Deserialize display buffer when deserializing edit sessions

Previously, we kept display buffer attributes in the edit session's
serialized state, then recreated a fresh display buffer each time when
deserializing edit sessions. Now that DisplayBuffer and TokenizedBuffer
are serializable, we can just include them directly when serializing
the edit session.

spec/app/edit-session-spec.coffee

@@ -15,6 +15,21 @@ describe "EditSession", ->
     buffer = editSession.buffer
     lineLengths = buffer.getLines().map (line) -> line.length
 
+  describe "@deserialize(state)", ->
+    it "restores selections and folds based on markers in the buffer", ->
+      editSession.setSelectedBufferRange([[1, 2], [3, 4]])
+      editSession.addSelectionForBufferRange([[5, 6], [7, 5]], isReversed: true)
+      editSession.foldBufferRow(4)
+      expect(editSession.isFoldedAtBufferRow(4)).toBeTruthy()
+
+      editSession2 = deserialize(editSession.serialize())
+
+      expect(editSession2.id).toBe editSession.id
+      expect(editSession2.getBuffer().getPath()).toBe editSession.getBuffer().getPath()
+      expect(editSession2.getSelectedBufferRanges()).toEqual [[[1, 2], [3, 4]], [[5, 6], [7, 5]]]
+      expect(editSession2.getSelection(1).isReversed()).toBeTruthy()
+      expect(editSession2.isFoldedAtBufferRow(4)).toBeTruthy()
+
   describe ".copy()", ->
     it "returns a different edit session with the same initial state", ->
       editSession.setSelectedBufferRange([[1, 2], [3, 4]])
@@ -1507,7 +1522,7 @@ describe "EditSession", ->
 
           describe "if 'softTabs' is false", ->
             it "insert a \t into the buffer", ->
-              editSession.softTabs = false
+              editSession.setSoftTabs(false)
               expect(buffer.lineForRow(0)).not.toMatch(/^\t/)
               editSession.indent()
               expect(buffer.lineForRow(0)).toMatch(/^\t/)
@@ -1526,7 +1541,7 @@ describe "EditSession", ->
             describe "when 'softTabs' is false", ->
               it "moves the cursor to the end of the leading whitespace and inserts enough tabs to bring the line to the suggested level of indentaion", ->
                 convertToHardTabs(buffer)
-                editSession.softTabs = false
+                editSession.setSoftTabs(false)
                 buffer.insert([5, 0], "\t\n")
                 editSession.setCursorBufferPosition [5, 0]
                 editSession.indent(autoIndent: true)
@@ -1546,7 +1561,7 @@ describe "EditSession", ->
             describe "when 'softTabs' is false", ->
               it "moves the cursor to the end of the leading whitespace and inserts \t into the buffer", ->
                 convertToHardTabs(buffer)
-                editSession.softTabs = false
+                editSession.setSoftTabs(false)
                 buffer.insert([7, 0], "\t\t\t\n")
                 editSession.setCursorBufferPosition [7, 1]
                 editSession.indent(autoIndent: true)
@@ -1633,7 +1648,7 @@ describe "EditSession", ->
         describe "when softTabs is disabled", ->
           it "indents line and retains selection", ->
             convertToHardTabs(buffer)
-            editSession.softTabs = false
+            editSession.setSoftTabs(false)
             editSession.setSelectedBufferRange([[0,3], [0,3]])
             editSession.indentSelectedRows()
             expect(buffer.lineForRow(0)).toBe "\tvar quicksort = function () {"
@@ -1650,7 +1665,7 @@ describe "EditSession", ->
         describe "when softTabs is disabled", ->
           it "indents line and retains selection", ->
             convertToHardTabs(buffer)
-            editSession.softTabs = false
+            editSession.setSoftTabs(false)
             editSession.setSelectedBufferRange([[0,4], [0,14]])
             editSession.indentSelectedRows()
             expect(buffer.lineForRow(0)).toBe "\tvar quicksort = function () {"
@@ -1677,7 +1692,7 @@ describe "EditSession", ->
         describe "when softTabs is disabled", ->
           it "indents selected lines (that are not empty) and retains selection", ->
             convertToHardTabs(buffer)
-            editSession.softTabs = false
+            editSession.setSoftTabs(false)
             editSession.setSelectedBufferRange([[9,1], [11,15]])
             editSession.indentSelectedRows()
             expect(buffer.lineForRow(9)).toBe "\t\t};"
@@ -2214,15 +2229,15 @@ describe "EditSession", ->
         expect(editSession.getSelectedBufferRange()).toEqual [[0, 0], [0, 2]]
 
   describe "soft-tabs detection", ->
-    it "assign soft / hard tabs based on the contents of the buffer, or uses the default if unknown", ->
+    it "assigns soft / hard tabs based on the contents of the buffer, or uses the default if unknown", ->
       editSession = project.open('sample.js', softTabs: false)
-      expect(editSession.softTabs).toBeTruthy()
+      expect(editSession.getSoftTabs()).toBeTruthy()
 
       editSession = project.open('sample-with-tabs.coffee', softTabs: true)
-      expect(editSession.softTabs).toBeFalsy()
+      expect(editSession.getSoftTabs()).toBeFalsy()
 
       editSession = project.open(null, softTabs: false)
-      expect(editSession.softTabs).toBeFalsy()
+      expect(editSession.getSoftTabs()).toBeFalsy()
 
   describe ".indentLevelForLine(line)", ->
     it "returns the indent level when the line has only leading whitespace", ->

src/app/cursor.coffee

@@ -357,7 +357,7 @@ class Cursor
   #
   # Returns a {Number}.
   getIndentLevel: ->
-    if @editSession.softTabs
+    if @editSession.getSoftTabs()
       @getBufferColumn() / @editSession.getTabLength()
     else
       @getBufferColumn()

src/app/edit-session.coffee

@@ -22,7 +22,7 @@ class EditSession
 
   ### Internal ###
 
-  @version: 3
+  @version: 4
 
   @deserialize: (state) ->
     new EditSession(state)
@@ -32,39 +32,41 @@ class EditSession
   displayBuffer: null
   cursors: null
   selections: null
-  softTabs: true
-  softWrap: false
   suppressSelectionMerging: false
 
   constructor: (optionsOrState) ->
     @cursors = []
     @selections = []
-
     if optionsOrState instanceof telepath.Document
-      project.editSessions.push(this)
       @state = optionsOrState
-      {@id, tabLength, softTabs, @softWrap} = @state.toObject()
-      @setBuffer(project.bufferForId(@state.get('bufferId')))
-      @setDisplayBuffer(new DisplayBuffer({@buffer, tabLength}))
-      @addSelection(marker) for marker in @findMarkers(@getSelectionMarkerAttributes())
+      @id = @state.get('id')
+      displayBuffer = deserialize(@state.get('displayBuffer'))
+      @setBuffer(displayBuffer.buffer)
+      @setDisplayBuffer(displayBuffer)
+      for marker in @findMarkers(@getSelectionMarkerAttributes())
+        marker.setAttributes(preserveFolds: true)
+        @addSelection(marker)
       @setScrollTop(@state.get('scrollTop'))
       @setScrollLeft(@state.get('scrollLeft'))
     else
-      {buffer, displayBuffer, tabLength, softTabs, @softWrap, suppressCursorCreation} = optionsOrState
+      {buffer, displayBuffer, tabLength, softTabs, softWrap, suppressCursorCreation} = optionsOrState
       @id = guid.create().toString()
+      displayBuffer ?= new DisplayBuffer({buffer, tabLength})
       @state = telepath.Document.create
         deserializer: 'EditSession'
         version: @constructor.version
         id: @id
+        bufferId: buffer.id
+        displayBuffer: displayBuffer.getState()
+        softWrap: softWrap ? false
+        softTabs: buffer.usesSoftTabs() ? softTabs ? true
         scrollTop: 0
         scrollLeft: 0
       @setBuffer(buffer)
-      @setDisplayBuffer(displayBuffer ? new DisplayBuffer({@buffer, tabLength}))
+      @setDisplayBuffer(displayBuffer)
       @addCursorAtScreenPosition([0, 0]) unless suppressCursorCreation
 
     @languageMode = new LanguageMode(this, @buffer.getExtension())
-    @softTabs = @buffer.usesSoftTabs() ? softTabs ? true
-
     @state.on 'changed', ({key, newValue}) =>
       switch key
         when 'scrollTop'
@@ -72,6 +74,8 @@ class EditSession
         when 'scrollLeft'
           @trigger 'scroll-left-changed', newValue
 
+    project.editSessions.push(this)
+
   setBuffer: (@buffer) ->
     @buffer.retain()
     @subscribe @buffer, "path-changed", =>
@@ -103,24 +107,16 @@ class EditSession
     @trigger 'destroyed'
     @off()
 
-  serialize: ->
-    @state.set
-      bufferId: @buffer.id
-      scrollTop: @getScrollTop()
-      scrollLeft: @getScrollLeft()
-      tabLength: @getTabLength()
-      softTabs: @softTabs
-      softWrap: @softWrap
-      cursorScreenPosition: @getCursorScreenPosition().serialize()
-    @state
-
+  serialize: -> @state.clone()
   getState: -> @serialize()
 
   # Creates an {EditSession} with the same initial state
   copy: ->
     tabLength = @getTabLength()
     displayBuffer = @displayBuffer.copy()
-    newEditSession = new EditSession({@buffer, displayBuffer, tabLength, @softTabs, @softWrap, suppressCursorCreation: true})
+    softTabs = @getSoftTabs()
+    softWrap = @getSoftWrap()
+    newEditSession = new EditSession({@buffer, displayBuffer, tabLength, softTabs, softWrap, suppressCursorCreation: true})
     newEditSession.setScrollTop(@getScrollTop())
     newEditSession.setScrollLeft(@getScrollLeft())
     for marker in @findMarkers(editSessionId: @id)
@@ -197,20 +193,26 @@ class EditSession
   # softWrapColumn - A {Number} defining the soft wrap limit
   setSoftWrapColumn: (@softWrapColumn) -> @displayBuffer.setSoftWrapColumn(@softWrapColumn)
 
+  getSoftTabs: ->
+    @state.get('softTabs')
+
   # Defines whether to use soft tabs.
   #
   # softTabs - A {Boolean} which, if `true`, indicates that you want soft tabs.
-  setSoftTabs: (@softTabs) ->
+  setSoftTabs: (softTabs) ->
+    @state.set('softTabs', softTabs)
 
   # Retrieves whether soft tabs are enabled.
   #
   # Returns a {Boolean}.
-  getSoftWrap: -> @softWrap
+  getSoftWrap: ->
+    @state.get('softWrap')
 
   # Defines whether to use soft wrapping of text.
   #
   # softTabs - A {Boolean} which, if `true`, indicates that you want soft wraps.
-  setSoftWrap: (@softWrap) ->
+  setSoftWrap: (softWrap) ->
+    @state.set('softWrap', softWrap)
 
   # Retrieves that character used to indicate a tab.
   #
@@ -286,7 +288,7 @@ class EditSession
 
   # Constructs the string used for tabs.
   buildIndentString: (number) ->
-    if @softTabs
+    if @getSoftTabs()
       _.multiplyString(" ", number * @getTabLength())
     else
       _.multiplyString("\t", Math.floor(number))
@@ -491,7 +493,7 @@ class EditSession
   #
   # bufferRange - The {Range} to perform the replace in
   normalizeTabsInBufferRange: (bufferRange) ->
-    return unless @softTabs
+    return unless @getSoftTabs()
     @scanInBufferRange /\t/, bufferRange, ({replace}) => replace(@getTabText())
 
   # Performs a cut to the end of the current line.

src/app/project.coffee

@@ -333,7 +333,6 @@ class Project
     options = _.extend(@defaultEditSessionOptions(), editSessionOptions)
     options.buffer = buffer
     editSession = new EditSession(options)
-    @editSessions.push editSession
     @trigger 'edit-session-created', editSession
     editSession