/*

File: URLLoading.m

Abstract: A Class controlling loading multiple URLs.

Version: 1.0

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*/

#import "URLLoader.h"

/*!

 * @abstract Private routines.

 */

@interface URLLoader(Private)

- (void)notifyDidBeginURL:(NSURL*)aURL;

- (void)notifyDidFinishURL:(NSURL*)aURL;

- (void)notifyDidFinishAll;

@end

@implementation URLLoader

- (id)initWithDelegate:(id)delegate {

    self = [super init];

    if (self == nil) return nil;

    fFinished = [NSMutableDictionary new];

    fPending = [NSMutableDictionary new];

    fLock = [NSRecursiveLock new];

    fDelegate = delegate;

    return self;

}

- (void)dealloc {

    [fLock lock];

    [fPending release];

    [fFinished release];

    [fLock unlock];

    [fLock release];

    [super dealloc];

}

- (void)load:(NSArray*)URLs {

    [fLock lock];

    [fPending removeAllObjects];

    [fFinished removeAllObjects];

    unsigned i=0;

    for (; i<[URLs count]; ++i) {

        //create a URLDataReceiver instance for each URL.

        URLDataReceiver* receiver = [[URLDataReceiver alloc] 

                                        initWithURL:[URLs objectAtIndex:i]

                                        delegate:self];

        //put the newly created receiver into pending list.

        [fPending setObject:receiver forKey:[URLs objectAtIndex:i]];

        [receiver startLoading];

        [receiver release];

        //notify the delegate.

        [self notifyDidBeginURL:[URLs objectAtIndex:i]];

    }

    [fLock unlock];

}

- (void)cancel {

    [fLock lock];

    [fPending removeAllObjects];

    [fFinished removeAllObjects];

    [fLock unlock];

}

- (void)reset {

    [self cancel];

}

- (NSData*)dataForURL:(NSURL*)aURL {

    [fLock lock];

    URLDataReceiver* receiver = [fFinished objectForKey:aURL];

    [fLock unlock];

    if (receiver == nil)

        return nil;

    else

        return [receiver receivedData];

}

- (NSEnumerator*)dataEnumerator {

    return [fFinished objectEnumerator];

}

- (NSEnumerator*)urlEnumerator {

    return [fFinished keyEnumerator];

}

/////////////////// URLDataReceiverDelegate Protocol //////////////////

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

    [fLock lock];

    NSURL* url = [dataReceiver url];

    //move receiver from pending list to finished list.

    [fPending removeObjectForKey:url];

    [fFinished setObject:dataReceiver forKey:url];

    //notify delegate that this url has finished.

    [self notifyDidFinishURL:url];

    //if pending list is empty, notify delegate that all URLs have finished.

    if ([fPending count] == 0)

        [self notifyDidFinishAll];

    [fLock unlock];

}

///////////////// Private /////////////////////////

- (void)notifyDidBeginURL:(NSURL*)aURL {

    if (fDelegate && [fDelegate respondsToSelector:@selector(URLLoader:didBeginURL:)])

        [fDelegate performSelector:@selector(URLLoader:didBeginURL:) withObject:self withObject:aURL];

}

- (void)notifyDidFinishURL:(NSURL*)aURL {

    if (fDelegate && [fDelegate respondsToSelector:@selector(URLLoader:didFinishURL:)])

        [fDelegate performSelector:@selector(URLLoader:didFinishURL:) withObject:self withObject:aURL];

}

- (void)notifyDidFinishAll {

    if (fDelegate && [fDelegate respondsToSelector:@selector(URLLoaderDidFinishAll:)])

        [fDelegate performSelector:@selector(URLLoaderDidFinishAll:) withObject:self];

}

@end