How to recover or prevent from accidental UNDO/REDO operations on Visual Studio 2010

Question

Case 1 (Overwritten undo/redo history)

1. You are editing source codes on "Program.cs". After a dedicated hour, You've done with 100 lines and typed "Ctrl+S"(Save).
2. To take a break, you left your desk without closing the "Program.cs" and Visual Studio. While you're leaving, your dog came to your desk and typed sequently
   "Ctrl+Z"(Undo) > "Ctrl+Z"(Undo) > ... (Until the original codes appered) > "a"(Type text).
3. You came back from a break but it's too late. You're pressing "Ctrl+Z"(Undo) or "Ctrl+Shift+Z"(Redo) to recover your 100 lines, but all you can get is the original codes or "a".

Case 2 (Discard undo/redo history)

1. You are editing source codes on "Program.cs". After a dedicated hour, You've done with 100 lines and typed "Ctrl+S"(Save).
2. To take a break, you left your desk without closing the "Program.cs" and Visual Studio. While you're leaving, your dog came to your desk and typed sequently
   "Ctrl+A"(All) > "a"(Type text) > "Ctrl+S"(Save) > "Ctrl+F4"(Close the src).
3. You came back from a break but it's too late. You're pressing "Ctrl+Z"(Undo) or "Ctrl+Shift+Z"(Redo) to recover your 100 lines, but all you can get is "a".

What i want to say through the above cases is "It's quite easy to lose the 100 lines."
I knew those possibilities and believed that i'll never catch of them, but the Second Case just happened 30 minutes ago by own mistake.

I want to know whether any solutions exist except SVN/GIT commit and rollback features.
Unfortunately, "Undo/Redo Last Global Action" didn't work for me.

Thank you for your help.

Answer 1

You asked for VS2010, but tagged this also for VS2012, and for VS2012 and onwards you have the Microsoft Devlabs AutoHistory extension which tracks local history. The extension is here: https://visualstudiogallery.msdn.microsoft.com/dfcb2438-180c-4f8a-983b-62d89e141fe3 , a blog on it is here: https://blogs.msdn.microsoft.com/visualstudio/2014/01/23/auto-history-extension-in-visual-studio-2013/

Example screenshot, the diff produced for a file where I added a Subtract method, saved it, then my dog came around and wiped it off and wrote "bbbbb" instead.