Always use serialized text when deserializing

package.json

@@ -42,7 +42,7 @@
     "fs-plus": "^2.0.0",
     "grim": "^1.2.1",
     "interval-skip-list": "^2.0.1",
-    "pathwatcher": "^5.0.0",
+    "pathwatcher": "^5.0.1",
     "serializable": "^1.0.0",
     "span-skip-list": "~0.2.0",
     "underscore-plus": "^1.0.0"

spec/text-buffer-spec.coffee

@@ -328,6 +328,35 @@ describe "TextBuffer", ->
       buffer.undo()
       expect(buffer.getText()).toBe "hello\nworld\r\nhow are you doing?"
 
+    it "does not allow the undo stack to grow without bound", ->
+      buffer = new TextBuffer(maxUndoEntries: 12)
+
+      # A transaction with 1 change uses 3 undo entries, so we can undo 4 of
+      # these transactions.
+      for i in [1...10]
+        buffer.append("#{i}\n")
+      expect(buffer.getLineCount()).toBe 10
+
+      undoCount = 0
+      undoCount++ while buffer.undo()
+      expect(undoCount).toBe 4
+      expect(buffer.getLineCount()).toBe 6
+
+      # A transaction with 2 changes uses 4 undo entries, so we can undo 3 of
+      # these transactions.
+      buffer.setText("")
+      buffer.clearUndoStack()
+      for i in [1...10]
+        buffer.transact ->
+          buffer.append(String(i))
+          buffer.append("\n")
+      expect(buffer.getLineCount()).toBe 10
+
+      undoCount = 0
+      undoCount++ while buffer.undo()
+      expect(undoCount).toBe 3
+      expect(buffer.getLineCount()).toBe 7
+
   describe "transactions", ->
     now = null
 
@@ -866,6 +895,8 @@ describe "TextBuffer", ->
 
       describe "when the serialized buffer had no unsaved changes", ->
         it "loads the current contents of the file at the serialized path", ->
+          buffer.append("!")
+          buffer.save()
           expect(buffer.isModified()).toBeFalsy()
           buffer2 = buffer.testSerialization()
 
@@ -877,6 +908,10 @@ describe "TextBuffer", ->
             expect(buffer2.getPath()).toBe(buffer.getPath())
             expect(buffer2.getText()).toBe(buffer.getText())
 
+            buffer.undo()
+            buffer2.undo()
+            expect(buffer2.getText()).toBe(buffer.getText())
+
       describe "when the serialized buffer had unsaved changes", ->
         describe "when the disk contents were changed since serialization", ->
           it "loads the disk contents instead of the previous unsaved state", ->

src/history.coffee

@@ -1,4 +1,4 @@
-SerializationVersion = 2
+SerializationVersion = 3
 
 class Checkpoint
   constructor: (@id, @snapshot, @isBoundary) ->
@@ -22,7 +22,7 @@ class History
     history.deserialize(state)
     history
 
-  constructor: (@delegate) ->
+  constructor: (@delegate, @maxUndoEntries) ->
     @nextCheckpointId = 0
     @undoStack = []
     @redoStack = []
@@ -93,6 +93,24 @@ class History
     @undoStack.push(change)
     @clearRedoStack()
 
+    if @undoStack.length - @maxUndoEntries > 0
+      spliceIndex = null
+      withinGroup = false
+      for entry, i in @undoStack
+        break if spliceIndex?
+        switch entry.constructor
+          when GroupStart
+            if withinGroup
+              throw new Error("Invalid undo stack state")
+            else
+              withinGroup = true
+          when GroupEnd
+            if withinGroup
+              spliceIndex = i
+            else
+              throw new Error("Invalid undo stack state")
+      @undoStack.splice(0, spliceIndex + 1) if spliceIndex?
+
   popUndoStack: ->
     snapshotBelow = null
     spliceIndex = null
@@ -225,6 +243,7 @@ class History
   deserialize: (state) ->
     return unless state.version is SerializationVersion
     @nextCheckpointId = state.nextCheckpointId
+    @maxUndoEntries = state.maxUndoEntries
     @undoStack = @deserializeStack(state.undoStack)
     @redoStack = @deserializeStack(state.redoStack)
 

src/text-buffer.coffee

@@ -77,6 +77,7 @@ class TextBuffer
   refcount: 0
   fileSubscriptions: null
   backwardsScanChunkSize: 8000
+  defaultMaxUndoEntries: 10000
   changeCount: 0
 
   ###
@@ -97,19 +98,18 @@ class TextBuffer
     @lineEndings = ['']
     @offsetIndex = new SpanSkipList('rows', 'characters')
     @setTextInRange([[0, 0], [0, 0]], text ? params?.text ? '', normalizeLineEndings: false)
-    @history = params?.history ? new History(this)
+    maxUndoEntries = params?.maxUndoEntries ? @defaultMaxUndoEntries
+    @history = params?.history ? new History(this, maxUndoEntries)
     @markerStore = params?.markerStore ? new MarkerStore(this)
     @setEncoding(params?.encoding)
     @setPreferredLineEnding(params?.preferredLineEnding)
 
     @loaded = false
     @transactCallDepth = 0
     @digestWhenLastPersisted = params?.digestWhenLastPersisted ? false
-    @modifiedWhenLastPersisted = params?.modifiedWhenLastPersisted ? false
-    @useSerializedText = @modifiedWhenLastPersisted isnt false
 
     @setPath(params.filePath) if params?.filePath
-    @load(true) if params?.load
+    @load() if params?.load
 
   # Called by {Serializable} mixin during deserialization.
   deserializeParams: (params) ->
@@ -125,7 +125,6 @@ class TextBuffer
     history: @history.serialize()
     encoding: @getEncoding()
     filePath: @getPath()
-    modifiedWhenLastPersisted: @isModified()
     digestWhenLastPersisted: @file?.getDigestSync()
     preferredLineEnding: @preferredLineEnding
 
@@ -1254,7 +1253,7 @@ class TextBuffer
     @emit 'will-reload' if Grim.includeDeprecatedAPIs
     if clearHistory
       @clearUndoStack()
-      @setTextInRange(@getRange(), @cachedDiskContents, normalizeLineEndings: false, undo: 'skip')
+      @setTextInRange(@getRange(), @cachedDiskContents ? "", normalizeLineEndings: false, undo: 'skip')
     else
       @setTextViaDiff(@cachedDiskContents)
     @emitModifiedStatusChanged(false)
@@ -1329,16 +1328,16 @@ class TextBuffer
     @updateCachedDiskContentsSync()
     @finishLoading()
 
-  load: (clearHistory=false) ->
-    @updateCachedDiskContents().then => @finishLoading(clearHistory)
+  load: ->
+    @updateCachedDiskContents().then => @finishLoading()
 
-  finishLoading: (clearHistory) ->
+  finishLoading: ->
     if @isAlive()
       @loaded = true
-      if @useSerializedText and @digestWhenLastPersisted is @file?.getDigestSync()
+      if @digestWhenLastPersisted is @file?.getDigestSync()
         @emitModifiedStatusChanged(true)
       else
-        @reload(clearHistory)
+        @reload(true)
     this
 
   destroy: ->