add change event support to the text document

Editor.js

@@ -120,6 +120,9 @@ function Editor(doc, renderer)
   addListener(container, "mousewheel", bind(this.onMouseWheel, this));
   
   this.doc = doc;
+  doc.addChangeListener(function(startRow, endRow) {
+    console.log(startRow, endRow);
+  });
   renderer.setDocument(doc);
   
   this.cursor = {
@@ -229,10 +232,11 @@ Editor.prototype =
   {      
     if (this.hasSelection())
     {
-      this.cursor = this.doc.remove(this.getSelectionRange());
+      this.cursor = this.doc.replace(this.getSelectionRange(), text);
       this.clearSelection();
+    } else {
+      this.cursor = this.doc.insert(this.cursor, text);
     }
-    this.cursor = this.doc.insert(this.cursor, text);        
     this.draw();
     this.renderer.scrollCursorIntoView();
   },

TextDocument.js

@@ -2,6 +2,8 @@ function TextDocument(text)
 {
   this.lines = this._split(text);
   this.modified = true;
+  
+  this.listeners = [];
 }
 
 TextDocument.prototype = 
@@ -10,6 +12,21 @@ TextDocument.prototype =
     return text.split(/[\n\r]/)
   },
   
+  addChangeListener : function(listener) {
+    this.listeners.push(listener);
+  },
+  
+  fireChangeEvent : function(firstRow, lastRow) 
+  {
+    if (lastRow === undefined) {
+      lastRow = this.lines.length-1;
+    }
+    
+    for (var i=0; i < this.listeners.length; i++) {
+      this.listeners[i](firstRow, lastRow);
+    };
+  },
+  
   getWidth : function()
   {
     if (this.modified) 
@@ -104,7 +121,17 @@ TextDocument.prototype =
     }
   },
   
-  insert : function(position, text) 
+  insert : function(position, text)
+  {
+    var end = this._insert(position, text);
+    this.fireChangeEvent(
+      position.row, 
+      position.row == end.row ? position.row : undefined
+    );
+    return end;
+  },
+  
+  _insert : function(position, text) 
   {
     this.modified = true;
     
@@ -153,6 +180,17 @@ TextDocument.prototype =
   },
    
   remove : function(range)
+  {
+    var end = this._remove(range);
+    
+    this.fireChangeEvent(
+      range.start.row, 
+      range.end.row == range.start.row ? range.start.row : undefined
+    );
+    return end;
+  },
+  
+  _remove : function(range)
   {
     this.modified = true;
     
@@ -170,11 +208,19 @@ TextDocument.prototype =
   
   replace : function(range, text)
   {
-    this.remove(range);
+    this._remove(range);
     if (text) {
-      return this.insert(range.start, text);
+      var end = this._insert(range.start, text);
     } else {
-      return range.start;
+      end = range.start;
     }
+    
+    var lastRemoved = range.end.column == 0 ? range.end.column-1 : range.end.column;
+    this.fireChangeEvent(
+      range.start.row, 
+      lastRemoved == end.row ? lastRemoved : undefined
+    );
+    
+    return end;
   }
 }