Support selecting editor lines from the gutter

Mouse events that occur in the gutter are forwarded to the
rendered lines with the y-coordinate translated to be the
leftmost pixel of the editor to simulate the event originating
from column 0 of the current line row.

Closes #287

spec/app/editor-spec.coffee

@@ -2225,21 +2225,44 @@ describe "Editor", ->
       runs ->
         expect(editor.getText()).toBe(originalPathText)
 
-  describe "when clicking a gutter line", ->
+  describe "when clicking in the gutter", ->
     beforeEach ->
-      rootView.attachToDom()
+      editor.attachToDom()
 
-    it "moves the cursor to the start of the selected line", ->
-      expect(editor.getCursorScreenPosition()).toEqual [0,0]
-      editor.gutter.find(".line-number:eq(1)").trigger 'click'
-      expect(editor.getCursorScreenPosition()).toEqual [1,0]
+    describe "when single clicking", ->
+      it "moves the cursor to the start of the selected line", ->
+        expect(editor.getCursorScreenPosition()).toEqual [0,0]
+        event = $.Event("mousedown")
+        event.pageY = editor.gutter.find(".line-number:eq(1)").offset().top
+        event.originalEvent = {detail: 1}
+        editor.gutter.find(".line-number:eq(1)").trigger event
+        expect(editor.getCursorScreenPosition()).toEqual [1,0]
 
-    it "selects to the start of the selected line when shift is pressed", ->
-      expect(editor.getSelection().getScreenRange()).toEqual [[0,0], [0,0]]
-      event = $.Event("click")
-      event.shiftKey = true
-      editor.gutter.find(".line-number:eq(1)").trigger event
-      expect(editor.getSelection().getScreenRange()).toEqual [[0,0], [1,0]]
+    describe "when shift-clicking", ->
+      it "selects to the start of the selected line", ->
+        expect(editor.getSelection().getScreenRange()).toEqual [[0,0], [0,0]]
+        event = $.Event("mousedown")
+        event.pageY = editor.gutter.find(".line-number:eq(1)").offset().top
+        event.originalEvent = {detail: 1}
+        event.shiftKey = true
+        editor.gutter.find(".line-number:eq(1)").trigger event
+        expect(editor.getSelection().getScreenRange()).toEqual [[0,0], [1,0]]
+
+    describe "when mousing down and then moving across multiple lines before mousing up", ->
+      it "selects the lines", ->
+        mousedownEvent = $.Event("mousedown")
+        mousedownEvent.pageY = editor.gutter.find(".line-number:eq(1)").offset().top
+        mousedownEvent.originalEvent = {detail: 1}
+        editor.gutter.find(".line-number:eq(1)").trigger mousedownEvent
+
+        mousemoveEvent = $.Event("mousemove")
+        mousemoveEvent.pageY = editor.gutter.find(".line-number:eq(5)").offset().top
+        mousemoveEvent.originalEvent = {detail: 1}
+        editor.gutter.find(".line-number:eq(5)").trigger mousemoveEvent
+
+        $(document).trigger 'mouseup'
+
+        expect(editor.getSelection().getScreenRange()).toEqual [[1,0], [5,30]]
 
   describe "when clicking below the last line", ->
     beforeEach ->

src/app/editor.coffee

@@ -385,7 +385,7 @@ class Editor extends View
       @destroyFold($(e.currentTarget).attr('fold-id'))
       false
 
-    @renderedLines.on 'mousedown', (e) =>
+    onMouseDown = (e) =>
       clickCount = e.originalEvent.detail
 
       screenPosition = @screenPositionFromMouseEvent(e)
@@ -403,6 +403,8 @@ class Editor extends View
 
       @selectOnMousemoveUntilMouseup()
 
+    @renderedLines.on 'mousedown', onMouseDown
+
     @on "textInput", (e) =>
       @insertText(e.originalEvent.data)
       false
@@ -419,6 +421,10 @@ class Editor extends View
       @gutter.widthChanged = (newWidth) =>
         @scrollView.css('left', newWidth + 'px')
 
+      @gutter.on 'mousedown', (e) =>
+        e.pageX = @renderedLines.offset().left
+        onMouseDown(e)
+
       @subscribe syntax, 'grammars-loaded', =>
         @reloadGrammar()
         for session in @editSessions

src/app/gutter.coffee

@@ -23,13 +23,6 @@ class Gutter extends View
     highlightLines = => @highlightLines()
     editor.on 'cursor:moved', highlightLines
     editor.on 'selection:changed', highlightLines
-    @on 'click', '.line-number', (e) =>
-      row = parseInt($(e.target).text()) - 1
-      position = new Point(row, 0)
-      if e.shiftKey
-        @editor().selectToScreenPosition(position)
-      else
-        @editor().setCursorScreenPosition(position)
 
     @calculateWidth()