ImageClient3-diagnostics/ImageClient.m

/*
 
File: ImageClient.m
 
Abstract: CFNetwork ImageClient Sample
 
Version: 1.0
 
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*/ 
#import "ImageClient.h"
#import "CFNetworkLoader.h"
#import "NSURLLoader.h"
#import <sys/socket.h>
#import <netinet/in.h>
 
const int kCFNetworkIndex = 0;
const int kFoundationIndex = 1;
 
const NSTimeInterval kRefetchInterval = 15.0;
 
@implementation ImageClient
 
- (id)init {
    if (self = [super init]) {
        cfnetworkLoader = [[CFNetworkLoader alloc] initWithImageClient:self];
        nsurlLoader = [[NSURLLoader alloc] initWithImageClient:self];
        useCFNetworkLoader = YES;
        srandomdev(); // Seed the random number generator
    }
    return self;
}
 
// Included for form's sake; our ImageClient object will be around for as long as the app is running
- (void)dealloc {
    if (reloadTimer) {
        [reloadTimer invalidate];
        [reloadTimer release];
    }
    [cfnetworkLoader release];
    [nsurlLoader release];
 
    [super dealloc];
}
 
// Create and start the timer that triggers a refetch every few seconds
- (void)startTimer {
    [self stopTimer];
    reloadTimer = [NSTimer scheduledTimerWithTimeInterval:kRefetchInterval target:self selector:@selector(refetch:) userInfo:nil repeats:YES];
    [reloadTimer retain];
}
 
// Stop the timer; prevent future loads until startTimer is called again
- (void)stopTimer {
    if (reloadTimer) {
        [reloadTimer invalidate];
        [reloadTimer release];
        reloadTimer = nil;
    }
}
 
/* Called when the user enters a new URL in the textfield */
- (IBAction)newURL:(id)sender {
 
    // Clean up any loads in progress & restart the timer
    if (reloadTimer) {
        [self stopTimer];
        [self cancelLoad];
    }
 
    NSString *urlString = [urlField stringValue];
    if (urlString && [urlString length]) {
        [self startTimer];
        [self startLoad];
    }
}
 
/* Triggered when the user chooses a different library for loading */ 
- (IBAction)libraryChanged:(id)sender {
    NSSegmentedControl *segControl = sender;
    int selectedLibrary = [segControl selectedSegment];
    if ((selectedLibrary == kCFNetworkIndex && !useCFNetworkLoader) || (selectedLibrary == kFoundationIndex && useCFNetworkLoader)) {
        [self stopTimer];
        [self cancelLoad];
        useCFNetworkLoader = (selectedLibrary == kCFNetworkIndex);
 
        if ([urlField stringValue] && [[urlField stringValue] length]) {
            [self startTimer];
            [self startLoad];
        }
    }
}
 
/* The method called by our timer */
- (void)refetch:(NSTimer *)timer {
    [self startLoad];
}
 
/* Starting and stopping loads */
- (void)startLoad {
    // choose a random picture from among 100
    long randomNum = random();
    int index = randomNum % 100;
    NSURL *url = [[NSURL alloc] initWithString:[NSString stringWithFormat:@"%@/%d.JPG", [[urlField stringValue] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]], index]];
    if (useCFNetworkLoader) {
        [cfnetworkLoader loadURL:url];
    } else {
        [nsurlLoader loadURL:url];
    }
    [url release];
}
 
- (void)cancelLoad {
    if (useCFNetworkLoader) {
        [cfnetworkLoader cancelLoad];
    } else {
        [nsurlLoader cancelLoad];
    }
    [imageView setImage:nil];
}
 
/* Called by the two loaders to report successful image loads */
- (void)setImageData:(NSData *)imageData {
    NSImage *image = [[NSImage alloc] initWithData:imageData];
    [imageView setImage:image];
    [image release];
}
 
/* Called by the two loaders to report errors while loading images */
- (void)errorOccurredLoadingImage: (CFNetDiagnosticRef)diagnostics {
    [self stopTimer];
    if (diagnostics) {
        NSBeginAlertSheet(@"Download failure", @"Network Diagnostics...", @"OK", nil, [imageView window], self, @selector(errorSheetDidEnd:returnCode:contextInfo:), NULL, (void*)diagnostics, @"Could not load an image from \"%@\"", [urlField stringValue]);
    } else {
        NSBeginAlertSheet(@"Download failure", @"OK", nil, nil, [imageView window], nil, NULL, NULL, NULL, @"Could not load an image from \"%@\"", [urlField stringValue]);
    }
}
 
// delegate call for the diagnostic sheet dropped in -errorOccurredLoadingImage:
- (void)errorSheetDidEnd:(NSWindow *)sheet returnCode:(int)returnCode contextInfo:(void *)contextInfo {
    CFNetDiagnosticRef diagnostics = (CFNetDiagnosticRef)contextInfo;
 
    if (returnCode == NSAlertDefaultReturn) {
        (void)CFNetDiagnosticDiagnoseProblemInteractively(diagnostics);
    }
    CFRelease(diagnostics);
}
@end