Do a better job cleaning up after Editors and EditSessions

- EditSessions destroy their Selections when they are destroyed
- Editors destroy their EditSessions when they are destroyed
- Editors unsubscribe from the document and window when they are
  removed from the DOM.
- When an EditSession is destroyed via any code path, the Editor with
  that EditSession removes it.
- Selections no longer trigger 'destroyed' events if their parent
  EditSession has already been destroyed.

These are all really intertwined, so I'm doing them as one commit
since that was the only way to keep the specs green.

spec/app/editor-spec.coffee

@@ -39,8 +39,9 @@ describe "Editor", ->
     rootView.remove()
 
   describe "construction", ->
-    it "throws an error if no editor session is given", ->
+    it "throws an error if no editor session is given unless deserializing", ->
       expect(-> new Editor).toThrow()
+      expect(-> new Editor(deserializing: true)).not.toThrow()
 
   describe ".copy()", ->
     it "builds a new editor with the same edit sessions, cursor position, and scroll position as the receiver", ->
@@ -70,7 +71,6 @@ describe "Editor", ->
       newEditor.height(editor.height())
       newEditor.width(editor.width())
 
-      editor.remove()
       newEditor.attachToDom()
       expect(newEditor.scrollTop()).toBe editor.scrollTop()
       expect(newEditor.scrollView.scrollLeft()).toBe 44

src/app/edit-session.coffee

@@ -55,8 +55,11 @@ class EditSession
     @destroyed = true
     @unsubscribe()
     @buffer.release()
+    selection.destroy() for selection in @getSelections()
     @displayBuffer.destroy()
-    @project.removeEditSession(this)
+    @project?.removeEditSession(this)
+    @trigger 'destroyed'
+    @off()
 
   serialize: ->
     buffer: @buffer.getPath()

src/app/editor.coffee

@@ -20,6 +20,8 @@ class Editor extends View
     autoIndentOnPaste: false
     nonWordCharacters: "./\\()\"'-_:,.;<>~!@#$%^&*|+=[]{}`~?"
 
+  @nextEditorId: 1
+
   @content: (params) ->
     @div class: @classes(params), tabindex: -1, =>
       @subview 'gutter', new Gutter
@@ -54,15 +56,17 @@ class Editor extends View
   newSelections: null
 
   @deserialize: (state, rootView) ->
+    editor = new Editor(mini: state.mini, deserializing: true)
     editSessions = state.editSessions.map (state) -> EditSession.deserialize(state, rootView.project)
-    editor = new Editor(editSession: editSessions[state.activeEditSessionIndex], mini: state.mini)
-    editor.editSessions = editSessions
+    editor.pushEditSession(editSession) for editSession in editSessions
+    editor.setActiveEditSessionIndex(state.activeEditSessionIndex)
     editor.isFocused = state.isFocused
     editor
 
-  initialize: ({editSession, @mini} = {}) ->
+  initialize: ({editSession, @mini, deserializing} = {}) ->
     requireStylesheet 'editor.css'
 
+    @id = Editor.nextEditorId++
     @lineCache = []
     @configure()
     @bindKeys()
@@ -75,19 +79,16 @@ class Editor extends View
     @newSelections = []
 
     if editSession?
-      @editSessions.push editSession
-      @setActiveEditSessionIndex(0)
+      @edit(editSession)
     else if @mini
-      editSession = new EditSession
+      @edit(new EditSession
         buffer: new Buffer()
         softWrap: false
         tabLength: 2
         softTabs: true
-
-      @editSessions.push editSession
-      @setActiveEditSessionIndex(0)
-    else
-      throw new Error("Editor initialization requires an editSession")
+      )
+    else if not deserializing
+      throw new Error("Editor must be constructed with an 'editSession' or 'mini: true' param")
 
   serialize: ->
     @saveScrollPositionForActiveEditSession()
@@ -431,10 +432,10 @@ class Editor extends View
         @selectToScreenPosition(@screenPositionFromMouseEvent(event))
         lastMoveEvent = event
 
-    $(document).on 'mousemove', moveHandler
+    $(document).on "mousemove.editor-#{@id}", moveHandler
     interval = setInterval(moveHandler, 20)
 
-    $(document).one 'mouseup', =>
+    $(document).one "mouseup.editor-#{@id}", =>
       clearInterval(interval)
       $(document).off 'mousemove', moveHandler
       reverse = @activeEditSession.getLastSelection().isReversed()
@@ -448,7 +449,7 @@ class Editor extends View
     @calculateDimensions()
     @hiddenInput.width(@charWidth)
     @setSoftWrapColumn() if @activeEditSession.getSoftWrap()
-    @subscribe $(window), "resize", => @requestDisplayUpdate()
+    @subscribe $(window), "resize.editor-#{@id}", => @requestDisplayUpdate()
     @focus() if @isFocused
 
     @resetDisplay()
@@ -457,14 +458,16 @@ class Editor extends View
 
   edit: (editSession) ->
     index = @editSessions.indexOf(editSession)
-
-    if index == -1
-      index = @editSessions.length
-      @editSessions.push(editSession)
-      @trigger 'editor:edit-session-added', [editSession, index]
-
+    index = @pushEditSession(editSession) if index == -1
     @setActiveEditSessionIndex(index)
 
+  pushEditSession: (editSession) ->
+    index = @editSessions.length
+    @editSessions.push(editSession)
+    editSession.on 'destroyed', => @editSessionDestroyed(editSession)
+    @trigger 'editor:edit-session-added', [editSession, index]
+    index
+
   getBuffer: -> @activeEditSession.buffer
 
   destroyActiveEditSession: ->
@@ -474,23 +477,18 @@ class Editor extends View
     return if @mini
 
     editSession = @editSessions[index]
-    destroySession = =>
-      if index is @getActiveEditSessionIndex() and @editSessions.length > 1
-        @loadPreviousEditSession()
-      _.remove(@editSessions, editSession)
+    destroySession = ->
       editSession.destroy()
-      @trigger 'editor:edit-session-removed', [editSession, index]
-      @remove() if @editSessions.length is 0
-      callback(index) if callback
+      callback?(index)
 
     if editSession.isModified() and not editSession.hasEditors()
       @promptToSaveDirtySession(editSession, destroySession)
     else
-      destroySession(editSession)
+      destroySession()
 
   destroyInactiveEditSessions: ->
     destroyIndex = (index) =>
-      index++ if @activeEditSession is @editSessions[index]
+      index++ if index is @getActiveEditSessionIndex()
       @destroyEditSessionIndex(index, destroyIndex) if @editSessions[index]
     destroyIndex(0)
 
@@ -499,6 +497,13 @@ class Editor extends View
       @destroyEditSessionIndex(index, destroyIndex) if @editSessions[index]
     destroyIndex(0)
 
+  editSessionDestroyed: (editSession) ->
+    index = @editSessions.indexOf(editSession)
+    @loadPreviousEditSession() if index is @getActiveEditSessionIndex() and @editSessions.length > 1
+    _.remove(@editSessions, editSession)
+    @trigger 'editor:edit-session-removed', [editSession, index]
+    @remove() if @editSessions.length is 0
+
   loadNextEditSession: ->
     nextIndex = (@getActiveEditSessionIndex() + 1) % @editSessions.length
     @setActiveEditSessionIndex(nextIndex)
@@ -663,7 +668,7 @@ class Editor extends View
     if @activeEditSession.getSoftWrap()
       @addClass 'soft-wrap'
       @_setSoftWrapColumn = => @setSoftWrapColumn()
-      $(window).on "resize", @_setSoftWrapColumn
+      $(window).on "resize.editor-#{@id}", @_setSoftWrapColumn
     else
       @removeClass 'soft-wrap'
       $(window).off 'resize', @_setSoftWrapColumn
@@ -750,15 +755,17 @@ class Editor extends View
     )
 
   remove: (selector, keepData) ->
-    return super if keepData
-
+    return super if keepData or @removed
     @trigger 'editor:will-be-removed'
-
-    @destroyEditSessions()
-
     if @pane() then @pane().remove() else super
     rootView?.focus()
 
+  afterRemove: ->
+    @removed = true
+    @destroyEditSessions()
+    $(window).off(".editor-#{@id}")
+    $(document).off(".editor-#{@id}")
+
   getEditSessions: ->
     new Array(@editSessions...)
 

src/app/selection.coffee

@@ -19,7 +19,7 @@ class Selection
     return if @destroyed
     @destroyed = true
     @editSession.removeSelection(this)
-    @trigger 'destroyed'
+    @trigger 'destroyed' unless @editSession.destroyed
     @cursor?.destroy()
 
   finalize: ->