How do I flag a folder as being a package?

Question

I used to think that folders needed to have an extension so that they are recognized as packages by the Finder. That extension would be declared in the owning application's Info.plist.

Obviously there is another, more elegant way, but I can't figure out how it is done.

E.g. the iPhoto Library is being treated as a package by the Finder. Yet it has no extension. mdls reveals that it indeed has "com.apple.package" in the content type tree. The actual content type is dynamically assigned.

How did iPhoto go about to create such a directory?

Answer 1

File and protocol are, to the best of my knowledge, only setup inside your apps Info.plist.

Apps get scanned, and the info in their plists get's added to LaunchServices settings.

Linkinus has 6 different Document Types declared, TextMate has 97, and CyberDuck has 3. I'll do some more searching but I think this is likely the preferred method.

Answer 2

Although you should not rely solely upon it, one thing to do is set the file's bundle bit. I've got a category on NSWorkspace to do just that:

- (void)setBundleBit:(BOOL)flag forFile:(NSString *)path
{
    FSRef fileRef;
    OSErr error = FSPathMakeRef((UInt8 *)[path fileSystemRepresentation], &fileRef, NULL);

    // Get the file's current info
    FSCatalogInfo fileInfo;
    if (!error)
    {
     error = FSGetCatalogInfo(&fileRef, kFSCatInfoFinderInfo, &fileInfo, NULL, NULL, NULL);
    }

    if (!error)
    {
     // Adjust the bundle bit
     FolderInfo *finderInfo = (FolderInfo *)fileInfo.finderInfo;
     if (flag) {
      finderInfo->finderFlags |= kHasBundle;
     }
     else {
      finderInfo->finderFlags &= ~kHasBundle;
     }

     // Set the altered flags of the file
     error = FSSetCatalogInfo(&fileRef, kFSCatInfoFinderInfo, &fileInfo);
    }

    if (error) {
     NSLog(@"OSError %i in -[NSWorkspace setBundleBit:forFile:]", error);
    }
}

Answer 3

There are two commands that may be of interest:

GetFileInfo iPhoto\ Library

attributes: avBstclinmedz

The B says that the "bundle" bit is set. The SetFile command lets you set them. These let you access the extended attributes in HFS+ (per the man page).

Here are the possible attributes:

A   Alias file
B   Bundle
C   Custom icon*
D   Desktop*
E   Hidden extension*
I   Inited*
M   Shared (can run multiple times)
N   No INIT resources
L   Locked
S   System (name locked)
T   Stationery
V   Invisible*
Z   Busy*