Important information on using QLColorCode with Xcode v3.2 and later

Xcode 3.2 (the version shipped with Snow Leopard) includes a Quick Look plugin that highlights source code. It only highlights a few languages, so you probably still want to use QLColorCode. However, the Quick Look server tends to pick the Xcode plugin over QLCC. This means that for any source code file aside from .c, .m, and the other languages that Xcode understands you'll see a plain text preview with no highlighting. To get QLCC to work properly you'll need to disable the Xcode plugin.

Symptoms

If you're having this problem you'll notice that:

1. .c, .m, and other "Xcode-approved" file types have highlighting. (The Xcode plugin handles them)
2. More obscure file types (.ml, .scala, .as, etc) do not have highlighting. (The Xcode plugin knows they're source code, thanks to QLCC, but doesn't know how to highlight them.) To test this, put the following into a file called foo.ml and quick look it. If the open keywords are not highlighted then you're experiencing the problem:

open Foo
open Bar

3. .plist files display as XML, with highlighting. (Xcode's plugin doesn't accept .plist files, so QLCC still gets them. If this doesn't work then QLCC isn't installed properly.)

Scripts

I have created two Applescripts to easily disable and restore the Xcode plugin with a simple double-click. They can be found in the Downloads section, named QLColorCodeScripts. If you want to know how to do it by hand, read on.

Details

The Xcode plugin is installed at:

/Developer/Applications/Xcode.app/Contents/Library/QuickLook/SourceCode.qlgenerator

The simplest way to disable it is to open Terminal.app and run these commands:

f=/Developer/Applications/Xcode.app/Contents/Library/QuickLook/SourceCode.qlgenerator
sudo mv $f.disabled /tmp/   # Move aside any previously disabled version
sudo mv $f $f.disabled

This will rename the plugin to SourceCode.qlgenerator.disabled, which will prevent it from being loaded by quicklookd. You will need to repeat this if you upgrade or reinstall Xcode.

A Note on Code Signing

The Xcode application is cryptographically signed. Disabling the SourceCode.qlgenerator plugin is safe: it will NOT invalidate the signature. You can confirm this by using the codesign command after disabling the plugin:

[n8gray@golux]% codesign -vv /Developer/Applications/Xcode.app
/Developer/Applications/Xcode.app: valid on disk
/Developer/Applications/Xcode.app: satisfies its Designated Requirement