/*

    File:       DNSSDRegistration.m

    Contains:   Uses the low-level DNS-SD API to manage a Bonjour service registration.

    Written by: DTS

    Copyright:  Copyright (c) 2011 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 "DNSSDRegistration.h"

#include <dns_sd.h>

#pragma mark * DNSSDRegistration

@interface DNSSDRegistration ()

// read-write versions of public properties

@property (copy,   readwrite) NSString * registeredDomain;

@property (copy,   readwrite) NSString * registeredName;

// private properties

@property (assign, readwrite) DNSServiceRef      sdRef;

// forward declarations

- (void)stopWithError:(NSError *)error notify:(BOOL)notify;

@end

@implementation DNSSDRegistration

@synthesize domain = domain_;

@synthesize type = type_;

@synthesize name = name_;

@synthesize port = port_;

@synthesize delegate = delegate_;

@synthesize registeredDomain = registeredDomain_;

@synthesize registeredName = registeredName_;

@synthesize sdRef = sdRef_;

- (id)initWithDomain:(NSString *)domain type:(NSString *)type name:(NSString *)name port:(NSUInteger)port

    // See comment in header.

{

    // domain may be nil or empty

    assert( ! [domain hasPrefix:@"."] );

    assert(type != nil);

    assert([type length] != 0);

    assert( ! [type hasPrefix:@"."] );

    assert(port > 0);

    assert(port < 65536);

    self = [super init];

    if (self != nil) {

        if ( ([domain length] != 0) && ! [domain hasSuffix:@"."] ) {

            domain = [domain stringByAppendingString:@"."];

        }

        if ( ! [type hasSuffix:@"."] ) {

            type = [type stringByAppendingString:@"."];

        }

        self->domain_ = [domain copy];

        self->type_   = [type copy];

        self->name_   = [name copy];

        self->port_   = port;

    }

    return self;

}

- (void)dealloc

{

    if (self->sdRef_ != NULL) {

        DNSServiceRefDeallocate(self->sdRef_);

    }

    [self->domain_ release];

    [self->type_ release];

    [self->name_ release];

    [self->registeredName_ release];

    [self->registeredDomain_ release];

    [super dealloc];

}

- (void)didRegisterWithDomain:(NSString *)domain name:(NSString *)name

    // Called when DNS-SD tells us that a registration has been added.

{

    // On the Mac this routine can get called multiple times, once for the "local." domain and again 

    // for wide-area domains.  As a matter of policy we ignore everything except the "local." 

    // domain.  The "local." domain is really the flagship domain here; that's what our clients 

    // care about.  If it works but a wide-area registration fails, we don't want to error out. 

    // Conversely, if a wide-area registration succeeds but the "local." domain fails, that 

    // is a good reason to fail totally.

    assert([domain caseInsensitiveCompare:@"local"] != NSOrderedSame);      // DNS-SD always gives us the trailing dot; complain otherwise.

    if ( [domain caseInsensitiveCompare:@"local."] == NSOrderedSame ) {

        self.registeredDomain = domain;

        self.registeredName   = name;

        if ([self.delegate respondsToSelector:@selector(dnssdRegistrationDidRegister:)]) {

            [self.delegate dnssdRegistrationDidRegister:self];

        }

    }

}

- (void)didUnregisterWithDomain:(NSString *)domain name:(NSString *)name

    // Called when DNS-SD tells us that a registration has been removed.

{

    #pragma unused(name)

    // The registration can be removed in the following cases:

    //

    // A. When you register with the default name (that is, passing the empty string 

    //    to the "name" parameter of DNSServiceRegister) /and/ you specify the 'no rename' 

    //    flags (kDNSServiceFlagsNoAutoRename) /and/ the computer name changes.

    //

    // B. When you successfully register in a domain and then the domain becomes unavailable 

    //    (for example, if you turn off Back to My Mac after registering).

    //

    // Case B we ignore based on the same policy outlined in -didRegisterWithDomain:name:.

    //

    // Case A is interesting and we handle it here.

    assert([domain caseInsensitiveCompare:@"local"] != NSOrderedSame);      // DNS-SD always gives us the trailing dot; complain otherwise.

    if ( [domain caseInsensitiveCompare:@"local."] == NSOrderedSame ) {

        [self stopWithError:[NSError errorWithDomain:NSNetServicesErrorDomain code:kDNSServiceErr_NameConflict userInfo:nil] notify:YES];

    }

}

static void RegisterReplyCallback(

    DNSServiceRef       sdRef,

    DNSServiceFlags     flags,

    DNSServiceErrorType errorCode,

    const char *        name,

    const char *        regtype,

    const char *        domain,

    void *              context

)

    // Called by DNS-SD when something happens with the registered service.

{

    DNSSDRegistration *    obj;

    #pragma unused(flags)

    #pragma unused(regtype)

    assert([NSThread isMainThread]);        // because sdRef dispatches to the main queue

    obj = (DNSSDRegistration *) context;

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

    assert(sdRef == obj->sdRef_);

    #pragma unused(sdRef)

    if (errorCode == kDNSServiceErr_NoError) {

        assert([[NSString stringWithUTF8String:regtype] caseInsensitiveCompare:obj.type] == NSOrderedSame);

        if (flags & kDNSServiceFlagsAdd) {

            [obj didRegisterWithDomain:[NSString stringWithUTF8String:domain] name:[NSString stringWithUTF8String:name]];

        } else {

            [obj didUnregisterWithDomain:[NSString stringWithUTF8String:domain] name:[NSString stringWithUTF8String:name]];

        }

    } else {

        [obj stopWithError:[NSError errorWithDomain:NSNetServicesErrorDomain code:errorCode userInfo:nil] notify:YES];

    }

}

- (void)start

    // See comment in header.

{

    DNSServiceErrorType     errorCode;

    if (self.sdRef == NULL) {

        NSString *  name;

        NSString *  domain;

        domain = self.domain;

        if (domain == nil) {

            domain = @"";

        }

        name = self.name;

        if (name == nil) {

            name = @"";

        }

        errorCode = DNSServiceRegister(&self->sdRef_, 0, kDNSServiceInterfaceIndexAny, [name UTF8String], [self.type UTF8String], [domain UTF8String], NULL, htons(self.port), 0, NULL, RegisterReplyCallback, self);

        if (errorCode == kDNSServiceErr_NoError) {

            errorCode = DNSServiceSetDispatchQueue(self.sdRef, dispatch_get_main_queue());

        }

        if (errorCode == kDNSServiceErr_NoError) {

            if ([self.delegate respondsToSelector:@selector(dnssdRegistrationWillRegister:)]) {

                [self.delegate dnssdRegistrationWillRegister:self];

            }

        } else {

            [self stopWithError:[NSError errorWithDomain:NSNetServicesErrorDomain code:errorCode userInfo:nil] notify:YES];

        }

    }

}

- (void)stopWithError:(NSError *)error notify:(BOOL)notify

    // An internal bottleneck for shutting down the object.

{

    if (notify) {

        if (error != nil) {

            if ([self.delegate respondsToSelector:@selector(dnssdRegistration:didNotRegister:)]) {

                [self.delegate dnssdRegistration:self didNotRegister:error];

            }

        }

    }

    self.registeredDomain = nil;

    self.registeredName = nil;

    if (self.sdRef != NULL) {

        DNSServiceRefDeallocate(self.sdRef);

        self.sdRef = NULL;

    }

    if (notify) {

        if ([self.delegate respondsToSelector:@selector(dnssdRegistrationDidStop:)]) {

            [self.delegate dnssdRegistrationDidStop:self];

        }

    }

}

- (void)stop

    // See comment in header.

{

    [self stopWithError:nil notify:NO];

}

@end