Restore selection on active edit session when undoing/redoing

The `do`, `undo`, and `redo` methods on operations take an optional editSession argument, which can be used to determine the context in which they are being run. We restore selections on that edit session instead of the session where the operations originally occurred.

src/app/buffer.coffee

@@ -151,11 +151,11 @@ class Buffer
   transact: (fn) ->
     @undoManager.transact(fn)
 
-  undo: ->
-    @undoManager.undo()
+  undo: (editSession) ->
+    @undoManager.undo(editSession)
 
-  redo: ->
-    @undoManager.redo()
+  redo: (editSession) ->
+    @undoManager.redo(editSession)
 
   save: ->
     @saveAs(@getPath())

src/app/edit-session.coffee

@@ -95,6 +95,7 @@ class EditSession
     new Point(row, column)
 
   getFileExtension: -> @buffer.getExtension()
+  getPath: -> @buffer.getPath()
   getEofBufferPosition: -> @buffer.getEofPosition()
   bufferRangeForBufferRow: (row) -> @buffer.rangeForRow(row)
   lineForBufferRow: (row) -> @buffer.lineForRow(row)
@@ -177,10 +178,10 @@ class EditSession
     @insertText($native.readFromPasteboard())
 
   undo: ->
-    @buffer.undo()
+    @buffer.undo(this)
 
   redo: ->
-    @buffer.redo()
+    @buffer.redo(this)
 
   foldSelection: ->
     selection.fold() for selection in @getSelections()
@@ -237,10 +238,15 @@ class EditSession
   transact: (fn) ->
     @buffer.transact =>
       oldSelectedRanges = @getSelectedBufferRanges()
-      @buffer.pushOperation(undo: => @setSelectedBufferRanges(oldSelectedRanges))
+      @buffer.pushOperation
+        undo: (editSession) ->
+          editSession?.setSelectedBufferRanges(oldSelectedRanges)
+
       fn()
       newSelectedRanges = @getSelectedBufferRanges()
-      @buffer.pushOperation(redo: => @setSelectedBufferRanges(newSelectedRanges))
+      @buffer.pushOperation
+        redo: (editSession) ->
+          editSession?.setSelectedBufferRanges(newSelectedRanges)
 
   getAnchors: ->
     new Array(@anchors...)

src/app/project.coffee

@@ -75,26 +75,30 @@ class Project
   getSoftWrap: -> @softWrap
   setSoftWrap: (@softWrap) ->
 
-  open: (filePath) ->
+  open: (filePath, editSessionOptions={}) ->
     if filePath?
       filePath = @resolve(filePath)
       buffer = @bufferWithPath(filePath) ? @buildBuffer(filePath)
     else
       buffer = @buildBuffer()
 
-    editSession = new EditSession
-      project: this
-      buffer: buffer
-      tabText: @getTabText()
-      autoIndent: @getAutoIndent()
-      softTabs: @getSoftTabs()
-      softWrap: @getSoftWrap()
-
+    @buildEditSession(buffer, editSessionOptions)
 
+  buildEditSession: (buffer, editSessionOptions) ->
+    options = _.extend(@defaultEditSessionOptions(), editSessionOptions)
+    options.project = this
+    options.buffer = buffer
+    editSession = new EditSession(options)
     @editSessions.push editSession
     @trigger 'new-edit-session', editSession
     editSession
 
+  defaultEditSessionOptions: ->
+    tabText: @getTabText()
+    autoIndent: @getAutoIndent()
+    softTabs: @getSoftTabs()
+    softWrap: @getSoftWrap()
+
   destroy: ->
     for editSession in _.clone(@editSessions)
       @removeEditSession(editSession)

src/app/undo-manager.coffee

@@ -7,7 +7,7 @@ class UndoManager
   redoHistory: null
   currentTransaction: null
 
-  constructor: (@buffer) ->
+  constructor: ->
     @startBatchCallCount = 0
     @undoHistory = []
     @redoHistory = []
@@ -29,18 +29,18 @@ class UndoManager
       @undoHistory.push(@currentTransaction) if @currentTransaction.length
       @currentTransaction = null
 
-  undo: ->
+  undo: (editSession) ->
     if batch = @undoHistory.pop()
       opsInReverse = new Array(batch...)
       opsInReverse.reverse()
-      op.undo?() for op in opsInReverse
+      op.undo?(editSession) for op in opsInReverse
       @redoHistory.push batch
       batch.oldSelectionRanges
 
-  redo: ->
+  redo: (editSession) ->
     if batch = @redoHistory.pop()
       for op in batch
-        op.do?()
-        op.redo?()
+        op.do?(editSession)
+        op.redo?(editSession)
       @undoHistory.push(batch)
       batch.newSelectionRanges