/*

File: CFNetworkLoader.m

Abstract: CFNetwork ImageClient Sample

Version: 1.0

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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];

}

static void proxyChanged(SCDynamicStoreRef store, CFArrayRef changedKeys, void *info) {

    CFNetworkLoader *self = (CFNetworkLoader *)info;

    [self proxyChanged];

}

@implementation CFNetworkLoader

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

    if (self = [super init]) {

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

        // Create the dynamic store, to monitor changes to the proxy dictionary

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

        systemDynamicStore = SCDynamicStoreCreate(NULL, CFSTR("ImageClient"), proxyChanged, &context);

        // Set up the store to monitor any changes to the proxies

        CFStringRef proxiesKey = SCDynamicStoreKeyCreateProxies(NULL);

        CFArrayRef keyArray = CFArrayCreate(NULL, (const void **)(&proxiesKey), 1, &kCFTypeArrayCallBacks);

        SCDynamicStoreSetNotificationKeys(systemDynamicStore, keyArray, NULL);

        CFRelease(keyArray);

        CFRelease(proxiesKey);

        // Add the dyanmic store with the run loop

        CFRunLoopSourceRef storeRLSource = SCDynamicStoreCreateRunLoopSource(NULL, systemDynamicStore, 0);

        CFRunLoopAddSource(CFRunLoopGetCurrent(), storeRLSource, kCFRunLoopCommonModes);

        CFRelease(storeRLSource);

        // Preload the proxy dictionary with the current settings

        proxyDictionary = SCDynamicStoreCopyProxies(systemDynamicStore);

    }

    return self;

}

- (void)dealloc {

    if (request) CFRelease(request);

    [self cancelLoad];

    if (proxyDictionary) CFRelease(proxyDictionary);

    // Need to invalidate the dynamic store's run loop source to get the store out of the run loop

    CFRunLoopSourceRef rls = SCDynamicStoreCreateRunLoopSource(NULL, systemDynamicStore, 0);

    CFRunLoopSourceInvalidate(rls);

    CFRelease(rls);

    CFRelease(systemDynamicStore);

    [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);

    /* Support for the default proxy - quick and dirty

       The code below would work, but is very expensive for repeated downloads, because each call, it recreates

       the state necessary for communicating with the system configuration server.  Use it for single-shot downloads only;

       for repeated downloads, maintain a dynamic store to watch for changes, as we do

       (see the -initWithImageClient:, above, for the necessary set up)

        CFDictionaryRef proxyDict = SCDynamicStoreCopyProxies(NULL);

        CFReadStreamSetProperty(readStream, kCFStreamPropertyHTTPProxy, proxyDict);

    */

    // proxyDictionary is maintained by systemDynamicStore and its callback; see the setup in -initWithClient: for details

    CFReadStreamSetProperty(readStream, kCFStreamPropertyHTTPProxy, proxyDictionary);

    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);

    }

}

// Callback for a change in the proxy dictionary

- (void)proxyChanged {

    CFRelease(proxyDictionary);

    proxyDictionary = SCDynamicStoreCopyProxies(systemDynamicStore);

}

@end