Using NSFileWrapper in NSDocument made of various files

cocoa, nsdocument, nsfilewrapper

Solution

Putting together bits and pieces from the documentation:

- (NSFileWrapper*) fileWrapperOfType:(NSString *)typeName error:(NSError *__autoreleasing *)outError {
    return self.documentFileWrapper;
}

- (BOOL) readFromFileWrapper:(NSFileWrapper *)fileWrapper ofType:(NSString *)typeName error:(NSError *__autoreleasing *)outError {
    self.documentFileWrapper = fileWrapper;
    return YES;
}

- (void) addFileToDocumentFromURL:(NSURL*)fileURL {
    NSData* fileData = [NSData dataWithContentsOfURL:fileURL];
    NSFileWrapper *fileWrapper = [[NSFileWrapper alloc] initRegularFileWithContents:fileData];
    fileWrapper.preferredFilename = [fileURL lastPathComponent];
    [self.documentFileWrapper addFileWrapper:fileWrapper];
    [self updateChangeCount:NSChangeDone];
}

- (void) removeFileFromDocumentWithName:(NSString*)name {
    NSFileWrapper *fileWrapper = [self.documentFileWrapper.fileWrappers objectForKey:name];
    if (fileWrapper) {
        [self.documentFileWrapper removeFileWrapper:fileWrapper];
        [self updateChangeCount:NSChangeDone];
    }
}

- (NSFileWrapper*) documentFileWrapper {
    if (!_documentFileWrapper) { // New document
        _documentFileWrapper = [[NSFileWrapper alloc] initDirectoryWithFileWrappers:nil];
    }
    return _documentFileWrapper;
}

Problem

I'm making a document-based Cocoa app in which the document is dynamic a collection of files (users can add or remove files). In particular, the Save and Open operations should be as fast as possible. If I understand the documentation correctly, I should use `NSFileWrapper` and implement `fileWrapperOfType:error` and `readFromFileWrapper:ofType:error:`. However, I can't find a complete code example. How should I implement the following methods? ``` #pragma mark - NSDocument - (NSFileWrapper *)fileWrapperOfType:(NSString *)typeName error:(NSError **)outError { return nil; } - (BOOL)readFromFileWrapper:(NSFileWrapper *)fileWrapper ofType:(NSString *)typeName error:(NSError **)outError { return YES; } #pragma mark - My methods - (void) addFileToDocumentFromURL:(NSURL*)fileURL { // Add a file to the document given the file URL } - (void) removeFileFromDocumentWithName:(NSString*)name { // Remove a file from the document given the file name } ```

Original source