Outlining a UIView

I recently was having some difficulty with some drawing in a UIView and decided that outlining the bounds of the view itself would help me to debug the problem.  (It did.  Instantly.)  All you have to do is to stroke the bounds rectangle of the view you’re in (this assumes you have already subclassed UIView for your custom view).  Add the following code to your drawRect: method:

  CGContextRef context = UIGraphicsGetCurrentContext();
  CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
  CGContextStrokeRect(context, self.bounds);

Update 17-Feb-2010:

This can be done without subclassing (or with, if you prefer) very easily. Simply access the view’s CA layer and set the border on it:

[[aView layer] setBorderWidth:1.0];

Sending email when a file changes in git

I am collaborating on a project right now where multiple developers may be making changes to a single Xcode project. Since in my experience, Xcode project files “don’t merge well,” we have setup git so it treats the Xcode project file (project.pbxproj) as if it were a binary. Consequently, it sucks to have too many outstanding changes to the Xcode project file that have to be merged back in manually. To help shorten the amount of time someone might be working on an out of date Xcode project file, I setup a post-commit hook on the git repository that sends email to the developers in case this particular file changes.


  1. Add the following “hooks” section to the config file for the target git repository, of course updating the email(s) as appropriate:
    	mailinglist = you@example.com someoneelse@example.com


  2. In the “hooks” directory in your repository, you should find a file named “post-commit.”  Add the following to the file:
    git show --pretty="format:" --name-only HEAD | grep project.pbxproj
    if [ $? -eq 0 ]; then
    	mail $(git config hooks.mailinglist) -s "Xcode project changed" <<-EOF
    Please pull the latest Xcode project.


  3. Make the post-commit file executable if you have not done so already.
    chmod +x post-commit


That’s it! Piece o’ cake, huh?  Anyway, even if my logic regarding the “mergability” (or lack thereof) of an Xcode project is flawed, the principle behind email notification on a single file is still valid.  I’m sure generalizing this to notify upon changes to a list of files is easy enough.

CruiseControl.rb+git (+xcodebuild!) on Mac OS X

With some encouragement from my colleagues, I expanded the original post here to be a more soup-to-nuts recipe for setting up CC.rb with git and xcodebuild on Mac OS X. Thanks, guys!

I am currently working on a cross-platform project which has multiple targets that need to build on Mac OS X. On my previous project, we were using CruiseControl.rb on linux to watch a Subversion repository for a Rails project and run all the associated tests upon checkin. Since we wanted to be like the Cool Kids on this new project, we of course decided to use git for source code management.  We use gitosis to manage multiple remote git repositories under a single user.  However, you can use any approach you want for the remote repository management as long as you can compose a git URL that points to it.


  • You have a Mac that is probably not your development machine that will serve as a Continuous Integration (CI) server.
  • You have a remote git repository that the CI machine can monitor and pull changes from.

It took a little doing to make CC.rb play nice on Mac OS X.  In addition to the typical CC.rb installation, getting CC.rb to launch at system startup using launchd took the proper file in the proper location. Nevertheless, the whole setup is pretty darned straightforward.  Here’s how I did it:

  1. I created a user named “continuousintegration.”  You can name yours anything you like, or use an existing user.  Log in as this user.
  2. Download and install CruiseControl.rb.  I unpacked it into the the home directory of the continuousintegration user.  So, the absolute path to the CC.rb installation directory in my case is:  /Users/continuousintegration/cruisecontrol.rb.
  3. Create the work directory for CC.rb.  In my case, I use /var/cruise as the work directory.  This required admin privileges to create; just make sure that your CI user has access to this directory.
    sudo mkdir /var/cruise
    sudo chown continuousintegration /var/cruise


  4. Add your git repository to CC.rb.
    cd ~/cruisecontrol.rb
    ./cruise add <project name> --url <git repository url> -s git


  5. At the root level of your git repository, add a file named cruise_config.rb. This provides some useful configuration information so that CC.rb knows what to do in order to build your project as well as whom to notify when the build fails. You provide the build command for CC.rb in cruise_config.rb by assigning to project.build_command. I actually made my build command point to ./ci_build.sh so that I can do anything I want for the build in a separate shell script named ci_build.sh in the git repository root. In my case, I am actually running xcodebuild to build a target I created in my Xcode project; you can do literally anything you want here, e. g. make check, rake… whatever! Witness my cruise_config.rb and ci_build.sh files. (If you create a ci_build.sh or equivalent file, be sure you make it executable.) Make sure you git push your changes to add the cruise_config.rb (and ci_build.sh if you choose to do so).
  6. You should now be able to start up CC.rb and look at the dashboard to see your project.
    ./cruise start

    Browse to http://localhost:3333

  7. Wait! You’re not finished yet! There’s one more step: setting up CC.rb to start every time the system starts up. This is accomplished by creating a plist file in /Library/LaunchDaemons which starts up CC.rb. (For more information on what’s going on here, see the Apple documentation or man launchd.)
    Download this plist file and copy it into /Library/LaunchDaemons

    sudo cp localcruisecontrol.plist.txt /Library/LaunchDaemons/local.cruisecontrol.plist

    Now when you restart the CI machine, CC.rb should start up automatically.

Setting up CC.rb all by itself tends to be pretty easy; it’s getting the daemon to run at system startup as well as getting your build to work properly that tend to be the problems. If you’re having trouble getting things running after following these directions, or if you find errors in these directions, please let me know.

Setting ruby executable path in TextMate

I just recently received an update to TextMate.  However, I discovered that I could no longer Run Focused Unit Test as it would complain:

in `check_gem_dependencies': undefined method `ruby_version' for Gem:Module (NoMethodError)

I got a clue when I noticed in the RubyMate window that the patch level of the ruby interpreter was different from the patch level of the ruby I use from a Terminal window.  Clearly, TextMate was using a different Ruby executable than I was the rest of the time.

I poked around in the Ruby bundle a little bit and noticed references to a variable TM_RUBY.  Looking around some more, I discovered in the Preferences under Advanced there is a Shell Variables tab.  I added a TM_RUBY variable there and pointed it to the ruby I wanted it to use (/usr/local/bin/ruby in my case).  Restarted TextMate, et voilà — Run Focused Unit Test works perfectly again.

Modern Day COMO File

We used to use command output (COMO) files all the time way back in the days of PRIMOS. Funny how I accidentally stumbled upon the Unix equivalent today — the script command — approximately 25 years later. Not sure what I’d use it for since we have redirection on Unix, but always good to learn something new.

Retain/Release, Properties, and ‘self’

I think I learned something today about Objective C properties and retain.  It seems that in a method where you reference a property, you need to use the form “self.property_name” if you want the assigned object to be automagically retained.  If you simply say “property_name = some_object” it doesn’t retain some_object!

Witness the source code and the associated results:

Source: Retain Release main.m


2008-12-22 20:52:18.824 RetainRelease[3623:10b] Before assignment: [a retainCount] = 1
2008-12-22 20:52:18.837 RetainRelease[3623:10b] After assignment: [a retainCount] = 1
2008-12-22 20:52:18.838 RetainRelease[3623:10b] Before assignment: [b retainCount] = 1
2008-12-22 20:52:18.839 RetainRelease[3623:10b] After assignment: [b retainCount] = 2
2008-12-22 20:52:18.842 RetainRelease[3623:10b] Final [oo retainCount] = 2

Seems to me proof that when you’re assigning to them, you should always reference properties on an object by prefixing them with “self“.

Caveat: Inside of the setter method for a property, do NOT use the “self.property” syntax. Otherwise, you end up in a infinite loop. Ask me how I know. 🙂 This is the best (and only) argument I can see for having a different behavior between the “self.property =” and “property =” usages.

Excellent summary of retain/release/autorelease

From this page on wikipedia:

In practice, retain, release and autorelease are straightforward. Some people seem to find it confusing but perhaps they think it’s more complicated than it is. To keep an object you’re given, retain it. Objects you make are already retained. To throw it away and refer to it no more, release it. If you write a factory method, autorelease it. If you are simply making use of an object returned by a factory method for a short while, do nothing.