From db4953c976ebd05c2fbf311a456ad200137b08f3 Mon Sep 17 00:00:00 2001
From: nightwing <amirjanyan@gmail.com>
Date: Mon, 17 Jun 2013 16:38:00 +0400
Subject: [PATCH] use operations for undo coalescence

---
 lib/ace/editor.js    | 22 +++++++++++-----------
 lib/ace/selection.js |  2 ++
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 572425ea..ff3bb3cd 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -175,38 +175,38 @@ var Editor = function(renderer, session) {
     this.$historyTracker = function(e) {
         if (!this.$mergeUndoDeltas)
             return;
-        var previous = this.previousCommand || {command:{}};
+
+
+        var prev = this.prevOp;
         var mergeableCommands = ["backspace", "del", "insertstring"];
+        // previous command was the same
+        var shouldMerge = prev.command && (e.command.name == prev.command.name);
         if (e.command.name == "insertstring") {
             var text = e.args;
             if (this.mergeNextCommand === undefined)
                 this.mergeNextCommand = true;
 
-            var shouldMerge = e.command.name == previous.command.name // previous command was the same
-                && !this.cursorMoved // cursor was not moved since last command
+            shouldMerge = shouldMerge
                 && this.mergeNextCommand // previous command allows to coalesce with
-                && (!/\s/.test(text) || /\s/.test(previous.args)) // previous insertion was of same type
+                && (!/\s/.test(text) || /\s/.test(prev.args)) // previous insertion was of same type
 
             this.mergeNextCommand = true;
         } else {
-            var shouldMerge = e.command.name == previous.command.name // previous command was the same
+            shouldMerge = shouldMerge
                 && mergeableCommands.indexOf(e.command.name) !== -1// the command is mergeable
-                && !this.cursorMoved // cursor was not moved since last command
         }
-        
+
         if (
             this.$mergeUndoDeltas != "always"
-            && Date.now() - this.sequenceStartTime < 2000
+            && Date.now() - this.sequenceStartTime > 2000
         ) {
             shouldMerge = false; // the sequence is too long
         }
-        
+
         if (shouldMerge)
             this.session.mergeUndoDeltas = true;
         else if (mergeableCommands.indexOf(e.command.name) !== -1)
             this.sequenceStartTime = Date.now();
-        this.cursorMoved = false;
-        this.previousCommand = e;
     };
 
     /**
diff --git a/lib/ace/selection.js b/lib/ace/selection.js
index 68a22a5c..50a5bd0e 100644
--- a/lib/ace/selection.js
+++ b/lib/ace/selection.js
@@ -258,6 +258,8 @@ var Selection = function(session) {
             this.setSelectionAnchor(range.start.row, range.start.column);
             this.selectTo(range.end.row, range.end.column);
         }
+        if (this.getRange().isEmpty())
+            this.$isEmpty = true;
         this.$desiredColumn = null;
     };