How to deserialize the IPXDefaultLibraryURLBookmark of the Photos plist - macos

Question

So, I've been trying to deserialize the IPXDefaultLibraryURLBookmark of the com.apple.Photos defaults (defaults read com.apple.Photos IPXDefaultLibraryURLBookmark) but no luck. Ideally I'd like a programmatic way in c++ to deserialize that value to retrieve the last known location of the photo
bookd0xUsersmateuscbPicturesPhotos Library.photoslibrary 0#˜ì5$r$Éò|åú¨A∫˙æJ file:///Macintosh HDÇ1tA∫‘}•$6465C0A4-1771-3C89-9055-147CEDFBBF2EÅÔ/∆72cd528f2dcfb4b3434986cf3caa02cc946333b8;00000000;00000000;0000000000000020;com.apple.app-sandbox.read-write;00000001;01000004;0000000002980783;/users/mateuscb/pictures/photos library.photoslibrary¥˛ˇˇˇdº‰#‘ î  H ( 8 t0 †–Ä®
I know its not a bplist, since the first format specifier denotes bookd.
But I have no clue what that is. I'm somewhat new to OSX development, so this may be something very basic I'm missing.
I want to retrieve the: /users/mateuscb/pictures/photos library.photoslibrary portion so I can find the defaults photoslibrary.
Unless there is another way to retrieve the default photoslibrary path?

Answer 1

I figured out how to retrieve the path to the .photoslibrary. I used CFURLCreateByResolvingBookmarkData to get a CFURLRef from the plist then used CFURLGetFileSystemRepresentation to get the full path as a string.
Help from this sample to retrieve sandbox preferences: https://gist.github.com/glebd/4759724
Here is my full solution:
int main(int argc, const char * argv[]) {
bool success = FALSE;
UInt8 photosUrlString[PATH_MAX];
struct passwd *pwd = getpwuid(getuid());
if (pwd == NULL){
Log("Unable to retrieve current user");
return 0;
}
const char *home = pwd->pw_dir;
if (home == NULL){
Log("Unable to retrieve current user directory");
return 0;
}
CFMutableStringRef preferencesPath = CFStringCreateMutable(NULL, 0);
if (preferencesPath) {
CFStringAppend(preferencesPath, CFStringCreateWithCStringNoCopy(NULL, home, kCFStringEncodingUTF8, NULL));
CFStringAppend(preferencesPath, CFSTR("/Library/Containers/com.apple.Photos/Data/Library/Preferences/com.apple.Photos"));
} else {
Log("Unable to create CFString of user directory");
return 0;
}
CFPropertyListRef photosUrlPrefs = CFPreferencesCopyValue(CFSTR("IPXDefaultLibraryURLBookmark"), preferencesPath, kCFPreferencesCurrentUser, kCFPreferencesCurrentHost);
CFRelease(preferencesPath);
if (photosUrlPrefs) {
CFTypeID prefsType = CFGetTypeID(photosUrlPrefs);
if (CFDataGetTypeID() == prefsType) {
CFDataRef photosUrlData = (CFDataRef) photosUrlPrefs;
CFErrorRef urlResolveError = nil;
CFURLRef photosUrl = CFURLCreateByResolvingBookmarkData(kCFAllocatorDefault, photosUrlData, NULL, NULL, NULL, NULL, &urlResolveError);
if (photosUrl == NULL) {
if(urlResolveError != NULL) {
CFStringRef resolveErrorString = CFErrorCopyDescription(urlResolveError);
if (resolveErrorString != NULL) {
char resolveErrorCString[PATH_MAX];
if (CFStringGetCString((CFStringRef) resolveErrorString, resolveErrorCString, sizeof(resolveErrorCString), kCFStringEncodingUTF8)) {
Log("Error resolving URL: %s", resolveErrorCString);
}
CFRelease(resolveErrorString);
}
} else {
Log("Error resolving URL, no resolveError");
}
} else {
success = CFURLGetFileSystemRepresentation(photosUrl, false, photosUrlString, sizeof(photosUrlString));
CFRelease(photosUrl);
}
} else {
Log("Url plist value is not CFData");
}
if (photosUrlPrefs != NULL) {
CFRelease(photosUrlPrefs);
}
}
if(success) {
Log("path: %s", photosUrlString);
}
return 0;
}