Question

To help simplify debugging of some custom Objective-C objects in the Xcode debugger window, I’ve created a set of data formatter strings for each of the objects, using the related Apple documentation and Xcode’s built-in data formatters as a guide.

My custom summary strings work great if I put it in /Developer/Library/Xcode/CustomDataViews/ with the data formatters that ship with Xcode. However, I’d rather not do that since a user may not have write privileges to that directory, and mixing custom formatters with the built-in ones can be confusing. Similarly, adding my own entries to ~/Library/Application Support/Apple/Developer Tools/CustomDataViews/CustomDataViews.plist also works, but that file is for user-defined values that override the defaults, and its entries are clobbered by changes in the Xcode debugger GUI. What I really want is to be able to place a file with my data formatters in a location so Xcode recognizes them, but users can still selectively override my settings (in another file) if desired.

The problem is that when I create a bundle (following the example of this Apple sample code) and install it (either in /Developer/Library/Xcode/CustomDataViews/ or any Library/Application Support/Apple/Developer Tools/CustomDataViews/ path), Xcode doesn’t recognize or use the custom formatters.

The documentation on the specifics of data formatter bundles is somewhat scanty (mostly a single header file in Xcode.app/Contents/PlugIns/GDBMIDebugging.xcplugin), possibly because the functionality isn’t one of the headline features of Xcode. 😉 Any help would be greatly appreciated.

Answer 1

I’ve recently been able to come back to this, and I believe I’ve found the answer.

I already knew that a data formatter bundle must include the property list file internally, named “Contents/Resources/*.plist“. However, for the bundle to actually work, it must also include an executable with the same name as the bundle in the Contents/MacOS/ directory. As far as I can tell, even a completely empty foo.c file is sufficient as long as you compile and link a binary. I didn’t even have to touch the Info.plist for a stock CFPlugin Bundle project in Xcode, just include the CustomDataViews.plist in the target resources.

Since I don’t need to define C functions to display any of the objects and structs I’m dealing with, the far easier approach is to just put the plist file (any name will do — mine is CHDataStructures.plist) into one of two locations:

• ~/Library/Application Support/Developer/Shared/Xcode/CustomDataViews/
• /Library/Application Support/Developer/Shared/Xcode/CustomDataViews/

Simple plist files are smaller, trivial to create, and easier to modify. Also, unlike when using bundles, I didn’t have to relaunch Xcode when I added, removed, or modified the plist; just starting a new debugging session was sufficient to cause new the data formatters to be updated. I think I was only creating a bundle because that’s what the sample code showed, but I can’t determine any advantages for my scenario, so I’m sticking with the plist.