/*

File: CFNetworkLoader.m

Abstract: CFNetwork ImageClient Sample

Version: 1.0

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Inc. may be used to endorse or promote products derived from the Apple

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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

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*/ 

#import "CFNetworkLoader.h"

#import "ImageClient.h"

#import "NSURLLoader.h"

#define BUFSIZE 4096

static void handleStreamEvent(CFReadStreamRef stream, CFStreamEventType type, void *clientCallBackInfo) {

    CFNetworkLoader *self = (CFNetworkLoader *)clientCallBackInfo;

    [self handleStreamEvent:type];

}

@implementation CFNetworkLoader

- (id)initWithImageClient:(ImageClient *)imgClient {

    if (self = [super init]) {

        imageClient = imgClient; // No retain because the ImageClient instance is retaining us

    }

    return self;

}

- (void)dealloc {

    if (request) CFRelease(request);

    [self cancelLoad];

    [super dealloc];

}

- (void)loadURL:(NSURL *)url {

    // set the request for the new transaction

    if (request) CFRelease(request);

    request = CFHTTPMessageCreateRequest(NULL, CFSTR("GET"), (CFURLRef)url, kCFHTTPVersion1_1);

    // Start the load

    [self loadRequest];

}

- (void)loadRequest {

    // Cancel any load currently in progress

    [self cancelLoad];

    // Start a fresh data to hold the downloaded image

    data = CFDataCreateMutable(NULL, 0);

    readStream = CFReadStreamCreateForHTTPRequest(NULL, request);

    CFStreamClientContext context = {0, self, NULL, NULL, NULL};

    CFReadStreamSetClient(readStream, kCFStreamEventHasBytesAvailable | kCFStreamEventEndEncountered | kCFStreamEventErrorOccurred, handleStreamEvent, &context);

    CFReadStreamScheduleWithRunLoop(readStream, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);

    CFReadStreamOpen(readStream);

}

- (void)cancelLoad {

    if (readStream) {

        CFReadStreamClose(readStream);

        CFReadStreamSetClient(readStream, kCFStreamEventNone, NULL, NULL);

        CFReadStreamUnscheduleFromRunLoop(readStream, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);

        CFRelease(readStream);

        readStream = NULL;

    }

    if (data) {

        CFRelease(data);

        data = NULL;

    }

}

// Callback for CFReadStream

- (void)handleStreamEvent:(CFStreamEventType)event {

    switch (event) {

        case kCFStreamEventHasBytesAvailable: {

            UInt8 buffer[BUFSIZE];

            int bytesRead = CFReadStreamRead(readStream, buffer, BUFSIZE);

            if (bytesRead > 0) {

                CFDataAppendBytes(data, buffer, bytesRead);

            }

            // Don't worry about bytesRead <= 0, because those will generate other events

            break;

        }

        case kCFStreamEventEndEncountered: 

            [imageClient setImageData:(NSData *)data];

            [self cancelLoad];

            break;

        case kCFStreamEventErrorOccurred: {

            CFNetDiagnosticRef diagnostics = CFNetDiagnosticCreateWithStreams(NULL, readStream, NULL);

            [imageClient errorOccurredLoadingImage:diagnostics];

            [self cancelLoad];

            break;

        }

        default:

            NSLog(@"Received unexpected stream event %d\n", event);

    }

}

@end