/*

    File:       QReachabilityOperation.h

    Contains:   Runs until a host's reachability attains a certain value.

    Written by: DTS

    Copyright:  Copyright (c) 2010 Apple Inc. All Rights Reserved.

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                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

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*/

#import "QReachabilityOperation.h"

@interface QReachabilityOperation ()

// read/write versions of public properties

@property (assign, readwrite) NSUInteger    flags;

// forward declarations

static void ReachabilityCallback(

    SCNetworkReachabilityRef    target,

    SCNetworkReachabilityFlags  flags,

    void *                      info

);

- (void)reachabilitySetFlags:(NSUInteger)newValue;

@end

@implementation QReachabilityOperation

- (id)initWithHostName:(NSString *)hostName

    // See comment in header.

{

    assert(hostName != nil);

    self = [super init];

    if (self != nil) {

        self->_hostName         = [hostName copy];

        self->_flagsTargetMask  = kSCNetworkReachabilityFlagsReachable | kSCNetworkReachabilityFlagsInterventionRequired;

        self->_flagsTargetValue = kSCNetworkReachabilityFlagsReachable;

    }

    return self;

}

- (void)dealloc

{

    [self->_hostName release];

    assert(self->_ref == NULL);

    [super dealloc];

}

@synthesize hostName         = _hostName;

@synthesize flagsTargetMask  = _flagsTargetMask;

@synthesize flagsTargetValue = _flagsTargetValue;

@synthesize flags            = _flags;

- (void)operationDidStart

    // Called by QRunLoopOperation when the operation starts.  This is our opportunity 

    // to install our run loop callbacks, which is exactly what we do.  The only tricky 

    // thing is that we have to schedule the reachability ref to run in all of the 

    // run loop modes specified by our client.

{

    Boolean                         success;

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

    assert(self->_ref == NULL);

    self->_ref = SCNetworkReachabilityCreateWithName(NULL, [self.hostName UTF8String]);

    assert(self->_ref != NULL);

    success = SCNetworkReachabilitySetCallback(self->_ref, ReachabilityCallback, &context);

    assert(success);

    for (NSString * mode in self.actualRunLoopModes) {

        success = SCNetworkReachabilityScheduleWithRunLoop(self->_ref, CFRunLoopGetCurrent(), (CFStringRef) mode);

        assert(success);

    }

}

static void ReachabilityCallback(

    SCNetworkReachabilityRef    target,

    SCNetworkReachabilityFlags  flags,

    void *                      info

)

    // Called by the system when the reachability flags change.  We just forward 

    // the flags to our Objective-C code.

{

    QReachabilityOperation *    obj;

    obj = (QReachabilityOperation *) info;

    assert([obj isKindOfClass:[QReachabilityOperation class]]);

    assert(target == obj->_ref);

    #pragma unused(target)

    [obj reachabilitySetFlags:flags];

}

- (void)reachabilitySetFlags:(NSUInteger)newValue

    // Called when the reachability flags change.  We just store the flags and then 

    // check to see if the flags meet our target criteria, in which case we stop the 

    // operation.

{

    assert( [NSThread currentThread] == self.actualRunLoopThread );

    self.flags = newValue;

    if ( (self.flags & self.flagsTargetMask) == self.flagsTargetValue ) {

        [self finishWithError:nil];

    }

}

- (void)operationWillFinish

    // Called by QRunLoopOperation when the operation finishes.  We just clean up 

    // our reachability ref.

{

    Boolean success;

    if (self->_ref != NULL) {

        for (NSString * mode in self.actualRunLoopModes) {

            success = SCNetworkReachabilityUnscheduleFromRunLoop(self->_ref, CFRunLoopGetCurrent(), (CFStringRef) mode);

            assert(success);

        }

        success = SCNetworkReachabilitySetCallback(self->_ref, NULL, NULL);

        assert(success);

        CFRelease(self->_ref);

        self->_ref = NULL;

    }

}

@end