Add TextEditor::set/isGutterVisible

Controls gutter visibility on individual editors.

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

spec/text-editor-component-spec.coffee

@@ -552,14 +552,29 @@ describe "TextEditorComponent", ->
       nextAnimationFrame()
       expect(lineNumbersNode.style.backgroundColor).toBe 'rgb(255, 0, 0)'
 
-    describe "when the editor.showLineNumbers config is false", ->
-      it "doesn't render any line numbers", ->
-        expect(component.refs.gutter).toBeDefined()
-        atom.config.set("editor.showLineNumbers", false)
-        expect(component.refs.gutter).not.toBeDefined()
-        atom.config.set("editor.showLineNumbers", true)
-        expect(component.refs.gutter).toBeDefined()
-        expect(component.lineNumberNodeForScreenRow(3)).toBeDefined()
+    it "hides or shows the gutter based on the '::isGutterVisible' property on the model and the global 'editor.showLineNumbers' config setting", ->
+      expect(component.refs.gutter?).toBe true
+
+      editor.setGutterVisible(false)
+      nextAnimationFrame()
+
+      expect(component.refs.gutter?).toBe false
+
+      atom.config.set("editor.showLineNumbers", false)
+      nextAnimationFrame()
+
+      expect(component.refs.gutter?).toBe false
+
+      editor.setGutterVisible(true)
+      nextAnimationFrame()
+
+      expect(component.refs.gutter?).toBe false
+
+      atom.config.set("editor.showLineNumbers", true)
+      nextAnimationFrame()
+
+      expect(component.refs.gutter?).toBe true
+      expect(component.lineNumberNodeForScreenRow(3)?).toBe true
 
     describe "fold decorations", ->
       describe "rendering fold decorations", ->

src/text-editor-component.coffee

@@ -160,7 +160,7 @@ TextEditorComponent = React.createClass
     Math.max(1, Math.ceil(editor.getHeight() / editor.getLineHeightInPixels()))
 
   shouldRenderGutter: ->
-    not @props.mini and @state.showLineNumbers
+    not @props.mini and @props.editor.isGutterVisible() and atom.config.get('editor.showLineNumbers')
 
   getInitialState: -> {}
 
@@ -463,7 +463,8 @@ TextEditorComponent = React.createClass
     scopeDescriptor = editor.getRootScopeDescriptor()
 
     subscriptions.add atom.config.observe 'editor.showIndentGuide', scope: scopeDescriptor, @setShowIndentGuide
-    subscriptions.add atom.config.observe 'editor.showLineNumbers', scope: scopeDescriptor, @setShowLineNumbers
+    subscriptions.add atom.config.onDidChange 'editor.showLineNumbers', scope: scopeDescriptor, @requestUpdate
+    subscriptions.add editor.onDidChangeGutterVisible @requestUpdate
     subscriptions.add atom.config.observe 'editor.scrollSensitivity', scope: scopeDescriptor, @setScrollSensitivity
 
   focused: ->
@@ -1010,9 +1011,6 @@ TextEditorComponent = React.createClass
   setShowInvisibles: (showInvisibles) ->
     atom.config.set('editor.showInvisibles', showInvisibles)
 
-  setShowLineNumbers: (showLineNumbers) ->
-    @setState({showLineNumbers})
-
   setScrollSensitivity: (scrollSensitivity) ->
     if scrollSensitivity = parseInt(scrollSensitivity)
       @scrollSensitivity = Math.abs(scrollSensitivity) / 100

src/text-editor.coffee

@@ -536,6 +536,17 @@ class TextEditor extends Model
 
   isMini: -> @mini
 
+  setGutterVisible: (gutterVisible) ->
+    unless gutterVisible is @gutterVisible
+      @gutterVisible = gutterVisible
+      @emitter.emit 'did-change-gutter-visible', @gutterVisible
+    @gutterVisible
+
+  isGutterVisible: -> @gutterVisible ? true
+
+  onDidChangeGutterVisible: (callback) ->
+    @emitter.on 'did-change-gutter-visible', callback
+
   # Set the number of characters that can be displayed horizontally in the
   # editor.
   #