Renders decoration changes.

spec/editor-spec.coffee

@@ -3207,7 +3207,7 @@ describe "Editor", ->
       expect(editor.getScrollTop()).toBe 0
 
   fdescribe "decorations", ->
-    it "can add decorations", ->
+    it "can add and remove decorations", ->
       decoration = {type: 'gutter-class', class: 'one'}
       editor.addDecorationForBufferRow(2, decoration)
       editor.addDecorationForBufferRow(2, decoration)
@@ -3215,3 +3215,7 @@ describe "Editor", ->
       decorations = editor.decorationsForBufferRow(2)
       expect(decorations).toHaveLength 1
       expect(decorations).toContain decoration
+
+      editor.removeDecorationForBufferRow(2, decoration)
+      decorations = editor.decorationsForBufferRow(2)
+      expect(decorations).toHaveLength 0

src/display-buffer.coffee

@@ -727,18 +727,20 @@ class DisplayBuffer extends Model
     for current in @decorations[bufferRow]
       return if _.isEqual(current, decoration)
     @decorations[bufferRow].push(decoration)
-    @emit 'decoration-changed', {bufferRow, add: decoration}
+    @emit 'decoration-changed', {bufferRow, decoration, action: 'add'}
 
   removeDecorationForBufferRow: (bufferRow, decoration) ->
     return unless @decorations[bufferRow]
 
     removed = @findDecorationsForBufferRow(bufferRow, decoration)
-    @decorations[bufferRow] = _.without(@decorations, removed)
-    @emit 'decoration-changed', {bufferRow, remove: removed}
+    @decorations[bufferRow] = _.without(@decorations[bufferRow], removed...)
+
+    for decoration in removed
+      @emit 'decoration-changed', {bufferRow, decoration, action: 'remove'}
 
   findDecorationsForBufferRow: (bufferRow, options) ->
     return unless @decorations[bufferRow]
-    (dec for dec in @decorations[bufferRow] when _.isEqual(options, _.pick(decoration, _.keys(options))))
+    (dec for dec in @decorations[bufferRow] when _.isEqual(options, _.pick(dec, _.keys(options))))
 
   addGutterClassForMarker: (bufferRow) ->
   removeGutterClassForMarker: (bufferRow) ->

src/editor.coffee

@@ -214,6 +214,7 @@ class Editor extends Model
     @subscribe @displayBuffer, 'grammar-changed', => @handleGrammarChange()
     @subscribe @displayBuffer, 'tokenized', => @handleTokenization()
     @subscribe @displayBuffer, 'soft-wrap-changed', (args...) => @emit 'soft-wrap-changed', args...
+    @subscribe @displayBuffer, "decoration-changed", (e) => @emit 'decoration-changed', e
 
   getViewClass: ->
     if atom.config.get('core.useReactEditor')

src/gutter-component.coffee

@@ -24,6 +24,7 @@ GutterComponent = React.createClass
     @lineNumberNodesById = {}
     @lineNumberIdsByScreenRow = {}
     @screenRowsByLineNumberId = {}
+    @decoratorUpdates = {}
 
   componentDidMount: ->
     @appendDummyLineNumber()
@@ -141,6 +142,7 @@ GutterComponent = React.createClass
     classes = "line-number"
     classes += ' foldable' if not softWrapped and @props.editor.isFoldableAtBufferRow(bufferRow)
     classes += ' folded' if @props.editor.isFoldedAtBufferRow(bufferRow)
+
     "<div class=\"#{classes}\" style=\"#{style}\" data-buffer-row=\"#{bufferRow}\" data-screen-row=\"#{screenRow}\">#{innerHTML}</div>"
 
   buildLineNumberInnerHTML: (bufferRow, softWrapped, maxLineNumberDigits) ->
@@ -159,6 +161,11 @@ GutterComponent = React.createClass
     @toggleClass node, 'foldable', not softWrapped and @props.editor.isFoldableAtBufferRow(bufferRow)
     @toggleClass node, 'folded', @props.editor.isFoldedAtBufferRow(bufferRow)
 
+    if @decoratorUpdates[bufferRow]?
+      for change in @decoratorUpdates[bufferRow]
+        node.classList[change.action](change.decoration.class)
+      delete @decoratorUpdates[bufferRow]
+
     unless @screenRowsByLineNumberId[lineNumberId] is screenRow
       {lineHeightInPixels} = @props
       node.style.top = screenRow * lineHeightInPixels + 'px'
@@ -176,4 +183,7 @@ GutterComponent = React.createClass
     if condition then node.classList.add(klass) else node.classList.remove(klass)
 
   onDecorationChanged: (change) ->
-    @forceUpdate()
+    if change.decoration.type == 'gutter-class'
+      @decoratorUpdates[change.bufferRow] ?= []
+      @decoratorUpdates[change.bufferRow].push change
+      @forceUpdate()