Category: Xcode


September 29th, 2009 — 2:44pm

I’ve finally gotten around to consolidating most of the bits of code I’ve posted on this blog over the years and put it in a repository. While the real NoodleKit is a much more extensive and cohesive toolkit that I use internally, this one will serve as a place where I put the odd scraps that I decide to open source. I guess I could’ve called it NoodleScraps but it doesn’t quite sound as nice.

If you’ve been following my blog for a while then there’s not much new here, codewise. There are a tweaks here and there plus the stuff should be 64-bit ready so it might be worth re-downloading just for that. It will be the place where I put future code so you should keep an eye on it.

The project is structured to build a framework but also has an examples directory (with corresponding targets) to demonstrate the use of the different classes. The current notion is to keep things compatible with 10.5. And, as usual, all code is released under the MIT license.

NoodleKit (hosted at github)


Comment » | Cocoa, Downloads, OS X, Programming, Quartz, User Interface, Xcode

Adventures in Debugging: Pref Pane Poppin’ Aplenty

April 23rd, 2008 — 3:34pm

As you may or may not know, Hazel is packaged as a preference pane. While you do all the configuration via the preference pane interface, the actual work of running your rules is done by background processes. The commandline tool that actually runs the rules is stored inside the pref pane bundle. I’ve kept it in the Resources part of the bundle for no good reason except that’s the catch all for all your bundle stuff. But then I thought, “why not stick it in the MacOS dir. That’s where executables are supposed to go, right?”

So, I went into XCode and created a new “Copy Files” phase to copy the built executables into the “executables” dir (which ends up being the MacOS dir in your bundle). I modified the code that launches the program to look in the right place (NSBundle’s -pathForAuxiliaryExecutable: for those of you keeping score at home). It seemed to work. My bundle was now a tad tidier with things in their proper place.

Later on, I was testing something else and noticed that when Hazel was running certain rules, the pref pane icon would show up in the dock and then disappear when the background program was done. Strange enough that a pref pane icon would appear in the dock; stranger that it was being triggered by a non-GUI program. More testing revealed that it happened when Hazel was executing AppleScripts. I tried isolating the AppleScript parts. I checked all sorts of paths. I couldn’t figure out what was causing it. The Pope was in town so maybe he was messing things up somehow.

I checked previous versions to isolate when the bug was introduced and discovered it was only in the last set of changes. Moving the executables back to Resources fixed it.

Problem solved but I had no idea why. After muttering about it in IRC, Mike Ash casually throws out the explanation: “the binary is hitting the window server, the window server notices that it’s in an executable directory of a bundle, sticks it in the Dock.”

Of course, it all sounds so simple when you hear the answer. Calling the AppleScript created the window server connection which then prompted it to throw the icon in the dock as if it were a regular app. Not sure how long it would have taken me to figure that out on my own.

The lesson here is that when faced with a crazy bug, ask Mike Ash. Really, though, don’t do that. He’ll crash his glider into me next chance he gets. The real lesson is that you should be careful about putting executables for background programs in the MacOS directory of your bundle.

Ok, so I can’t pin this one on the Pope. All I know is that I don’t get these types of problems when the Dalai Lama is in town.

2 comments » | Cocoa, Debugging, Hazel, Programming, Xcode

Weak Linking

December 5th, 2007 — 6:05pm

It’s been a while since I posted. Since then, Leopard has been released and it’s been keeping me busy. Now that I’ve finally upgraded my dev machine to Leopard, I’ve started implementing Leopard-specific functionality. I still want to maintain Tiger-compatibility but there are cases where I need to reference new symbols in Leopard. These articles 1 2 tell you what you need to know, though I thought I’d provide a boiled down guide to what you need to do.

For the purposes of this article, we’ll assume we want a binary that will run on Tiger or later but have access to Leopard-only functionality. In this case, the deployment target is Tiger and the Target SDK (which API version you are using) is Leopard.

  • In Xcode, Project->Edit Project Settings->General. For Cross-Develop Using Target SDK, select the latest OS version whose features you want to use. In this case, Mac OS X 10.5
  • targetsdk.png

  • Click on the Build tab. Make sure the Configuration pop-up is set to All Configurations. Set Mac OS X Deployment Target to the minimum OS version you want to support (Mac OS X 10.4).
  • deploymenttarget.png

In most cases, this is all you need to do. Why’s that? It’s because Apple defines Availability macros that they use to set what symbols are available for different OS releases, based on the settings you just made above. If your target SDK is a later version than your deployment target, the symbols unique to the later target are weak-linked. This means that if the symbol does not exist, it will be set to NULL. As indicated in the articles linked above, you can compare these symbols to NULL before using them. Note that this mostly pertains to things like C functions. For Objective-C, you can check for the existence of classes using NSClassFromString(). For methods, just use -respondsToSelector:. What this all allows is for your program to dynamically use Leopard-specific functionality if it’s available. You can test for specific functionality without relying on doing a broader OS version check.

Of course, there are cases where things don’t work out of the box. For instance, it seems the headers for some lower level APIs aren’t set up with the Availability macros. In such a case, you can do your own prototype, this time asserting the weak linking:

extern void somefunction() __attribute__((weak_import));

If you don’t do this, somefunction() will end up being non-null even on older OS versions which will screw up your check for the function’s existence.

And then there are issues that aren’t based on API so much as behavior. For instance, if there was a bug in Tiger that was fixed in Leopard. It’s not the type of thing your program can detect so in such cases you’ll have to resort to version checking.

Nothing particularly new here but thought it might be helpful for people doing the OS version straddle for the first time.

1 comment » | Carbon, Cocoa, OS X, Programming, Xcode

XCode Odds & Ends: Automated Builds

April 5th, 2007 — 1:38pm

It is a bit serendipitous that Gus Mueller’s discussion of Automated Builds on the Late Night Cocoa podcast should happen soon after I finally got my own act together and automated most of my build process. So, taking advantage of the momentum I thought I’d ramble on for a bit on the topic.

My process does not do as much as Gus’ (I don’t automatically upload) and it’s all triggered from within XCode when I do a Release build (Gus uses a script) but the important part is in the end I have a procedure that does most of the tedious parts for me. The problem with automating the process with XCode is that there are certain types of phases or resources that it doesn’t not handle natively so you have to script them yourself or it’s not obvious how to do it the right way. I thought I’d go over a couple of the oddball cases. Not all will be applicable but hopefully you can find something useful.

Code Stripping

This is something I neglected to deal with for the longest time. The notion is to strip your code but keep an unstripped version around so that you can use it with atos when you get a stack trace. I never got around to figuring out the right combination of settings on my own but this post gives you everything you need. Just stick this in a shell script phase after the product is built and use the XCode settings outlined in the comments. A big thanks to Andy O’Meara and Rob Barris for figuring it all out and sharing.

Building DMGs

This is one a bit trickier. Everyone seems to have their own methods and requirements for this so I’ll just point out some specific things here. First off, it’s all done with hdituil. If you don’t feel like learning hdiutil there are higher-level commandline programs and scripts you can use such as buildDMG or DropDMG (the latter is a GUI app which also comes with a commandline program).

In my case, I don’t construct the DMG from scratch. I created a template disk image with placeholders for my files. There are ways to deal with icon positioning programmatically but really, it’s just easier to do it by hand, save the image and use it over and over again. During a build, I mount the disk image, replace the files and then unmount. The disk image is then converted to a compressed format. For the mounting part, use the “-private” flag. It prevents Finder from seeing it so you don’t have to deal with the DMG window popping up while it’s being packaged. Unfortunately, my current script has some quirks specific to me so I’m not posting it but feel free to drop me a line if you have questions.

Also, credit goes to Jonathan Wight for providing the ideas and script that formed the basis of the DMG build procedure outlined above.

Useful Commandline Tools

If you are building an app then this is not an issue but for preference panes, it’s common to have a customized Finder icon for the .prefPane file itself (note that the icon specified in your bundle is for within the System Preferences app). For this, I downloaded the osxutils package. It contains a commandline program called “seticon” which, as the name indicates, sets an icon on a file. There are other little commandline programs to do things like set the Finder comment or the color label.

[Update: Tom Harrington was kind enough to point out my boneheadedness. Setting bundle icons in Info.plist for pref panes works fine so using the seticon program above is totally unnecessary. There was a misconfiguration in my project that lead to my faulty assumption that you had to set it separately.]

There’s also SetFile (comes with the dev tools) which is useful for setting HFS+ attributes. For instance, if you want to script setting the background image file in your DMG to be invisible, a SetFile -a V yourfile will do the trick.

So, basically most of the things you can and want to do to files in the Finder can be done on the commandline (therefore making them available for scripts).

XCode and External Targets/Dependencies

This is something that I always forget how to do. If your project has a dependency on some other project, such as a framework, you can drag the xcodeproj file into your project. But to create an actual dependency between your target and the external target, you can’t drag the thing underneath your target nor can you do a “Get Info” on the external target and check off the targets it’s a part of. Instead, select your target and do a “Get Info” on it. Under the “General” tab, hit the plus (+) button at the bottom to add the external product as a dependency. Also, you need to have both projects build to the same directory (“Get Info”->”General” tab). Now, building your target will build the dependent target as necessary. The important thing is that you do not depend on specific files. If you find yourself typing in paths that refer to another project’s build directory, you are probably doing it incorrectly.

XCode and Applescripts

I have some Applescripts in my project. Before, I saved them as .scpt files which are already compiled. Because they were already compiled, XCode’s “Compile AppleScripts” phase didn’t apply. Since I wanted to convert them to be “Run only”, I added a shell script build phase to use osacompile but this was a little clunky. I had to run it once to get XCode to generate the new .scpt files and then I added those to the XCode project so that they could be copied into the bundle during a build.

Instead of using .scpt, I now use plain, uncompiled .applescript files. XCode knows how to deal with these via the “Compile AppleScripts” phase. To make the compiled script “Run only”, add “-x” to the OTHER_OSAFLAGS setting in your build settings. Note that you may have to add “OTHER_OSAFLAGS” if it doesn’t exist.

• • •

So, that’s it for my random XCode tips. My build procedure is not perfect. I need to better automate versioning but for now it’s relatively pain free. If you have any tidbits, post them here.

2 comments » | Xcode

Search and Replace in Xcode

January 27th, 2007 — 5:59pm

This issue came up twice in the past couple weeks thus triggering my rule that if something comes up more than once then others may be interested in it. So, here’s a little tip that may save you some frustration.

When using regular expressions with Xcode’s search, the docs mention that XCode uses the ICU library. Naturally, you’d think it would use ICU’s syntax for specifying backreferences in the replace string, which would be to use variables consisting of a dollar sign ($) followed by the number of the capture group being referenced.

Of course, if that were the case, I probably wouldn’t be writing this tip. Using $ for backreferences turns “Search & Replace” into “Search & Destroy”. The syntax is to use backslash (\) instead of dollar sign. In short, \1 instead of $1.

Type the following in an Xcode editor window: “$1 works in replace strings.”

Now perform the following search & replace:


Ok, maybe this example makes things more confusing. If in doubt, just remember: $ = bad, \ = good in Xcode Find panel.

As to why Xcode does not use the ICU syntax in the replace strings, beats me. If anyone has a simple explanation, send it my way though I also welcome apocryphal anecdotes and crackpot conspiracy theories (extra points if you can convincingly implicate the Trilateral Commission).

11 comments » | OS X, Programming, Software, Xcode

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