The topic says it all. I've got a .app file here, but the Xcode project is no longer available to me. Is there any way to take the .app file and reverse engineer an Xcode project from it so I can view the code used to make it?
First, the source code is signed and encrypted.
Second, you're likely legally not allowed to decrypt this source if you are in the United States, Cuba, North Korea and many other countries. I fear it even applies to your own code, since it was encrypted by Apple tools, with an Apple key. Check this with a lawyer, guy in black with scary words and a nice Porsche.
Third, Objective-C being a compiled language, and LLVM allowing you to do some optimization, you would have a real hard time going back to anything slightly readable. This is no Java/C#.
Four, you'd better be really, really sure that "the app file is no longer available to me" means you have a legal right to the source in some way. Stealing source code carries some hefty penalties, with fines you can buy yourself a Porsche with. Ask a lawyer :p
By design this cannot be done. The best you can do is run the app and try to reverse engineer it based on functionality. Stealing the source code is a no-no (and not just because Apple says so).
It would be very very difficult. There's no one click solution. However, you could look at class-dump and otool. Just be aware that it's a very manual effort, you'll still be piecing everything together yourself.
When you say "the Xcode project is no longer available to me" then I would assume you have written the code or at least have seen it.
It will be definitely much faster to rewrite it than to try to decompile it.
I've noticed a discrepancy with some source files in our system whereby some contain source-control checkin comments, and some do not. These comments are added automatically to the top of the file when it is checked in:
* $Log: //vm1/Projects/Morpheus/Sleep.bdy-arc $
--
-- Rev 1.14 Apr 14 2009 15:32:52 John Smith
--Fixed bugs 2292 and 2230.
This seems to have been quite prevelant in all the compainies with which I have worked, but I must confess that I struggle to see the point. Generally the comments aren't that good, are ofen left by people who have long since departed, and even when they are of a high standard it is difficult to tie them to physical code changes.
It also strikes me, that you are physically changing the file that you are checking in. Now, this may not be such a problem with files that will be compiled, but could be a disaster with others, e.g. JavaScript files.
So really, my query is what was the motivation in concept behind providing this functionality in the first instance? Does anyone actually find these comments useful?
Also, I would be curious to know if this was feature that is commonly supported within Source Control systems. I am aware of it with PVCS, VSS and Subversion (Subversion Keyword Substitution), however I wonder if it is also available in some of the more popular DVCSs.
Your help, as always is much appreciated.
You are right - this is, on balance, not a very useful feature of revision control systems! Yes, companies like an audit trail, but this is provided by the revision control system's log command; yes, it means that the log is available if the revision control system is not - but in that case, Fixed bug 1234 probably isn't very meaningful :-) And, as you allude to, in order to tie the changes down to specific lines, you still need the help of the revision control system.
You are also correct that changing the file as it is being committed can give rise to issues - I once saw an issue where a colleague carefully ensured that his code compiled, then committed it, only to be flamed because the files he'd committed didn't compile. It turned out that the comment was something like Clean up /tmp/*.txt, and the C compiler was treating the /* as a comment-start character (and complaining because it was already inside a comment).
Another issue with logs in files is that they only make sense for linear working - once you're developing with multiple branches (in the way that distributed source tools like git/mercurial/bazaar encourage) having the log in the source file itself only serves to create merge conflicts almost all of the time.
For this reason, modern tools tend not to implement this functionality. Indeed subversion doesn't - its keyword substitution deliberately doesn't allow inclusion of log history.
So really, my query is what was the
motivation in concept behind providing
this functionality in the first
instance? Does anyone actually find
these comments useful?
When the sources are mirrored to an external location (source packages, source code index etc) then the version control information might not be available. For such cases this information might be useful.
So really, my query is what was the motivation in concept behind providing this functionality in the first instance? Does anyone actually find these comments useful?
In some companies, audit controls are a big concern. Auditors want to be able to trace from the incident system to the actual code changes. Fixed bugs 2292 and 2230. provides a trace back from the code to the incident system.
Some companies require the incident number as a part of the source control change log comments for the same reason.
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I read all over the Internet (various sites and blogs) about version control. How great it is and how all developers NEED to use it because it is very useful.
Here is the question: do I really need this? I'm a front-end developer (usually just HTML/CSS/JavaScript) and I NEVER had a problem like "Wow, my files from yesterday!".
I've tried to use it, installed Subversion and TortoiseSVN, I understand the concept behind version control but... I can't use it (weird for me).
OK, so... Is that bad? I usually work alone (freelancer) and I had no client that asked me to use Subversion (but it never is too late for this, right?). So, should I start and struggle to learn to use Subversion (or something similar?) Or it's just a waste of time?
Related question: Good excuses NOT to use version control.
Here's a scenario that may illustrate the usefulness of source control even if you work alone.
Your client asks you to implement an ambitious modification to the website. It'll take you a couple of weeks, and involve edits to many pages. You get to work.
You're 50% done with this task when the client calls and tells you to drop what you're doing to make an urgent but more minor change to the site. You're not done with the larger task, so it's not ready to go live, and the client can't wait for the smaller change. But he also wants the minor change to be merged into your work for the larger change.
Maybe you are working on the large task in a separate folder containing a copy of the website. Now you have to figure out how to do the minor change in a way that can be deployed quickly. You work furiously and get it done. The client calls back with further refinement requests. You do this too and deploy it. All is well.
Now you have to merge it into the work in progress for the major change. What did you change for the urgent work? You were working too fast to keep notes. And you can't just diff the two directories easily now that both have changes relative to the baseline you started from.
The above scenario shows that source control can be a great tool, even if you work solo.
You can use branches to work on longer-term tasks and then merge the branch back into the main line when it's done.
You can compare whole sets of files to other branches or to past revisions to see what's different.
You can track work over time (which is great for reporting and invoicing by the way).
You can recover any revision of any file based on date or on a milestone that you defined.
For solo work, Subversion or Git is recommended. Anyone is free to prefer one or the other, but either is clearly better than not using any version control. Good books are "Pragmatic Version Control using Subversion, 2nd Edition" by Mike Mason or "Pragmatic Version Control Using Git" by Travis Swicegood.
There are lots of benefits, yes you need it.
What tools/techniques can benefit a solo developer?
Best Version control for lone developer
You don't need version control any more than a trapese artist needs a safety net. It's like backing up your hard drive—most of the time it seems redundant as nothing happens but it will be needed eventually. There's no maybes here. It will happen. And you can never predict when and the past is a poor indicator as to when it will happen. It may happen only once ever in the future but even if you know it'll happen once you won't know how bad it will be.
Yes!
Do it. It won't hurt you..
I usually switch from Laptop to PC and back and it's absolutely great to have your code somewhere in a central repository.
Sometimes it's great to go just revert to the latest revision because you screwed up something that would be too difficult to fix..
The biggest advantage that is missing is being able to re-produce the source code that generated an old build.
At build time, you tag the source control with 'Build 4.26'. The next day you start coding Build 4.27. Three months later, when a client says, "I'm using Build 4.26, and there's a bug in the Frickershaw feature. I can't upgrade to any other build because of some changes to file formats you made in build 4.27. Is there anything you can do for me? I'm willing to pay."
Then, you can checkout a branch of the 4.26 source code... fix the Frickershaw feature, and then re-build the package for the user in about an hour or two. Then you can switch back to version 4.39, and keep working.
In the same vein, you can track down the exact point at which a bug was added. Test versions 4.25 for the bug, then 4.20, then 4.10 and eventually find the bug was introduced in version 4.12. Then you look for all changes made between 'Build 4.11' and 'Build 4.12', and then focus on the Frickershaw feature. You can quickly find the source code for the bug without ever debugging it.
Branching doesn't seem useful to you? Have you never wanted to just try something out to see if it would work? I do a lot of plain old html/css stuff too, and I find that invaluable. There is literally no danger in branching to test something, seeing if it works, and deciding "meh" and then just rolling back.
I've never needed to get to a backup (knock on wood), but I find just the rolling back functionality invaluable.
A few perks as a freelancer:
Know definitively what you changed in every single file and when (as long as you check in often)
Rollback to any version in your past. Surprising how often this is valuable.
Track a set of changes as a 'release'. This way you know what each client is currently using and what's in development.
Backup
The ability to easily share a project if you suddenly aren't solo
Try a DVCS like Git or Bazaar. They are incredibly easy to set up, easy to use, and offer all the important features of Subversion, CVS, etc.
The key is that you can revert back to a working version when you break something, which is often much faster than undoing the change manually.
I wouldn't hire a contractor without them integrating into our processes. They would have to access code via our SVN, and would be unlikely to get paid without meeting unit testing and code review requirements.
If contracting I'd make sure to have solid experience of both VSS (check-in/out) and CVS (merge & conflict) models.
Working on your own you have a great opportunity to play and learn with the latest - I'd be trying out Git.
As a lone developer you can think of source control as an unlimited undo - one that works across sessions and reboots.
A minor advantage of source control for me is that I work on multiple development computers. It is easy to move my work around between machines.
The greatest advantage in my opinion has already been listed. It allows me to sleep at night knowing that if we have to roll-back a change it will be fairly easy.
I think the main advantage in moving from a "keep-all-versions file system" to a source code control system lies in the fact that the sccs adds structure to all those versions you kept of all those files, and provides you with records of "what was the consistent state of the whole file system at point X".
In other words, "Which version of file A goes with which versions of B, C, D, ...".
And an afterthought (¡!): the special act of committing or checking in makes you think about "what is this?", and the resulting log message can, hopefully, serve as memory...
The literal answer to this question is, No, you do not NEED version control.
You do, however, WANT version control, even if you don't know it.
That said, many SCM tools can be mysterious or downright unpleasant to use until you break through the Grok Barrier, so let's revise that a bit:
"You do, however, want EASY-TO-USE version control." And it's out there...download a bunch of recommended visual clients and give them a whirl, then try whichever maps best to the way you think.
Which leads to the question you meant to ask:
Why do I want to use version control?"
Answer: Version control allows you to be FEARLESS!
Yes you need it.
At the very least, for a single developer shop, you need to move code into a ProjectName-Date-Time directory several times a day.
That is, write a script that will automatically back up your working directory at lunch and at quitting time, without overwriting other back ups.
This can grow pretty fast, so eventually you'll want to save only the differences between files, which is what a VC application does.
Since you usually work alone, I would say that it is a good idea to use version control. One of the main benefits I have found in using version control (Subversion in my case), is that when working alone it gives me more confidence in trying a new approach to the problem. You can always branch to a new method or framework of solving the problem and see if you like it better. If it turns out that this branch doesn't work, you can just abandon it and go back to the old method. This also makes it easier to try out the different solutions side by side.
So, if you have ever seen a different approach to solving a problem and you wanted to try it out, I would definitely use version control as a tool to make this easier.
If you are working on your own, and are performing backups on a regular basis, VC may not be needed (unless you count your backups as version history). As soon as you start working with another developer, you should get version control in place so that you don't start over-writing each other's work.
Even if you don't need it right now, it is something you will need whenever you work in a team.
Having a history of changes to your html/css/javascript can be a godsend. Being able to compare your front-end to the code a month, or several months ago can really go a long way in figuring out why suddenly the template is all askew.
Plus if you ever want/need to get help on your project(s), you'll have an easy system to distribute, track, and deploy updated content.
Definitely do it, you'll thank yourself once you get used to it.
Checkout (one time)
Update (beginning of day)
Commit (end of task/change after testing)
That's all there is to it. Don't commit EVERY single modification that you're refreshing in the browser, just the one's you want to go live.
Think if it like a backup. It is a little irritating until the day you need it. Then the amount of work you lose is directly proportional to the frequency of your backups.
Another benifit is being able to look at old ways you did things that may have become obsolete in a certain spot but could be usefull in another. Just cut and paste the old code that you got when doing a compare.
That is unless you like reinventing the wheel you already reinvented...
When things can go wrong they will.
It is very nice to have the ability to reference code you may have deleted a month ago, or to recover the entire project after a hardware failure or upgrade.
There may also be a point in the future when the project is worked on by more than you. The ability to prevent (or control) branching and versioning is a must in an environment like that.
Must must must must must must. You must use version control.
This is of the deepest importance.
If you don't understand why now, you will one day.
When your client phones up in a panic because something is broken on the live site and it's a regression, you'll be glad you can just open TortoiseSVN and see what it was you did last Tuesday that caused the breakage.
It's really odd. Ever since I started using version control, I've very occasionally had the need to look up old copies of my code and use them. I never needed to do this before...probably because the idea of doing didn't really stick. It's easy not to notice those times when you could have found version control helpful.
Search within an entire codebase. It's a killer feature, mainly because the search gets actioned on another machine so you can get on with your work undisturbed.
Which incidentally, is the reason why we didn't change to SourceGear Vault. It can't do this. We're still looking for a SourceSafe-compatible replacement for... well, SourceSafe. Despite what everyone says, it hasn't let us down yet*
* this may just be a matter of time.
I think you've made the right decision to use some kind of version control. For simplicity, I'd go with SVN (ignore CVS as SVN is basically a "better" CVS)
SVN can work with "local" repositories right on the filesystem and on lots of platform so you don't have to bite off too much in infrastructure (servers, networks, etc)
Great resource for SVN: http://svnbook.red-bean.com
I don't know much about GIT, but it being open source and gain lots of mindshare probably has alot of similar advantages!
Borrowing a quote from somewhere: You might not need it now, but when you do, you'll be glad you did.
Happy versioning!
Although old and crude, we have found Microsoft Visual SourceSafe to work. It works great for keeping version history. If you are not to worried about branching, which being the solo developer you may not, it might just fit the bill.
As far as checking in, finding a good checkpoint can be a challenge, but checking in on every save will only make versioning hard to track.
"Do I really need version control?"
Yes. Unless you write perfect code that never needs to get changed.
An example:
I had a requirement. I built up a webpage, spent a day or so on the page, it's Section 508 compatibility (this was about 6-7 years ago), and uploaded to the website. Next the requirement was changed drastically. I spend another day working on the page (and Hayuge Excel files didn't convert into accessible HTML easily). About a week later, client switches asks that we go back to Version A. Source control would have done this in about 10 minutes. As it was, I had to blow another %$#^^&$# day on the task.
Yes, you need version control either for development purposes or simply for storing your documents. This way, you can go back in time if you're required to do so in order to revert changes or mistake made on a code or documents.
Once you start working on a team that references ever upgrading "components" from multiple callers/applications, version control will be an absolute must. In that environment, there is no way that you can keep up with all the permutations of possible change.
You need version control just like you need insurance in life.
You need version control to manage different file versions. With it, you can get and work on the files from different places and it facilitates team members to collaborate on the same project.