpose()
+      'editor:upper-case': => editor.upperCase()
+      'editor:lower-case': => editor.lowerCase()
+
+    unless mini
+      @addCommandListeners
+        'core:move-up': => editor.moveCursorUp()
+        'core:move-down': => editor.moveCursorDown()
+        'core:move-to-top': => editor.moveCursorToTop()
+        'core:move-to-bottom': => editor.moveCursorToBottom()
+        'core:select-up': => editor.selectUp()
+        'core:select-down': => editor.selectDown()
+        'core:select-to-top': => editor.selectToTop()
+        'core:select-to-bottom': => editor.selectToBottom()
+        'editor:indent': => editor.indent()
+        'editor:auto-indent': => editor.autoIndentSelectedRows()
+        'editor:indent-selected-rows': => editor.indentSelectedRows()
+        'editor:outdent-selected-rows': => editor.outdentSelectedRows()
+        'editor:newline': => editor.insertNewline()
+        'editor:newline-below': => editor.insertNewlineBelow()
+        'editor:newline-above': => editor.insertNewlineAbove()
+        'editor:add-selection-below': => editor.addSelectionBelow()
+        'editor:add-selection-above': => editor.addSelectionAbove()
+        'editor:split-selections-into-lines': => editor.splitSelectionsIntoLines()
+        'editor:toggle-soft-tabs': => editor.toggleSoftTabs()
+        'editor:toggle-soft-wrap': => editor.toggleSoftWrap()
+        'editor:fold-all': => editor.foldAll()
+        'editor:unfold-all': => editor.unfoldAll()
+        'editor:fold-current-row': => editor.foldCurrentRow()
+        'editor:unfold-current-row': => editor.unfoldCurrentRow()
+        'editor:fold-selection': => neditor.foldSelectedLines()
+        'editor:fold-at-indent-level-1': => editor.foldAllAtIndentLevel(0)
+        'editor:fold-at-indent-level-2': => editor.foldAllAtIndentLevel(1)
+        'editor:fold-at-indent-level-3': => editor.foldAllAtIndentLevel(2)
+        'editor:fold-at-indent-level-4': => editor.foldAllAtIndentLevel(3)
+        'editor:fold-at-indent-level-5': => editor.foldAllAtIndentLevel(4)
+        'editor:fold-at-indent-level-6': => editor.foldAllAtIndentLevel(5)
+        'editor:fold-at-indent-level-7': => editor.foldAllAtIndentLevel(6)
+        'editor:fold-at-indent-level-8': => editor.foldAllAtIndentLevel(7)
+        'editor:fold-at-indent-level-9': => editor.foldAllAtIndentLevel(8)
+        'editor:toggle-line-comments': => editor.toggleLineCommentsInSelection()
+        'editor:log-cursor-scope': => editor.logCursorScope()
+        'editor:checkout-head-revision': => editor.checkoutHead()
+        'editor:copy-path': => editor.copyPathToClipboard()
+        'editor:move-line-up': => editor.moveLineUp()
+        'editor:move-line-down': => editor.moveLineDown()
+        'editor:duplicate-lines': => editor.duplicateLines()
+        'editor:join-lines': => editor.joinLines()
+        'editor:toggle-indent-guide': => atom.config.toggle('editor.showIndentGuide')
+        'editor:toggle-line-numbers': =>  atom.config.toggle('editor.showLineNumbers')
+        'editor:scroll-to-cursor': => editor.scrollToCursorPosition()
+        'core:page-up': => editor.pageUp()
+        'core:page-down': => editor.pageDown()
+
+  addCommandListeners: (listenersByCommandName) ->
+    {parentView} = @props
+
+    for command, listener of listenersByCommandName
+      parentView.command command, listener
+
+  observeConfig: ->
+    @subscribe atom.config.observe 'editor.fontFamily', @setFontFamily
+    @subscribe atom.config.observe 'editor.fontSize', @setFontSize
+    @subscribe atom.config.observe 'editor.showIndentGuide', @setShowIndentGuide
+
+  setFontSize: (fontSize) ->
+    @setState({fontSize})
+
+  setLineHeight: (lineHeight) ->
+    @setState({lineHeight})
+
+  setFontFamily: (fontFamily) ->
+    @setState({fontFamily})
+
+  setShowIndentGuide: (showIndentGuide) ->
+    @setState({showIndentGuide})
+
+  onFocus: ->
+    @refs.scrollView.focus()
+
+  onInputFocused: ->
+    @setState(focused: true)
+
+  onInputBlurred: ->
+    @setState(focused: false)
+
+  onVerticalScroll: (scrollTop) ->
+    {editor} = @props
+
+    return if scrollTop is editor.getScrollTop()
+
+    animationFramePending = @pendingScrollTop?
+    @pendingScrollTop = scrollTop
+    unless animationFramePending
+      requestAnimationFrame =>
+        @props.editor.setScrollTop(@pendingScrollTop)
+        @pendingScrollTop = null
+
+  onHorizontalScroll: (scrollLeft) ->
+    {editor} = @props
+
+    return if scrollLeft is editor.getScrollLeft()
+
+    animationFramePending = @pendingScrollLeft?
+    @pendingScrollLeft = scrollLeft
+    unless animationFramePending
+      requestAnimationFrame =>
+        @props.editor.setScrollLeft(@pendingScrollLeft)
+        @pendingScrollLeft = null
+
+  onMouseWheel: (event) ->
+    # Only scroll in one direction at a time
+    {wheelDeltaX, wheelDeltaY} = event
+    if Math.abs(wheelDeltaX) > Math.abs(wheelDeltaY)
+      @refs.horizontalScrollbar.getDOMNode().scrollLeft -= wheelDeltaX
+    else
+      @refs.verticalScrollbar.getDOMNode().scrollTop -= wheelDeltaY
+
+    event.preventDefault()
+
+  clearPreservedRowRange: ->
+    @preservedRowRange = null
+    @scrollingVertically = false
+    @requestUpdate()
+
+  clearPreservedRowRangeAfterDelay: null # Created lazily
+
+  onBatchedUpdatesStarted: ->
+    @batchingUpdates = true
+
+  onBatchedUpdatesEnded: ->
+    updateRequested = @updateRequested
+    @updateRequested = false
+    @batchingUpdates = false
+    if updateRequested
+      @requestUpdate()
+
+  onScreenLinesChanged: (change) ->
+    {editor} = @props
+    @pendingChanges.push(change)
+    @requestUpdate() if editor.intersectsVisibleRowRange(change.start, change.end + 1) # TODO: Use closed-open intervals for change events
+
+  onSelectionAdded: (selection) ->
+    {editor} = @props
+    @requestUpdate() if editor.selectionIntersectsVisibleRowRange(selection)
+
+  onScrollTopChanged: ->
+    @preservedRowRange = @getRenderedRowRange()
+    @scrollingVertically = true
+    @clearPreservedRowRangeAfterDelay ?= debounce(@clearPreservedRowRange, 200)
+    @clearPreservedRowRangeAfterDelay()
+    @requestUpdate()
+
+  onSelectionRemoved: (selection) ->
+    {editor} = @props
+    @requestUpdate() if editor.selectionIntersectsVisibleRowRange(selection)
+
+  onCursorsMoved: ->
+    @cursorsMoved = true
+
+  requestUpdate: ->
+    if @batchingUpdates
+      @updateRequested = true
+    else
+      @forceUpdate()
+
+  measureHeightAndWidth: ->
+    @refs.scrollView.measureHeightAndWidth()
+
+  consolidateSelections: (e) ->
+    e.abortKeyBinding() unless @props.editor.consolidateSelections()

src/editor-scroll-view-component.coffee

@@ -0,0 +1,198 @@
+React = require 'react'
+{div} = require 'reactionary'
+{debounce} = require 'underscore-plus'
+
+InputComponent = require './input-component'
+LinesComponent = require './lines-component'
+CursorsComponent = require './cursors-component'
+SelectionsComponent = require './selections-component'
+
+module.exports =
+EditorScrollViewComponent = React.createClass
+  displayName: 'EditorScrollViewComponent'
+
+  measurementPending: false
+  overflowChangedEventsPaused: false
+  overflowChangedWhilePaused: false
+
+  render: ->
+    {editor, fontSize, fontFamily, lineHeight, showIndentGuide} = @props
+    {scrollHeight, scrollWidth, renderedRowRange, pendingChanges, scrollingVertically} = @props
+    {cursorBlinkPeriod, cursorBlinkResumeDelay, cursorsMoved, onInputFocused, onInputBlurred} = @props
+
+    if @isMounted()
+      inputStyle = @getHiddenInputPosition()
+      inputStyle.WebkitTransform = 'translateZ(0)'
+
+      contentStyle =
+        height: scrollHeight
+        minWidth: scrollWidth
+        WebkitTransform: "translate3d(#{-editor.getScrollLeft()}px, #{-editor.getScrollTop()}px, 0)"
+
+    div className: 'scroll-view',
+      InputComponent
+        ref: 'input'
+        className: 'hidden-input'
+        style: inputStyle
+        onInput: @onInput
+        onFocus: onInputFocused
+        onBlur: onInputBlurred
+
+      div className: 'scroll-view-content', style: contentStyle, onMouseDown: @onMouseDown,
+        CursorsComponent({editor, cursorsMoved, cursorBlinkPeriod, cursorBlinkResumeDelay})
+        LinesComponent {
+          ref: 'lines', editor, fontSize, fontFamily, lineHeight, showIndentGuide,
+          renderedRowRange, pendingChanges, scrollingVertically
+        }
+        div className: 'underlayer',
+          SelectionsComponent({editor})
+
+  componentDidMount: ->
+    @getDOMNode().addEventListener 'overflowchanged', @onOverflowChanged
+    window.addEventListener('resize', @onWindowResize)
+
+    @measureHeightAndWidth()
+
+  componentDidUnmount: ->
+    window.removeEventListener('resize', @onWindowResize)
+
+  componentDidUpdate: ->
+    @pauseOverflowChangedEvents()
+
+  onOverflowChanged: ->
+    if @overflowChangedEventsPaused
+      @overflowChangedWhilePaused = true
+    else
+      @requestMeasurement()
+
+  onWindowResize: ->
+    @requestMeasurement()
+
+  pauseOverflowChangedEvents: ->
+    @overflowChangedEventsPaused = true
+    @resumeOverflowChangedEventsAfterDelay ?= debounce(@resumeOverflowChangedEvents, 500)
+    @resumeOverflowChangedEventsAfterDelay()
+
+  resumeOverflowChangedEvents: ->
+    if @overflowChangedWhilePaused
+      @overflowChangedWhilePaused = false
+      @requestMeasurement()
+
+  resumeOverflowChangedEventsAfterDelay: null
+
+  requestMeasurement: ->
+    return if @measurementPending
+
+    @measurementPending = true
+    requestAnimationFrame =>
+      @measurementPending = false
+      @measureHeightAndWidth()
+
+  onInput: (char, replaceLastCharacter) ->
+    {editor} = @props
+
+    if replaceLastCharacter
+      editor.transact ->
+        editor.selectLeft()
+        editor.insertText(char)
+    else
+      editor.insertText(char)
+
+  onMouseDown: (event) ->
+    {editor} = @props
+    {detail, shiftKey, metaKey} = event
+    screenPosition = @screenPositionForMouseEvent(event)
+
+    if shiftKey
+      editor.selectToScreenPosition(screenPosition)
+    else if metaKey
+      editor.addCursorAtScreenPosition(screenPosition)
+    else
+      editor.setCursorScreenPosition(screenPosition)
+      switch detail
+        when 2 then editor.selectWord()
+        when 3 then editor.selectLine()
+
+    @selectToMousePositionUntilMouseUp(event)
+
+  selectToMousePositionUntilMouseUp: (event) ->
+    {editor} = @props
+    dragging = false
+    lastMousePosition = {}
+
+    animationLoop = =>
+      requestAnimationFrame =>
+        if dragging
+          @selectToMousePosition(lastMousePosition)
+          animationLoop()
+
+    onMouseMove = (event) ->
+      lastMousePosition.clientX = event.clientX
+      lastMousePosition.clientY = event.clientY
+
+      # Start the animation loop when the mouse moves prior to a mouseup event
+      unless dragging
+        dragging = true
+        animationLoop()
+
+      # Stop dragging when cursor enters dev tools because we can't detect mouseup
+      onMouseUp() if event.which is 0
+
+    onMouseUp = ->
+      dragging = false
+      window.removeEventListener('mousemove', onMouseMove)
+      window.removeEventListener('mouseup', onMouseUp)
+      editor.finalizeSelections()
+
+    window.addEventListener('mousemove', onMouseMove)
+    window.addEventListener('mouseup', onMouseUp)
+
+  selectToMousePosition: (event) ->
+    @props.editor.selectToScreenPosition(@screenPositionForMouseEvent(event))
+
+  screenPositionForMouseEvent: (event) ->
+    pixelPosition = @pixelPositionForMouseEvent(event)
+    @props.editor.screenPositionForPixelPosition(pixelPosition)
+
+  pixelPositionForMouseEvent: (event) ->
+    {editor} = @props
+    {clientX, clientY} = event
+
+    editorClientRect = @getDOMNode().getBoundingClientRect()
+    top = clientY - editorClientRect.top + editor.getScrollTop()
+    left = clientX - editorClientRect.left + editor.getScrollLeft()
+    {top, left}
+
+  getHiddenInputPosition: ->
+    {editor} = @props
+    return {top: 0, left: 0} unless @isMounted() and editor.getCursor()?
+
+    {top, left, height, width} = editor.getCursor().getPixelRect()
+    top = top - editor.getScrollTop()
+    top = Math.max(0, Math.min(editor.getHeight() - height, top))
+    left = left - editor.getScrollLeft()
+    left = Math.max(0, Math.min(editor.getWidth() - width, left))
+
+    {top, left}
+
+  # Measure explicitly-styled height and width and relay them to the model. If
+  # these values aren't explicitly styled, we assume the editor is unconstrained
+  # and use the scrollHeight / scrollWidth as its height and width in
+  # calculations.
+  measureHeightAndWidth: ->
+    return unless @isMounted()
+
+    node = @getDOMNode()
+    computedStyle = getComputedStyle(node)
+    {editor} = @props
+
+    unless computedStyle.height is '0px'
+      clientHeight = node.clientHeight
+      editor.setHeight(clientHeight) if clientHeight > 0
+
+    unless computedStyle.width is '0px'
+      clientWidth = node.clientWidth
+      editor.setWidth(clientWidth) if clientHeight > 0
+
+  focus: ->
+    @refs.input.focus()

src/editor-view.coffee

@@ -1482,16 +1482,11 @@ class EditorView extends View
       html = @buildEmptyLineHtml(showIndentGuide, eolInvisibles, htmlEolInvisibles, indentation, editor, mini)
       line.push(html) if html
     else
-      firstNonWhitespacePosition = text.search(/\S/)
-      firstTrailingWhitespacePosition = text.search(/\s*$/)
-      lineIsWhitespaceOnly = firstTrailingWhitespacePosition is 0
       position = 0
       for token in tokens
         @updateScopeStack(line, scopeStack, token.scopes)
-        hasLeadingWhitespace =  position < firstNonWhitespacePosition
+        hasIndentGuide = not mini and showIndentGuide
-        hasTrailingWhitespace = position + token.value.length > firstTrailingWhitespacePosition
+        line.push(token.getValueAsHtml({invisibles, hasIndentGuide}))
-        hasIndentGuide = not mini and showIndentGuide and (hasLeadingWhitespace or lineIsWhitespaceOnly)
-        line.push(token.getValueAsHtml({invisibles, hasLeadingWhitespace, hasTrailingWhitespace, hasIndentGuide}))
         position += token.value.length
 
     @popScope(line, scopeStack) while scopeStack.length > 0

src/editor.coffee

@@ -136,10 +136,6 @@ class Editor extends Model
   atom.deserializers.add(this)
   Delegator.includeInto(this)
 
-  @properties
-    scrollTop: 0
-    scrollLeft: 0
-
   deserializing: false
   callDisplayBufferCreatedHook: false
   registerEditor: false
@@ -153,6 +149,9 @@ class Editor extends Model
     'autoDecreaseIndentForBufferRow', 'toggleLineCommentForBufferRow', 'toggleLineCommentsForBufferRows',
     toProperty: 'languageMode'
 
+  @delegatesProperties '$lineHeight', '$defaultCharWidth', '$height', '$width',
+    '$scrollTop', '$scrollLeft', 'manageScrollPosition', toProperty: 'displayBuffer'
+
   constructor: ({@softTabs, initialLine, tabLength, softWrap, @displayBuffer, buffer, registerEditor, suppressCursorCreation}) ->
     super
 
@@ -217,7 +216,10 @@ class Editor extends Model
     @subscribe @displayBuffer, 'soft-wrap-changed', (args...) => @emit 'soft-wrap-changed', args...
 
   getViewClass: ->
-    require './editor-view'
+    if atom.config.get('core.useReactEditor')
+      require './react-editor-view'
+    else
+      require './editor-view'
 
   destroyed: ->
     @unsubscribe()
@@ -232,8 +234,6 @@ class Editor extends Model
     displayBuffer = @displayBuffer.copy()
     softTabs = @getSoftTabs()
     newEditor = new Editor({@buffer, displayBuffer, tabLength, softTabs, suppressCursorCreation: true, registerEditor: true})
-    newEditor.setScrollTop(@getScrollTop())
-    newEditor.setScrollLeft(@getScrollLeft())
     for marker in @findMarkers(editorId: @id)
       marker.copy(editorId: newEditor.id, preserveFolds: true)
     newEditor
@@ -269,18 +269,6 @@ class Editor extends Model
   # Controls visiblity based on the given {Boolean}.
   setVisible: (visible) -> @displayBuffer.setVisible(visible)
 
-  # Called by {EditorView} when the scroll position changes so it can be
-  # persisted across reloads.
-  setScrollTop: (@scrollTop) -> @scrollTop
-
-  getScrollTop: -> @scrollTop
-
-  # Called by {EditorView} when the scroll position changes so it can be
-  # persisted across reloads.
-  setScrollLeft: (@scrollLeft) -> @scrollLeft
-
-  getScrollLeft: -> @scrollLeft
-
   # Set the number of characters that can be displayed horizontally in the
   # editor.
   #
@@ -301,6 +289,9 @@ class Editor extends Model
   # softTabs - A {Boolean}
   setSoftTabs: (@softTabs) -> @softTabs
 
+  # Public: Toggle soft tabs for this editor
+  toggleSoftTabs: -> @setSoftTabs(not @getSoftTabs())
+
   # Public: Get whether soft wrap is enabled for this editor.
   getSoftWrap: -> @displayBuffer.getSoftWrap()
 
@@ -309,6 +300,9 @@ class Editor extends Model
   # softWrap - A {Boolean}
   setSoftWrap: (softWrap) -> @displayBuffer.setSoftWrap(softWrap)
 
+  # Public: Toggle soft wrap for this editor
+  toggleSoftWrap: -> @setSoftWrap(not @getSoftWrap())
+
   # Public: Get the text representing a single level of indent.
   #
   # If soft tabs are enabled, the text is composed of N spaces, where N is the
@@ -394,13 +388,7 @@ class Editor extends Model
   #
   # Returns a {Number}.
   indentLevelForLine: (line) ->
-    if match = line.match(/^[\t ]+/)
+    @displayBuffer.indentLevelForLine(line)
-      leadingWhitespace = match[0]
-      tabCount = leadingWhitespace.match(/\t/g)?.length ? 0
-      spaceCount = leadingWhitespace.match(/[ ]/g)?.length ? 0
-      tabCount + (spaceCount / @getTabLength())
-    else
-      0
 
   # Constructs the string used for tabs.
   buildIndentString: (number) ->
@@ -421,6 +409,15 @@ class Editor extends Model
   # filePath - A {String} path.
   saveAs: (filePath) -> @buffer.saveAs(filePath)
 
+  checkoutHead: ->
+    if path = @getPath()
+      atom.project.getRepo()?.checkoutHead(path)
+
+  # Copies the current file path to the native clipboard.
+  copyPathToClipboard: ->
+    path = @getPath()
+    atom.clipboard.write(path) if path?
+
   # Public: Returns the {String} path of this editor's text buffer.
   getPath: -> @buffer.getPath()
 
@@ -599,6 +596,9 @@ class Editor extends Model
   # Returns an {Array} of {String}s.
   getCursorScopes: -> @getCursor().getScopes()
 
+  logCursorScope: ->
+    console.log @getCursorScopes()
+
   # Public: For each selection, replace the selected text with the given text.
   #
   # text - A {String} representing the text to insert.
@@ -1178,6 +1178,16 @@ class Editor extends Model
   setSelectedBufferRange: (bufferRange, options) ->
     @setSelectedBufferRanges([bufferRange], options)
 
+  # Public: Set the selected range in screen coordinates. If there are multiple
+  # selections, they are reduced to a single selection with the given range.
+  #
+  # screenRange - A {Range} or range-compatible {Array}.
+  # options - An options {Object}:
+  #   :reversed - A {Boolean} indicating whether to create the selection in a
+  #     reversed orientation.
+  setSelectedScreenRange: (screenRange, options) ->
+    @setSelectedBufferRange(@bufferRangeForScreenRange(screenRange, options), options)
+
   # Public: Set the selected ranges in buffer coordinates. If there are multiple
   # selections, they are replaced by new selections with the given ranges.
   #
@@ -1202,6 +1212,7 @@ class Editor extends Model
   # Remove the given selection.
   removeSelection: (selection) ->
     _.remove(@selections, selection)
+    @emit 'selection-removed', selection
 
   # Reduce one or more selections to a single empty selection based on the most
   # recently added cursor.
@@ -1218,6 +1229,9 @@ class Editor extends Model
     else
       false
 
+  selectionScreenRangeChanged: (selection) ->
+    @emit 'selection-screen-range-changed', selection
+
   # Public: Get current {Selection}s.
   #
   # Returns: An {Array} of {Selection}s.
@@ -1328,6 +1342,14 @@ class Editor extends Model
   getSelectedBufferRanges: ->
     selection.getBufferRange() for selection in @getSelectionsOrderedByBufferPosition()
 
+  # Public: Get the {Range}s of all selections in screen coordinates.
+  #
+  # The ranges are sorted by their position in the buffer.
+  #
+  # Returns an {Array} of {Range}s.
+  getSelectedScreenRanges: ->
+    selection.getScreenRange() for selection in @getSelectionsOrderedByBufferPosition()
+
   # Public: Get the selected text of the most recently added selection.
   #
   # Returns a {String}.
@@ -1431,9 +1453,26 @@ class Editor extends Model
   moveCursorToNextWordBoundary: ->
     @moveCursors (cursor) -> cursor.moveToNextWordBoundary()
 
+  scrollToCursorPosition: ->
+    @getCursor().autoscroll()
+
+  pageUp: ->
+    @setScrollTop(@getScrollTop() - @getHeight())
+
+  pageDown: ->
+    @setScrollTop(@getScrollTop() + @getHeight())
+
   moveCursors: (fn) ->
-    fn(cursor) for cursor in @getCursors()
+    @movingCursors = true
-    @mergeCursors()
+    @batchUpdates =>
+      fn(cursor) for cursor in @getCursors()
+      @mergeCursors()
+      @movingCursors = false
+      @emit 'cursors-moved'
+
+  cursorMoved: (event) ->
+    @emit 'cursor-moved', event
+    @emit 'cursors-moved' unless @movingCursors
 
   # Public: Select from the current cursor position to the given position in
   # screen coordinates.
@@ -1735,7 +1774,9 @@ class Editor extends Model
   # execution and revert any changes performed up to the abortion.
   #
   # fn - A {Function} to call inside the transaction.
-  transact: (fn) -> @buffer.transact(fn)
+  transact: (fn) ->
+    @batchUpdates =>
+      @buffer.transact(fn)
 
   # Public: Start an open-ended transaction.
   #
@@ -1755,6 +1796,12 @@ class Editor extends Model
   # within the transaction.
   abortTransaction: -> @buffer.abortTransaction()
 
+  batchUpdates: (fn) ->
+    @emit 'batched-updates-started'
+    result = fn()
+    @emit 'batched-updates-ended'
+    result
+
   inspect: ->
     "<Editor #{@id}>"
 
@@ -1771,6 +1818,66 @@ class Editor extends Model
   getSelectionMarkerAttributes: ->
     type: 'selection', editorId: @id, invalidate: 'never'
 
+  getVerticalScrollMargin: -> @displayBuffer.getVerticalScrollMargin()
+  setVerticalScrollMargin: (verticalScrollMargin) -> @displayBuffer.setVerticalScrollMargin(verticalScrollMargin)
+
+  getHorizontalScrollMargin: -> @displayBuffer.getHorizontalScrollMargin()
+  setHorizontalScrollMargin: (horizontalScrollMargin) -> @displayBuffer.setHorizontalScrollMargin(horizontalScrollMargin)
+
+  getLineHeight: -> @displayBuffer.getLineHeight()
+  setLineHeight: (lineHeight) -> @displayBuffer.setLineHeight(lineHeight)
+
+  getScopedCharWidth: (scopeNames, char) -> @displayBuffer.getScopedCharWidth(scopeNames, char)
+  setScopedCharWidth: (scopeNames, char, width) -> @displayBuffer.setScopedCharWidth(scopeNames, char, width)
+
+  getScopedCharWidths: (scopeNames) -> @displayBuffer.getScopedCharWidths(scopeNames)
+
+  clearScopedCharWidths: -> @displayBuffer.clearScopedCharWidths()
+
+  getDefaultCharWidth: -> @displayBuffer.getDefaultCharWidth()
+  setDefaultCharWidth: (defaultCharWidth) -> @displayBuffer.setDefaultCharWidth(defaultCharWidth)
+
+  setHeight: (height) -> @displayBuffer.setHeight(height)
+  getHeight: -> @displayBuffer.getHeight()
+
+  setWidth: (width) -> @displayBuffer.setWidth(width)
+  getWidth: -> @displayBuffer.getWidth()
+
+  getScrollTop: -> @displayBuffer.getScrollTop()
+  setScrollTop: (scrollTop) -> @displayBuffer.setScrollTop(scrollTop)
+
+  getScrollBottom: -> @displayBuffer.getScrollBottom()
+  setScrollBottom: (scrollBottom) -> @displayBuffer.setScrollBottom(scrollBottom)
+
+  getScrollLeft: -> @displayBuffer.getScrollLeft()
+  setScrollLeft: (scrollLeft) -> @displayBuffer.setScrollLeft(scrollLeft)
+
+  getScrollRight: -> @displayBuffer.getScrollRight()
+  setScrollRight: (scrollRight) -> @displayBuffer.setScrollRight(scrollRight)
+
+  getScrollHeight: -> @displayBuffer.getScrollHeight()
+  getScrollWidth: (scrollWidth) -> @displayBuffer.getScrollWidth(scrollWidth)
+
+  getVisibleRowRange: -> @displayBuffer.getVisibleRowRange()
+
+  intersectsVisibleRowRange: (startRow, endRow) -> @displayBuffer.intersectsVisibleRowRange(startRow, endRow)
+
+  selectionIntersectsVisibleRowRange: (selection) -> @displayBuffer.selectionIntersectsVisibleRowRange(selection)
+
+  pixelPositionForScreenPosition: (screenPosition) -> @displayBuffer.pixelPositionForScreenPosition(screenPosition)
+
+  pixelPositionForBufferPosition: (bufferPosition) -> @displayBuffer.pixelPositionForBufferPosition(bufferPosition)
+
+  screenPositionForPixelPosition: (pixelPosition) -> @displayBuffer.screenPositionForPixelPosition(pixelPosition)
+
+  pixelRectForScreenRange: (screenRange) -> @displayBuffer.pixelRectForScreenRange(screenRange)
+
+  scrollToScreenRange: (screenRange) -> @displayBuffer.scrollToScreenRange(screenRange)
+
+  scrollToScreenPosition: (screenPosition) -> @displayBuffer.scrollToScreenPosition(screenPosition)
+
+  scrollToBufferPosition: (bufferPosition) -> @displayBuffer.scrollToBufferPosition(bufferPosition)
+
   # Deprecated: Call {::joinLines} instead.
   joinLine: ->
     deprecate("Use Editor::joinLines() instead")

src/gutter-component.coffee

@@ -0,0 +1,83 @@
+React = require 'react'
+{div} = require 'reactionary'
+{isEqual, isEqualForProperties, multiplyString} = require 'underscore-plus'
+SubscriberMixin = require './subscriber-mixin'
+
+module.exports =
+GutterComponent = React.createClass
+  displayName: 'GutterComponent'
+  mixins: [SubscriberMixin]
+
+  render: ->
+    div className: 'gutter',
+      @renderLineNumbers() if @isMounted()
+
+  renderLineNumbers: ->
+    {editor, renderedRowRange, scrollTop, scrollHeight} = @props
+    [startRow, endRow] = renderedRowRange
+    charWidth = editor.getDefaultCharWidth()
+    lineHeight = editor.getLineHeight()
+    maxDigits = editor.getLastBufferRow().toString().length
+    style =
+      width: charWidth * (maxDigits + 1.5)
+      height: scrollHeight
+      WebkitTransform: "translate3d(0, #{-scrollTop}px, 0)"
+
+    lineNumbers = []
+    tokenizedLines = editor.linesForScreenRows(startRow, endRow - 1)
+    tokenizedLines.push({id: 0}) if tokenizedLines.length is 0
+    for bufferRow, i in editor.bufferRowsForScreenRows(startRow, endRow - 1)
+      if bufferRow is lastBufferRow
+        lineNumber = '•'
+      else
+        lastBufferRow = bufferRow
+        lineNumber = (bufferRow + 1).toString()
+
+      key = tokenizedLines[i]?.id
+      screenRow = startRow + i
+      lineNumbers.push(LineNumberComponent({key, lineNumber, maxDigits, bufferRow, screenRow, lineHeight}))
+      lastBufferRow = bufferRow
+
+    div className: 'line-numbers', style: style,
+      lineNumbers
+
+  componentWillUnmount: ->
+    @unsubscribe()
+
+  # Only update the gutter if the visible row range has changed or if a
+  # non-zero-delta change to the screen lines has occurred within the current
+  # visible row range.
+  shouldComponentUpdate: (newProps) ->
+    {renderedRowRange, pendingChanges, scrollTop} = @props
+
+    return true unless isEqualForProperties(newProps, @props, 'renderedRowRange', 'scrollTop', 'lineHeight')
+
+    for change in pendingChanges when change.screenDelta > 0 or change.bufferDelta > 0
+      return true unless change.end <= renderedRowRange.start or renderedRowRange.end <= change.start
+
+    false
+
+LineNumberComponent = React.createClass
+  displayName: 'LineNumberComponent'
+
+  render: ->
+    {bufferRow, screenRow, lineHeight} = @props
+    div
+      className: "line-number line-number-#{bufferRow}"
+      style: {top: screenRow * lineHeight}
+      'data-buffer-row': bufferRow
+      'data-screen-row': screenRow
+      dangerouslySetInnerHTML: {__html: @buildInnerHTML()}
+
+  buildInnerHTML: ->
+    {lineNumber, maxDigits} = @props
+    if lineNumber.length < maxDigits
+      padding = multiplyString('&nbsp;', maxDigits - lineNumber.length)
+      padding + lineNumber + @iconDivHTML
+    else
+      lineNumber + @iconDivHTML
+
+  iconDivHTML: '<div class="icon-right"></div>'
+
+  shouldComponentUpdate: (newProps) ->
+    not isEqualForProperties(newProps, @props, 'lineHeight', 'screenRow')

src/input-component.coffee

@@ -0,0 +1,51 @@
+punycode = require 'punycode'
+{last, isEqual} = require 'underscore-plus'
+React = require 'react'
+{input} = require 'reactionary'
+
+module.exports =
+InputComponent = React.createClass
+  displayName: 'InputComponent'
+
+  render: ->
+    {className, style, onFocus, onBlur} = @props
+
+    input {className, style, onFocus, onBlur}
+
+  getInitialState: ->
+    {lastChar: ''}
+
+  componentDidMount: ->
+    @getDOMNode().addEventListener 'input', @onInput
+    @getDOMNode().addEventListener 'compositionupdate', @onCompositionUpdate
+
+  # Don't let text accumulate in the input forever, but avoid excessive reflows
+  componentDidUpdate: ->
+    if @lastValueLength > 500 and not @isPressAndHoldCharacter(@state.lastChar)
+      @getDOMNode().value = ''
+      @lastValueLength = 0
+
+  # This should actually consult the property lists in /System/Library/Input Methods/PressAndHold.app
+  isPressAndHoldCharacter: (char) ->
+    @state.lastChar.match /[aeiouAEIOU]/
+
+  shouldComponentUpdate: (newProps) ->
+    not isEqual(newProps.style, @props.style)
+
+  onInput: (e) ->
+    e.stopPropagation()
+    valueCharCodes = punycode.ucs2.decode(@getDOMNode().value)
+    valueLength = valueCharCodes.length
+    replaceLastChar = valueLength is @lastValueLength
+    @lastValueLength = valueLength
+    lastChar = String.fromCharCode(last(valueCharCodes))
+    @props.onInput?(lastChar, replaceLastChar)
+
+  onFocus: ->
+    @props.onFocus?()
+
+  onBlur: ->
+    @props.onBlur?()
+
+  focus: ->
+    @getDOMNode().focus()

src/lines-component.coffee

@@ -0,0 +1,140 @@
+React = require 'react'
+{div, span} = require 'reactionary'
+{debounce, isEqual, isEqualForProperties, multiplyString} = require 'underscore-plus'
+{$$} = require 'space-pen'
+
+DummyLineNode = $$(-> @div className: 'line', style: 'position: absolute; visibility: hidden;', => @span 'x')[0]
+AcceptFilter = {acceptNode: -> NodeFilter.FILTER_ACCEPT}
+
+module.exports =
+LinesComponent = React.createClass
+  displayName: 'LinesComponent'
+
+  render: ->
+    if @isMounted()
+      {editor, renderedRowRange, lineHeight, showIndentGuide} = @props
+      [startRow, endRow] = renderedRowRange
+
+      lines =
+        for tokenizedLine, i in editor.linesForScreenRows(startRow, endRow - 1)
+          LineComponent({key: tokenizedLine.id, tokenizedLine, showIndentGuide, lineHeight, screenRow: startRow + i})
+
+    div {className: 'lines'}, lines
+
+  componentWillMount: ->
+    @measuredLines = new WeakSet
+
+  componentDidMount: ->
+    @measureLineHeightAndCharWidth()
+
+  shouldComponentUpdate: (newProps) ->
+    return true unless isEqualForProperties(newProps, @props,  'renderedRowRange', 'fontSize', 'fontFamily', 'lineHeight', 'showIndentGuide')
+
+    {renderedRowRange, pendingChanges} = newProps
+    for change in pendingChanges
+      return true unless change.end <= renderedRowRange.start or renderedRowRange.end <= change.start
+
+    false
+
+  componentDidUpdate: (prevProps) ->
+    @measureLineHeightAndCharWidth() unless isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily', 'lineHeight')
+    @clearScopedCharWidths() unless isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily')
+    @measureCharactersInNewLines() unless @props.scrollingVertically
+
+  measureLineHeightAndCharWidth: ->
+    node = @getDOMNode()
+    node.appendChild(DummyLineNode)
+    lineHeight = DummyLineNode.getBoundingClientRect().height
+    charWidth = DummyLineNode.firstChild.getBoundingClientRect().width
+    node.removeChild(DummyLineNode)
+
+    {editor} = @props
+    editor.setLineHeight(lineHeight)
+    editor.setDefaultCharWidth(charWidth)
+
+  measureCharactersInNewLines: ->
+    [visibleStartRow, visibleEndRow] = @props.renderedRowRange
+    node = @getDOMNode()
+
+    for tokenizedLine, i in @props.editor.linesForScreenRows(visibleStartRow, visibleEndRow - 1)
+      unless @measuredLines.has(tokenizedLine)
+        lineNode = node.children[i]
+        @measureCharactersInLine(tokenizedLine, lineNode)
+
+  measureCharactersInLine: (tokenizedLine, lineNode) ->
+    {editor} = @props
+    rangeForMeasurement = null
+    iterator = null
+    charIndex = 0
+
+    for {value, scopes}, tokenIndex in tokenizedLine.tokens
+      charWidths = editor.getScopedCharWidths(scopes)
+
+      for char in value
+        unless charWidths[char]?
+          unless textNode?
+            rangeForMeasurement ?= document.createRange()
+            iterator =  document.createNodeIterator(lineNode, NodeFilter.SHOW_TEXT, AcceptFilter)
+            textNode = iterator.nextNode()
+            textNodeIndex = 0
+            nextTextNodeIndex = textNode.textContent.length
+
+          while nextTextNodeIndex <= charIndex
+            textNode = iterator.nextNode()
+            textNodeIndex = nextTextNodeIndex
+            nextTextNodeIndex = textNodeIndex + textNode.textContent.length
+
+          i = charIndex - textNodeIndex
+          rangeForMeasurement.setStart(textNode, i)
+          rangeForMeasurement.setEnd(textNode, i + 1)
+          charWidth = rangeForMeasurement.getBoundingClientRect().width
+          editor.setScopedCharWidth(scopes, char, charWidth)
+
+        charIndex++
+
+    @measuredLines.add(tokenizedLine)
+
+  clearScopedCharWidths: ->
+    @measuredLines.clear()
+    @props.editor.clearScopedCharWidths()
+
+
+LineComponent = React.createClass
+  displayName: 'LineComponent'
+
+  render: ->
+    {screenRow, lineHeight} = @props
+
+    style =
+      top: screenRow * lineHeight
+      position: 'absolute'
+
+    div className: 'line', style: style, 'data-screen-row': screenRow, dangerouslySetInnerHTML: {__html: @buildInnerHTML()}
+
+  buildInnerHTML: ->
+    if @props.tokenizedLine.text.length is 0
+      @buildEmptyLineHTML()
+    else
+      @buildScopeTreeHTML(@props.tokenizedLine.getScopeTree())
+
+  buildEmptyLineHTML: ->
+    {showIndentGuide, tokenizedLine} = @props
+    {indentLevel, tabLength} = tokenizedLine
+
+    if showIndentGuide and indentLevel > 0
+      indentSpan = "<span class='indent-guide'>#{multiplyString(' ', tabLength)}</span>"
+      multiplyString(indentSpan, indentLevel + 1)
+    else
+      "&nbsp;"
+
+  buildScopeTreeHTML: (scopeTree) ->
+    if scopeTree.children?
+      html = "<span class='#{scopeTree.scope.replace(/\./g, ' ')}'>"
+      html += @buildScopeTreeHTML(child) for child in scopeTree.children
+      html += "</span>"
+      html
+    else
+      "<span>#{scopeTree.getValueAsHtml({hasIndentGuide: @props.showIndentGuide})}</span>"
+
+  shouldComponentUpdate: (newProps) ->
+    not isEqualForProperties(newProps, @props, 'showIndentGuide', 'lineHeight', 'screenRow')

src/package.coffee

@@ -290,6 +290,7 @@ class Package
     $(event.target).trigger(event)
     @restoreEventHandlersOnBubblePath(bubblePathEventHandlers)
     @unsubscribeFromActivationEvents()
+    false
 
   unsubscribeFromActivationEvents: ->
     return unless atom.workspaceView?

src/react-editor-view.coffee

@@ -0,0 +1,81 @@
+{View, $} = require 'space-pen'
+React = require 'react'
+EditorComponent = require './editor-component'
+
+module.exports =
+class ReactEditorView extends View
+  @content: -> @div class: 'editor react-wrapper'
+
+  focusOnAttach: false
+
+  constructor: (@editor) ->
+    super
+
+  getEditor: -> @editor
+
+  Object.defineProperty @::, 'lineHeight', get: -> @editor.getLineHeight()
+  Object.defineProperty @::, 'charWidth', get: -> @editor.getDefaultCharWidth()
+
+  scrollTop: (scrollTop) ->
+    if scrollTop?
+      @editor.setScrollTop(scrollTop)
+    else
+      @editor.getScrollTop()
+
+  scrollLeft: (scrollLeft) ->
+    if scrollLeft?
+      @editor.setScrollLeft(scrollLeft)
+    else
+      @editor.getScrollLeft()
+
+  scrollToScreenPosition: (screenPosition) ->
+    @editor.scrollToScreenPosition(screenPosition)
+
+  scrollToBufferPosition: (bufferPosition) ->
+    @editor.scrollToBufferPosition(bufferPosition)
+
+  afterAttach: (onDom) ->
+    return unless onDom
+    @attached = true
+    @component = React.renderComponent(EditorComponent({@editor, parentView: this}), @element)
+
+    node = @component.getDOMNode()
+
+    @underlayer = $(node).find('.underlayer')
+
+    @gutter = $(node).find('.gutter')
+    @gutter.removeClassFromAllLines = (klass) =>
+      @gutter.find('.line-number').removeClass(klass)
+
+    @gutter.addClassToLine = (bufferRow, klass) =>
+      lines = @gutter.find(".line-number-#{bufferRow}")
+      lines.addClass(klass)
+      lines.length > 0
+
+    @focus() if @focusOnAttach
+
+    @trigger 'editor:attached', [this]
+
+  pixelPositionForBufferPosition: (bufferPosition) ->
+    @editor.pixelPositionForBufferPosition(bufferPosition)
+
+  pixelPositionForScreenPosition: (screenPosition) ->
+    @editor.pixelPositionForScreenPosition(screenPosition)
+
+  appendToLinesView: (view) ->
+    view.css('position', 'absolute')
+    @find('.scroll-view-content').prepend(view)
+
+  beforeRemove: ->
+    React.unmountComponentAtNode(@element)
+    @attached = false
+    @trigger 'editor:detached', this
+
+  getPane: ->
+    @closest('.pane').view()
+
+  focus: ->
+    if @component?
+      @component.onFocus()
+    else
+      @focusOnAttach = true

src/scrollbar-component.coffee

@@ -0,0 +1,54 @@
+React = require 'react'
+{div} = require 'reactionary'
+{isEqualForProperties} = require 'underscore-plus'
+
+module.exports =
+ScrollbarComponent = React.createClass
+  render: ->
+    {orientation, className, scrollHeight, scrollWidth} = @props
+
+    div {className, @onScroll},
+      switch orientation
+        when 'vertical'
+          div className: 'scrollbar-content', style: {height: scrollHeight}
+        when 'horizontal'
+          div className: 'scrollbar-content', style: {width: scrollWidth}
+
+  componentDidMount: ->
+    {orientation} = @props
+
+    unless orientation is 'vertical' or orientation is 'horizontal'
+      throw new Error("Must specify an orientation property of 'vertical' or 'horizontal'")
+
+  shouldComponentUpdate: (newProps) ->
+    switch @props.orientation
+      when 'vertical'
+        not isEqualForProperties(newProps, @props, 'scrollHeight', 'scrollTop')
+      when 'horizontal'
+        not isEqualForProperties(newProps, @props, 'scrollWidth', 'scrollLeft')
+
+  componentDidUpdate: ->
+    {orientation, scrollTop, scrollLeft} = @props
+    node = @getDOMNode()
+
+    switch orientation
+      when 'vertical'
+        node.scrollTop = scrollTop
+        @props.scrollTop = node.scrollTop # Ensure scrollTop reflects actual DOM without triggering another update
+      when 'horizontal'
+        node.scrollLeft = scrollLeft
+        @props.scrollLeft = node.scrollLeft # Ensure scrollLeft reflects actual DOM without triggering another update
+
+  onScroll: ->
+    {orientation, onScroll} = @props
+    node = @getDOMNode()
+
+    switch orientation
+      when 'vertical'
+        scrollTop = node.scrollTop
+        @props.scrollTop = scrollTop # Ensure scrollTop reflects actual DOM without triggering another update
+        onScroll(scrollTop)
+      when 'horizontal'
+        scrollLeft = node.scrollLeft
+        @props.scrollLeft = scrollLeft # Ensure scrollLeft reflects actual DOM without triggering another update
+        onScroll(scrollLeft)

src/selection-component.coffee

@@ -0,0 +1,11 @@
+React = require 'react'
+{div} = require 'reactionary'
+
+module.exports =
+SelectionComponent = React.createClass
+  displayName: 'SelectionComponent'
+
+  render: ->
+    div className: 'selection',
+      for regionRect, i in @props.selection.getRegionRects()
+        div className: 'region', key: i, style: regionRect

src/selection.coffee

@@ -1,12 +1,10 @@
 {Point, Range} = require 'text-buffer'
-{Emitter} = require 'emissary'
+{Model} = require 'theorist'
 {pick} = require 'underscore-plus'
 
 # Public: Represents a selection in the {Editor}.
 module.exports =
-class Selection
+class Selection extends Model
-  Emitter.includeInto(this)
-
   cursor: null
   marker: null
   editor: null
@@ -14,7 +12,8 @@ class Selection
   wordwise: false
   needsAutoscroll: null
 
-  constructor: ({@cursor, @marker, @editor}) ->
+  constructor: ({@cursor, @marker, @editor, id}) ->
+    @assignId(id)
     @cursor.selection = this
     @marker.on 'changed', => @screenRangeChanged()
     @marker.on 'destroyed', =>
@@ -77,8 +76,9 @@ class Selection
     options.reversed ?= @isReversed()
     @editor.destroyFoldsIntersectingBufferRange(bufferRange) unless options.preserveFolds
     @modifySelection =>
-      @cursor.needsAutoscroll = false if options.autoscroll?
+      @cursor.needsAutoscroll = false if @needsAutoscroll?
       @marker.setBufferRange(bufferRange, options)
+      @autoscroll() if @needsAutoscroll
 
   # Public: Returns the starting and ending buffer rows the selection is
   # highlighting.
@@ -91,6 +91,9 @@ class Selection
     end = Math.max(start, end - 1) if range.end.column == 0
     [start, end]
 
+  autoscroll: ->
+    @editor.scrollToScreenRange(@getScreenRange())
+
   # Public: Returns the text in the selection.
   getText: ->
     @editor.buffer.getTextInRange(@getBufferRange())
@@ -570,6 +573,48 @@ class Selection
   compare: (otherSelection) ->
     @getBufferRange().compare(otherSelection.getBufferRange())
 
+  # Get the pixel dimensions of rectangular regions that cover selection's area
+  # on the screen. Used by SelectionComponent for rendering.
+  getRegionRects: ->
+    lineHeight = @editor.getLineHeight()
+    {start, end} = @getScreenRange()
+    rowCount = end.row - start.row + 1
+    startPixelPosition = @editor.pixelPositionForScreenPosition(start)
+    endPixelPosition = @editor.pixelPositionForScreenPosition(end)
+
+    if rowCount is 1
+      # Single line selection
+      rects = [{
+        top: startPixelPosition.top
+        height: lineHeight
+        left: startPixelPosition.left
+        width: endPixelPosition.left - startPixelPosition.left
+      }]
+    else
+      # Multi-line selection
+      rects = []
+
+      # First row, extending from selection start to the right side of screen
+      rects.push {
+        top: startPixelPosition.top
+        left: startPixelPosition.left
+        height: lineHeight
+        right: 0
+      }
+      if rowCount > 2
+        # Middle rows, extending from left side to right side of screen
+        rects.push {
+          top: startPixelPosition.top + lineHeight
+          height: (rowCount - 2) * lineHeight
+          left: 0
+          right: 0
+        }
+      # Last row, extending from left side of screen to selection end
+      rects.push {top: endPixelPosition.top, height: lineHeight, left: 0, width: endPixelPosition.left }
+
+    rects
+
   screenRangeChanged: ->
     screenRange = @getScreenRange()
     @emit 'screen-range-changed', screenRange
+    @editor.selectionScreenRangeChanged(this)

src/selections-component.coffee

@@ -0,0 +1,16 @@
+React = require 'react'
+{div} = require 'reactionary'
+SelectionComponent = require './selection-component'
+
+module.exports =
+SelectionsComponent = React.createClass
+  displayName: 'SelectionsComponent'
+
+  render: ->
+    {editor} = @props
+
+    div className: 'selections',
+      if @isMounted()
+        for selection in editor.getSelections()
+          if not selection.isEmpty() and editor.selectionIntersectsVisibleRowRange(selection)
+            SelectionComponent({key: selection.id, selection})

src/space-pen-extensions.coffee

@@ -69,4 +69,6 @@ jQuery(document.body).on 'show.bs.tooltip', ({target}) ->
 jQuery.fn.setTooltip.getKeystroke = getKeystroke
 jQuery.fn.setTooltip.humanizeKeystrokes = humanizeKeystrokes
 
+Object.defineProperty jQuery.fn, 'element', get: -> @[0]
+
 module.exports = spacePen

src/subscriber-mixin.coffee

@@ -0,0 +1,4 @@
+{Subscriber} = require 'emissary'
+SubscriberMixin = componentDidUnmount: -> @unsubscribe()
+Subscriber.extend(SubscriberMixin)
+module.exports = SubscriberMixin

src/token.coffee

@@ -20,6 +20,8 @@ class Token
   scopes: null
   isAtomic: null
   isHardTab: null
+  hasLeadingWhitespace: false
+  hasTrailingWhitespace: false
 
   constructor: ({@value, @scopes, @isAtomic, @bufferDelta, @isHardTab}) ->
     @screenDelta = @value.length
@@ -40,7 +42,7 @@ class Token
   whitespaceRegexForTabLength: (tabLength) ->
     WhitespaceRegexesByTabLength[tabLength] ?= new RegExp("([ ]{#{tabLength}})|(\t)|([^\t]+)", "g")
 
-  breakOutAtomicTokens: (tabLength, breakOutLeadingWhitespace) ->
+  breakOutAtomicTokens: (tabLength, breakOutLeadingSoftTabs) ->
     if @hasSurrogatePair
       outputTokens = []
 
@@ -48,14 +50,14 @@ class Token
         if token.isAtomic
           outputTokens.push(token)
         else
-          outputTokens.push(token.breakOutAtomicTokens(tabLength, breakOutLeadingWhitespace)...)
+          outputTokens.push(token.breakOutAtomicTokens(tabLength, breakOutLeadingSoftTabs)...)
-        breakOutLeadingWhitespace = token.isOnlyWhitespace() if breakOutLeadingWhitespace
+        breakOutLeadingSoftTabs = token.isOnlyWhitespace() if breakOutLeadingSoftTabs
 
       outputTokens
     else
       return [this] if @isAtomic
 
-      if breakOutLeadingWhitespace
+      if breakOutLeadingSoftTabs
         return [this] unless /^[ ]|\t/.test(@value)
       else
         return [this] unless /\t/.test(@value)
@@ -64,13 +66,13 @@ class Token
       regex = @whitespaceRegexForTabLength(tabLength)
       while match = regex.exec(@value)
         [fullMatch, softTab, hardTab] = match
-        if softTab and breakOutLeadingWhitespace
+        if softTab and breakOutLeadingSoftTabs
-          outputTokens.push(@buildSoftTabToken(tabLength, false))
+          outputTokens.push(@buildSoftTabToken(tabLength))
         else if hardTab
-          breakOutLeadingWhitespace = false
+          breakOutLeadingSoftTabs = false
-          outputTokens.push(@buildHardTabToken(tabLength, true))
+          outputTokens.push(@buildHardTabToken(tabLength))
         else
-          breakOutLeadingWhitespace = false
+          breakOutLeadingSoftTabs = false
           value = match[0]
           outputTokens.push(new Token({value, @scopes}))
 
@@ -127,7 +129,7 @@ class Token
       scopeClasses = scope.split('.')
       _.isSubset(targetClasses, scopeClasses)
 
-  getValueAsHtml: ({invisibles, hasLeadingWhitespace, hasTrailingWhitespace, hasIndentGuide})->
+  getValueAsHtml: ({invisibles, hasIndentGuide})->
     invisibles ?= {}
     if @isHardTab
       classes = 'hard-tab'
@@ -142,7 +144,7 @@ class Token
       leadingHtml = ''
       trailingHtml = ''
 
-      if hasLeadingWhitespace and match = LeadingWhitespaceRegex.exec(@value)
+      if @hasLeadingWhitespace and match = LeadingWhitespaceRegex.exec(@value)
         classes = 'leading-whitespace'
         classes += ' indent-guide' if hasIndentGuide
         classes += ' invisible-character' if invisibles.space
@@ -152,9 +154,10 @@ class Token
 
         startIndex = match[0].length
 
-      if hasTrailingWhitespace and match = TrailingWhitespaceRegex.exec(@value)
+      if @hasTrailingWhitespace and match = TrailingWhitespaceRegex.exec(@value)
+        tokenIsOnlyWhitespace = match[0].length is @value.length
         classes = 'trailing-whitespace'
-        classes += ' indent-guide' if hasIndentGuide and not hasLeadingWhitespace
+        classes += ' indent-guide' if hasIndentGuide and not @hasLeadingWhitespace and tokenIsOnlyWhitespace
         classes += ' invisible-character' if invisibles.space
 
         match[0] = match[0].replace(CharacterRegex, invisibles.space) if invisibles.space

src/tokenized-buffer.coffee

@@ -185,14 +185,16 @@ class TokenizedBuffer extends Model
     line = @buffer.lineForRow(row)
     tokens = [new Token(value: line, scopes: [@grammar.scopeName])]
     tabLength = @getTabLength()
-    new TokenizedLine({tokens, tabLength})
+    indentLevel = @indentLevelForRow(row)
+    new TokenizedLine({tokens, tabLength, indentLevel})
 
   buildTokenizedTokenizedLineForRow: (row, ruleStack) ->
     line = @buffer.lineForRow(row)
     lineEnding = @buffer.lineEndingForRow(row)
     tabLength = @getTabLength()
+    indentLevel = @indentLevelForRow(row)
     { tokens, ruleStack } = @grammar.tokenizeLine(line, ruleStack, row is 0)
-    new TokenizedLine({tokens, ruleStack, tabLength, lineEnding})
+    new TokenizedLine({tokens, ruleStack, tabLength, lineEnding, indentLevel})
 
   # FIXME: benogle says: These are actually buffer rows as all buffer rows are
   # accounted for in @tokenizedLines
@@ -207,6 +209,36 @@ class TokenizedBuffer extends Model
   stackForRow: (row) ->
     @tokenizedLines[row]?.ruleStack
 
+  indentLevelForRow: (row) ->
+    line = @buffer.lineForRow(row)
+
+    if line is ''
+      nextRow = row + 1
+      lineCount = @getLineCount()
+      while nextRow < lineCount
+        nextLine = @buffer.lineForRow(nextRow)
+        return @indentLevelForLine(nextLine) unless nextLine is ''
+        nextRow++
+
+      previousRow = row - 1
+      while previousRow >= 0
+        previousLine = @buffer.lineForRow(previousRow)
+        return @indentLevelForLine(previousLine) unless previousLine is ''
+        previousRow--
+
+      0
+    else
+      @indentLevelForLine(line)
+
+  indentLevelForLine: (line) ->
+    if match = line.match(/^[\t ]+/)
+      leadingWhitespace = match[0]
+      tabCount = leadingWhitespace.match(/\t/g)?.length ? 0
+      spaceCount = leadingWhitespace.match(/[ ]/g)?.length ? 0
+      tabCount + (spaceCount / @getTabLength())
+    else
+      0
+
   scopesForPosition: (position) ->
     @tokenForPosition(position).scopes
 
@@ -306,6 +338,9 @@ class TokenizedBuffer extends Model
   getLastRow: ->
     @buffer.getLastRow()
 
+  getLineCount: ->
+    @buffer.getLineCount()
+
   logLines: (start=0, end=@buffer.getLastRow()) ->
     for row in [start..end]
       line = @lineForScreenRow(row).text

src/tokenized-line.coffee

@@ -1,12 +1,16 @@
 _ = require 'underscore-plus'
 
+idCounter = 1
+
 module.exports =
 class TokenizedLine
-  constructor: ({tokens, @lineEnding, @ruleStack, @startBufferColumn, @fold, tabLength}) ->
+  constructor: ({tokens, @lineEnding, @ruleStack, @startBufferColumn, @fold, @tabLength, @indentLevel}) ->
-    @tokens = @breakOutAtomicTokens(tokens, tabLength)
+    @tokens = @breakOutAtomicTokens(tokens)
     @startBufferColumn ?= 0
     @text = _.pluck(@tokens, 'value').join('')
     @bufferDelta = _.sum(_.pluck(@tokens, 'bufferDelta'))
+    @id = idCounter++
+    @markLeadingAndTrailingWhitespaceTokens()
 
   copy: ->
     new TokenizedLine({@tokens, @lineEnding, @ruleStack, @startBufferColumn, @fold})
@@ -106,14 +110,25 @@ class TokenizedLine
       delta = nextDelta
     delta
 
-  breakOutAtomicTokens: (inputTokens, tabLength) ->
+  breakOutAtomicTokens: (inputTokens) ->
     outputTokens = []
-    breakOutLeadingWhitespace = true
+    breakOutLeadingSoftTabs = true
     for token in inputTokens
-      outputTokens.push(token.breakOutAtomicTokens(tabLength, breakOutLeadingWhitespace)...)
+      outputTokens.push(token.breakOutAtomicTokens(@tabLength, breakOutLeadingSoftTabs)...)
-      breakOutLeadingWhitespace = token.isOnlyWhitespace() if breakOutLeadingWhitespace
+      breakOutLeadingSoftTabs = token.isOnlyWhitespace() if breakOutLeadingSoftTabs
     outputTokens
 
+  markLeadingAndTrailingWhitespaceTokens: ->
+    firstNonWhitespacePosition = @text.search(/\S/)
+    firstTrailingWhitespacePosition = @text.search(/\s*$/)
+    lineIsWhitespaceOnly = firstTrailingWhitespacePosition is 0
+    position = 0
+    for token, i in @tokens
+      token.hasLeadingWhitespace =  position < firstNonWhitespacePosition
+      # Only the *last* segment of a soft-wrapped line can have trailing whitespace
+      token.hasTrailingWhitespace = @lineEnding? and (position + token.value.length > firstTrailingWhitespacePosition)
+      position += token.value.length
+
   isComment: ->
     for token in @tokens
       continue if token.scopes.length is 1
@@ -134,3 +149,33 @@ class TokenizedLine
     for token in @tokens
       return column if token is targetToken
       column += token.bufferDelta
+
+  getScopeTree: ->
+    return @scopeTree if @scopeTree?
+
+    scopeStack = []
+    for token in @tokens
+      @updateScopeStack(scopeStack, token.scopes)
+      _.last(scopeStack).children.push(token)
+
+    @scopeTree = scopeStack[0]
+    @updateScopeStack(scopeStack, [])
+    @scopeTree
+
+  updateScopeStack: (scopeStack, desiredScopes) ->
+    # Find a common prefix
+    for scope, i in desiredScopes
+      break unless scopeStack[i]?.scope is desiredScopes[i]
+
+    # Pop scopes until we're at the common prefx
+    until scopeStack.length is i
+      poppedScope = scopeStack.pop()
+      _.last(scopeStack)?.children.push(poppedScope)
+
+    # Push onto common prefix until scopeStack equals desiredScopes
+    for j in [i...desiredScopes.length]
+      scopeStack.push(new Scope(desiredScopes[j]))
+
+class Scope
+  constructor: (@scope) ->
+    @children = []

src/workspace-view.coffee

@@ -71,6 +71,7 @@ class WorkspaceView extends View
     projectHome: path.join(fs.getHomeDirectory(), 'github')
     audioBeep: true
     destroyEmptyPanes: true
+    useReactEditor: false
 
   @content: ->
     @div class: 'workspace', tabindex: -1, =>

static/editor.less

@@ -2,6 +2,64 @@
 @import "octicon-utf-codes";
 @import "octicon-mixins";
 
+.editor.react {
+  .underlayer {
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    left: 0;
+    right: 0;
+    z-index: -2;
+  }
+
+  .lines {
+    z-index: -1;
+  }
+
+  .horizontal-scrollbar {
+    position: absolute;
+    left: 0;
+    right: 0;
+    bottom: 0;
+
+    height: 15px;
+    overflow-x: auto;
+    overflow-y: hidden;
+    z-index: 3;
+
+    .scrollbar-content {
+      height: 15px;
+    }
+  }
+
+  .scroll-view {
+    overflow: hidden;
+  }
+
+  .scroll-view-content {
+    position: relative;
+    width: 100%;
+  }
+
+  .gutter {
+    padding-left: 0.5em;
+    padding-right: 0.5em;
+
+    .line-number {
+      position: absolute;
+      left: 0;
+      right: 0;
+      padding: 0;
+      white-space: nowrap;
+
+      .icon-right {
+        padding: 0;
+        padding-left: .1em;
+      }
+    }
+  }
+}
+
 .editor {
   overflow: hidden;
   cursor: text;
@@ -28,7 +86,6 @@
 .editor .gutter .line-number {
   padding-left: .5em;
   opacity: 0.6;
-  position: relative;
 }
 
 .editor .gutter .line-numbers {

static/panes.less

@@ -38,7 +38,7 @@
         background-color: @pane-item-background-color;
       }
 
-      > * {
+      > *, > .react-wrapper > * {
         position: absolute;
         top: 0;
         right: 0;