/*

File: URLDataReceiver.h

Abstract: A Class encapsulating the asynchronous loading functionality of NSURLConnection.

Version: 1.0

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*/ 

#import <Cocoa/Cocoa.h>

/*!

 * @abstract Load data from a URL.

 *

 * This class asynchronously load data from a URL using NSURLConnection.

 */

@interface URLDataReceiver : NSObject {

    int fStatus;

    NSURL* fURL;

    NSMutableData* fReceived; /**< Received data */

    NSError* fError; /**< Last error if an error occurs during loading.*/

    id fDelegate;

    NSRecursiveLock* fLock;

    NSURLConnection* fConnection;

}

/*!

 * delegate must conform to URLDataReceiverDelegate protocol.

 */

- (id)initWithURL:(NSURL*)aURL delegate:(id)delegate;

/*!

 * @abstract Start loading data.

 */

- (void)startLoading;

/*!

 * @abstract Cancel data loading.

 *

 * It does nothing, if it is not currently loading.

 * Cacelling will reset the data that has been received.

 */

- (void)cancel;

/*!

 * @abstract return received data.

 *

 * Return nil if the loading failed or encountered any errors.

 */

- (NSData*)receivedData;

- (NSURL*)url;

/*!

 * @abstract Return last error.

 *

 * @note The return value can be nil, which indicates a successful load.

 */

- (NSError*)lastError;

@end

/*!

 * @abstract URLDataReceiverDelegate protocol.

 */

@interface NSObject(URLDataReceiverDelegate)

/*!

 * @abstract Notify delegate that loading has finished.

 *

 * The delegate can use lastError to query if there is any error.

 */

- (void)URLDataReceiverDidFinish:(URLDataReceiver*)dataReceiver;

@end