NGAReachability.m #1

//
//  Reachability.m
//  MBMenuExtra
//
//  Created by Michael Bishop on 12/22/09.
//  Copyright 2009 Perforce Software. All rights reserved.
//

#import "NGAReachability.h"
static void PrintReachabilityFlags(
                                   const char *                hostname, 
                                   SCNetworkConnectionFlags    flags, 
                                   const char *                comment
                                   )
// Prints a line that records a reachability transition. 
// This includes the current time, the new state of the 
// reachability flags (from the flags parameter), and the 
// name of the host (from the hostname parameter).
{
    time_t      now;
    struct tm   nowLocal;
    char        nowLocalStr[30];
    
    assert(hostname != NULL);
    
    if (comment == NULL) {
        comment = "";
    }
    
    (void) time(&now);
    (void) localtime_r(&now, &nowLocal);
    (void) strftime(nowLocalStr, sizeof(nowLocalStr), "%X", &nowLocal);
    
    fprintf(stdout, "%s %c%c%c%c%c%c%c %s%s\n",
            nowLocalStr,
            (flags & kSCNetworkFlagsTransientConnection)  ? 't' : '-',
            (flags & kSCNetworkFlagsReachable)            ? 'r' : '-',
            (flags & kSCNetworkFlagsConnectionRequired)   ? 'c' : '-',
            (flags & kSCNetworkFlagsConnectionAutomatic)  ? 'C' : '-',
            (flags & kSCNetworkFlagsInterventionRequired) ? 'i' : '-',
            (flags & kSCNetworkFlagsIsLocalAddress)       ? 'l' : '-',
            (flags & kSCNetworkFlagsIsDirect)             ? 'd' : '-',
            hostname,
            comment
            );
}

void
ReachabilityCallback(
                     SCNetworkReachabilityRef target,
                     SCNetworkReachabilityFlags flags,
                     void *info
                     );


@interface NGAReachability ()

-(void)MB_reachabilityFlagsDidChange:(SCNetworkReachabilityFlags)flags;

@end


@implementation NGAReachability

-(id)initWithName:(NSString*)name
{
    if ( (self = [super init]) == nil )
        return nil;
    
    reachabilityRef = SCNetworkReachabilityCreateWithName( kCFAllocatorDefault, [name UTF8String] );
    _context.version = 0;
    _context.info = self;

    if ( !reachabilityRef )
        return nil;

    SCNetworkReachabilitySetCallback( reachabilityRef, ReachabilityCallback, &_context );

    _name = [name retain];

    return self;
}

-(void)dealloc
{
    [self stop];
    NSAssert( _block == nil, @"_block should be nil from stopping in the stop method" );
    if ( reachabilityRef )
        CFRelease(reachabilityRef);
    [_name release];
    [super dealloc];
}

-(BOOL)startWithBlock:(ReachabilityCallbackBlock)block;
{
    if ( reachabilityRef == NULL )
        return NO;
    
    if ( block != _block )
    {
        [_block release];
        _block = [block copy];
    }
    SCNetworkReachabilityScheduleWithRunLoop( reachabilityRef, CFRunLoopGetCurrent(), 
                                             kCFRunLoopDefaultMode );
    return YES;
}

-(BOOL)stop
{
    [_block release];
    _block = nil;
    if ( reachabilityRef == NULL )
        return YES;
    return SCNetworkReachabilityUnscheduleFromRunLoop( reachabilityRef, CFRunLoopGetMain(), kCFRunLoopDefaultMode );
}


-(void)MB_reachabilityFlagsDidChange:(SCNetworkReachabilityFlags)flags
{
//    PrintReachabilityFlags( [_name UTF8String], flags, NULL );
    _block( flags );
}


- (BOOL)isReachableWithoutRequiringConnection:(SCNetworkReachabilityFlags)flags
{
    // kSCNetworkReachabilityFlagsReachable indicates that the specified nodename or address can
    // be reached using the current network configuration.
    BOOL isReachable = flags & kSCNetworkReachabilityFlagsReachable;
    
    // This flag indicates that the specified nodename or address can
    // be reached using the current network configuration, but a
    // connection must first be established.
    //
    // If the flag is false, we don't have a connection. But because CFNetwork
    // automatically attempts to bring up a WWAN connection, if the WWAN reachability
    // flag is present, a connection is not required.
    BOOL noConnectionRequired = !(flags & kSCNetworkReachabilityFlagsConnectionRequired);
    
    return (isReachable && noConnectionRequired) ? YES : NO;
}


@end

void
ReachabilityCallback(
    SCNetworkReachabilityRef target,
    SCNetworkReachabilityFlags flags,
    void *info)
{
    NGAReachability * reachability = (NGAReachability*)info;
    [reachability MB_reachabilityFlagsDidChange:flags];
}