gistfile1.m

int main(int argc, const char * argv[])
{
    @autoreleasepool {
        
        
        // Create a pretend Desktop and Documents folder
        NSString * desktopFolderPath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"Desktop"];
        NSString * documentsFolderPath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"Documents"];
        [[NSFileManager defaultManager] createDirectoryAtPath:desktopFolderPath withIntermediateDirectories:NO attributes:nil error:nil];
        [[NSFileManager defaultManager] createDirectoryAtPath:documentsFolderPath withIntermediateDirectories:NO attributes:nil error:nil];
        
        
        // URLs which we will reference
        NSURL * projectURLInDesktop = [NSURL fileURLWithPath:[desktopFolderPath stringByAppendingPathComponent:@"Project"]];
        NSURL * resourceURLInDesktop = [NSURL fileURLWithPath:[desktopFolderPath stringByAppendingPathComponent:@"Resource"]];
        NSURL * projectURLInDocuments = [NSURL fileURLWithPath:[documentsFolderPath stringByAppendingPathComponent:@"Project"]];
        NSURL * resourceURLInDocuments = [NSURL fileURLWithPath:[documentsFolderPath stringByAppendingPathComponent:@"Resource"]];
        
        
        
        
        // 1) User creates a file named Resource on the desktop
        [[NSData data] writeToURL:resourceURLInDesktop atomically:YES];
        
        // 2) User uses our application to create a project file named Project on the Desktop
        [[NSData data] writeToURL:projectURLInDesktop atomically:YES];
        
        
        
        // 3) User adds a reference to Resource into the project. Project will
        // contain an NSURL bookmark to Resource, and that bookmark will be
        // relative to the Project file's URL on the desktop.
        NSData * resourceBookmarkData = [resourceURLInDesktop bookmarkDataWithOptions:0
                                                       includingResourceValuesForKeys:nil
                                                                        relativeToURL:projectURLInDesktop
                                                                                error:nil];
        
        
        // 4) Pretend that resourceBookmarkData is saved into the Project file
        // 5) Pretend that time has passed and our application has been quit.
        
        
        // 6) In Finder, let's say the user takes Project and Resource off of
        // the Desktop and moves them both into the Documents folder.
        [[NSFileManager defaultManager] moveItemAtURL:projectURLInDesktop toURL:projectURLInDocuments error:nil];
        [[NSFileManager defaultManager] moveItemAtURL:resourceURLInDesktop toURL:resourceURLInDocuments error:nil];
        
        
        // 7) Pretend that the user now creates a new file named Resource on
        // the Desktop. This file is entirely unrelated to Project.
        [[NSData data] writeToURL:resourceURLInDesktop atomically:YES];
        
        
        // 8) The user now opened our application again, and opens the Project.
        // When Project opens, it should resolve the bookmark data which
        // points to Resource. Since we saved the bookmark data as relative
        // to the Project file URL, when resolving the URL, it should be resolved
        // relative to the current Project file URL.
        NSURL * resolvedResourceURL = [NSURL URLByResolvingBookmarkData:resourceBookmarkData
                                                                options:0
                                                          relativeToURL:projectURLInDocuments
                                                    bookmarkDataIsStale:NULL
                                                                  error:nil];
        
        // 9) At this point, we expect that the resolved URL should point to
        // the Resource file in the Documents folder, however it resolves
        // to the Resource file in the Desktop folder.
        
        // When the bookmark was created the relative path from Project to
        // Resource was simply "../Resource". When resolving the bookmark,
        // given that Project is in Documents, the resolved URL should
        // be "Documents/Project" + "../Resource" = "Documents/Resource".
        
        NSLog(@"Resolved URL file path should end in Documents/Resource.");
        NSLog(@"Resolved URL file path: %@", [resolvedResourceURL relativePath]);
        
        
        
        // --- Cleanup ---
        [[NSFileManager defaultManager] removeItemAtURL:resourceURLInDesktop error:nil];
        [[NSFileManager defaultManager] removeItemAtURL:projectURLInDocuments error:nil];
        [[NSFileManager defaultManager] removeItemAtURL:resourceURLInDocuments error:nil];
        [[NSFileManager defaultManager] removeItemAtPath:desktopFolderPath error:nil];
        [[NSFileManager defaultManager] removeItemAtPath:documentsFolderPath error:nil];
    }
    return 0;
}