/*

     File: iTunesRSSParser.h

 Abstract: Base class for the two parsers, this class handles interactions with a delegate object (the SongsViewController in this sample) and provides basic functionality common to both parsers.

  Version: 1.4

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*/

#import <UIKit/UIKit.h>

typedef enum {

    XMLParserTypeAbstract = -1,

    XMLParserTypeNSXMLParser = 0,

    XMLParserTypeLibXMLParser

} XMLParserType;

@class iTunesRSSParser, Song;

// Protocol for the parser to communicate with its delegate.

@protocol iTunesRSSParserDelegate <NSObject>

@optional

// Called by the parser when parsing is finished.

- (void)parserDidEndParsingData:(iTunesRSSParser *)parser;

// Called by the parser in the case of an error.

- (void)parser:(iTunesRSSParser *)parser didFailWithError:(NSError *)error;

// Called by the parser when one or more songs have been parsed. This method may be called multiple times.

- (void)parser:(iTunesRSSParser *)parser didParseSongs:(NSArray *)parsedSongs;

@end

#pragma mark -

@interface iTunesRSSParser : NSObject {

    id <iTunesRSSParserDelegate> __weak delegate;

    NSMutableArray *parsedSongs;

    // This time interval is used to measure the overall time the parser takes to download and parse XML.

    NSTimeInterval startTimeReference;

    NSTimeInterval downloadStartTimeReference;

    double parseDuration;

    double downloadDuration;

    double totalDuration;

}

@property (nonatomic, weak) id <iTunesRSSParserDelegate> delegate;

@property (nonatomic, strong) NSMutableArray *parsedSongs;

@property NSTimeInterval startTimeReference;

@property NSTimeInterval downloadStartTimeReference;

@property double parseDuration;

@property double downloadDuration;

@property double totalDuration;

+ (NSString *)parserName;

+ (XMLParserType)parserType;

- (void)start;

// Subclasses must implement this method. It will be invoked on a secondary thread to keep the application responsive.

// Although NSURLConnection is inherently asynchronous, the parsing can be quite CPU intensive on the device, so

// the user interface can be kept responsive by moving that work off the main thread. This does create additional

// complexity, as any code which interacts with the UI must then do so in a thread-safe manner.

- (void)downloadAndParse:(NSURL *)url;

// Subclasses should invoke these methods and let the superclass manage communication with the delegate.

// Each of these methods must be invoked on the main thread.

- (void)downloadStarted;

- (void)downloadEnded;

- (void)parseEnded;

- (void)parsedSong:(Song *)song;

- (void)parseError:(NSError *)error;

- (void)addToParseDuration:(NSNumber *)duration;

@end